AF157: Heat shock protein Hsp20

List allergens from this family:

Routes of exposure:
Include only IUIS approved allergens.

Biochemical properties

Members of this family act as chaperones that can protect other proteins against heat-induced denaturation and aggregation [1]. Hsp20 proteins seem to form large hetero-oligomeric aggregates. HSP20 proteins are evolutionarily related to α-crystallin, an abundant constituent of the eye lens of most vertebrate species [2].

Allergens from this family

Cas s 9 from chestnut is a Hsp20 that was found to bind IgE from nearly half of the tested chestnut-allergic patients.



  1. Bakthisaran R, Tangirala R, Rao Ch M:
    Small heat shock proteins: Role in cellular functions and pathology.
    Biochim Biophys Acta 2015, 1854, 291-319. [PubMed] [Full Text]
  2. Groenen PJ, Merck KB, de Jong WW, Bloemendal H:
    Structure and modifications of the junior chaperone alpha-crystallin. From lens transparency to molecular pathology.
    Eur J Biochem 1994, 225, 1-19. [PubMed]


Links to Pfam

Family-defining Pfam domains (at least one of these domains is present in each family member):

Pfam domain Pfam clan
PF00011 Hsp20/alpha crystallin family CL0190 HSP20-like chaperone superfamily

Links to Wikipedia


If you have updates or corrections for this entry, please contact the site administrator: .