title: The sarcoplasmic reticulum: an organized patchwork of specialized domains.
abstract: The sarcoplasmic reticulum (SR) of skeletal muscle cells is a convoluted structure composed of a variety of tubules and cisternae, which share a continuous lumen delimited by a single continuous membrane, branching to form a network that surrounds each myofibril. In this network, some specific domains basically represented by the longitudinal SR and the junctional SR can be distinguished. These domains are mainly dedicated to Ca(2+) homeostasis in relation to regulation of muscle contraction, with the longitudinal SR representing the sites of Ca(2+) uptake and storage and the junctional SR representing the sites of Ca(2+) release. To perform its functions, the SR takes contact with other cellular elements, the sarcolemma, the contractile apparatus and the mitochondria, giving rise to a number of interactions, most of which are still to be defined at the molecular level. This review will describe some of the most recent advancements in understanding the organization of this complex network and its specific domains. Furthermore, we shall address initial evidence on how SR proteins are retained at distinct SR domains.
authors.affiliation: Molecular Medicine Section, Department of Neuroscience and Interuniversitary Institute of Myology, University of Siena, 53100 Siena, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Rossi
authors.forename: Virginia
authors.initials: V
authors.lastname: Barone
authors.forename: Emiliana
authors.initials: E
authors.lastname: Giacomello
authors.forename: Vincenza
authors.initials: V
authors.lastname: Cusimano
authors.forename: Vincenzo
authors.initials: V
authors.lastname: Sorrentino
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D006706:Homeostasis; D006801:Humans; D008928:Mitochondria / Q000378:metabolism; D008954:Models, Biological; D009119:Muscle Contraction; D009132:Muscles / Q000378:metabolism; D009210:Myofibrils / Q000378:metabolism; D015388:Organelles / Q000378:metabolism; D017434:Protein Structure, Tertiary; D012519:Sarcoplasmic Reticulum / Q000378:metabolism*
chemical_list: D002118:Calcium