Toward a Molecular Understanding of the Structure–Function of Ryanodine Receptor Ca<SUP>2+</SUP> Release Channels: Perspectives From Recombinant Expression Systems

Cardiff University, Cardiff, Wales, United Kingdom
Cell Biochemistry and Biophysics (Impact Factor: 1.68). 02/2005; 42(2):197-222. DOI: 10.1385/CBB:42:2:197
Source: PubMed


Identification of the genetic basis of human diseases linked to dysfunctional free calcium (Ca2+) signaling has triggered an explosion of interest in the functional characterization of the molecular components regulating intracellular Ca2+ homeostasis. There is a growing appreciation of the central role of intracellular ryanodine-sensitive Ca2+ release channel (RyR) regulation in skeletal and cardiac muscle pathologies, including malignant hyperthermia, heart failure, and sudden cardiac death. The use of cloned RyR isoforms and recombinant expression techniques has greatly facilitated the elucidation of the molecular basis of RyR Ca2+ release functionality. This review will focus on the recombinant techniques used in the functional characterization of recombinant RyR isoforms and the insights that these approaches have yielded in unraveling the mechanistic basis of RyR channel functionality.

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    • "Ryanodine receptors (RyRs) are homotetrameric intracellular calcium release channels in the membranes of the endoplasmic (ER) and sarcoplasmic reticulum (SR) (George et al. 2005, Meissner 2002, 2004). Each subunit consists of ~5000 amino acid residues (George et al. 2005). There are three isoforms of the ryanodine receptor: the RyR1 isoform is expressed predominantly in skeletal muscle, the RyR2 isoform predominates in cardiac muscle, and the RyR3 isoform is expressed in a variety of tissues (Sorrentino 1995). "

    Full-text · Chapter · Nov 2011
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    • "We hope that these may form the focus of another review chapter in the near future. The reader is referred to a number of recent reviews for further information into voltage-gated (Jones, 1998, 2003; Catterall, 2000; Sather and McCleskey, 2003) calcium release (Sutko and Airey, 1996; George et al., 2005; Wehrens et al., 2005) and store-operated channels (Parekh and Putney, 2005). "
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    ABSTRACT: Ion channels underlie the electrical activity of cells. Calcium channels have a unique functional role, because not only do they participate in this activity, they form the means bywhich electrical signals are converted to responses within the cell. Calcium concentrations in the cytoplasm of cells are maintained at a low level, and calcium channels activate quickly such that the opening of ion channels can rapidly change the cytoplasmic environment. Once inside the cell, calcium acts as a “second messenger” prompting responses by binding to a variety of calcium sensitive proteins. Calcium channels are known to play an important role in stimulating muscle contraction, in neurotransmitter secretion, gene regulation, activating other ion channels, controlling the shape and duration of action potentials and many other processes. Since calcium plays an integral role in cell function, and since excessive quantities can be toxic, its movement is tightly regulated and controlled through a large variety of mechanisms.
    Full-text · Chapter · Dec 2006
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    • "Recently, presynaptic ryanodine-sensitive Ca 2+ stores have been implicated in spontaneous, as well as depolarisationinduced , exocytosis in the central and peripheral nervous system. The ryanodine receptor Ca 2+ -release channel (RyR) is a large-conductance, cation-selective channel expressed in both excitable and non-excitable cells (Fill and Copello, 2002; Williams et al., 2001; George et al., 2005). Three mammalian RyR isoforms encoded by distinct genes have been purified, and their amino acid sequence deduced by cDNA cloning indicates ~70% identity. "
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    ABSTRACT: The ryanodine receptor (RyR) is a widely expressed intracellular calcium (Ca(2+))-release channel regulating processes such as muscle contraction and neurotransmission. Snapin, a ubiquitously expressed SNARE-associated protein, has been implicated in neurotransmission. Here, we report the identification of snapin as a novel RyR2-interacting protein. Snapin binds to a 170-residue predicted ryanodine receptor cytosolic loop (RyR2 residues 4596-4765), containing a hydrophobic segment required for snapin interaction. Ryanodine receptor binding of snapin is not isoform specific and is conserved in homologous RyR1 and RyR3 fragments. Consistent with peptide fragment studies, snapin interacts with the native ryanodine receptor from skeletal muscle, heart and brain. The snapin-RyR1 association appears to sensitise the channel to Ca(2+) activation in [(3)H]ryanodine-binding studies. Deletion analysis indicates that the ryanodine receptor interacts with the snapin C-terminus, the same region as the SNAP25-binding site. Competition experiments with native ryanodine receptor and SNAP25 suggest that these two proteins share an overlapping binding site on snapin. Thus, regulation of the association between ryanodine receptor and snapin might constitute part of the elusive molecular mechanism by which ryanodine-sensitive Ca(2+) stores modulate neurosecretion.
    Full-text · Article · Jul 2006 · Journal of Cell Science
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