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We have developed a procedure to isolate, from skeletal muscle, enriched terminal cisternae of sarcoplasmic reticulum (SR), which retain morphologically intact junctional "feet" structures similar to those observed in situ. The fraction is largely devoid of transverse tubule, plasma membrane, mitochondria, triads (transverse tubules junctionally associated(More)
The recent success of pancreatic islet transplantation has generated considerable enthusiasm. To better understand the quality and characteristics of human islets used for transplantation, we performed detailed analysis of islet architecture and composition using confocal laser scanning microscopy. Human islets from six separate isolations provided by three(More)
We have recently described a preparation of junctional terminal cisternae (JTC) from fast skeletal muscle of rabbit hind leg. The fraction differs from other heavy sarcoplasmic reticulum (SR) fractions in that it contains a substantial amount of junctional face membrane (JFM) (15-20% of the membrane) with morphologically well-defined junctional feet(More)
The action of ruthenium red (RR) on Ca2+ loading by and Ca2+ release from the sarcoplasmic reticulum (SR) of chemically skinned skeletal muscle fibers of the rabbit was investigated. Ca2+ loading, in the presence of the precipitating anion pyrophosphate, was monitored by a light-scattering method. Ca2+ release was indirectly measured by following tension(More)
Sarcoplasmic reticulum (SR) serves a central role in calcium uptake and release, thereby regulating muscle relaxation and contraction, respectively. Recently, we have isolated fractions referable to longitudinal tubules (R2) and terminal cisternae (R4), the two major types of sarcoplasmic reticulum (A. Saito et al. (1984) J. Cell Biol. 99, 875-885). The(More)
Junctional terminal cisternae are a recently isolated sarcoplasmic reticulum fraction containing two types of membranes, the junctional face membrane with morphologically intact "feet" structures and the calcium pump membrane [Saito, A., Seiler, S., Chu, A., & Fleischer, S. (1984) J. Cell Biol. 99, 875-885]. In this study, the Ca2+ fluxes of junctional(More)
The junctional face membrane plays a key role in excitation-contraction coupling in skeletal muscle. A protein of 350 kDa, tentatively identified as a component of the junctional feet, connects transverse tubules to terminal cisternae of sarcoplasmic reticulum [Kawamoto, Brunschwig, Kim & Caswell (1986) J. Cell Biol. 103, 1405-1414]. The membrane topology(More)