The growth factor-inducible immediate-early gene 3CH134 encodes a protein-tyrosine-phosphatase

Proc Natl Acad Sci U S A. 1993 Jun 1;90(11):5292-6. doi: 10.1073/pnas.90.11.5292.

Abstract

Stimulation of fibroblasts with serum growth factors results in the rapid activation of a set of immediate-early genes, among them 3CH134. We have purified a bacterially expressed form of the 3CH134-encoded polypeptide and demonstrated that it has intrinsic protein-tyrosine-phosphatase (PTPase; protein-tyrosine-phosphate phosphohydrolase, EC 3.1.3.48) activity in vitro. This activity is optimal at pH 7.5, is sensitive to vanadate and cysteinyl modifying agents, and is insensitive to a panel of serine/threonine phosphatase inhibitors. Purified 3CH134 protein displays a high degree of selectivity among the tyrosine-phosphorylated polypeptide substrates tested. Under our assay conditions, the rates of dephosphorylation are in the order EDNDYINASL peptide < myelin basic protein < reduced, carboxyamidomethylated, and maleylated lysozyme (RCML) < p42mapk. There is a 200-fold range in rates for these substrates, with p42mapk dephosphorylated 15-fold more rapidly than RCML. Although 3CH134 is most closely related to the tyrosine/serine dual-specificity phosphatase VH1, we failed to detect any 3CH134-directed activity on casein or RCML phosphorylated on serine/threonine residues by cAMP-dependent protein kinase. Since 3CH134 expression is controlled transcriptionally and posttranscriptionally, it may represent a class of PTPases whose activity is regulated at the level of protein synthesis and degradation.

Publication types

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

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Calcium-Calmodulin-Dependent Protein Kinases
  • Cell Cycle Proteins*
  • Cell Line
  • Chromatography, Affinity
  • Chromatography, Ion Exchange
  • Dual Specificity Phosphatase 1
  • Electrophoresis, Polyacrylamide Gel
  • Enzyme Induction
  • Gene Expression Regulation, Enzymologic / drug effects
  • Growth Substances / pharmacology*
  • Humans
  • Immediate-Early Proteins*
  • Kinetics
  • Mice
  • Molecular Sequence Data
  • Molecular Weight
  • Moths
  • Phosphoprotein Phosphatases*
  • Protein Kinases / metabolism
  • Protein Phosphatase 1
  • Protein Tyrosine Phosphatases / genetics*
  • Protein Tyrosine Phosphatases / isolation & purification
  • Protein Tyrosine Phosphatases / metabolism
  • Protein-Tyrosine Kinases / genetics
  • Proteins / genetics*
  • Proteins / isolation & purification
  • Proteins / metabolism*
  • Receptor, Insulin
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Sequence Homology, Amino Acid
  • Substrate Specificity
  • Transcription, Genetic
  • Transfection

Substances

  • Cell Cycle Proteins
  • Growth Substances
  • Immediate-Early Proteins
  • Proteins
  • Recombinant Proteins
  • Protein Kinases
  • Protein-Tyrosine Kinases
  • Receptor, Insulin
  • Calcium-Calmodulin-Dependent Protein Kinases
  • Phosphoprotein Phosphatases
  • Protein Phosphatase 1
  • DUSP1 protein, human
  • Dual Specificity Phosphatase 1
  • Dusp1 protein, mouse
  • Protein Tyrosine Phosphatases