Open AccessDefined sequence segments of the small heat shock proteins HSP25 and αB‐crystallin inhibit actin polymerization
Author(s) -
Wieske Martin,
Benndorf Rainer,
Behlke Joachim,
Dölling Rudolf,
Grelle Gerlinde,
Bielka Heinz,
Lutsch Gudrun
Publication year - 2001
Publication title -
european journal of biochemistry
Language(s) - English
Resource type - Journals
eISSN - 1432-1033
pISSN - 0014-2956
DOI - 10.1046/j.1432-1327.2001.02082.x
Subject(s) - actin , polymerization , sequence (biology) , heat shock protein , actina , crystallin , shock (circulatory) , chemistry , microfilament , microbiology and biotechnology , biophysics , cytoskeleton , biology , biochemistry , polymer , medicine , cell , gene , organic chemistry
The interaction of small heat shock proteins (sHSPs) with the actin cytoskeleton has been described and some members of this family, e.g. chicken and murine HSP25 (HSP27), inhibit the polymerization of actin in vitro . To analyse the molecular basis of this interaction, we synthesized a set of overlapping peptides covering the complete sequence of murine HSP25 and tested the effect of these peptides on actin polymerization in vitro by fluorescence spectroscopy and electron microscopy. Two peptides comprising the sequences W43 to R57 (peptide 6) and I92 to N106 (peptide 11) of HSP25 were found to be potent inhibitors of actin polymerization. Phosphorylation of N‐terminally extended peptide 11 at serine residues known to be phosphorylated in vivo resulted in decline of their inhibitory activity. Interestingly, peptides derived from the homologous peptide 11 sequence of murine αB‐crystallin showed the same behaviour. The results suggest that both HSP25 and αB‐crystallin have the potential to inhibit actin polymerization and that this activity is regulated by phosphorylation.