Towards an Understanding of Integrative Brain Functions

Signal transduction of molecules at the glutamatergic postsynaptic membrane

Mary B. Kennedy*
Division of Biology 216-76, California Institute of Technology, Pasadena, CA 91125, USA¹

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Abstract
We have applied techniques from modern molecular biology and biochemistry to unravel the complex molecular structure of the postsynaptic membrane at glutamargic synapses in the central nervous system. We have characterized a set of new proteins that are constituents of the postsynaptic density, including PSD-95, densin-180, citron (a rho/rac effector protein), and synaptic gp130 Ras GAP (a new Ras GTPase-activating protein). The structure of PSD-95 revealed a new protein motif, the PDZ domain, that plays an important role in the assembly of signal transduction complexes at intercellular junctions. More recently, we have used new imaging tools to observe the dynamics of authophosphorylation of CaM kinase II in intact hoppocampal tissue. We have been able to detect changes in the amount of autophosphorylated CaM kinase II in dendrites, invidual synapses, and somas of hippocampal neurons following induction of long-term potentiation by tetanic stimulation. In addition, we have observed a specific increase in the concentration of CaM kinase II in dendrites of neurons receiving tetanic stimulation. This increase appears to be the result of dendritic synthesis of new protein. Over the next several years we will apply similar methods to study regulatory changes that occur at the molecular level in glutamatergic synapses in the CNS as the brain processes and stores new information.

Corresponding author: kennedym@cco.caltech.edu
1) Lab home page UR
http://www.cco.caltech.edu/~mbklab/.index.html

Brain Research Reviews 26 (1998) 243-257
Copyright © 1998 Elsevier Science B. V. All rights reserved.