Interaction of a Sarcolipin Pentamer and Monomer with the Sarcoplasmic Reticulum Calcium Pump, SERCA

Abstract

The sequential rise and fall of cytosolic calcium underlies the contraction-relaxation cycle of muscle cells. While contraction is initiated by the release of calcium from the sarcoplasmic reticulum, muscle relaxation involves the active transport of calcium back into the sarcoplasmic reticulum. This re-uptake of calcium is catalysed by the sarco-endoplasmic reticulum Ca2+-ATPase (SERCA), which plays a lead role in muscle contractility. SERCA activity is regulated by small membrane protein subunits, most well-known being phospholamban (PLN) and sarcolipin (SLN).