The vertebrate muscle Z-disc: sarcomere anchor for structure and signalling.
The Z-disc, appearing as a fine dense line forming sarcomere boundaries in striated muscles, when studied in detail reveals crosslinked filament arrays that transmit tension and house myriads of proteins with diverse functions. At the Z-disc the barbed ends of the antiparallel actin filaments from adjoining sarcomeres interdigitate and are crosslinked primarily by layers of alpha-actinin. The Z-disc is therefore the site of polarity reversal of the actin filaments, as needed to interact with the bipolar myosin filaments in successive sarcomeres. The layers of alpha-actinin determine the Z-disc width: fast fibres have narrow (approximately 30-50 nm) Z-discs and slow and cardiac fibres have wide (approximately 100 nm) Z-discs. Comprehensive reviews on the roles of the numerous proteins located at the Z-disc in signalling and disease have been published; the aim here is different, namely to review the advances in structural aspects of the Z-disc.
Luther
Pradeep K
PK
Molecular Medicine Section, National Heart and Lung Institute, Imperial College London, London, UK. p.luther@imperial.ac.uk
D008841:Actin Cytoskeleton / Q000502:physiology / Q000648:ultrastructure; D000185:Actinin / Q000502:physiology / Q000648:ultrastructure; D000818:Animals; D021961:Cell Membrane Structures / Q000502:physiology / Q000648:ultrastructure; D006801:Humans; D009119:Muscle Contraction / Q000502:physiology; D018485:Muscle Fibers, Skeletal / Q000502:physiology* / Q000648:ultrastructure; D009124:Muscle Proteins / Q000378:metabolism; D018482:Muscle, Skeletal / Q000502:physiology* / Q000648:ultrastructure*; D012518:Sarcomeres / Q000502:physiology* / Q000648:ultrastructure; D015398:Signal Transduction / Q000502:physiology
D009124:Muscle Proteins; D000185:Actinin