During low-flow ischemia and reperfusion, MyBP-C is dephosphorylated and degraded, which may initiate changes in myofibril thick filament structure and contribute to contractile dysfunction.
Dephosphorylation and degradation of MyBP-C during low-flow ischemia and reperfusion may contribute to myocardial stunning and contractile dysfunction.
BACKGROUND: Contractile dysfunction develops in the chronically instrumented canine myocardium after bouts of low-flow ischemia and persists after reperfusion. The objective of this study is to identify whether changes in the phosphorylation state of myosin-binding protein C (MyBP-C) are a potential cause of dysfunction. METHODS AND RESULTS: During low-flow ischemia, MyBP-C is dephosphorylated, and the number of actomyosin cross-bridges in the central core of the sarcomere decreases as thick filaments dissemble from the periphery of the myofibril. During reperfusion, MyBP-C remains dephosphorylated, and its degradation is accelerated. CONCLUSIONS: Dephosphorylation of MyBP-C may initiate changes in myofibril thick filament structure that decrease the interaction of myosin heads with actin thin filaments. Limiting the formation of actomyosin cross-bridges may contribute to the contractile dysfunction that is apparent after low-flow ischemia. Breakdown of MyBP-C during reperfusion may prolong myocardial stunning.
Decker et al. (Tue,) conducted a other in Low-flow ischemia and myocardial stunning. Low-flow ischemia and reperfusion was evaluated on Phosphorylation state of MyBP-C and myofibril structure. During low-flow ischemia and reperfusion, MyBP-C is dephosphorylated and degraded, which may initiate changes in myofibril thick filament structure and contribute to contractile dysfunction.
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