cd10230: HYOU1-like_NBD (this model, PSSM-Id:212672 is obsolete and has been replaced by 466828)
Nucleotide-binding domain of human HYOU1 and similar proteins
This subgroup includes human HYOU1 (also known as human hypoxia up-regulated 1, GRP170; HSP12A; ORP150; GRP-170; ORP-150; the human HYOU1 gene maps to11q23.1-q23.3) and Saccharomyces cerevisiae Lhs1p (also known as Cer1p, SsI1). Mammalian HYOU1 functions as a nucleotide exchange factor (NEF) for HSPA5 (alos known as BiP, Grp78 or HspA5) and may also function as a HSPA5-independent chaperone. S. cerevisiae Lhs1p, does not have a detectable endogenous ATPase activity like canonical HSP70s, but functions as a NEF for Kar2p; it's interaction with Kar2p is stimulated by nucleotide-binding. In addition, Lhs1p has a nucleotide-independent holdase activity that prevents heat-induced aggregation of proteins in vitro. This subgroup belongs to the 105/110 kDa heat shock protein (HSP105/110) subfamily of the HSP70-like family. HSP105/110s are believed to function generally as co-chaperones of HSP70 chaperones, acting as NEFs, to remove ADP from their HSP70 chaperone partners during the ATP hydrolysis cycle. HSP70 chaperones assist in protein folding and assembly, and can direct incompetent "client" proteins towards degradation. Like HSP70 chaperones, HSP105/110s have an N-terminal nucleotide-binding domain (NBD) and a C-terminal substrate-binding domain (SBD). For HSP70 chaperones, the nucleotide sits in a deep cleft formed between the two lobes of the NBD. The two subdomains of each lobe change conformation between ATP-bound, ADP-bound, and nucleotide-free states. ATP binding opens up the substrate-binding site; substrate-binding increases the rate of ATP hydrolysis. Hsp70 chaperone activity is also regulated by J-domain proteins.
Jiyao W et al.(2023). "The conserved domain database in 2023.",