2k2f
Solution structure of Ca2+-S100A1-RyRP12
Structural highlights
FunctionRYR2_RAT Cytosolic calcium-activated calcium channel that mediates the release of Ca(2+) from the sarcoplasmic reticulum into the cytosol and thereby plays a key role in triggering cardiac muscle contraction. Aberrant channel activation can lead to cardiac arrhythmia. In cardiac myocytes, calcium release is triggered by increased Ca(2+) cytosolic levels due to activation of the L-type calcium channel CACNA1C. The calcium channel activity is modulated by formation of heterotetramers with RYR3. Required for cellular calcium ion homeostasis. Required for embryonic heart development.[UniProtKB:Q92736][1] [2] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedIn heart and skeletal muscle an S100 protein family member, S100A1, binds to the ryanodine receptor (RyR) and promotes Ca(2+) release. Using competition binding assays, we further characterized this system in skeletal muscle and showed that Ca(2+)-S100A1 competes with Ca(2+)-calmodulin (CaM) for the same binding site on RyR1. In addition, the NMR structure was determined for Ca(2+)-S100A1 bound to a peptide derived from this CaM/S100A1 binding domain, a region conserved in RyR1 and RyR2 and termed RyRP12 (residues 3616-3627 in human RyR1). Examination of the S100A1-RyRP12 complex revealed residues of the helical RyRP12 peptide (Lys-3616, Trp-3620, Lys-3622, Leu-3623, Leu-3624, and Lys-3626) that are involved in favorable hydrophobic and electrostatic interactions with Ca(2+)-S100A1. These same residues were shown previously to be important for RyR1 binding to Ca(2+)-CaM. A model for regulating muscle contraction is presented in which Ca(2+)-S100A1 and Ca(2+)-CaM compete directly for the same binding site on the ryanodine receptor. S100A1 and calmodulin compete for the same binding site on ryanodine receptor.,Wright NT, Prosser BL, Varney KM, Zimmer DB, Schneider MF, Weber DJ J Biol Chem. 2008 Sep 26;283(39):26676-83. Epub 2008 Jul 23. PMID:18650434[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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