Vitković L, Steisslinger H W, Aloyo V J, Mersel M
Laboratory of Molecular Biology, National Institute of Neurological and Communicative Disorders and Stroke, Bethesda, MD 20892.
Proc Natl Acad Sci U S A. 1988 Nov;85(21):8296-300. doi: 10.1073/pnas.85.21.8296.
One of the neuronal growth-associated proteins, GAP-43 (molecular mass, approximately 43 kDa; pI 4.3), is abundant in growth-cone membranes and corresponds to a major protein kinase C substrate, the 46-kDa phosphoprotein (pp46), of a growth-cone-enriched subcellular fraction. This protein has the following additional designations (depending on context): B-50 (phospholipid metabolism), F1 (synaptic plasticity), and p57 (calmodulin binding). We show that a protein with the same molecular mass and isoelectric point as GAP-43, which interacts with anti-GAP-43 antibodies on immunoblots, is present in the plasma membranes of cultured neonatal rat cortical astrocytes. Double-immunofluorescence labeling of cells with a serum against glial fibrillary acidic protein and anti-GAP-43 antibody was observed. Furthermore, astrocytic protein was phosphorylated in vitro by protein kinase C and comigrated in two-dimensional PAGE with GAP-43. The data indicate that GAP-43, heretofore believed to be neuron-specific, is present in at least one class of glial cells.
神经元生长相关蛋白之一，GAP-43（分子量约43 kDa；等电点4.3），在生长锥膜中含量丰富，并且与生长锥富集的亚细胞组分中的一种主要蛋白激酶C底物，即46 kDa磷蛋白（pp46）相对应。该蛋白还有以下其他名称（取决于上下文）：B-50（磷脂代谢）、F1（突触可塑性）和p57（钙调蛋白结合）。我们发现，在培养的新生大鼠皮质星形胶质细胞的质膜中存在一种与GAP-43分子量和等电点相同的蛋白，该蛋白在免疫印迹上与抗GAP-43抗体相互作用。观察到用抗胶质纤维酸性蛋白血清和抗GAP-43抗体对细胞进行双重免疫荧光标记。此外，星形胶质细胞蛋白在体外被蛋白激酶C磷酸化，并在双向聚丙烯酰胺凝胶电泳中与GAP-43共迁移。数据表明，迄今被认为是神经元特异性的GAP-43存在于至少一类胶质细胞中。
