title: Front-signal-dependent accumulation of the RHOA inhibitor FAM65B at leading edges polarizes neutrophils.
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.
authors.affiliation: 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.
authors.forename: Kun
authors.initials: K
authors.lastname: Gao
authors.affiliation: Vascular Biology and Therapeutic Program, Department of Pharmacology, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06410, USA.
authors.forename: Wenwen
authors.initials: W
authors.lastname: Tang
authors.affiliation: Vascular Biology and Therapeutic Program, Department of Pharmacology, Yale University School of Medicine, 10 Amistad Street, New Haven, CT 06410, USA.
authors.forename: Yuan
authors.initials: Y
authors.lastname: Li
authors.affiliation: 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.
authors.forename: Pingzhao
authors.initials: P
authors.lastname: Zhang
authors.affiliation: 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.
authors.forename: Dejie
authors.initials: D
authors.lastname: Wang
authors.affiliation: 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.
authors.forename: Long
authors.initials: L
authors.lastname: Yu
authors.affiliation: 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.
authors.forename: Chenji
authors.initials: C
authors.lastname: Wang
authors.affiliation: 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.
authors.forename: Dianqing
authors.initials: D
authors.lastname: Wu
mesh_terms: D000818:Animals; D002448:Cell Adhesion / Q000502:physiology; D015815:Cell Adhesion Molecules; D002633:Chemotaxis / Q000502:physiology; D058544:Class Ib Phosphatidylinositol 3-Kinase; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D018994:Myosin Light Chains / Q000235:genetics / Q000378:metabolism; D009504:Neutrophils / Q000166:cytology / Q000378:metabolism*; D054799:Phospholipase C beta / Q000235:genetics / Q000378:metabolism; D010766:Phosphorylation / Q000502:physiology; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D020741:rho GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D015815:Cell Adhesion Molecules; D018994:Myosin Light Chains; D011506:Proteins; C104952:RIPOR2 protein, human; C066737:RHOA protein, human; D058544:Class Ib Phosphatidylinositol 3-Kinase; C546764:Pik3cg protein, mouse; D054799:Phospholipase C beta; C526380:RhoA protein, mouse; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein
keywords: Chemotaxis; FAM65B; Neutrophil; Polarization; RHOA