Recombinant Human E3 ubiquitin-protein ligase CHIP (STUB1)

Uniprot Id

Q9UNE7

Target Species

Human

Target Name

STUB1

Target Full Name

E3 ubiquitin-protein ligase CHIP

Target Function

E3 ubiquitin-protein ligase which targets misfolded chaperone substrates towards proteasomal degradation. Collaborates with ATXN3 in the degradation of misfolded chaperone substrates: ATXN3 restricting the length of ubiquitin chain attached to STUB1/CHIP substrates and preventing further chain extension. Ubiquitinates NOS1 in concert with Hsp70 and Hsp40. Modulates the activity of several chaperone complexes, including Hsp70, Hsc70 and Hsp90. Mediates transfer of non-canonical short ubiquitin chains to HSPA8 that have no effect on HSPA8 degradation. Mediates polyubiquitination of DNA polymerase beta (POLB) at 'Lys-41', 'Lys-61' and 'Lys-81', thereby playing a role in base-excision repair: catalyzes polyubiquitination by amplifying the HUWE1/ARF-BP1-dependent monoubiquitination and leading to POLB-degradation by the proteasome. Mediates polyubiquitination of CYP3A4. Ubiquitinates EPHA2 and may regulate the receptor stability and activity through proteasomal degradation. Acts as a co-chaperone for HSPA1A and HSPA1B chaperone proteins and promotes ubiquitin-mediated protein degradation. Negatively regulates the suppressive function of regulatory T-cells (Treg) during inflammation by mediating the ubiquitination and degradation of FOXP3 in a HSPA1A/B-dependent manner. Likely mediates polyubiquitination and downregulates plasma membrane expression of PD-L1/CD274, an immune inhibitory ligand critical for immune tolerance to self and antitumor immunity. Negatively regulates TGF-beta signaling by modulating the basal level of SMAD3 via ubiquitin-mediated degradation. May regulate myosin assembly in striated muscles together with UBE4B and VCP/p97 by targeting myosin chaperone UNC45B for proteasomal degradation. Mediates ubiquitination of RIPK3 leading to its subsequent proteasome-dependent degradation.

Target Involvement

Spinocerebellar ataxia, autosomal recessive, 16 (SCAR16)

Target Subcellular Location

Cytoplasm. Nucleus.

Target Tissue Specificity

Expressed in differentiated myotubes (at protein level). Highly expressed in skeletal muscle, heart, pancreas, brain and placenta. Detected in kidney, liver and lung.

Target Synonyms

Antigen NY CO 7; Antigen NY-CO-7; C terminus of Hsp70-interacting protein; Carboxy terminus of Hsp70 interacting protein; Carboxy terminus of Hsp70-interacting protein; Carboxy terminus of Hsp70p interacting protein; CHIP; CHIP_HUMAN; CLL associated antigen KW 8; CLL-associated antigen KW-8; E3 ubiquitin protein ligase CHIP; E3 ubiquitin-protein ligase CHIP; Heat shock protein A binding protein 2 (c terminal); HSPABP2; NY CO 7; PP1131; SDCCAG7; Serologically defined colon cancer antigen 7; STIP1 homology and U Box containing protein 1; STIP1 homology and U box containing protein 1 E3 ubiquitin protein ligase; STIP1 homology and U box-containing protein 1; STUB 1; STUB1; UBOX 1; UBOX1

Target Background

This gene encodes a protein containing tetratricopeptide repeat and a U-box that functions as a ubiquitin ligase/cochaperone. The encoded protein binds to and ubiquitinates shock cognate 71 kDa protein (Hspa8) and DNA polymerase beta (Polb), among other targets. Mutations in this gene cause spinocerebellar ataxia, autosomal recessive 16. Alternative splicing results in multiple transcript variants. There is a pseudogene for this gene on chromosome 2.