A variant of XXXX nonmuscle tropomyosin found in fibroblasts by using two-dimensional electrophoresis.

@entity1 @entity462 @entity1133 @entity3208 @entity535 @entity2340 @entity1521 @entity214
In an analysis of 12 @entity1 fibroblast cell lines by two-dimensional electrophoresis, one cell line (1493) was found to contain a major protein variant (Cytosk: 12; for the convention used in spot numbering, see Anderson, N. L. (1981) Proc. Natl. Acad. Sci. U. S. A. 78, 2407-2411) not present in any of the other 11 cell lines. Biochemical characterization of the variant protein included determination of its subcellular location, partial @entity535 composition, behavior on @entity3208 ( @entity214 ) versus @entity214 / @entity1133 gels, and partial proteolytic digestion patterns. All of these methods showed that Cytosk:12 is related to Cytosk:11. Both proteins are located in the cytoskeleton, contain little @entity462 or @entity1521 and no detectable @entity2340 , shift together to a higher apparent molecular weight when electrophoresed in the presence of @entity214 and 8 M @entity1133 versus @entity214 alone, and have identical products after partial proteolysis according to Cleveland et al. (Cleveland, D. W., Fischer, S. G., Kirschner, M. W., and Laemmli, U. K. (1977) J. Biol. Chem. 252, 1102-1106). Preparation of nonmuscle tropomyosin resulted in the partial purification of both Cytosk:11 and :12. The data suggest that Cytosk:11 is fibroblast nonmuscle tropomyosin and that Cytosk:12 in cell line 1493 is a charge variant of that protein.
