Front-signal-dependent accumulation of the RHOA inhibitor FAM65B at leading edges polarizes neutrophils
Front-signal-dependent accumulation of the RHOA inhibitor FAM65B at leading edges polarizes neutrophils
复制标题
RHOA 抑制剂 FAM65B 在前缘的前信号依赖性积累使中性粒细胞极化
DOI：
10.1242/jcs.161497
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发表时间：
2015-03-01
影响因子：
4
通讯作者：
Wu, Dianqing
中科院分区：
文献类型：
--
作者：
Gao, Kun;Tang, Wenwen;Wu, Dianqing
中性粒细胞极化的一个标志是活性RHOA和磷酸化肌球蛋白轻链(pMLC，也称为MYL2)的背部定位。然而，这种两极分化的机制并不完全清楚。在这里，我们证明了FAM65B，一种新发现的RHOA抑制剂，对极化是重要的。当FAM65B被磷酸化时，它与14-3-3家族蛋白结合并变得更稳定。在中性粒细胞中，趋化剂刺激FAM65B的磷酸化在很大程度上依赖于来自细胞前端的信号，包括由磷脂酶Cβ(PLC Beta)和磷脂酰肌醇3-激酶伽马(PI3K Gamma)介导的信号，导致FAM65B在前沿聚集。相应地，FAM65B缺乏中性粒细胞导致RHOA活性增加，pMLC定位于细胞前部，并在流动状态下与内皮细胞的趋化性、方向性和粘附性缺陷。这些数据共同阐明了受刺激的中性粒细胞中RHOA和pMLC极化的机制，这是通过FAM65B在前沿直接抑制RHOA来实现的。
A hallmark of neutrophil polarization is the back localization of active RHOA and phosphorylated myosin light chain (pMLC, also known as MYL2). However, the mechanism for the polarization is not entirely clear. Here, we show that FAM65B, a newly identified RHOA inhibitor, is important for the polarization. When FAM65B is phosphorylated, it binds to 14-3-3 family proteins and becomes more stable. In neutrophils, chemoattractants stimulate FAM65B phosphorylation largely depending on the signals from the front of the cells that include those mediated by phospholipase C beta (PLC beta) and phosphoinositide 3-kinase gamma (PI3K gamma), leading to FAM65B accumulation at the leading edge. Concordantly, FAM65B deficiency in neutrophils resulted in an increase in RHOA activity and localization of pMLC to the front of cells, as well as defects in chemotaxis directionality and adhesion to endothelial cells under flow. These data together elucidate a mechanism for RHOA and pMLC polarization in stimulated neutrophils through direct inhibition of RHOA by FAM65B at the leading edge.