The problem of protein kinase activity of small heat shock protein Hsp22 (H11 or HspB8)

Department of Biochemistry, Lomonosov Moscow State University, Moskva, Moscow, Russia
Biochemical and Biophysical Research Communications (Impact Factor: 2.3). 12/2004; 325(3):649-52. DOI: 10.1016/j.bbrc.2004.10.074
Source: PubMed


The recently described protein denoted H11, Hsp22 or HspB8 seems to participate in regulation of proliferation, apoptosis, and cardiac hypertrophy. Mutation of Hsp22 causes distal motor neuropathy. Multitude action of Hsp22 is supposed to be due to its protein kinase and/or chaperone-like activities. There are many indirect evidences indicating that Hsp22 possesses intrinsic protein kinase activity. However, low homology to protein kinases, low extent of autophosphorylation, lack of significant protein kinase activity with commonly used substrates, and lack of information on stoichiometry, kinetics, and substrate specificity make the existence of intrinsic protein kinase activity of Hsp22 questionable. It is supposed that protein kinase activity ascribed to Hsp22 is due to contaminating protein kinases. Hsp22 is highly homologous to small heat shock proteins and effectively prevents aggregation of denatured protein both in vitro and in vivo. Therefore, it is supposed that chaperone-like activity is of great importance for Hsp22 functioning.

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    • "autophosphorylation assays, raising the possibility for contaminations by associated protein kinases (Depre et al. 2002; Kim et al. 2004a, b). In contrast, there are many strong data in support of the chaperone-like activity of HspB8. "

    The Big Book on Small Heat Shock Proteins, Springer edited by Robert M. Tanguay • Lawrence E. Hightower, 01/2015: chapter 18: pages 435-456; Springer International Publishing AG Switzerland., ISBN: ISBN 978-3-319-16077-1 (eBook)
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