title: The motor activity of myosin-X promotes actin fiber convergence at the cell periphery to initiate filopodia formation.
abstract: Filopodia are actin-rich fingerlike protrusions found at the leading edge of migrating cells and are believed to play a role in directional sensing. Previous studies have shown that myosin-X (myoX) promotes filopodia formation and that this is mediated through its ability to deliver specific cargoes to the cell periphery (Tokuo, H., and M. Ikebe. 2004. Biochem Biophys. Commun. 319:214-220; Zhang, H., J.S. Berg, Z. Li, Y. Wang, P. Lang, A.D. Sousa, A. Bhaskar, R.E. Cheney, and S. Stromblad. 2004. Nat. Cell Biol. 6:523-531; Bohil, A.B., B.W. Robertson, and R.E. Cheney. 2006. Proc. Natl. Acad. Sci. USA. 103:12411-12416; Zhu, X.J., C.Z. Wang, P.G. Dai, Y. Xie, N.N. Song, Y. Liu, Q.S. Du, L. Mei, Y.Q. Ding, and W.C. Xiong. 2007. Nat. Cell Biol. 9:184-192). In this study, we show that the motor function of myoX and not the cargo function is critical for initiating filopodia formation. Using a dimer-inducing technique, we find that myoX lacking its cargo-binding tail moves laterally at the leading edge of lamellipodia and induces filopodia in living cells. We conclude that the motor function of the two-headed form of myoX is critical for actin reorganization at the leading edge, leading to filopodia formation.
authors.affiliation: Department of Physiology, University of Massachusetts Medical School, Worcester, MA 01655, USA.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Tokuo
authors.forename: Katsuhide
authors.initials: K
authors.lastname: Mabuchi
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Ikebe
mesh_terms: D000199:Actins / Q000378:metabolism*; D000818:Animals; D019556:COS Cells; D016764:Cell Polarity; D002470:Cell Survival; D002522:Chlorocebus aethiops; D019281:Dimerization; D051379:Mice; D020409:Molecular Motor Proteins / Q000378:metabolism*; D009218:Myosins / Q000737:chemistry / Q000172:deficiency / Q000378:metabolism*; D041681:NIH 3T3 Cells; D011554:Pseudopodia / Q000378:metabolism*; D011993:Recombinant Fusion Proteins / Q000378:metabolism
chemical_list: D000199:Actins; D020409:Molecular Motor Proteins; C409064:Myo10 protein, mouse; D011993:Recombinant Fusion Proteins; D009218:Myosins