Forschung & Innovation
Publikationen
Ca2+ Signaling in Striated Muscle Cells During Intracellular Acidosis
PMU Autor*in
Boris Musset
Alle Autor*innen
Florentina Pluteanu, Boris Musset, Andreas Rinne
Fachzeitschrift
Biomolecules
Kurzfassung
The cytosolic pH (pH(i)) of mammalian cells is tightly maintained at values similar to 7.2. Cytoplasmic acidosis (pH(i) < 6.8) occurs when the intracellular proton concentration ([H+](i)) exceeds the buffering capacity of the cytosol and transport processes to extrude protons are exhausted. During intracellular acidosis, the contractility of cardiac and skeletal muscle cells is strongly reduced, often at sufficient Ca2+ levels. A contraction of striated muscle is achieved when the intracellular calcium (Ca2+) concentration rises above resting levels. The amplitude and kinetics of Ca2+ signals are controlled by Ca2+ handling proteins and force is generated if Ca2+ ions interact with contractile filaments of the sarcomere. Some aspects of this phenomenon, such as the biochemical origin of excessive protons in working muscle cells and molecular interactions of protons with Ca2+ handling proteins or contractile filaments, are not yet fully understood. This review summarizes our current understanding of how striated muscle cells handle Ca2+ and H+ and how a rise in [H+](i) may interfere with Ca2+ signaling in the working skeletal muscle (fatigue) or during ischemic events in cardiac muscle. Finally, we briefly address experimental strategies to measure Ca2+ signaling at different pH values with fluorescent probes and highlight their limitations.
Keywords
Calcium Signaling, ACIDOSIS, Cardiac muscle, Contractility, excitation-contraction coupling (ECC), Skeletal muscle