2. Academic Validation
  3. 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

  • J Cell Sci. 2015 Mar 1;128(5):992-1000. doi: 10.1242/jcs.161497.
Kun Gao 1,  Wenwen Tang 2,  Yuan Li 2,  Pingzhao Zhang 3,  Dejie Wang 4,  Long Yu 3,  Chenji Wang 5,  Dianqing Wu 6
Affiliations

Affiliations

  • 1 State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, Institute of Genetics, School of Life Sciences, Fudan University, 220 Handan Road, Shanghai 200433, P.R. China Vascular Biology and Therapeutic Program, Department of Pharmacology, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06410, USA.
  • 2 Vascular Biology and Therapeutic Program, Department of Pharmacology, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06410, USA.
  • 3 State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, Institute of Genetics, School of Life Sciences, Fudan University, 220 Handan Road, Shanghai 200433, P.R. China Institutes of Biomedical Sciences, Fudan University, Shanghai, 200032, P. R. China.
  • 4 State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, Institute of Genetics, School of Life Sciences, Fudan University, 220 Handan Road, Shanghai 200433, P.R. China.
  • 5 State Key Laboratory of Genetic Engineering, Collaborative Innovation Center for Genetics and Development, Institute of Genetics, School of Life Sciences, Fudan University, 220 Handan Road, Shanghai 200433, P.R. China chenjiwang@fudan.edu.cn dan.wu@yale.edu.
  • 6 Vascular Biology and Therapeutic Program, Department of Pharmacology, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06410, USA chenjiwang@fudan.edu.cn dan.wu@yale.edu.
PMID: 25588844 DOI: 10.1242/jcs.161497
Abstract

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 Cβ (PLCβ) and phosphoinositide 3-kinase γ (PI3Kγ), 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.

Keywords

Chemotaxis; FAM65B; Neutrophil; Polarization; RHOA.

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