An alteration of the human c-abl protein in K562 leukemia cells unmasks associated tyrosine kinase activity

Cell. 1984 Jul;37(3):1035-42. doi: 10.1016/0092-8674(84)90438-0.


The v-abl protein is known to be a tyrosine-specific protein kinase. However, its normal cellular homolog, c-abl P150, is not detectably phosphorylated on tyrosine in vivo or in vitro. The lack of associated tyrosine kinase activity for the c-abl protein seems paradoxical since it is the c-abl-derived sequences of the v-abl protein that encode the kinase activity. We have detected an altered human c-abl protein (P210) with associated tyrosine kinase activity in the K562 leukemia cell line. K562 cells are known to have a 9:22 chromosomal translocation involving the c-abl locus and have amplified the c-able gene 4 to 8 fold. The altered P210 human c-abl is serologically and structurally related to the normal c-abl protein. A structural alteration of the human c-abl protein. K562 cells may have unmasked its associated tyrosine kinase activity. This altered c-abl protein may have important implications for a mechanism of activation of this oncogene.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Cell Transformation, Viral*
  • DNA, Neoplasm / genetics
  • Gene Expression Regulation
  • Humans
  • Leukemia, Experimental / enzymology
  • Leukemia, Experimental / genetics*
  • Neoplasm Proteins / genetics
  • Oncogenes*
  • Peptide Fragments / analysis
  • Phosphoproteins / physiology
  • Phosphotyrosine
  • Protein Kinases / genetics*
  • Protein-Tyrosine Kinases
  • Tyrosine / analogs & derivatives
  • Tyrosine / metabolism


  • DNA, Neoplasm
  • Neoplasm Proteins
  • Peptide Fragments
  • Phosphoproteins
  • Phosphotyrosine
  • Tyrosine
  • Protein Kinases
  • Protein-Tyrosine Kinases