THE J-DOMAIN FAMILY AND THE RECRUITMENT OF CHAPERONE POWER

The defining feature of the Hsp40 chaperone family is a similar to 70- amino-acid-residue signature, termed the J domain, that is necessary f or orchestrating interactions with its Hsp70 chaperone partner(s), J-d omain proteins play important regulatory roles as co-chaperones, recru iting Hsp70 partners and accelerating the ATP-hydrolysis step of the c haperone cycle, Certain proteins could have acquired a J domain in ord er to present a specific substrate(s) to an Hsp70 partner and thus cap italize upon chaperone activities when carrying out cellular functions , J-domain proteins participate in complex biological processes, such as cell-cycle control by DNA tumor viruses, regulation of protein kina ses and exocytosis.