Mellor H, Flynn P, Nobes C D, Hall A, Parker P J
Protein Phosphorylation Laboratory, Imperial Cancer Research Fund, 44 Lincoln's Inn Fields, London WC2A 3PX, United Kingdom.
J Biol Chem. 1998 Feb 27;273(9):4811-4. doi: 10.1074/jbc.273.9.4811.
RhoB has been shown to be an endosomal GTPase both by immunocytochemistry and electron microscopy, however, its role in endocytosis is unknown. Elucidation of the cellular roles of other members of this superfamily of signaling proteins has come with the identification of their downstream partners. We show here that the recently isolated serine/threonine kinase PRK1 is targeted to the endosomal compartment by RhoB. This is established both through immunofluorescence and cell fractionation. PRK1 is shown to interact with activated RhoB in cells and is localized to endosomes through its Rho-binding HR1 domain. Translocation of PRK1 to the endosomal compartment by RhoB is accompanied by a shift in the electrophoretic mobility of the kinase indicative of an accompanying activation.
通过免疫细胞化学和电子显微镜研究表明，RhoB是一种内体GTP酶，然而，其在胞吞作用中的作用尚不清楚。随着该信号蛋白超家族其他成员下游伙伴的鉴定，人们对它们在细胞中的作用有了更深入的了解。我们在此表明，最近分离出的丝氨酸/苏氨酸激酶PRK1被RhoB靶向定位于内体区室。这一结论通过免疫荧光和细胞分级分离得以证实。研究表明，PRK1在细胞中与活化的RhoB相互作用，并通过其Rho结合HR1结构域定位于内体。RhoB将PRK1转运至内体区室的同时，激酶的电泳迁移率发生改变，这表明其伴随有激活现象。
