Localization of the protein kinase C phosphorylation/calmodulin-binding substrate RC3 in dendritic spines of neostriatal neurons.
Localization of the protein kinase C phosphorylation/calmodulin-binding substrate RC3 in dendritic spines of neostriatal neurons.
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DOI：
10.1073/pnas.89.18.8581
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发表时间：
1992-09
影响因子：
11.1
通讯作者：
J. Watson;J. Sutcliffe;Robin S. Fisher
中科院分区：
文献类型：
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作者：
J. Watson;J. Sutcliffe;Robin S. Fisher
啮齿动物蛋白RC3在出生后发育和成熟过程中主要由前脑神经元表达。RC3及其牛神经颗粒素/B-50免疫活性C-激酶底物(BICKS)含有与突触前43-kDa生长相关蛋白(GAP-43)类似的蛋白激酶C磷酸化和钙调蛋白结合的重叠位点。然而，形态学证据表明，RC3具有突触后定位。为了验证这一假设，我们使用了两种针对RC3中不重叠序列的合成肽的多克隆抗血清，并通过免疫组织化学、高尔基体染色/金标记法和相关的光学/电子显微镜比较了它们在成年大鼠新纹状体中结合的细胞分布。观察RC3免疫反应的体细胞和点状分布。体细胞RC3存在于所有神经元表型(中等刺细胞、中等刺细胞和大刺细胞)的细胞室和核质室中。点状RC3主要存在于树突棘中。与43 kDa的生长相关蛋白相比，RC3在轴突中很少出现。我们认为RC3在突触后聚集在新纹状体神经元的树突棘中。我们认为，在突触发育和重塑过程中，RC3作为蛋白激酶C介导的分子级联的“第三信使”底物。
The rodent protein RC3 is expressed mainly by forebrain neurons during postnatal development and maturity. RC3 and its bovine homolog neurogranin/B-50 immunoreactive C-kinase substrate (BICKS) contain overlapping sites for protein kinase C phosphorylation and calmodulin binding that resemble those of the presynaptic 43-kDa growth-associated protein (GAP-43). However, morphological evidence suggests that RC3 has a postsynaptic localization. To test this hypothesis, we used two polyclonal antisera against synthetic peptides corresponding to nonoverlapping sequences within RC3 and compared cellular distributions of their binding in neostriatum of adult rats by immunohistochemistry, Golgi impregnation/gold toning, and correlative light/electron microscopy. Somatic and punctate patterns of RC3 immunoreactivity were observed. Somatic RC3 was found in cyto- and nucleoplasmic compartments of all neuronal phenotypes (medium spiny, medium aspiny, and large aspiny cells). Punctate RC3 was found mostly in dendritic spines. In contrast to the 43-kDa growth-associated protein, RC3 was seen infrequently in axons. We conclude that RC3 accumulates postsynaptically in dendritic spines of neostriatal neurons. We propose that RC3 acts as a "third messenger" substrate of protein kinase C-mediated molecular cascades during synaptic development and remodeling.