Mammalian CARMIL inhibits actin filament capping by capping protein.

ABSTRACT: Actin polymerization in cells occurs via filament elongation at the barbed end. Proteins that cap the barbed end terminate this elongation. Heterodimeric capping protein (CP) is an abundant and ubiquitous protein that caps the barbed end. We find that the mouse homolog of the adaptor protein CARMIL (mCARMIL) binds CP with high affinity and decreases its affinity for the barbed end. Addition of mCARMIL to cell extracts increases the rate and extent of Arp2/3 or spectrin-actin seed-induced polymerization. In cells, GFP-mCARMIL concentrates in lamellipodia and increases the fraction of cells with large lamellipodia. Decreasing mCARMIL levels by siRNA transfection lowers the F-actin level and slows cell migration through a mechanism that includes decreased lamellipodia protrusion. This phenoty

SUBMITTER: Yang C 

PROVIDER: S-EPMC2628720 | biostudies-literature | 2005 Aug

REPOSITORIES: biostudies-literature