An embryonic myosin isoform enables stretch activation and cyclical power in Drosophila jump muscle.

ABSTRACT: The mechanism behind stretch activation (SA), a mechanical property that increases muscle force and oscillatory power generation, is not known. We used Drosophila transgenic techniques and our new muscle preparation, the jump muscle, to determine if myosin heavy chain isoforms influence the magnitude and rate of SA force generation. We found that Drosophila jump muscles show very low SA force and cannot produce positive power under oscillatory conditions at pCa 5.0. However, we transformed the jump muscle to be moderately stretch-activatable by replacing its myosin isoform with an embryonic isoform (EMB). Expressing EMB, jump muscle SA force increased by 163% and it generated net positive power. The rate of SA force development decreased by 58% with EMB expression. Power generation is Pi d

SUBMITTER: Zhao C 

PROVIDER: S-EPMC3686345 | biostudies-literature | 2013 Jun

REPOSITORIES: biostudies-literature