Biological and biochemical properties of human rasH genes mutated at codon 61

Channing J. Der, Toren Finkel, Geoffrey M. Cooper

Research output: Contribution to journalArticlepeer-review

389 Scopus citations


Using site-directed mutagenesis, we have introduced mutations encoding 17 different amino acids at codon 61 of the human rasH gene. Fifteen of these substitutions increased rasH transforming activity. The remaining two mutants, encoding proline and glutamic acid, displayed transforming activities similar to the normal gene. Overall, these mutants vary over 1000-fold in transforming potency. Increased levels of p21 expression were required for transformation by weakly transforming mutants. The mutant proteins were unaltered in guanine nucleotide binding properties. However, all 17 different mutant proteins displayed equivalently reduced rates of GTP hydrolysis, 8- to 10-fold lower than the normal protein. There was no quantitative correlation between reduction in GTPase activity and transformation, indicating that reduced GTP hydrolysis is not sufficient to activate ras transforming potential.

Original languageEnglish (US)
Pages (from-to)167-176
Number of pages10
Issue number1
StatePublished - Jan 17 1986
Externally publishedYes

ASJC Scopus subject areas

  • Cell Biology
  • Molecular Biology
  • Medicine(all)


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