PROSITE documentation PDOC00791
Small heat shock protein (sHSP) domain profile


Prokaryotic and eukaryotic organisms respond to heat shock or other environmental stress by inducing the synthesis of proteins collectively known as heat-shock proteins (HSP) [1]. According to their molecular weight, HSPs are classified into several families such as HSP100, HSP90, HSP70, HSP60, and small HSPs (sHSPs) with molecular size ranging from 15 to 30 kDas [2,3,4,5,7,8]. These seem to act as chaperones that can protect other proteins against heat-induced denaturation and aggregation. sHSP proteins seem to form large heterooligomeric aggregates; their family is currently composed of the following members:

  • Vertebrate heat shock protein HSP27 (HSP25), induced by a variety of environmental stresses.
  • Drosophila heat shock proteins HSP22, HSP23, HSP26, HSP27, HSP67BA and BC.
  • Caenorhabditis elegans HSP16 multigene family.
  • Fungal HSP26 (budding yeast) and HSP30 (Neurospora crassa and Aspergillus Nidulans).
  • Plant small HSP's. Plants have four classes of HSP20: classes I and II which are cytoplasmic, class III which is chloroplastic and class IV which is found in the endomembrane.
  • α-crystallin A and B chains. α-crystallin is an abundant constituent of the eye lens of most vertebrate species. Its main function appears to be to maintain the correct refractive index of the lens. It is also found in other tissues where it seems to act as a chaperone [6].
  • Schistosoma mansoni major egg antigen p40. Structurally, p40 is built of two tandem sHSP domains.
  • A variety of prokaryotic proteins: ibpA and ibpB from Escherichia coli, hsp18 from Clostridium acetobutylicum, spore protein SP21 (HSPA) from Stigmatella aurantiaca, Mycobacterium leprae 18 Kd antigen and Mycobacterium tuberculosis 14 Kd antigen.
  • Methanococcus jannaschii hypothetical protein MJ0285.

The sHSP family possess a conserved domain of approximately 80 to 100 amino acids. The sHSP domain forms a sandwich of two β-pleated sheets (see <PDB:2WJ5>) [6,7,8].

The profile we developed covers the entire sHSP domain.

Last update:

March 2017 / Text and profile revised.


Technical section

PROSITE method (with tools and information) covered by this documentation:

SHSP, PS01031; Small heat shock protein (sHSP) domain profile  (MATRIX)


1AuthorsLindquist S. Craig E.A.
TitleThe heat-shock proteins.
SourceAnnu. Rev. Genet. 22:631-677(1988).
PubMed ID2853609

2Authorsde Jong W.W. Leunissen J.A.M. Voorter C.E.M.
SourceMol. Biol. Evol. 10:103-126(1993).

3AuthorsCaspers G.J. Leunissen J.A.M. de Jong W.W.
TitleThe expanding small heat-shock protein family, and structure predictions of the conserved 'alpha-crystallin domain'.
SourceJ. Mol. Evol. 40:238-248(1995).
PubMed ID7723051

4AuthorsJaenicke R. Creighton T.E.
TitleJunior chaperones.
SourceCurr. Biol. 3:234-235(1993).
PubMed ID15335775

5AuthorsJakob U. Buchner J.
TitleAssisting spontaneity: the role of Hsp90 and small Hsps as molecular chaperones.
SourceTrends Biochem. Sci. 19:205-211(1994).
PubMed ID7914036

6AuthorsGroenen P.J.T.A. Merck K.B. de Jong W.W. Bloemendal H.
TitleStructure and modifications of the junior chaperone alpha-crystallin. From lens transparency to molecular pathology.
SourceEur. J. Biochem. 225:1-19(1994).
PubMed ID7925426

7AuthorsBagneris C. Bateman O.A. Naylor C.E. Cronin N. Boelens W.C. Keep N.H. Slingsby C.
TitleCrystal structures of alpha-crystallin domain dimers of alphaB-crystallin and Hsp20.
SourceJ. Mol. Biol. 392:1242-1252(2009).
PubMed ID19646995

8AuthorsPandey B. Kaur A. Gupta O.P. Sharma I. Sharma P.
TitleIdentification of HSP20 gene family in wheat and barley and their differential expression profiling under heat stress.
SourceAppl. Biochem. Biotechnol. 175:2427-2446(2015).
PubMed ID25503087

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