Hsp72 chaperone function is dispensable for protection against stress-induced apoptosis

Cell Stress Chaperones. 2009 May;14(3):253-63. doi: 10.1007/s12192-008-0079-4. Epub 2008 Sep 26.

Abstract

In addition to its role as a molecular chaperone, heat shock protein 72 (Hsp72) protects cells against a wide range of apoptosis inducing stresses. However, it is unclear if these two roles are functionally related or whether Hsp72 inhibits apoptosis by a mechanism independent of chaperone activity. The N-terminal adenosine triphosphatase domain, substrate-binding domain and the C-terminal EEVD regulatory motif of Hsp72 are all essential for chaperone activity. In this study, we show that Hsp72 mutants with a functional substrate-binding domain but lacking chaperone activity retain their ability to protect cells against apoptosis induced by heat and tumor necrosis factor alpha. In contrast, a deletion mutant lacking a functional substrate-binding domain has no protective capacity. The ability of the Hsp72 substrate-binding domain to inhibit apoptosis independent of the regulatory effects of the adenosine triphosphate-binding domain indicates that the inhibition of apoptosis may involve a stable binding interaction with a regulatory substrate rather than Hsp72 chaperone activity.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Animals
  • Apoptosis / physiology*
  • Cell Line
  • HSP72 Heat-Shock Proteins / genetics
  • HSP72 Heat-Shock Proteins / metabolism*
  • Humans
  • Mice
  • Mutation
  • Stress, Physiological / physiology*

Substances

  • HSP72 Heat-Shock Proteins