Hsp40

These proteins ( J protein) and NEF cochaperones regulate the Hsp70 reaction cycle. The Hsp40 proteins constitute a large family with more than 40 members in humans. All of them contain a J domain, which binds to the N-terminal ATPase domain of Hsp70 and the adjacent linker region. Canonical Hsp40s (members of classes I and II) function as chaperones independently and recruit Hsp70 to nonnative substrate proteins. Other Hsp40s (class III) are more diverse and combine the J domain with a variety of functional modules. The interaction with Hsp70 strongly stimulates the hydrolysis of Hsp70-bound ATP to ADP, resulting in stable substrate binding by Hsp70 in the closed conformation ^[1] to the rescue.

References

1. ↑ Kim YE, Hipp MS, Bracher A, Hayer-Hartl M, Hartl FU. Molecular chaperone functions in protein folding and proteostasis. Annu Rev Biochem. 2013;82:323-55. doi: 10.1146/annurev-biochem-060208-092442. PMID:23746257 doi:http://dx.doi.org/10.1146/annurev-biochem-060208-092442