T-tubules: a key structure of cardiac function and dysfunction.
The sarcolemmal membrane of mammalian ventricular cardiomyocytes are characterised by the presence of invaginations called transverse tubules (T-tubules) which constitute a network, the transverse tubule system. T-tubules occur at the Z line as transverse elements with also longitudinal extensions. While the existence of T-tubules has been known since a long time, recent studies have suggested their structure and function can be more complex than previously believed. Many of the proteins involved in excitation-contraction coupling process are concentrated within the T-tubular network, suggesting T-tubules are a highly specialized membrane system. Thus, T-tubules are a key determinant of cardiac cell function. The fundamental role of T-tubules is emphasized by changes in their structure and protein expression occurring during pathologies such as cardiac hypertrophy and heart failure. This review summarizes recent studies which highlight the key-role of the T-tubules in the regulation of cardiac function. Changes observed in pathological conditions are also discussed.
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EA3212 Laboratoire de physiologie cellulaire, Université de Caen, 14032 Caen, France.
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D020013:Calcium Signaling / Q000502:physiology; D021961:Cell Membrane Structures / Q000502:physiology / Q000648:ultrastructure; D006321:Heart / Q000502:physiology*; D006331:Heart Diseases / Q000503:physiopathology*; D006801:Humans; D032383:Myocytes, Cardiac / Q000502:physiology / Q000648:ultrastructure*; D012508:Sarcolemma / Q000502:physiology / Q000648:ultrastructure; D012519:Sarcoplasmic Reticulum / Q000502:physiology / Q000648:ultrastructure