[HSP7C_BOVIN] Acts as a repressor of transcriptional activation. Inhibits the transcriptional coactivator activity of CITED1 on Smad-mediated transcription. Chaperone. Component of the PRP19-CDC5L complex that forms an integral part of the spliceosome and is required for activating pre-mRNA splicing. May have a scaffolding role in the spliceosome assembly as it contacts all other components of the core complex (By similarity). [AUXI_BOVIN] Recruits HSPA8/HSC70 to clathrin-coated vesicles and promotes uncoating of clathrin-coated vesicles.
The many protein processing reactions of the ATP-hydrolyzing Hsp70s are regulated by J cochaperones, which contain J domains that stimulate Hsp70 ATPase activity and accessory domains that present protein substrates to Hsp70s. We report the structure of a J domain complexed with a J responsive portion of a mammalian Hsp70. The J domain activates ATPase activity by directing the linker that connects the Hsp70 nucleotide binding domain (NBD) and substrate binding domain (SBD) toward a hydrophobic patch on the NBD surface. Binding of the J domain to Hsp70 displaces the SBD from the NBD, which may allow the SBD flexibility to capture diverse substrates. Unlike prokaryotic Hsp70, the SBD and NBD of the mammalian chaperone interact in the ADP state. Thus, although both nucleotides and J cochaperones modulate Hsp70 NBD:linker and NBD:SBD interactions, the intrinsic persistence of those interactions differs in different Hsp70s and this may optimize their activities for different cellular roles.
Structural basis of J cochaperone binding and regulation of Hsp70.,Jiang J, Maes EG, Taylor AB, Wang L, Hinck AP, Lafer EM, Sousa R Mol Cell. 2007 Nov 9;28(3):422-33. PMID:17996706
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
↑ Fotin A, Cheng Y, Grigorieff N, Walz T, Harrison SC, Kirchhausen T. Structure of an auxilin-bound clathrin coat and its implications for the mechanism of uncoating. Nature. 2004 Dec 2;432(7017):649-53. Epub 2004 Oct 24. PMID:15502813 doi:10.1038/nature03078