Gispen W H, Nielander H B, De Graan P N, Oestreicher A B, Schrama L H, Schotman P
Rudolf Magnus Institute, University of Utrecht, The Netherlands.
Mol Neurobiol. 1991;5(2-4):61-85. doi: 10.1007/BF02935540.
The neuronal phosphoprotein B-50/GAP-43 has been implicated in neuritogenesis during developmental stages of the nervous system and in regenerative processes and neuronal plasticity in the adult. The protein appears to be a member of a family of acidic substrates of protein kinase C (PKC) that bind calmodulin at low calcium concentrations. Two of these substrates, B-50 and neurogranin, share the primary sequence coding for the phospho- and calmodulin-binding sites and might exert similar functions in axonal and dendritic processes, respectively. In the adult brain, B-50 is exclusively located at the presynaptic membrane. During neuritogenesis in cell culture, the protein is translocated to the growth cones, i.e., into the filopodia. In view of many positive correlations between B-50 expression and neurite outgrowth and the specific localization of B-50, a role in growth cone function has been proposed. Its phosphorylation state may regulate the local intracellular free calmodulin and calcium concentrations or vice versa. Both views link the B-50 protein to processes of signal transduction and transmitter release.
神经元磷蛋白B - 50/GAP - 43在神经系统发育阶段的神经突形成、成体的再生过程以及神经元可塑性中发挥作用。该蛋白似乎是蛋白激酶C（PKC）酸性底物家族的成员，在低钙浓度下与钙调蛋白结合。其中两种底物，B - 50和神经颗粒素，共享编码磷酸化和钙调蛋白结合位点的一级序列，可能分别在轴突和树突过程中发挥相似功能。在成体大脑中，B - 50仅位于突触前膜。在细胞培养的神经突形成过程中，该蛋白会转运至生长锥，即丝状伪足。鉴于B - 50表达与神经突生长之间存在许多正相关关系以及B - 50的特定定位，有人提出其在生长锥功能中发挥作用。其磷酸化状态可能调节局部细胞内游离钙调蛋白和钙浓度，反之亦然。这两种观点都将B - 50蛋白与信号转导和递质释放过程联系起来。
