Institute of Cell Biology and Immunology, University of Stuttgart, 70569 Stuttgart, Germany Panatecs GmbH, 72070 Tübingen, Germany.
Mol Biol Cell. 2011 Mar 1;22(5):570-80. doi: 10.1091/mbc.E10-05-0427. Epub 2011 Jan 5.
The multifunctional signal adapter protein Ras and Rab interactor 1 (RIN1) is a Ras effector protein involved in the regulation of epithelial cell processes such as cell migration and endocytosis. RIN1 signals via two downstream pathways, namely the activation of Rab5 and Abl family kinases. Protein kinase D (PKD) phosphorylates RIN1 at serine 351 in vitro, thereby regulating interaction with 14-3-3 proteins. Here, we report the identification of serine 292 in RIN1 as an in vivo PKD phosphorylation site. PKD-mediated phosphorylation at this site was confirmed with a phospho-specific antibody and by mass spectrometry. We demonstrate that phosphorylation at serine 292 controls RIN1-mediated inhibition of cell migration by modulating the activation of Abl kinases. We further provide evidence that RIN1 in vivo phosphorylation at serine 351 occurs independently of PKD. Collectively, our data identify a novel PKD signaling pathway through RIN1 and Abl kinases that is involved in the regulation of actin remodeling and cell migration.
多功能信号衔接蛋白 Ras 和 Rab 相互作用蛋白 1（RIN1）是一种 Ras 效应蛋白，参与调节上皮细胞过程，如细胞迁移和内吞作用。RIN1 通过两条下游途径发出信号，即 Rab5 和 Abl 家族激酶的激活。蛋白激酶 D（PKD）在体外将 RIN1 磷酸化丝氨酸 351，从而调节与 14-3-3 蛋白的相互作用。在这里，我们报告了鉴定 RIN1 中丝氨酸 292 为体内 PKD 磷酸化位点。PKD 介导的该位点磷酸化通过磷酸特异性抗体和质谱得到证实。我们证明丝氨酸 292 的磷酸化通过调节 Abl 激酶的激活来控制 RIN1 介导的细胞迁移抑制。我们进一步提供证据表明，RIN1 体内丝氨酸 351 的磷酸化独立于 PKD 发生。总之，我们的数据确定了一条通过 RIN1 和 Abl 激酶的新的 PKD 信号通路，该通路参与调节肌动蛋白重塑和细胞迁移。
