Table 2.
Classification of heat shock proteins based on their molecular weight.
| Name | Size (kDa) | Bacterial Homolog |
Location | Functions |
|---|---|---|---|---|
| HSP 100 | 104/110 | Clp | Cytosol, nucleus | Mitigate severe stress |
| HSP 90 | 90 | HtpG | Cytosol, nucleus | Part of the steroid hormone receptor complex; stabilize substrate proteins; and inhibit protein aggregation |
| HSP 70 | 72 | Dna K | Cytosol, nucleus | Highly stress inducible |
| HSC 70 | 73 | Dna K | cytosol | Constitutively expressed |
| HSP 60 | 60 | GroEL | Mitochondria, chloroplast, and nucleus | Assists protein folding |
| HSP 40 | 47 | Dna J | Endoplasmic reticulum | Co-chaperone of Dna K; protein folding and refolding |
| Small HSPs | 20–34 | IbpA/B | Cytosol, nucleus | Prevent aggregation of proteins |
| HSP10 | 10 | GroES | mitochondria, chloroplast | Assist as a co-chaperone |
| Ubiquitin | 8 | Cytosol, nucleus | Involved in non-lysosomal protein degradation |