Possible modifications of vimentin following acquisition of triton insolubility

Radiolabeled vimentin after a one-hour pulse of cultured human skin fibroblasts can be detected in both soluble and insoluble fractions. The proteolytic products of newly synthesized vimentin in the insoluble fraction differ markedly in their molecular weights and isoelectric points from those of total insoluble vimentin. The newly synthesized insoluble vimentin instead displays a degradation pattern similar to that of soluble vimentin. Our results suggest that molecular modifications of vimentin occur after its acquisition of insolubility which change the pattern of vimentin proteolysis.