Endogenous cardiac troponin T modulates Ca(2+)-mediated smooth muscle contraction.

ABSTRACT: Mechanisms linked to actin filaments have long been thought to cooperate in smooth muscle contraction, although key molecules were unclear. We show evidence that cardiac troponin T (cTnT) substantially contributes to Ca(2+)-mediated contraction in a physiological range of cytosolic Ca(2+) concentration ([Ca(2+)](i)). cTnT was detected in various smooth muscles of the aorta, trachea, gut and urinary bladder, including in humans. Also, cTnT was distributed along with tropomyosin in smooth muscle cells, suggesting that these proteins are ready to cause smooth muscle contraction. In chemically permeabilised smooth muscle of cTnT(+/-) mice in which cTnT reduced to ~50%, the Ca(2+)-force relationship was shifted toward greater [Ca(2+)](i), indicating a sizeable contribution of cTnT to smooth mus

SUBMITTER: Kajioka S 

PROVIDER: S-EPMC3522072 | biostudies-literature | 2012

REPOSITORIES: biostudies-literature