Lamellipodial localization of Dictyostelium myosin heavy chain kinase A is mediated via F-actin binding by the coiled-coil domain

Myosin heavy chain kinase A (MHCK A) modulates myosin 11 filament assembly in the amoeba Dictyostelium discoideum. MHCK A localization in vivo is dynamically regulated during chemotaxis, phagocytosis, and other polarized cell motility events, with preferential recruitment into anterior filamentous actin (F-actin)-rich structures. The current work reveals that an amino-terminal segment of MHCK A, previously identified as forming a coiled-coil, mediates anterior localization. MHCK A co-sediments with F-actin, and deletion of the amino-terminal domain eliminated actin binding. These results indicate that the anterior localization of MHCK A is mediated via direct binding to F-actin, and reveal the presence of an actin-binding function not preciously detected by primary sequence evaluation of the coiled-coil domain. (C) 2002 Published by Elsevier Science B.V. on behalf of the Federation of European Biochemical Societies.