Functional groups of ryanodine receptors in rat ventricular cells

摘要: Ryanodine receptors (RyR2s) are ion channels in the sarcoplasmic reticulum (SR) that responsible for Ca2+ release rat ventricular myocytes. Localization of RyR2s is therefore crucial our understanding contraction and other Ca2+-dependent intracellular processes. Recent results (e.g. circular waves sparks perinuclear area) raised questions about classical views RyR2 distribution organization within cells. A spark a fluorescent signal reflecting activation small group RyR2s. Frequency spatio-temporal characteristics depend on state cytoplasmic intraluminal macromolecular complexes regulating cardiac function. We employed electron microscopy, confocal imaging spontaneous immunofluorescence to visualize myocytes evaluate local involvement regulation functional activity group. An microscopy study revealed axial tubules transverse–axial tubular system probably do not have junctions with network SR (nSR). The nSR was found be wrapped around intermyofibrillar mitochondria contained structures similar feet junctional cleft. Treatment antibodies against showed addition SR, number can localized at middle sarcomere zone mitochondria. Recordings existence groups these compartments. 20% were colocalized or corbular (Z-line zone). Z-line A-band zones very similar, whereas from 25% longer. Analysis initiation sites same cluster suggested 18–25 producing spark. Because similarity sarcomeric ultrastructural nSR, we suggest ∼20 regulatory proteins. Our data allowed us conclude significant located These could contribute excitation–contraction coupling, mitochondrial nuclear signalling, gene regulation, but their raises many additional questions.