Phosphorylation site substrate specificity determinants for the Pim-1 protooncogene-encoded protein kinase

Biochem Cell Biol. 1997;75(2):153-62.

Abstract

Pim-1 is an oncogene-encoded serine-threonine kinase that is expressed primarily in cells of the hematopoietic system and germ line. The full-length coding regions of both human and Xenopus laevis Pim-1 were expressed as recombinant bacterial fusion proteins that autophosphorylated in vitro and exhibited phosphotransferase activity towards various exogenous substrates. The consensus sequence for phosphorylation by Pim-1 was defined by stepwise replacement of the amino acids in peptide substrate analogues based on the carboxyl-terminal segment of human ribosomal protein S6 (residues 229-249). The optimal substrate peptide for Pim-1 was determined to be Lys/Arg-Lys/Arg-Arg-Lys/Arg-Leu-Ser/Thr-X, where X is an amino acid residue with a small side chain. These results were confirmed using X. laevis Pim-1 expressed in COS cells. These findings could permit the identification of physiological substrates of Pim-1 and predict the location of phosphorylation sites within these proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Blotting, Western
  • COS Cells
  • Consensus Sequence
  • Humans
  • Phosphorylation
  • Protein Kinase Inhibitors
  • Protein-Serine-Threonine Kinases / biosynthesis
  • Protein-Serine-Threonine Kinases / genetics*
  • Proto-Oncogene Proteins / biosynthesis
  • Proto-Oncogene Proteins / genetics*
  • Proto-Oncogene Proteins c-pim-1
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Fusion Proteins / chemistry*
  • Substrate Specificity
  • Xenopus

Substances

  • Protein Kinase Inhibitors
  • Proto-Oncogene Proteins
  • Recombinant Fusion Proteins
  • PIM1 protein, human
  • Protein-Serine-Threonine Kinases
  • Proto-Oncogene Proteins c-pim-1