Isoform switching from SM-B to SM-A myosin results in decreased contractility and altered expression of thin filament regulatory proteins

Gopal J. Babu, Gail J. Pyne, Yingbi Zhou, Chris Okwuchukuasanya, Joseph E. Brayden, George Osol, Richard J. Paul, Robert B. Low, Muthu Periasamy

Research output: Contribution to journalArticle

28 Scopus citations

Abstract

We previously generated an isoform-specific gene knockout mouse in which SM-B myosin is permanently replaced by SM-A myosin. In this study, we examined the effects of SM-B myosin loss on the contractile properties of vascular smooth muscle, specifically peripheral mesenteric vessels and aorta. The absence of SM-B myosin leads to decreased velocity of shortening and increased isometric force generation in mesenteric vessels. Surprisingly, the same changes occur in aorta, which contains little or no SM-B myosin in wild-type animals. Calponin and activated mitogen-activated protein kinase expression is increased and caldesmon expression is decreased in aorta, as well as in bladder. Light chain-17b isoform (LC17b) expression is increased in aorta. These results suggest that the presence or absence of SM-B myosin is a critical determinant of smooth muscle contraction and that its loss leads to additional changes in thin filament regulatory proteins.

Original languageEnglish (US)
Pages (from-to)C723-C729
JournalAmerican Journal of Physiology - Cell Physiology
Volume287
Issue number3 56-3
DOIs
Publication statusPublished - Sep 1 2004
Externally publishedYes

    Fingerprint

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cell Biology

Keywords

  • Aorta
  • Caldesmon
  • Calponin
  • Mesenteric vessels

Cite this