Canine and feline cardiac Z-lines and Z-rods were examined by electron microscopy before and after digestion of muscle fibers with Ca2+-activated protease (CAF). Removal by CAF of electron-dense material which covers Z-lines and Z-rods exposed interdigitating longitudinal filaments (6-7 nm in diameter) apparently continuous with thin filaments of the respective I-bands. The newly exposed longitudinal filaments of CAF-treated Z-lines and of CAF-treated Z-rods bound heavy meromyosin and therefore are actin. The width of Z-lines and length of Z-rods are determined by the amount of overlap of actin filaments of opposite polarity. The oblique filaments in Z-lines and Z-rods are responsible for the perpendicular periodicity of Z-lines and Z-rods, and are attributed to alpha-actinin.
Article| February 01 1983
Evidence for actin involvement in cardiac Z-lines and Z-line analogues.
R M Robson
M H Stromer
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1983) 96 (2): 435–442.
M Yamaguchi, R M Robson, M H Stromer; Evidence for actin involvement in cardiac Z-lines and Z-line analogues.. J Cell Biol 1 February 1983; 96 (2): 435–442. doi: https://doi.org/10.1083/jcb.96.2.435
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