We have produced and characterized monoclonal antibodies that label antigenic determinants distributed among three distinct, nonoverlapping peptide domains of the 200-kD heavy chain of avian smooth muscle myosin. Mice were immunized with a partially phosphorylated chymotryptic digest of adult turkey gizzard myosin. Hybridoma antibody specificities were determined by solid-phase indirect radioimmunoassay and immunoreplica techniques. Electron microscopy of rotary-shadowed samples was used to directly visualize the topography of individual [antibody.antigen] complexes. Antibody TGM-1 bound to a 50-kD peptide of subfragment-1 (S-1) previously found to be associated with actin binding and was localized by immunoelectron microscopy to the distal aspect of the myosin head. However, there was no antibody-dependent inhibition of the actin-activated heavy meromyosin ATPase, nor was antibody TGM-1 binding to actin-S-1 complexes inhibited. Antibody TGM-2 detected an epitope of the subfragment-2 (S-2) domain of heavy meromyosin but not the S-2 domain of intact myosin or rod, consistent with recognition of a site exposed by chymotryptic cleavage of the S-2:light meromyosin junction. Localization of TGM-2 to the carboxy-terminus of S-2 was substantiated by immunoelectron microscopy. Antibody TGM-3 recognized an epitope found in the light meromyosin portion of myosin. All three antibodies were specific for avian smooth muscle myosin. Of particular interest is that antibody TGM-1, unlike TGM-3, bound poorly to homogenates of 19-d embryonic smooth muscles. This indicates the expression of different myosin heavy chain epitopes during smooth muscle development.
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1 July 1985
Article|
July 01 1985
Localization and topography of antigenic domains within the heavy chain of smooth muscle myosin.
M D Schneider
J R Sellers
M Vahey
Y A Preston
R S Adelstein
Online ISSN: 1540-8140
Print ISSN: 0021-9525
J Cell Biol (1985) 101 (1): 66–72.
Citation
M D Schneider, J R Sellers, M Vahey, Y A Preston, R S Adelstein; Localization and topography of antigenic domains within the heavy chain of smooth muscle myosin.. J Cell Biol 1 July 1985; 101 (1): 66–72. doi: https://doi.org/10.1083/jcb.101.1.66
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