Ryanodine receptor Ca2+ channel

Chu, A., Fill, M., Stefani, E., and Entman, M. L. (1993). Cytoplasmic Ca2+ Does not Inhibit the Cardiac Muscle Sarcoplasmic Reticulum Ryanodine Receptor Ca2+ Channel, Although Ca(2+)-induced Ca2+ Inactivation of Ca2+ Release is Observed in Native Vesicles. J Membr Biol 135(1) 49—59. 

In skeletal muscle open voltage-gated L-type Ca2+ channels can interact directly with muscle ER (sarcoplasmic reticulum) ryanodine receptors to open the ryanodine receptor Ca2+ channel and thence elevate cytosolic Ca2+ concentration from sarcoplamic. reticulum Ca2+ stores. However in neurons and cardiac muscle activation of PM voltage-gated Ca2+ channels indirectly activates ryanodine receptor Ca2+ channels as outlined in the section on Ligand-gated Ca2+ channels . 

While skeletal muscle ryanodine receptors are involved in excitation — contraction coupling through direct interactions with voltage-gated Ca2+ channels, in other cell types ryanodine receptor Ca2+ channels located on the ER membrane are opened by cADPR in a Ca2+-CaM-dependent fashion. Ca2+ and plant metabolites such as the diterpenoid alkaloid ryanodine and the methylxanthine caffeine promote opening of the ryanodine receptor Ca2+ channel. Ryanodine can also negatively modulate the receptor (Table 4.4). 

Randriamampita C, Tsien RY 1993 Emptying of intracellular Ca2+ stores releases a novel small messenger that stimulates Ca2+ influx. Nature 364 809-814 Sutko JL, Airey JA 1996 Ryanodine receptor Ca2+ release channels does diversity in form equal diversity in function Physiol Rev 76 1027-1071... 

Kitazawa T, Kobayashi S, Horiuti K, Somlyo AV, Somlyo AP 1989 Receptor coupled, permeabilized smooth muscle role of the phosphatidylinositol cascade, G proteins and modulation of the contractile response to Ca2+. J Biol Chem 264 5339-5342 Lopez-Lopez JR, Shacklock PS, Balke CW, Wier WG 1995 Local calcium transients triggered by single L-type calcium channel currents in cardiac cells. Science 268 1042-1045 Marks AR, Fleischer S, Tempst P 1990 Surface topography analysis of the ryanodine receptor/ junctional channel complex based on proteolysis sensitivity mapping. J Biol Chem 265 13143-13149... 

Neylon CB, Richards SM, Larsen MA, Agrotis A, Bobik A 1995 Multiple types of ryanodine receptor/Ca2+ release channels are expressed in vascular smooth muscle. Biochem Biophys Res Commun 215 814—821... 

ZhuGe R, Fogarty KE, Tuft RA, Lifshitz LM, Sayar K, Walsh JV 2000 Dynamics of signaling between Ca2+ sparks and Ca2+-activated K+ channels studied with a novel image-based method for direct intracellular measurement of ryanodine receptor Ca2+ current. J Gen... 

Intracellular, ER-located, ligand-gated Ca2+ channels include the inositol-1,4,5-triphosphate (IP3) receptor, the ryanodine receptor (RyR), the NAADP receptor and the sphingolipid receptor [157-159]. The IP3 receptor Ca2+ channel is opened by IP3 generated as a result of G protein-(or RTK)-mediated PLC activation [159]. 

Meissner G (1994) Ryanodine receptor/Ca2+ release channels and their regulation by endogenous effectors. Annu Rev Physiol 56 485-508. 

Hidalgo, C. (2005). Cross Talk Between Ca2+ and Redox Signalling Cascades in Muscle and Neurons Through the Combined Activation of Ryanodine Receptors/Ca2+ Release Channels. Philos Trans R Soc Land B Biol Sci 360(1464) 2237 16. 

Anderson K, Lai F., Liu QY, Rousseau E, Erickson HP, Meissner G. 1989.. Structural and functional characterization of the purified cardiac ryanodine receptor-Ca2+ release channel complex. J Biol Chem 264 1329-35. 

Sorcin (soluble resistance-related calcium binding protein) was isolated from multidrug-resistant cells and is expressed in a few mammalian tissues such as skeletal muscle, heart, and brain. In the heart, sorcin interacts with the ryanodine receptor and L-type Ca2+-channels regulating excitation in contraction coupling. 

A regenerative process whereby an intracellular Ca2+ channel (IP3 receptor or Ryanodine receptor) is itself stimulated by Ca2+, allowing thereby Ca2+ to promote its own release from intracellular stores. 

Inwardly Rectifying K+ Channels ATP-dependent K+ Channels Voltage-dependent Ca2+ Channels Ryanodine Receptor Voltage-dependent Na2+ Channels... 

Voltage-dependent Ca2+ Channels Ca2+ Channel Blockers Ryanodine Receptor... 

Ryanodine receptor (RyR) is an intracellular Ca2+ release channel in the sarcoplasmic reticulum (SR) or the endoplasmic reticulum (ER). RyR binds ryanodine (a plant alkaloid, see Drugs) with a high affinity, after which it is named. 

S100A1 is the most abundant in the myocardium but is also expressed in brain and other tissues. S100A1 was found to stimulate Ca2+-induced Ca2+-release (CICR) in skeletal muscle terminal cisternae. In the presence of nanomolar Ca2+-concentrations, S100A1 binds to the ryanodine receptor increasing its channel open probability, and was shown to enhance SR Ca2+-release and contractile performance. Several animal models (over expressing S100A1 or S100A1-deficient mice) have... 

Sarcoplasmic reticulum (SR) is a form of the smoothfaced endoplasmic reticulum (ER) in muscles. It functions as an intracellular Ca2+ store for muscle contraction. Ca2+ is energetically sequestered into the SR by Ca2+-pump/sarcoplasmic endoplasmic reticulum Ca2+-ATPase (SERCA) and released via Ca2+ release channels on stimuli (ryanodine receptor in striated muscles and inositol 1,4,5-trisphosphate receptor in most smooth muscles). Endoplasmic reticulum in non-muscle tissues also functions as an intracellular Ca2+ store. 

Calcium couples muscle membrane excitation to filament contraction. Important work has focused on the proteins present in the T-tubule/SR junction. One protein, an integral component of the T-tubular membrane, is a form of L-type, dihydropyridine-sensitive, voltage-dependent calcium channel. Another, the ryanodine receptor (RyR), is a large protein associated with the SR membrane in the triad that may couple the conformational changes in the Ca2+ channel protein induced by T-tubular depolarization to the Ca2+ release from the SR (Fig. 43-6). 

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