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Heat shock 10kDa protein 1
Symbols HSPE1 ; CPN10; EPF; GROES; HSP10
External IDs OMIM600141 MGI104680 HomoloGene20500 GeneCards: HSPE1 Gene
RNA expression pattern
PBB GE HSPE1 205133 s at tn.png
More reference expression data
Species Human Mouse
Entrez 3336 15528
Ensembl ENSG00000115541 ENSMUSG00000073676
UniProt P61604 Q64433
RefSeq (mRNA) NM_002157 NM_008303
RefSeq (protein) NP_002148 NP_032329
Location (UCSC) Chr 2:
198.36 – 198.37 Mb
Chr 1:
55.09 – 55.09 Mb
PubMed search [1] [2]
PDB 1g31 EBI.jpg
gp31 co-chaperonin from bacteriophage t4
Symbol Cpn10
Pfam PF00166
Pfam clan CL0296
InterPro IPR020818
SCOP 1lep

Heat shock 10 kDa protein 1 (Hsp10) also known as chaperonin 10 (cpn10) or early-pregnancy factor (EPF) is a protein that in humans is encoded by the HSPE1 gene. The homolog in E. coli is GroES that is a chaperonin which usually works in conjunction with GroEL.[1]

Structure and function[edit]

GroES exists as a ring-shaped oligomer of between six to eight identical subunits, while the 60 kDa chaperonin (cpn60 - or groEL in bacteria) forms a structure comprising 2 stacked rings, each ring containing 7 identical subunits.[2] These ring structures assemble by self-stimulation in the presence of Mg2+-ATP. The central cavity of the cylindrical cpn60 tetradecamer provides an isolated environment for protein folding whilst cpn-10 binds to cpn-60 and synchronizes the release of the folded protein in an Mg2+-ATP dependent manner.[3] The binding of cpn10 to cpn60 inhibits the weak ATPase activity of cpn60.

Escherichia coli GroES has also been shown to bind ATP cooperatively, and with an affinity comparable to that of GroEL.[4] Each GroEL subunit contains three structurally distinct domains: an apical, an intermediate and an equatorial domain. The apical domain contains the binding sites for both GroES and the unfolded protein substrate. The equatorial domain contains the ATP-binding site and most of the oligomeric contacts. The intermediate domain links the apical and equatorial domains and transfers allosteric information between them. The GroEL oligomer is a tetradecamer, cylindrically shaped, that is organised in two heptameric rings stacked back to back. Each GroEL ring contains a central cavity, known as the `Anfinsen cage', that provides an isolated environment for protein folding. The identical 10 kDa subunits of GroES form a dome-like heptameric oligomer in solution. ATP binding to GroES may be important in charging the seven subunits of the interacting GroEL ring with ATP, to facilitate cooperative ATP binding and hydrolysis for substrate protein release.


GroES has been shown to interact with GroEL.[5][6]


  1. ^ "Entrez Gene: HSPE1 heat shock 10kDa protein 1 (chaperonin 10)". 
  2. ^ Hemmingsen SM, Woolford C, van der Vies SM, Tilly K, Dennis DT, Georgopoulos CP et al. (May 1988). "Homologous plant and bacterial proteins chaperone oligomeric protein assembly". Nature 333 (6171): 330–4. doi:10.1038/333330a0. PMID 2897629. 
  3. ^ Schmidt A, Schiesswohl M, Völker U, Hecker M, Schumann W (June 1992). "Cloning, sequencing, mapping, and transcriptional analysis of the groESL operon from Bacillus subtilis". J. Bacteriol. 174 (12): 3993–9. PMC 206108. PMID 1350777. 
  4. ^ Martin J, Geromanos S, Tempst P, Hartl FU (November 1993). "Identification of nucleotide-binding regions in the chaperonin proteins GroEL and GroES". Nature 366 (6452): 279–82. doi:10.1038/366279a0. PMID 7901771. 
  5. ^ Samali A, Cai J, Zhivotovsky B, Jones DP, Orrenius S (April 1999). "Presence of a pre-apoptotic complex of pro-caspase-3, Hsp60 and Hsp10 in the mitochondrial fraction of jurkat cells". EMBO J. 18 (8): 2040–8. doi:10.1093/emboj/18.8.2040. PMC 1171288. PMID 10205158. 
  6. ^ Lee KH, Kim HS, Jeong HS, Lee YS (October 2002). "Chaperonin GroESL mediates the protein folding of human liver mitochondrial aldehyde dehydrogenase in Escherichia coli". Biochem. Biophys. Res. Commun. 298 (2): 216–24. doi:10.1016/S0006-291X(02)02423-3. PMID 12387818. 

Further reading[edit]

External links[edit]

This article incorporates text from the public domain Pfam and InterPro IPR020818