The Abl-related gene (Arg) requires its F-actin-microtubule cross-linking activity to regulate lamellipodial dynamics during fibroblast adhesion.
Microtubules (MTs) help establish and maintain cell polarity by promoting actin-dependent membrane protrusion at the leading edge of the cell, but the molecular mechanisms that mediate cross-talk between actin and MTs during this process are unclear. We demonstrate that the Abl-related gene (Arg) nonreceptor tyrosine kinase is required for dynamic lamellipodial protrusions after adhesion to fibronectin. arg-/- fibroblasts exhibit reduced lamellipodial dynamics as compared with wild-type fibroblasts, and this defect can be rescued by reexpression of an Arg-yellow fluorescent protein fusion. We show that Arg can bind MTs with high affinity and cross-link filamentous actin (F-actin) bundles and MTs in vitro. MTs concentrate and insert into Arg-induced F-actin-rich cell protrusions. Arg requires both its F-actin-binding domains and its MT-binding domain to rescue the defects in lamellipodial dynamics of arg-/- fibroblasts. These findings demonstrate that Arg can mediate physical contact between F-actin and MTs at the cell periphery and that this cross-linking activity is required for Arg to regulate lamellipodial dynamics in fibroblasts.
Miller
Ann L
AL
Department of Molecular Biophysics and Biochemistry, Yale University, SHMC-E31, 333 Cedar St., New Haven, CT 06520, USA.
Wang
Yinxiang
Y
Mooseker
Mark S
MS
Koleske
Anthony J
AJ
D008841:Actin Cytoskeleton / Q000378:metabolism; D000199:Actins / Q000378:metabolism* / Q000648:ultrastructure; D000818:Animals; D001665:Binding Sites / Q000235:genetics; D002448:Cell Adhesion / Q000235:genetics; D002461:Cell Line, Transformed; D002465:Cell Movement / Q000235:genetics; D005347:Fibroblasts / Q000378:metabolism* / Q000648:ultrastructure; D005353:Fibronectins / Q000378:metabolism; D005786:Gene Expression Regulation / Q000235:genetics; D051379:Mice; D008870:Microtubules / Q000378:metabolism* / Q000648:ultrastructure; D017711:Nonlinear Dynamics; D011485:Protein Binding / Q000235:genetics; D017434:Protein Structure, Tertiary / Q000235:genetics; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D011554:Pseudopodia / Q000378:metabolism* / Q000648:ultrastructure
D000199:Actins; D005353:Fibronectins; C426236:ARG tyrosine kinase; D011505:Protein-Tyrosine Kinases