title: Molecular architecture of Ca2+ signaling control in muscle and heart cells.
abstract: Ca2+ signaling in skeletal and cardiac muscles is a bi-directional process that involves cross-talk between signaling molecules in the sarcolemmal membrane and Ca2+ release machinery in the intracellular organelles. Maintenance of a junctional membrane structure between the sarcolemmal membrane and the sarcoplasmic reticulum (SR) provides a framework for the conversion of action potential arrived at the sarcolemma into release of Ca2+ from the SR, leading to activation of a variety of physiological processes. Activity-dependent changes in Ca2+ storage inside the SR provides a retrograde signal for the activation of store-operated Ca2+ channel (SOC) on the sarcolemmal membrane, which plays important roles in the maintenance of Ca2+ homeostasis in physiology and pathophysiology. Research progress during the last 30 years had advanced our understanding of the cellular and molecular mechanisms for the control of Ca2+ signaling in muscle and cardiovascular physiology. Here we summarize the functions of three key molecules that are located in the junctional membrane complex of skeletal and cardiac muscle cells: junctophilin as a "glue" that physiologically links the SR membrane to the sarcolemmal membrane for formation of the junctional membrane framework, mitsugumin29 as a muscle-specific synaptophysin family protein that contributes to maintain the coordinated Ca2+ signaling in skeletal muscle, and TRIC as a novel cation-selective channel located on the SR membrane that provides counter-ion current during the rapid process of Ca2+ release from the SR.
authors.affiliation: Department of Physiology and Biophysics, Robert Wood Johnson Medical School, Piscataway, NJ, USA.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Zhao
authors.forename: Daiju
authors.initials: D
authors.lastname: Yamazaki
authors.forename: Sho
authors.initials: S
authors.lastname: Kakizawa
authors.forename: Zui
authors.initials: Z
authors.lastname: Pan
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Takeshima
authors.forename: Jianjie
authors.initials: J
authors.lastname: Ma
mesh_terms: D000200:Action Potentials / Q000502:physiology; D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D020013:Calcium Signaling / Q000502:physiology*; D006801:Humans; D017136:Ion Transport / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000166:cytology / Q000378:metabolism*; D032383:Myocytes, Cardiac / Q000166:cytology / Q000378:metabolism*; D012508:Sarcolemma / Q000378:metabolism*; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*; D016708:Synaptophysin / Q000378:metabolism
chemical_list: D015220:Calcium Channels; D016708:Synaptophysin; D002118:Calcium