PBIO SEMINAR SERIES

A Unified Model for Optimizing Actin Filament Lengths in Muscle

October 01, 2009

Ryan Littlefield
University of Washington

Host: Wordeman

The overlap of actin and myosin filaments is precisely regulated in striated muscle to produce maximal contractile force. My research shows that the giant protein nebulin is not a strict “molecular ruler”, yet may stabilize a central core region of skeletal muscle actin filaments. Instead, regulated polymerization at the “slow-growing” ends accounts for actin filament extensions observed beyond the end of nebulin. Together, these observations suggest a unified model for how actin filament lengths may be matched to thick filaments to optimize overlap in a variety of contractile systems, including vertebrate cardiac muscle, invertebrate muscle, and smooth muscle.