TABLE 1.

Eukaryotic and prokaryotic molecular chaperone and stress protein families

Family	Alternative name(s)		Function
	Prokaryotes	Eukaryotes
Chaperonins	GroEL, GroES	Hsp60, TriC, CCT	Folding of proteins within cage structure
Thioredoxin	Trx, DsbA to DsbE, glutaredoxin	Trx, glutaredoxin, protein disulfide isomerase	Protein thiol-disulfide exchange
Small Hsps	IbpA, IbpB	Hsp25/27, α-crystallins	Adsorption of unfolded chains to prevent stress aggregation
Peptidyl-prolyl isomerases	Cyclophilins, FKBPs, parvulins	Cyclophilins, FKBPs, parvulins	Isomerization of peptide bond preceding proline
GrpE	GrpE	GrpE	ADP/ATP exchange factor interacting with DnaK/DnaJ
Hsp40/DnaJ	DnaJ, CbpA, RcsG	Hsp40, Hdj2, Mtj1	Hsp70 cochaperones regulating Hsp70 activity
Hsp70	DnaK, Hsc66, BiP, mitochondrial Hsp70, etc.	Many (e.g., Hsp70, Hsc70)	Prevention of aggregation of unfolded protein chains
Hsp90	HtpG	Hsp90, Gp96	Regulation of assembly of signal transduction proteins
Hsp100	ClpA, ClpB, ClpC, ClpX, ClpY	Hsp100	Disassembly of oligomers and aggregates
Prefoldin nascent chain-associated complex	Prefoldin	Nascent chain-associated complex	Binding to nascent chains as they emerge from ribosomes