Stack J H, Herman P K, Schu P V, Emr S D
Howard Hughes Medical Institute, University of California, San Diego, School of Medicine, La Jolla 92093-0668.
EMBO J. 1993 May;12(5):2195-204. doi: 10.1002/j.1460-2075.1993.tb05867.x.
The Vps15 protein kinase and the Vps34 phosphatidylinositol 3-kinase (PI 3-kinase) are required for the sorting of soluble hydrolases to the yeast vacuole. Over-production of Vps34p suppresses the growth and vacuolar protein sorting defects associated with vps15 kinase domain mutants, suggesting that Vps15p and Vps34p functionally interact. Subcellular fractionation and sucrose density gradients indicate that Vps15p is responsible for the association of Vps34p with an intracellular membrane fraction. Chemical cross-linking and native immunoprecipitation experiments demonstrate that Vps15p and Vps34p interact as components of a hetero-oligomeric protein complex. In addition, we show that an intact Vps15 protein kinase domain is required for activation of the Vps34 PI 3-kinase, suggesting that the Vps34 lipid kinase is regulated by a Vps15p-mediated protein phosphorylation event. We propose that Vps15p and Vps34p function together as components of a membrane-associated signal transduction complex that regulates intracellular protein trafficking decisions through protein and lipid phosphorylation events.
Vps15蛋白激酶和Vps34磷脂酰肌醇3激酶（PI 3激酶）是可溶性水解酶分选至酵母液泡所必需的。Vps34p的过量表达可抑制与vps15激酶结构域突变体相关的生长和液泡蛋白分选缺陷，这表明Vps15p和Vps34p在功能上相互作用。亚细胞分级分离和蔗糖密度梯度分析表明，Vps15p负责Vps34p与细胞内膜部分的结合。化学交联和天然免疫沉淀实验证明，Vps15p和Vps34p作为异源寡聚蛋白复合物的组成成分相互作用。此外，我们发现完整的Vps15蛋白激酶结构域是激活Vps34 PI 3激酶所必需的，这表明Vps34脂质激酶受Vps15p介导的蛋白磷酸化事件调控。我们提出，Vps15p和Vps34p作为膜相关信号转导复合物的组成成分共同发挥作用，该复合物通过蛋白和脂质磷酸化事件调节细胞内蛋白运输决策。
