StudyofintracellularlocalizationofIP3-receptortype2

IP3R I型（IP3R-I）被PKA磷酸化，这导致碳苯酚（CCh）诱导IP3R-I释放ca的增强。在firag和PKG Iβ存在的情况下，IP3R-I与这些分子形成复合物，这导致PKA磷酸化的丧失和cch诱导的ca释放的增强。IP3R II型（IP3R-II）也能与IRAG和PKG Iβ形成复合物。然而，PKA对IP3R-II的磷酸化和碳苯酚（CCh）诱导IP3R-II释放ca的增强并没有通过形成复合物而被抑制。在这项研究中，我们确定了IP3R分子与IRAG相互作用所必需的区域。在IP3R-I中，该区域离磷酸化位点较近，而在IP3R-II中，该区域离磷酸化位点较远。这一结果表明ip3r - 1与IRAG的相互作用在空间上不允许PKA进入topphospylation位点。

IP3R type I (IP3R-I) was phosphorylated by PKA and this causesthe potentiation of carbachol (CCh)-induced Ca-release from IP3R-I. In the presence ofIRAG and PKG Iβ, IP3R-I forms a complex with these molecules and this causes theloss of both the phosphorylation by PKA and the potentiation of CCh-inducedCa-release. IP3R type II (IP3R-II) also be able to form a complex with IRAG and PKG Iβ. However, the phosphorylation of IP3R-II by PKA and the potentiation of carbachol(CCh)-induced Ca-release from IP3R-II were not inhibited by forming a complex. Inthis study, we identified the regions of IP3R molecules, which were required forinteraction with IRAG. In the IP3R-I, the region was much close to the phosphorylationsite, while it was far from the phosphorylation site in the IP3R-II. This result indicatedthat the interaction of IP3R-I with IRAG spatially did not permit PKA to access tophosphorylation site.