80K-H Interacts with Inositol 1,4,5-Trisphosphate (IP3) Receptors and Regulates IP3-induced Calcium Release Activity*
80K-H Interacts with Inositol 1,4,5-Trisphosphate (IP3) Receptors and Regulates IP3-induced Calcium Release Activity*
复制标题
DOI：
10.1074/jbc.m805828200
复制
发表时间：
2009-01
影响因子：
4.8
通讯作者：
Katsuhiro Kawaai;C. Hisatsune;Y. Kuroda;A. Mizutani;T. Tashiro;K. Mikoshiba
中科院分区：
文献类型：
--
作者：
Katsuhiro Kawaai;C. Hisatsune;Y. Kuroda;A. Mizutani;T. Tashiro;K. Mikoshiba
肌醇1，4，5-三磷酸受体（Inositol 1，4，5-trisphosphate receptor，IP 3Rs）是介导内质网钙离子释放的细胞内通道蛋白，参与许多生物学过程（如受精、分泌和突触可塑性）。最近的报道表明，IP 3 R活性受到几种相互作用分子（例如，与肌醇1，4，5-三磷酸、亨廷顿蛋白、早老素、DANGER和细胞色素c一起释放的IP 3 R结合蛋白）的严格调节，并且这种调节的扰动引起细胞内Ca 2+升高，导致几种疾病（例如，亨廷顿病和阿尔茨海默病）。本研究通过酵母双杂交技术筛选到了一个与IP 3Rs羧基端尾相互作用的蛋白激酶C底物80 K-H（80 K-H）。80 K-H在体外直接与IP 3R 1（IP 3R 1）相互作用，并在细胞裂解物中与IP 3R 1共免疫沉淀。免疫细胞化学和免疫组织化学染色显示80 K-H与IP 3R 1共定位于COS-7细胞和海马神经元。我们还表明，纯化的重组80 K-H蛋白直接增强IP 3诱导的Ca 2+释放活性的Ca 2+释放测定使用小鼠小脑微粒体。此外，80 K-H还能调节ATP诱导的细胞内Ca ~（2+）释放。因此，我们的研究结果表明，80 K-H是一种新的调节IP 3 R活性，它可能有助于神经功能。
Inositol 1,4,5-trisphosphate receptors (IP3Rs) are intracellular channel proteins that mediate calcium (Ca2+) release from the endoplasmic reticulum, and they are involved in many biological processes (e.g. fertilization, secretion, and synaptic plasticity). Recent reports show that IP3R activity is strictly regulated by several interacting molecules (e.g. IP3R binding protein released with inositol 1,4,5-trisphosphate, huntingtin, presenilin, DANGER, and cytochrome c), and perturbation of this regulation causes intracellular Ca2+ elevation leading to several diseases (e.g. Huntington disease and Alzheimer disease). In this study, we identified protein kinase C substrate 80K-H (80K-H) to be a novel molecule interacting with the COOH-terminal tail of IP3Rs by yeast two-hybrid screening. 80K-H directly interacted with IP3R type 1 (IP3R1) in vitro and co-immunoprecipitated with IP3R1 in cell lysates. Immunocytochemical and immunohistochemical staining revealed that 80K-H colocalized with IP3R1 in COS-7 cells and in hippocampal neurons. We also showed that the purified recombinant 80K-H protein directly enhanced IP3-induced Ca2+ release activity by a Ca2+ release assay using mouse cerebellar microsomes. Furthermore 80K-H was found to regulate ATP-induced Ca2+ release in living cells. Thus, our findings suggest that 80K-H is a novel regulator of IP3R activity, and it may contribute to neuronal functions.