Nebulin and Lmod2 are critical for specifying thin-filament length in skeletal muscle
Balázs Kiss, Jochen Gohlke, Paola Tonino, Zaynab Hourani, Justin Kolb, Joshua Strom, Olga Alekhina, John E. Smith, Coen Ottenheijm, Carol C. Gregorio, Henk Granzier
Abstract
gene; nebulin was either shortened or lengthened by 115 nm. Its effect on thin-filament length was studied using high-resolution structural and functional techniques. Results revealed that thin-filament length is strictly regulated by the length of nebulin in fast muscles. Nebulin's control is less tight in slow muscle types where a distal nebulin-free thin-filament segment exists, the length of which was found to be regulated by leiomodin-2 (Lmod2). We propose that strict length control by nebulin promotes high-speed shortening and that dual-regulation by nebulin/Lmod2 enhances contraction efficiency.