Nonmuscle Myosin II Localizes to the Z-Lines and Intercalated Discs of Cardiac Muscle and to the Z-Lines of Skeletal Muscle
Document Type
Article
Publication Date
1-1-2000
Description
To understand the role of nonmuscle myosin II in cardiac and skeletal muscle, we used a number of polyclonal antibodies, three detecting nonmuscle myosin heavy chain II-B (NMHC II-B) and two detecting NMHC II-A, to examine the localization of these two proteins in fresh-frozen, acetone-fixed sections of normal human and mouse hearts and human skeletal muscles. Results were similar in both species and were confirmed by examination of fresh- frozen sections of human hearts subjected to no fixation or to treatment with either 4% p-formaldehyde or 50% glycerol. NMHC II-B was diffusely distributed in the cytoplasm of cardiac myocytes during development, but after birth it was localized to the Z-lines and intercalated discs. Dual labeling showed almost complete colocalization of NMHC II-B with α-actinin. Whereas endothelial cells, smooth muscle cells and fibroblasts showed strong immunoreactivity for NMHC II-A and NMHC II-B, cardiac myocytes only showed reactivity for the latter. The Z-lines of human skeletal muscle cells, in contrast to those of cardiac myocytes, gave positive reactions for both NMHC II-A and NMHC II-B. The presence of a motor protein in the Z-lines and intercalated discs raises the possibility that these structures may play a more dynamic role in the contraction/relaxation mechanism of cardiac and skeletal muscle than has been previously suspected.
Citation Information
Takeda, Kazuyo; Yu, Zu Xi; Qian, Sujuan; Chin, Thomas K.; Adelstein, Robert S.; and Ferrans, Victor J.. 2000. Nonmuscle Myosin II Localizes to the Z-Lines and Intercalated Discs of Cardiac Muscle and to the Z-Lines of Skeletal Muscle. Cell Motility and the Cytoskeleton. Vol.46(1). 59-68. https://doi.org/10.1002/(SICI)1097-0169(200005)46:1<59::AID-CM6>3.0.CO;2-Q PMID: 10842333 ISSN: 0886-1544