MOLECULAR MECHANISMS UNDERLYING GAP-43 FUNCTION

描述：大量证据表明， 相关蛋白GAP-43在神经元可塑性调节中的作用 发展和学习。 然而， GAP-43控制这些功能是未知的。 本提案使用 GAP-43的功能结构域分析，以及其 与rabaptin-5（一种介导内吞膜的蛋白质）相互作用 融合，描绘GAP-43参与的分子事件， 神经突生长和神经递质释放。 首先，假设 GAP-43的特定结构域可以与特定的信号传导途径连接， 它在神经递质释放的不同过程中的作用， 将测试神经突生长。 GAP-43突变体破坏了 蛋白质的结构域将在PC 12细胞和缺乏的神经元中表达。 GAP-43 这些突变体与钙调素、蛋白激酶 C，并且将评估GTP结合蛋白G 0，随后评估 这些突变对神经递质释放和过程生长的影响 将被量化。 第二个要检验的假设是， GAP-43与钙调素和蛋白激酶C的相互作用与其 在突触前末梢与rabaptin-5相互作用。 域映射， 共定位研究和定量功能测定将阐明 GAP-43与Rabaptin-5结合的功能作用，并证明 涉及这些分子的内吞膜融合事件是否包括 神经递质释放和神经突生长之间的分子联系。 从拟议研究中获得的数据将开始提供统一的 已知GAP-43具有多种功能的分子机制， 参加

DESCRIPTION: A large body of evidence implicates the neuronal growth associated protein GAP-43 in the modulation of neuronal plasticity during both development and learning. However, the molecular mechanisms by which GAP-43 controls these functions are not known. The present proposal uses analyses of functional domains of GAP-43, coupled with studies of its interaction with rabaptin-5, a protein that mediates endocytic membrane fusion, to delineate the molecular events underlying GAP-43 participation in neurite outgrowth ad neurotransmitter release. First, the hypothesis that specific domains of GAP-43 can be linked to specific signaling pathways and to its roles in the distinct processes of neurotransmitter release and neurite outgrowth will be tested. GAP-43 mutants that disrupt functional domains of the protein will be expressed in PC12 cells and neurons lacking GAP-43. The interactions of these mutants with calmodulin, protein kinase C, and the GTP-binding protein G0 will be evaluated, following which the effects of these mutations on neurotransmitter release and process outgrowth will be quantified. The second hypothesis to be tested is that the known interactions of GAP-43 with calmodulin and protein kinase C are tied to its interactions with rabaptin-5 in the presynaptic terminal. Domain mapping, co-localization studies, and quantitative functional assays will clarify the functional role of the binding of GAP-43 to rabaptin-5, and demonstrate whether endocytic membrane fusion events involving these molecules comprise a molecular link between neurotransmitter release and neurite outgrowth. The data obtained from the proposed studies will begin to provide unifying molecular mechanisms for the diverse functions in which GAP-43 is known to participate.