title: Junctional sarcoplasmic reticulum transmembrane proteins in the heart.
abstract: The uptake of calcium into the sarcoplasmic reticulum (SR) and its subsequent release from the SR play a key role in the regulation of the cytosolic calcium concentration and the excitation-contraction coupling in cardiac muscle. While calcium uptake, catalyzed by the calcium-dependent ATPase, is thought to occur throughout the SR, the release of calcium is controlled by a complex of proteins localized to a distinct region, the junctional SR. This complex consists of the calcium release channel or ryanodine receptor (RyR), the high capacity calcium-binding protein calsequestrin located in the lumen of the junctional SR, and the junctional SR transmembrane proteins triadin 1 and junctin which are hypothesized to anchor calsequestrin to the RyR. Transgenic mice with cardiac-specific overexpression of triadin 1 or junctin show distinct cardiac phenotypes with altered cellular and subcellular morphology, changes in contractile properties and/or in the expression of junctional SR proteins suggesting that these junctional sarcoplasmic reticulum transmembrane proteins are of functional relevance for the regulation of calcium release in the heart.
authors.affiliation: Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Domagkstr. 12, 48149 Münster, Germany.
authors.forename: Frank U
authors.initials: FU
authors.lastname: Müller
authors.forename: Uwe
authors.initials: U
authors.lastname: Kirchhefer
authors.forename: Frank
authors.initials: F
authors.lastname: Begrow
authors.forename: Uta
authors.initials: U
authors.lastname: Reinke
authors.forename: Joachim
authors.initials: J
authors.lastname: Neumann
authors.forename: Wilhelm
authors.initials: W
authors.lastname: Schmitz
mesh_terms: D000818:Animals; D002135:Calcium-Binding Proteins; D002352:Carrier Proteins / Q000378:metabolism*; D008565:Membrane Proteins; D006899:Mixed Function Oxygenases; D009124:Muscle Proteins / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
chemical_list: D002135:Calcium-Binding Proteins; D002352:Carrier Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; C498269:TRDN protein, human; C070048:triadin; D006899:Mixed Function Oxygenases