• Register
X
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

X

Leaving Community

Are you sure you want to leave this community? Leaving the community will revoke any permissions you have been granted in this community.

No
Yes

Interaction of heat-shock protein 90 beta isoform (HSP90 beta) with cellular inhibitor of apoptosis 1 (c-IAP1) is required for cell differentiation.

Members of the inhibitor of apoptosis protein (IAP) family have demonstrated functions in cell death, cell signalling, cell migration and mitosis. Several of them are E3 enzymes in the ubiquitination of proteins that leads to their degradation by the proteosomal machinery. We previously reported that one of them, cellular inhibitor of apoptosis protein-1 (c-IAP1), migrated from the nucleus to the surface of the Golgi apparatus in cells undergoing differentiation. Here, we show that c-IAP1 is a client protein of the stress protein HSP90 beta. In three distinct cellular models, the two proteins interact and migrate from the nucleus to the cytoplasm along the differentiation process through a leptomycin B-sensitive pathway. Inhibition of HSP90 proteins by small chemical molecules and specific depletion of HSP90 beta isoform by siRNA both lead to auto-ubiquitination of c-IAP1 and its degradation by the proteasome machinery. This chaperone function of HSP90 towards c-IAP1 is specific of its beta isoform as specific depletion of HSP90alpha does not affect c-IAP1 content. Chemical inhibition of HSP90 or siRNA-mediated depletion of HSP90 beta both inhibit cell differentiation, which can be reproduced by siRNA-mediated depletion of c-IAP1. Altogether, these results suggest that HSP90 beta prevents auto-ubiquitination and degradation of its client protein c-IAP1, whose depletion would be sufficient to inhibit cell differentiation.

Pubmed ID: 18239673

Authors

  • Didelot C
  • Lanneau D
  • Brunet M
  • Bouchot A
  • Cartier J
  • Jacquel A
  • Ducoroy P
  • Cathelin S
  • Decologne N
  • Chiosis G
  • Dubrez-Daloz L
  • Solary E
  • Garrido C

Journal

Cell death and differentiation

Publication Data

May 14, 2008

Associated Grants

None

Mesh Terms

  • Animals
  • Cell Differentiation
  • Cell Line, Tumor
  • Cell Nucleus
  • Epithelial Cells
  • HSP90 Heat-Shock Proteins
  • Humans
  • Inhibitor of Apoptosis Proteins
  • Macrophages
  • Protein Isoforms
  • RNA, Small Interfering