The neuronal growth-associated protein GAP-43 interacts with rabaptin-5 and participates in endocytosis.

Structural plasticity of nerve cells is a requirement for activity-dependent changes in the brain. The growth-associated protein GAP-43 is thought to be one determinant of such plasticity, although the molecular mechanism by which it mediates dynamic structural alterations at the synapse is not known. GAP-43 is bound by calmodulin when ...
Ca2+ levels are low, and releases the calmodulin when Ca2+ levels rise, suggesting that calmodulin may act as a negative regulator of GAP-43 during periods of low activity in the neurons. To identify the function of GAP-43 during activity-dependent increases in Ca2+ levels, when it is not bound to calmodulin, we sought proteins with which GAP-43 interacts in the presence of Ca2+. We show here that rabaptin-5, an effector of the small GTPase Rab5 that mediates membrane fusion in endocytosis, is one such protein. We demonstrate that GAP-43 regulates endocytosis and synaptic vesicle recycling. Modulation of endocytosis by GAP-43, in association with rabaptin-5, may constitute a common molecular mechanism by which GAP-43 regulates membrane dynamics during its known roles in activity-dependent neurotransmitter release and neurite outgrowth.
Mesh Terms:
Brain Chemistry, Calmodulin, DNA, Complementary, Endocytosis, Endosomes, Fetus, Fluorescent Antibody Technique, GAP-43 Protein, Gene Expression, Gene Library, Humans, Membrane Proteins, Microscopy, Electron, Neurons, RNA, Messenger, Synaptic Vesicles, Vesicular Transport Proteins
J. Neurosci.
Date: Oct. 01, 1998
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