Negative regulation of cell growth and differentiation by TSG101 through association with p21(Cip1/WAF1)

Proc Natl Acad Sci U S A. 2002 Apr 16;99(8):5430-5. doi: 10.1073/pnas.082123999. Epub 2002 Apr 9.

Abstract

TSG101 was discovered in a screen for tumor susceptibility genes and has since been shown to have a multiplicity of biological effects. However, the basis for TSG101's ability to regulate cell growth has not been elucidated. We report here that the TSG101 protein binds to the cyclin/cyclin-dependent kinase (CDK) inhibitor (CKI) p21(Cip1/WAF1) and increases stability of the p21 protein in HEK293F cells and differentiating primary keratinocytes, suppressing differentiation in a p21-dependent manner. In proliferating keratinocytes where the p21 protein is relatively stable, TSG101 does not affect the stability or expression of p21 but shows p21-dependent recruitment to cyclin/CDK complexes, inhibits cyclin/CDK activity, and causes strong growth suppression to a much greater extent in p21+/+ than in p21-/- cells. Conversely, suppression of endogenous TSG101 expression by an antisense TSG101 cDNA causes doubling of the fraction of keratinocytes in the S phase of the cell cycle as occurs during p21 deficiency. Our results indicate that TSG101 has a direct role in the control of growth and differentiation in primary epithelial cells, and that p21 is an important mediator of these TSG101 functions.

Publication types

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

MeSH terms

  • Animals
  • CDC2-CDC28 Kinases*
  • Cell Differentiation
  • Cell Division
  • Cell Line
  • Cyclin-Dependent Kinase 2
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclin-Dependent Kinases / metabolism
  • Cyclins / chemistry
  • Cyclins / physiology*
  • DNA, Complementary / metabolism
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / physiology*
  • Down-Regulation
  • Endosomal Sorting Complexes Required for Transport
  • Green Fluorescent Proteins
  • Humans
  • Keratinocytes / metabolism
  • Luminescent Proteins / metabolism
  • Mice
  • Oligonucleotides, Antisense / chemistry
  • Phosphorylation
  • Precipitin Tests
  • Protein Binding
  • Protein Serine-Threonine Kinases / metabolism
  • Recombinant Fusion Proteins / metabolism
  • Retinoblastoma Protein / metabolism
  • S Phase
  • Time Factors
  • Transcription Factors / chemistry
  • Transcription Factors / physiology*
  • Transfection
  • Two-Hybrid System Techniques

Substances

  • CDKN1A protein, human
  • Cdkn1a protein, mouse
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins
  • DNA, Complementary
  • DNA-Binding Proteins
  • Endosomal Sorting Complexes Required for Transport
  • Luminescent Proteins
  • Oligonucleotides, Antisense
  • Recombinant Fusion Proteins
  • Retinoblastoma Protein
  • Transcription Factors
  • Tsg101 protein
  • Green Fluorescent Proteins
  • Protein Serine-Threonine Kinases
  • CDC2-CDC28 Kinases
  • CDK2 protein, human
  • Cdk2 protein, mouse
  • Cyclin-Dependent Kinase 2
  • Cyclin-Dependent Kinases