Interaction of neurochondrin with the melanin-concentrating hormone receptor 1 interferes with G protein-coupled signal transduction but not agonist-mediated internalization
Interaction of neurochondrin with the melanin-concentrating hormone receptor 1 interferes with G protein-coupled signal transduction but not agonist-mediated internalization
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DOI：
10.1074/jbc.m602889200
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发表时间：
2006-10-27
影响因子：
4.8
通讯作者：
Baechner, Dietmar
中科院分区：
文献类型：
--
作者：
Francke, Felix;Ward, Richard J.;Baechner, Dietmar
在酵母双杂交试验中，使用黑色素浓集激素受体1（MCHR 1）的C-末端尾部作为诱饵筛选人脑cDNA文库，鉴定了神经突生长相关因子neurochondrin。这种相互作用在覆盖、下拉和免疫共沉淀试验中得到验证。缺失定位将结合限制在神经软骨素的C末端和MCHR 1的近端C末端，该区域已知参与G蛋白结合和信号转导。MCHR 1的这个区域也能够与肌动蛋白和中间体结合蛋白periplakin相互作用。MCHR 1与neurochondrin和periplakin的相互作用是竞争性的，表明这两种蛋白质结合到MCHR 1的重叠区域。虽然神经软骨素不干扰黑色素浓集性蛋白酶介导的受体内化，但它确实通过G α（i/o）和G α（q/11）家族G蛋白抑制G蛋白偶联的信号转导，如通过在转染的哺乳动物细胞中的钙动员，以及通过降低黑色素浓集激素促进[S-35]鸟苷5 '-3-O-（硫代）三磷酸与G α（o 1）和G α（11）结合的能力。免疫组织化学显示神经软骨素和MCHR 1在啮齿动物脑内的共表达，表明神经软骨素可能参与MCHR 1信号的调节，并在体内调节黑色素浓缩酶介导的功能中发挥作用。
Screening of a human brain cDNA library using the C-terminal tail of the melanin-concentrating hormone receptor 1(MCHR1) as bait in a yeast two-hybrid assay resulted in the identification of the neurite-outgrowth related factor, neurochondrin. This interaction was verified in overlay, pulldown, and co-immunoprecipitation assays. Deletion mapping confined the binding to the C terminus of neurochondrin and to the proximal C terminus of MCHR1, a region known to be involved in G protein binding and signal transduction. This region of the MCHR1 is also able to interact with the actin- and intermediate filament-binding protein, periplakin. Interactions of MCHR1 with neurochondrin and periplakin were competitive, indicating that these two proteins bind to overlapping regions of MCHR1. Although neurochondrin did not interfere with melanin-concentrating hormone-mediated internalization of the receptor, it did inhibit G protein-coupled signal transduction via both G alpha(i/o) and G alpha(q/11) family G proteins as measured by each of melanin-concentrating hormone-induced G protein-activated inwardly rectifying K+ channel activity of voltage-clamped amphibian oocytes, by calcium mobilization in transfected mammalian cells, and by reduction in the capacity of melanin-concentrating hormone to promote binding of [S-35]guanosine 5'-3-O-(thio)triphosphate to both G alpha(o1) and G alpha(11). Immunohistochemistry revealed co-expression of neurochondrin and MCHR1 within the rodent brain, suggesting that neurochondrin may be involved in the regulation of MCHR1 signaling and play a role in modulating melanin-concentrating hormone-mediated functions in vivo.