Characterization of a multidomain adaptor protein, p140Cap, as part of a pre-synaptic complex
Characterization of a multidomain adaptor protein, p140Cap, as part of a pre-synaptic complex
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DOI：
10.1111/j.1471-4159.2008.05585.x
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发表时间：
2008-10-01
影响因子：
4.7
通讯作者：
Nagata, Koh-ichi
中科院分区：
文献类型：
--
作者：
Ito, Hidenori;Atsuzawa, Kimie;Nagata, Koh-ichi
p140Cap （Cas-associated protein）是一种连接蛋白，被认为在非神经元细胞的细胞粘附、生长和Src酪氨酸激酶相关信号传导中起关键作用。据报道，它还与突触前膜蛋白相互作用，突触体相关蛋白为25kda，并可能参与神经元分泌。然而，p140Cap在神经元细胞中的特性和精确功能几乎是未知的。通过生化分析，我们发现p140Cap在大鼠大脑中以发育阶段依赖的方式表达，并且在成年大鼠的突触质膜中相对丰富。免疫组化显示p140Cap定位于大鼠脑内的神经pil中，免疫荧光分析在原代培养的大鼠海马神经元突触中检测到p140Cap。电子显微镜进一步显示突触前和突触后的定位。筛选p140Cap结合蛋白发现了一个多结构域衔接蛋白vinexin，其第三个Src-homology 3结构域与p140Cap的c端Pro-rich基序相互作用。在COS7和大鼠脑中证实了这两种蛋白之间的免疫复合物。我们还澄清了突触前蛋白synaptophysin与p140Cap相互作用。这些结果表明p140Cap参与神经递质释放、突触形成/维持和信号传导。
p140Cap (Cas-associated protein) is an adaptor protein considered to play pivotal roles in cell adhesion, growth and Src tyrosine kinase-related signaling in non-neuronal cells. It is also reported to interact with a pre-synaptic membrane protein, synaptosome-associated protein of 25 kDa, and may participate in neuronal secretion. However, properties and precise functions of p140Cap in neuronal cells are almost unknown. Here we show, using biochemical analyses, that p140Cap is expressed in rat brain in a developmental stage-dependent manner, and is relatively abundant in the synaptic plasma membrane fraction in adults. Immunohistochemistry showed localization of p140Cap in the neuropil in rat brain and immunofluorescent analyses detected p140Cap at synapses of primary cultured rat hippocampal neurons. Electron microscopy further revealed localization at pre- and post-synapses. Screening of p140Cap-binding proteins identified a multidomain adaptor protein, vinexin, whose third Src-homology 3 domain interacts with the C-terminal Pro-rich motif of p140Cap. Immunocomplexes between the two proteins were confirmed in COS7 and rat brain. We also clarified that a pre-synaptic protein, synaptophysin, interacts with p140Cap. These results suggest that p140Cap is involved in neurotransmitter release, synapse formation/maintenance, and signaling.