Small heat shock proteins HSP27 (HspB1), αB-crystallin (HspB5) and HSP22 (HspB8) as regulators of cell death

Int J Biochem Cell Biol. 2012 Oct;44(10):1622-31. doi: 10.1016/j.biocel.2012.04.002. Epub 2012 Apr 13.


Hsp27, αB-crystallin and HSP22 are ubiquitous small heat shock proteins (sHsp) whose expression is induced in response to a wide variety of unfavorable physiological and environmental conditions. These sHsp protect cells from otherwise lethal conditions mainly by their involvement in cell death pathways such as necrosis, apoptosis or autophagy. At a molecular level, the mechanisms accounting for sHsp functions in cell death are (1) prevention of denatured proteins aggregation, (2) regulation of caspase activity, (3) regulation of the intracellular redox state, (4) function in actin polymerization and cytoskeleton integrity and (5) proteasome-mediated degradation of selected proteins. In cancer cells, these sHsp are often overexpressed and associated with increased tumorigenicity, cancer cells metastatic potential and resistance to chemotherapy. Altogether, these properties suggest that Hsp27, αB-crystallin and Hsp22 are appropriate targets for modulating cell death pathways. In the present, we briefly review recent reports showing molecular evidence of cell death regulation by these sHsp and co-chaperones. This article is part of a Directed Issue entitled: Small HSPs in physiology and pathology.

Publication types

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

MeSH terms

  • Animals
  • Apoptosis Regulatory Proteins / genetics
  • Apoptosis Regulatory Proteins / metabolism
  • Apoptosis Regulatory Proteins / physiology*
  • Cell Death*
  • Gene Expression
  • HSP27 Heat-Shock Proteins / genetics
  • HSP27 Heat-Shock Proteins / metabolism
  • HSP27 Heat-Shock Proteins / physiology*
  • Heat-Shock Proteins / genetics
  • Heat-Shock Proteins / metabolism
  • Heat-Shock Proteins / physiology*
  • Humans
  • Organ Specificity
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism
  • Protein-Serine-Threonine Kinases / physiology*
  • alpha-Crystallin B Chain / genetics
  • alpha-Crystallin B Chain / metabolism
  • alpha-Crystallin B Chain / physiology*


  • Apoptosis Regulatory Proteins
  • CRYAB protein, human
  • HSP27 Heat-Shock Proteins
  • HSPB1 protein, human
  • HSPB8 protein, human
  • Heat-Shock Proteins
  • alpha-Crystallin B Chain
  • Protein-Serine-Threonine Kinases