Interview with the 2012 Nobel Laureates in Chemistry Robert J. Lefkowitz and Brian K. Kobilka, on 6 December 2012. The interviewer is Nobelprize.org’s Adam Smith.
Robert Lefkowitz and Brian Kobilka, welcome to Stockholm, indeed a snowy, wintry, beautiful Stockholm. It could look more inviting, but very different from North Carolina and the bay area this time of the year.
Robert J. Lefkowitz: Indeed. We only get snow maybe once every three or four years. It has been kind of a treat!
You are here for Nobel Week, the culmination of two months of fairly frenzied activity I imagine since the calls came. How have those last two months been? How have you found it?
Brian Kobilka: A bit overwhelming. It would have been a busy two months had this not happened, but it has been an extraordinarily busy time.
I am sure. How about you?
Robert J. Lefkowitz: I had been warned. As soon as this happened, I spoke with several colleagues, Harold Varmus and Joe Goldstein, old friends and colleagues and they warned me about just how intense it was. But I must say it was, as Brian said, I found it a bit overwhelming right up to our arrival here. It is something that nothing, I think, prepares you for.
I suppose not. And you had the added ownness of being the first Nobel Laureate from Duke University?
Robert J. Lefkowitz: Yes, indeed. This caused quite a bit of ruckus, that it was the first, and they likened it to when we won our first NCAA basketball championship under the very famous coach K, coach Krzyzewski. I think one of the most exciting things that happened to me, during this period of time was that I was honoured at Cameron Indoor Stadium, which is the basketball stadium, by coach K and the basketball team that presented me with a jersey with a number one on it and my name. Which seemed to impress my children perhaps even a bit more than the Nobel Prize itself.
It is nice that intellectual pursuits and athletic pursuits have reached the level.
Robert J. Lefkowitz: Indeed.
It is hard to count Nobel Laureates from institutions because you never know where the people are associated. I have heard Stanford themselves say that you are number 27.
Brian Kobilka: That is probably right, yes. It is not quite as big of a deal there.
I am sure it is still a very big deal. One thing that often is said, is whether it gets you a parking space on campus?
Brian Kobilka: I am afraid not.
Not yet. If you win two prizes.
Robert J. Lefkowitz: How about your own bathroom, do you get that?
Brian Kobilka: No, no.
Robert J. Lefkowitz: Me neither.
Anyway, you have been awarded for your work in the field of G protein coupled receptors, GPCRs. These are the gateways to the cell together with ion channels. It is commonly said that 50% of medicines acts through G protein coupled receptors. It is hard to imagine really that forty years ago when you started to work in the field, the concept of the receptor itself was still not all that widely accepted. It was still some doubt as to whether they existed.
Robert J. Lefkowitz: Yes, there was a great deal of scepticism about this and in fact in my Nobel Lecture on Saturday I am going to review some of this. Frankly, I could give the whole lecture on that topic, but I will not. But remarkably the scepticism we shared even by some of the giants of the pharmacology field, such as Raymond Ahlquist. He was a very famous American pharmacologist who won the very distinguished Lasker prize for first putting forth the idea that there could be two types of receptor for adrenalin which he called alpha and beta receptors, that was in 1948. That was based on some classical pharmacological work that he had done. But as late as 1973, which is when I was just beginning some of this work, he published an article basically saying that it was essentially arrogant of people to even think that these things really existed. For him they were just sort of an idea, a way of organizing thinking. But he did not really … there was not really a concept that these was specific molecules if you will. They were just viewed as some very unclear nebulous pattern of forces on the surface of cells, that could somehow allow them to interact.
That is interesting! Because the first half of the 20th century was really the golden age of neurotransmitter research. This slew of neurotransmitters was discovered, and their functions were to some extent understood, yet nobody knew how they operated.
Robert J. Lefkowitz: This is correct, and in fact the earliest ideas about receptors came from a British pharmacologist named J. N. Langley. More than hundred years ago he wrote about the idea that there must be something, that we now know as a receptor. But interestingly, forty years later, his student Henry Dale – talking about neurotransmitters – he won the Nobel Prize, I am not sure what year, for his work on cholinergic neurotransmission and in the mid-forties he wrote an article mocking his mentor Langley for saying that there was such a thing as receptors. He said: It does not really teach us anything to say, the receptors, there is of course something about cells that allows them to interact with molecules. But giving it a name just does not really make any sense.
So why did you choose that field for your own research when you started research?
Robert J. Lefkowitz: I had been at the NIH for a fellowship in 1968 to 1970 and this was the golden age of second messenger signalling. Earl Sutherland had recently won the Nobel Prize for his discovery of cyclic AMP which is a molecule generated on the inner surface of the cell membrane when what we now know GPCRs are activated. My mentors there Jesse Roth and Ira Pastan thought it might be possible to label the receptors because they felt they existed. They were what would be called molecular endocrinologists and they thought it would be possible to label them with radioactively labelled materials. I was assigned the project of trying to label a receptor for ACTH, Adrenocorticotropic hormone, which works through a G-protein couple receptor and I spent my two years there radioactively labelling ACTH and showing that I could bind it to some sites on the plasma membrane of a tumour which was responsive to ACTH, so it was an ACTH responsive cancer that I passed in nude mice. We were successful in doing that. The work did not really go any further than just developing these radioligands, but really, the idea caught fire in my imagination!
It gave you an inkling that you could …
Robert J. Lefkowitz: Do this, right. Further on in my carrier I was a cardiology fellow a couple of years later and I really wanted to pick up this theme, but I wanted something more cardiovascularly related and the adrenergic receptor seemed to fit the bill more so than ACTH, so that is why I turned to the adrenergic receptors in the early seventies.
I would just like to pause there. One thing that defines you both, you are both cardiologists.
Brian Kobilka: I had the intention of becoming a cardiologist.
Robert J. Lefkowitz: What are you talking about, you did the fellowship?!
Brian Kobilka: Yes, so then I started out in Bob’s lab and that was pretty much, with the exception of the intensive care unit, the only thing that I really did to complete my cardiology fellowship, which I did not complete.
But you started out with the intention of becoming a medical doctor? And then you transitioned to research. I was going to ask you both, what sort of flipped you away from medicine onto the bench?
Brian Kobilka: I think I had the intention of, at the time I was in training in internal medicine in St Louis, of being an academic physician. Which meant that I would continue seeing patients and I would find some line of research. At the time I was really very interested in intensive care medicine and I believe there were not intensive care medicine fellowships at the time. It was either cardiology or pneumology and so I decided to go into cardiology. I learned that … I was also really interested in research, although I cannot at the time say I was really interested in adrenergic receptors. I was interested in the concept of using adrenaline in other compounds like that in intensive care unit. And Duke hade a fantastic research program for cardiology fellows. You could go to Duke, you could spend at least a year and a half doing research and you could do it up front, which was really attractive to me after spending three years taking care of patients and really wanting to try out research. I do not know how many places I applied to, but I was very happy to be accepted into Duke and very happy that Bob chose to let me in his lab.
We will come to your lab environment soon. When was the last time you saw a patient?
Brian Kobilka: Actually, I continued to see patients while I was a fellow, primarily moonlighting and weekends, and I am not sure, but I think I can say this now since the statute of limitations is up, but when I moved to Stanford my wife Tong Sun started medical school, so our children were old enough to go to school. She started in medical school in Stanford, so we had a very large mortgage in tuition, and I continued to moonlight for quite a few years in emergency rooms.
Maybe you are still moonlighting, maybe we should not talk about this … How about you, Bob, you had wanted to be a doctor?
Robert J. Lefkowitz: I very much wanted to be a physician, and had harboured that goal, I would say from the time I was eight or ten years old. Like Brian, I learned last week, a very similar experience, I was inspired by my family physician, who made house calls, and I decided that is it, that’s what I want to do, and I thought about nothing else in terms of a goal, right through grade school, high school and college. I would say that Brian, for what I know, who actually showed an interest in research earlier than I, because as I understand Brian had a mentor experience in college, and I think even won an award for his research thesis at Yale, if I am not mistaken. I had absolutely no research experience until I went to the NIH in 1968. In fact, in medical school we had a couple of opportunities to do two month’s electives in research – I never took one – I had no interest in it, I wanted only the clinical electives, so called sub-internships.
But in the late 60s, the Vietnam war was raging and many of us were opposed to that war on multiple grounds, there was a drift, physicians were drifted. You had to go in after two years of training which many of us did not want to do, so there were few options, they were very competitive to get, that would get you out of going to Vietnam. One was to join the United States public health service as a commissioned officer and be assigned to the NIH for two years. Very very competitive to get such positions, but I had a strong academic record, and I was able to get that, and it seemed like a good thing to do, because like Brian, I pictured myself someday as an academic physician and I vaguely had it in my head that academic physicians did some research. So, I figured, well, I get my research papers and I go. And that is where I got started in research.
Now there is a very interesting and timely piece in, I guess, last week’s issue of Science, by Mike Brown and Joe Goldstein, in which they review basically the history of that year, and remarkably it turns out between 1964 and 1972, I think is the slice they took, I became the ninth Nobel Laureate to have trained. I actually went through the list. Six of us came between 1967-70 and when I say came, I do not mean there were a hundred of us each year – in a year there might have been eight or ten or twelve – so it was a remarkably high success rate.
And they are going in that article to regret the loss of that kind of training environment.
Robert J. Lefkowitz: Exactly. It was a remarkable environment. They tried to dissect what it was about it that made it so remarkable. I think they do a pretty good job, but there are some things that cannot be fully understood. Obviously, they got the best talent coming in, because we were so competitive to get the positions and there were some wonderful mentors there, but … maybe something else, that is harder to define.
Anyway, avoiding the draft in fact led you to your research career somehow.
Robert J. Lefkowitz: Exactly, right. It was not what I had imagined at all, and I certainly did not have a smooth start, things went very poorly at first.
When did you give up on patients?
Robert J. Lefkowitz: I actually made teaching rounds for 30 years at Duke. I would do one rotation a year, six weeks, from age 30 to age 60, at my 60th birthday, for a variety of reasons, I hang up my stethoscope.
At Duke, you pursued this difficult task of purifying the β-adrenergic receptor, it took 15 years to purify and clone, that is quite an undertaking. Did you have, as you were on that path, the goal of that purification so that you were always looking that far ahead?
Robert J. Lefkowitz: Definitely. That was a goal for many, many years. Something interesting that … at least it is my view of things now, and maybe it is revisionist history, but when I look back on that period, my sense is that it almost never occurred to me we would fail. I always believed we would be successful. When I look back on it now, it was kind of crazy, but that is my sense of it now. I always assumed it would all work, I did not know when or how long it would take, but sooner or later we would get there. It never occurred to me that maybe it would not work at all and it would be a total dead end.
Along the way you have to be generating enough material that keeps it all moving.
Robert J. Lefkowitz: Moving, right. Exactly, and I think Brian had similar experiences these last 15 years with his crystallography, or I do not know, maybe you did entertain the idea that it would not work at all? Or did you always think someday I will get there?
Brian Kobilka: I think I always thought some day I will get there.
Robert J. Lefkowitz: I think that kind of optimism, what did you call it once?
Brian Kobilka: Henrik, a colleague of mine from Bob’s lab calls it ‘irrational optimism’.
Robert J. Lefkowitz: Irrational optimism, yes, sometimes that’s … I think it’s a good leadership, quality, because it is sort of infectious, I think, in terms of the troops, the folks in the lab, if they think the boss has any doubt we’re going to get there, that doesn’t foster the kind of attitude that you want.
Let’s talk about the lab a bit because you have had an immensely productive lab, both in the sense of papers and discoveries, but also in the sense of people. You have had more than 200 people? You must have got a research environment going which people want to join. What was the secret of it?
Robert J. Lefkowitz: That’s a very good question. I think there probably are a number of elements. One of course is the old business of success breeds success, if a program is successful then people want to come because there is high visibility research going on. As to why we were so successful, I mean there is a lot of mystical stuff, like I’m a great judge of talent, that’s how Brian came to my laboratory. I say that and we both laugh because when he came to interview as I recall, I was out of town.
Brian Kobilka: Right there, yes.
Robert J. Lefkowitz: I wasn’t there, and I think he even made a second visit, and I was also not there. But in any case, as I wasn’t there, so obviously I’m a good judge of talent, and I took him anyway, sight unseen. I think one of the things about working in a lab is to have good esprit de corps, which can’t be 100%, there is always going to be some odd balls or some oil and water mixtures of people just doesn’t get along, but I think in general we had good chemistry of people in the laboratory. I think I always brought to the endeavor a real sense of enthusiasm for what we are doing. Enthusiasm is something that you can’t fake, you can’t fool people. I remember at my 60th birthday party that Brian was at and many of the fellows came to, they were giving various talks about what they remembered. I remember one postdoc from that era, a wonderful guy named Rick Serione, who is now a professor of … has a name chair, in chemistry actually, at Cornell, was saying that one of the things that kept him going is that he always sensed from me that his project, which was a reconstitution of the receptor after it was purified, was the most important project in the lab, and he liked that, until one day he talked to some other guy and he said: No, I felt my project was the most important. It turned out that everybody thought their project was the most, and I guess somehow I transmitted that, because probably I believed it, including Brian’s, which really was the most important project in the lab.
With Bob sitting here maybe it is not the right place to ask you, or maybe it is the right place, does that rhyme with your experiences of Bob’s lab?
Brian Kobilka: I would say yes. He was always very enthusiastic and encouraging, and you felt that you could try anything. I don’t actually remember there being any kind of limit on even what we could spend to try something that was completely sometimes crazy.
Robert J. Lefkowitz: I think one of the things I taught Brian was how to go into debt in the laboratory, and he has been very god at that, the reason he is I am sure he could tell you about. The folks in the lab probably didn’t even know it, bur on several occasions when things really got hot, and we were making progress on a project, I would just overspend, I would just not care about the budget, we would just do what we needed to do. I was called on the carpet on several occasions, both by the chairman in medicine, named Jim Weingarten, and also by the head of the Howard Hughes medical institute. The administrator of the Hughes institute, a guy named Kenny Wright, he was a good old Southern boy, and I remember on two occasions they sent him down specifically, as he put it, to ‘slap me on the wrist and take me up behind the woodshed’ because I had totally overspent my budget and he was there to sort of arrange things in. On the other hand, we were doing good work and he was kind to give me a wink, but he brought the message anyway.
I know that you have a very large number of people coming from all over the world to help you celebrate here, you’ve got this get-together of 50+ people …
Robert J. Lefkowitz: Yes, at the moment, it is up to 55 with a few family members.
I suppose that speaks to the social aspect of all this, that it’s not just productive and supportive but you are also becoming friends, lasting relationships. I’d like to talk a little bit about that.
Robert J. Lefkowitz: Yes, and I think Brian will have a lot to say about this as well. I think both of us have tended to view our laboratories as a second family, I mean you really get close to this people, and they really are … as a mentor they are like your kids, and like your kids when they leave the nest doesn’t mean you’re finished with them, it goes on for a lifetime. Then I think some of the relationships amongst the trainees that they make within the laboratory, people who are in the lab at the same time I think become colleagues and friends for life and it’s a very, very special bond. In my own laboratory probably, if there was a peak period when things were rolling, it was really the eighties and into the early nineties, many of the people who were in my lab at that time are acknowledged leaders in our field and are good friends and colleagues of Brian. I think it speaks to the way they feel to not just about me but about Brian, that they are all coming here at their own expense and unable to get into the ceremonies, but just to be here with us I think speaks to that family aspects of things.
In a way that is at odds with how science might be often perceived by the public. We have got the image of the lone scientist coming up with ideas and pursuing their goals and indeed that’s in some way supported by the Nobel Prize which selects individuals for the prize. Yet of course it is a very social affair. And in your case even a family affair, because you and your wife were together in the lab.
Brian Kobilka: It’s true. There’s no conscious decision that it is going to be that way, but it seems that at least part of my success is finding people that both I enjoy working with and are willing to engage in very challenging projects. My wife in particular I would say particularly during the past decade where some of the projects in the lab were too risky for graduate students and post doctor fellows, she would be enrolling up her sleeves next to me and working on these projects and also helping out fellows and graduate students with really difficult projects to make it at least more feasible for them to engage in these high-risk projects.
When you pick people to join your lab, what do you look for? People you can get on with foremost?
Brian Kobilka: It’s very important that not only I get along with them, that they get along with other people in the lab, it’s really important to have chemistry in the lab. I would say that the lab has been most successful when people work together on again, very challenging projects, sharing ideas, sharing reagents, really take teaming on projects – I think that’s really key to having a productive and enjoyable experience.
Robert J. Lefkowitz: I think something that is very important both to Brian and myself is the mentoring of the young people. People often ask me, because I have been successful in training so many people, ‘What are the keys to mentorship?’ It’s like everything else, there’s not one right way to do it, just like there’s not one right way to do science. I think many people consider both Brian and myself for good mentors but our personalities couldn’t be more different, so obviously we can’t possibly mentor people in the same way, and yet we both seem to wind up doing a fairly good job of it. I think a lot of this is just a matter of are you willing to invest yourself in people and really care about them and care about their careers and success. And challenge them! To put things in front of them which they really have to reach to get to. If you can give somebody the experience of working right at their potential, really doing something which tests them and extends their limits and let them feel what it is like to succeed at that level – then you have done it, because then they know what it feels like, they know what they are capable of and they are willing to challenge themselves in the future.
You have to know them pretty well to know what to challenge them with?
Robert J. Lefkowitz: Exactly. For me personally getting to know people, getting in their head, because you challenge different people in different ways, it takes different kinds of things. The whole issue of how much to direct people, it’s a delicate balance, you can direct them too much, they may be successful in the short term, but they never gain the confidence that they can really do it by themselves. Or you can direct them too little, and they just drift and become unfocused etc. So the question is to provide enough direction but not too much direction. Of course, there’s nobody who can tell you what that is, you just have to figure that out individually.
But it must be a lovely feeling when you see that it works and the person thrive.
Robert J. Lefkowitz: Absolutely. I’m aware of some very very distinguished scientists who, in the course of long careers have not trained that many successful people and you say: ‘Why is that?’. And at least in a couple of cases I’m thinking about I think I know the answer. I think it is because they so closely directed their trainees while they were there that they really did not really have a chance to develop their own independent thinking and confidence to really do things on their own.
One other aspect of this, and then we move on, by generating 200+ people from the lab I suppose you are also generating, it’s a bit of a nasty thing to say, 200 competitors, you are seeding a lot of people who are interested in the same stuff.
Robert J. Lefkowitz: Absolutely, in a sense it is true. Then it becomes a matter of … Competition is in the eye of the beholder. Brian, when he left my laboratory, continued along, doing things that I might have worked on, sometimes I did work on, but I guess it’s like your kids, I can’t imagine ever feeling competitive with one of my kids even if they were doing exactly what I was doing – it just does not work that way. I think that’s the familial aspect to it – how could any of them compete with me, they are like my kids.
And you have been in a pretty competitive place for the last fifteen years going for this crystal structure, because there were other big groups heading down the same road, but in this case there’s not the familial bonds, they are just the groups out there.
Brian Kobilka: Yes, and I have to say that even among some of my competitors there’s been a great deal of collegiality and collaboration as well, I would say, particularly with Gebhard Schertler who was one of the earlier structural people in GPCRs, in fact he generated the first structure, he was a … we call it two-dimensional crystals, it was a low-resolution structure, it was really our first view of what GPCR looked like. He has always been a great colleague, he in fact took us to the beamline when we got our first crystals which weren’t good enough to get a structure but they were small and too small to actually study in a conventional synchrotron. Gebhard was really interested in developing microfocus micron beam crystallography and he had worked with scientists at the ESRF on the first really high quality microfocus beam, sometimes called mini-beams. He took my pretty lousy crystals and brought me to his synchrotron, we went to ESRF, Tung Sun would join me in the trip. He really taught me how to start collecting data from very small crystals. We’ve been friends and competitors, in some respects.
Robert J. Lefkowitz: Brian makes a really good point. I have found, in my career, that competition per se doesn’t necessarily – I’m talking about outside the family now – competition per se doesn’t necessarily mean difficulties. I have had direct competitors who I have had lovely personal relationships with, and I have had others which were not so pleasant. So it is not the competition per se, it is more a matter of the personalities.
I suppose so. In some ways it is there to keep you at the top of your game.
Robert J. Lefkowitz: You know that the competition does drive a lot of science. I think all of us are inherently somewhat competitive.
If we just return to the lab. You came into the lab and were involved in other stages of this β–adrenergic purification and cloning experiment where the structure of the β–adrenergic receptor was revealed. That acted in a phrase that seems very appropriate, as the Rosetta stone unleashing lots of other G-protein coupled receptor structures and revealing that there was this super family. I have often heard people say that in retrospect of course there was a super family, it was obvious, but was it obvious as you went into it?
Robert J. Lefkowitz: Not in the least. When we were cloning, we had first been successful in getting what we knew to be valid clones for the receptor. It’s not like today, it’s amazing to think back. How many nucleotides were there in the open reading frame … a couple of thousand?
Brian Kobilka: Yes, 1,500.
Robert J. Lefkowitz: And how long did it take between us and Merck to sequence that piece of DNA?
Brian Kobilka: I don’t remember.
Robert J. Lefkowitz: That wasn’t a day or two, was it?
Brian Kobilka: No, wasn’t a day or two.
Robert J. Lefkowitz: It was probably a matter of weeks.
Brian Kobilka: Probably between 100 and 200 base pairs.
Robert J. Lefkowitz: While we were sequencing it, word began to get around on campus, I don’t know if you know this story… Word got around the campus: we had it. OK. And I don’t remember who, but somebody … We had part of the sequence, I don’t know how many base pairs, and we knew we had the right thing because we already could see some of the five peptides that we knew were in there from our sequencing of pure protein. And a colleague said: ‘What does it look like?’ And I remember distinctly saying to him ‘It doesn’t look like anything, why should it look like anything, this is the first one’. So that shows you the extent to which we were not expecting what we eventually found which was the homology with rhodopsin. This even now, the functional analogies between rhodopsin and transducin and the /- – -/ with the βreceptor, the G protein, those functional analogies were clear, and I think by then it was probably clear that transducin and Gs were members of a family. Nonetheless, nobody was expecting the βreceptor and rhodopsin to look alike, it was only later, after the full sequence emerged that these homologies became clear. But in the early going I thought we were describing the very first … they were so generous.
Was it with great pleasure that you realized that you were suddenly opening up this super family, or was it in fact a sense of oh, other people knew this already, other people could have tweaked this?
Robert J. Lefkowitz: Shortly after we reported our clone, about four months later, Elliott Ross, Dallas, reported on another, the β1–adrenergic receptor, from a turkey, and it looked very similar. Then /- – -/ Anouma, a little bit later, reported on two muscarinic receptors. Very quickly, within a year or less, we had those, and then we, Brian, cloned the α2–adrenergic receptor again, within about a year based on protein sequence that we had. Very quickly it was filling out that there was this family. I think in the moment we cloned the β2 I think it was a Heureka moment, but I don’t think any of us … and we /- – -/ right enough for a paper maybe they are all going to look like this, but I don’t think any of us really conceived just how large and diverse this family was going to be. And certainly of course the olfactory receptors which came four, five years later doubled the number of receptors right on the spot. It’s like all discoveries – many discoveries – you don’t fully appreciate the significance in the moment, it becomes clearer and clearer and clearer over the years.
Your lab continued to discover things about the structure and function of GPCRs, or mass, so to speak, there were lots of discoveries pouring out. Meanwhile you then moved away, went to Stanford and began this quest. What you eventually produced was the high-resolution structure of a GCPR with ligand and G protein attached, there was the whole kit and kaboodle. I remember in 2004 you commented, in an article that we asked you to write, you thought you might be a year or two away from the structure and I guess the high-resolution structures. It seemed to take longer than you thought it might. It must have been difficult.
Brian Kobilka: Yes, it was difficult. In 2004 I think we were starting to get crystals so I felt that … I am not sure I said that we would get it, I said somebody would get it. There were of course a lot of rumours.
Robert J. Lefkowitz: You were telling me, I remember, there was a rumour that so and so had it. You were quite nervous about it.
Brian Kobilka: There were some really detailed rumours which I don’t know how they ever originated but … I knew that we had succeeded, and other individuals were telling me that they had crystals, I think it was the logical assumption that it would happen sooner or … but it took much longer than I thought.
It was a good sign at that point that you were thinking about it harder than other people, at least as hard as anybody else was, because the question I think we asked was ‘When will the structure come and what needs to be done in order to get there?’ We asked 20 people to answer that and they wrote back this much. You wrote about this much, so you obviously had a lot of thoughts.
Brian Kobilka: I had been working on this project for a long time, not just crystallography but trying to understand the protein using other approaches, particularly by biochemical and biophysical approaches, these were much lower resolutions. Particularly fluorescence spectroscopy really told us a lot about the protein, how it behaved, and I think in many respects that experience, with these different approaches, told us a lot about what we probably needed to do to overcome the obstacles we were having with getting the high-quality crystals, ultimately informed us about the different approaches that ultimately succeeded.
One other thing that struck me at the time, this was an article that was written for one of the Nature journals, that you said this in, you were very giving with your suggestions, you seemed to be revealing quite a lot about the way you were thinking in the answers you gave, and again, it speaks to the idea of being a collaborative person rather than a secretive person.
Brian Kobilka: I hope that’s true. Of course, I wanted to be the first and I probably wasn’t completely revealing …
Robert J. Lefkowitz: It is interesting when I think back at the situation Brian found himself in, I guess about 2006 or -07, when it was clear the field was converging on a crystal structure and there were several players and nobody knew who would get there first, but let’s go back in time to 1985-86. As a very young fellow he was actually put in a very similar position because we were in direct competition with probably several, but we knew about one. Early on, they were ahead of us, but then, because of a bunch of circumstances, we leaped from the whole thing, it happened very fast for us when it finally happened. But it was a similar kind of deal with a lot of pressure, intense competition – who is going to get there first? He basically had had that experience once before, at the very beginning of his career, and now here he was 25 years later, in the same position. And he and I talked, I tried to advise him as best I could, I wasn’t involved in the science of course, an older head, just as I was to tell people that the key to Brian’s success is that whenever it gets important decisions to make, he discusses them with me – and then does the opposite, and this has led to a great deal of success on his part.
Everybody needs a sounding board; you obviously have an appetite for these high-pressure situations. We don’t have very long left, but I would like to just touch very briefly on the medical aspects. As I said in the beginning, about 50% of medicines acts through GCPRs, but there are a lot of off target effects and side effects. Would you like to say how the work that you do has impacted, or will impact, the development in medicines?
Robert J. Lefkowitz: I think that in particular the recent work that both Brian and I have been doing – totally different kinds of work – each in their own way has implications for potentially developing more specific medications, by which we mean medications which have less side effects. If you look back over the history of pharmacology at least during the 40 years that I have been involved, there have been several advances that have helped us to … by “us” I mean others, I mean the drug /- – -/, the tailor GPCR targeted drugs with less side effects. The first development was the elucidation of previously unknown receptor sub-types. The cloning revolution changed everything. When I started my career I think there were three adrenergic receptors and then early on, I guess around the time in the early med-seventies a fourth was discovered. By the time we got done with our cloning we had eight and then a ninth was added. There was one dopamine receptor, it went to five; there was one muscarinic, it went to five; there were one or two or three or – I forget – tone receptors that went to 15. With the advent of these greater and greater receptor subtype you could get more and more specific actions because you didn’t have to get the off-target effects from a different subtype. But now I think there may be even other ways in which we can get greater specificity.
One of the things I’ve worked on during the past decade has been the fact that in addition to signaling to the inside of cells through G-proteins the receptors can also signal through a different molecule called β-arrestin. This is a molecule that we discovered about more than 20 years ago as a key part of the mechanism which turns the receptors off, it turns them off with respective G-protein signaling but at the same time, we’ve only come to appreciate recently, serves as an alternate signaling mechanism. Now it turns out that you can design drugs which will activate signaling either through the G-protein or the /- – -/ through the same receptor. For some drugs it turns out that the desired effect through that drug actually is being mediated through G-proteins, but some of the side effects are being mediated through β-arrestin signaling or vice versa. If you had a drug which can target one or the other mechanism you may be able to get a few side effects, in fact there are several examples of such compounds which are now on early phase clinical trials. So that may be an example of how my work in recent years may have implications for getting even more specific drugs with less side effects than we’ve had.
And as for the crystal structure?
Brian Kobilka: I think there are two ways that we might facilitate the development of more selective drugs. One is as we learn more and more about the binding pockets particularly how related receptors are so similar to each other in terms of /- – -/ assets from the binding pocket. We’re discovering that just outside of the binding pocket there’s greater diversity that could be sampled and in some drugs do sample this, for example it’s a structure that we recently obtained that hasn’t been published yet, it’s a drug called /- – -/ which is used to treat asthma. It’s extraordinarily selective for the β2 over the β1 and it is partly because it extends out of the, what we call /- – -/ pocket into more of the /- – -/ surface samples between β1 and β2. I think that’s an opportunity for the structures will give us an opportunity to actually design drugs that might be more selective. The other is to take advantage of unconventional binding pockets. First of all there are also allosteric binding pockets that are for example the most clinic receptors are well-known. There may be other druggable surfaces on the receptor including surfaces on the inside of the receptor that we might explore, that will also have greater structural differences from even close related receptors, say for β1 and β2. Those are a couple of opportunities to develop more selective drugs.
So for the first time it is really possible to use the structure to do structure aided drug design?
Brian Kobilka: Yes, and I think a colleague of ours, Brian Shoichet, has really been at the fore front of using computational /- – -/ and shown, as he likes to say, that GCPRs is really great binding pockets for /- – -/ screening.
Just to wind up, something that happened on that day in October when you got the call was that you were both converted into chemists, because you were awarded the Nobel Prize in Chemistry. I guess if you’re doing crystallography that is fine, but in your case, I imagine it was a bit of a surprise to be awarded the Chemistry Prize.
Robert J. Lefkowitz: It was indeed a big surprise and in fact I was telling somebody recently that I only succeeded in telling two of my five children personally about the prize because of Facebook, it spreads very rapidly, but one of my sons had learnt about this almost immediately on Facebook. He lives in New York and he called his sister, out in California, so it is 3 o’clock in the morning her time, all excited he says “Dad won the Nobel Prize” – this was Wednesday morning – and she merely says “No, he didn’t”. She says “You’re mistaken”. “No no, I just heard, he won.” She said “No no, you heard the prize was announced on Monday, in Medicine, and he didn’t get it. He said “No, he got it in Chemistry.” “Chemistry? What’s that all about?” It is interesting. In my career I published hundreds and hundreds of papers, but the single publication vehicle in which I’ve published the overwhelming majority of my work is The Journal of Biological Chemistry, it’s the single journal by far, there’s not even a closed section. In that sense, if there is a term that could be applied to my work I guess it is biochemistry or biological chemistry, which is a branch of chemistry. We have had some fun with the fact that we are now chemists.
I was going to ask the last question, does it matter how it is labelled, does it matter whether it is chemistry or biochemistry?
Robert J. Lefkowitz: I think in a sense not. I think what it shows is just how the interface between chemistry and biology and medicine … I have been called a lot of things in my time, not all pleasant, but I can handle chemist. Over the years, people have always gone: Well Bob, you’ll win the Nobel Prize someday. It was nice to hear although it didn’t seem to be happening, but if it happened, I always assumed it would be in medicine and not in chemistry. I think I have Brian to thank for that.
Brian Kobilka: I think I might even take a little at it to like in being awarded the chemistry prize. I think medicine and physiology are wonderful as well, but I’ve sort of been a chemist and want to be for the years.
It was a great pleasure to speak to you both. Thank you very much indeed. It just remains for me to wish you a wonderful Nobel Week in Stockholm.
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