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Harvey murine sarcoma virus p21 ras protein: biological and biochemical significance of the cysteine nearest the carboxy terminus.
Author(s) -
Willumsen B.M.,
Norris K.,
Papageorge A.G.,
Hubbert N.L.,
Lowy D.R.
Publication year - 1984
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1984.tb02177.x
Subject(s) - biology , cysteine , virology , n terminus , virus , c terminus , microbiology and biotechnology , peptide sequence , biochemistry , amino acid , enzyme , gene
Previous studies of premature chain termination mutants and in frame deletion mutants of the p21 ras transforming protein encoded by the transforming gene of Harvey murine sarcoma virus (Ha‐MuSV) have suggested that the C terminus is required for cellular transformation, lipid binding, and membrane localization. We have now further characterized the post‐translational processing of these mutants and have also studied two C‐terminal v‐rasH point mutants: one encodes serine in place of cysteine‐186, the other threonine for valine‐187. The Thr‐187 mutant was transformation‐competent, and its p21 protein was processed normally, as was the p21 encoded by a transformation‐competent deletion mutant from which amino acids 166‐175 had been deleted. The Ser‐186 mutant was defective for transformation. The p21s encoded by the Ser‐186 mutant and by the previously described transformation‐defective mutants did not undergo the posttranslational processing common to biologically active ras proteins: their electrophoretic migration rate did not change, they remained in the cytosol, and they failed to bind lipid. Since the cell‐encoded ras proteins also contain this cysteine, we conclude that this amino acid residue is required for all ras proteins.