Possible involvement of a new molecule, PRIP in exocytosis

我们分离了一种新的蛋白质，PRIP(PLC相关但催化失活的蛋白质)，随后产生了基因缺陷小鼠(KO小鼠)。KO小鼠表现出促性腺激素和胰岛素的上调，表明PRIP可能参与了囊泡融合过程中常见的事件。因此，在目前的研究中，我们探索了PRIP参与胞吐作用的机制。结果提示，PRIP通过占据分泌所需的膜磷脂与PH结构域，并通过C2结构域干扰SNARE蛋白，负性参与PC12细胞致密核小泡的分泌。此外，PRIP还通过调节蛋白磷酸酶的活性参与胞吐作用的磷酸化调控。

We have isolated a novel protein, PRIP(PLC-related but catalytically inactive protein), followed by generation of the gene-deficient mice(KO mice). KO mice exhibited up-regulation of gonadotropins and insulin, indicating that PRIP might be involved in events common to vesicular fusion processes. In the current studies, therefore, we have explored the mechanisms by which PRIP is involved in exocytosis. The results suggest that PRIP is negatively involved in the dense-core vesicle secretion of PC12 cells, by occupying the membrane phospholipids required for the secretion with the PH domain, and interfering SNARE proteins by the C2 domains. Furthermore, PRIP is involved in the phospho-modulation of exocytosis by regulating activities of protein phosphatases.