Regulation of actin polymerization and adhesion-dependent cell edge protrusion by the Abl-related gene (Arg) tyrosine kinase and N-WASp.
Extracellular cues stimulate the Abl family nonreceptor tyrosine kinase Arg to promote actin-based cell edge protrusions. Several Arg-interacting proteins are potential links to the actin cytoskeleton, but exactly how Arg stimulates actin polymerization and cellular protrusion has not yet been fully elucidated. We used affinity purification to identify N-WASp as a novel binding partner of Arg. N-WASp activates the Arp2/3 complex and is an effector of Abl. We find that the Arg SH3 domain binds directly to N-WASp. Arg phosphorylates N-WASp on Y256, modestly increasing the affinity of Arg for N-WASp, an interaction that does not require the Arg SH2 domain. The Arg SH3 domain stimulates N-WASp-dependent actin polymerization in vitro, and Arg phosphorylation of N-WASp weakly stimulates this effect. Arg and N-WASp colocalize to adhesion-dependent cell edge protrusions in vivo. The cell edge protrusion defects of arg-/- fibroblasts can be complemented by re-expression of an Arg-yellow fluorescent protein (YFP) fusion, but not by an N-WASp binding-deficient Arg SH3 domain point mutant. These results suggest that Arg promotes actin-based protrusions in response to extracellular stimuli through phosphorylation of and physical interactions with N-WASp.
Department of Cell Biology, Yale University, New Haven, Connecticut 06520, USA.
Matthew M
MM
Miller
Stefanie
S
Lapetina
Stacey M
SM
MacGrath
Mindan K
MK
Sfakianos
Thomas D
TD
Pollard
Anthony J
AJ
Koleske
D000199:Actins / Q000737:chemistry / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000166:cytology / Q000378:metabolism; D002417:Cattle; D002448:Cell Adhesion; D022081:Cell Surface Extensions / Q000378:metabolism*; D006801:Humans; D051379:Mice; D009154:Mutation; D010766:Phosphorylation; D055503:Protein Multimerization; D020836:Protein Structure, Quaternary; D021381:Protein Transport; D011505:Protein-Tyrosine Kinases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal / Q000378:metabolism*; D018909:src Homology Domains
D000199:Actins; D051317:Wiskott-Aldrich Syndrome Protein, Neuronal; C426236:ARG tyrosine kinase; D011505:Protein-Tyrosine Kinases