Open AccessBiochemical characterization of polypeptides encoded by mutated human Ha-ras1 genes.
Author(s) -
Wendy W. Colby,
Joel S. Hayflick,
Scott G. Clark,
Arthur D. Levinson
Publication year - 1986
Publication title -
molecular and cellular biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.14
H-Index - 327
eISSN - 1067-8824
pISSN - 0270-7306
DOI - 10.1128/mcb.6.2.730
Subject(s) - gtpase , biology , gtp' , biochemistry , guanine , gene , transferase , residue (chemistry) , guanine nucleotide exchange factor , nucleotide , enzyme
We expressed six forms of p21-ras polypeptides in Escherichia coli with differing transformation potentials resulting from amino acid substitutions at position 12. The ability of the encoded p21's to autophosphorylate, bind guanine nucleotides, and hydrolyze GTP was assessed. All versions of p21 bound GTP equivalently; the kinase activity, while dependent upon residue 12, did not correlate with the transforming potential of the polypeptide. All transforming versions exhibited an impaired GTPase activity, while a novel nontransforming derivative [p21(pro-12)] possessed an enhanced GTPase activity. These results provide strong support for the proposal that an impairment of the cellular p21 GTPase activity can unmask its transforming potential.