Protein: E3 ubiquitin-protein ligase CHIP (EC 2.3.2.27) (Carboxy terminus of Hsp70-interacting protein) (RING-type E3 ubiquitin transferase CHIP) (STIP1 homology and U box-containing protein 1) (Q9WUD1)
Organism: Mus musculus (Mouse)
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 (By similarity). Modulates the activity of several chaperone complexes, including Hsp70, Hsc70 and Hsp90 (By similarity). Mediates transfer of non-canonical short ubiquitin chains to HSPA8 that have no effect on HSPA8 degradation (By similarity). 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 (By similarity). Mediates polyubiquitination of CYP3A4 (By similarity). Ubiquitinates EPHA2 and may regulate the receptor stability and activity through proteasomal degradation (By similarity). 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. Catalyzes monoubiquitination of SIRT6, preventing its degradation by the proteasome. Likely mediates polyubiquitination and down-regulates plasma membrane expression of PD-L1/CD274, an immune inhibitory ligand critical for immune tolerance to self and antitumor immunity (By similarity). Negatively regulates TGF-beta signaling by modulating the basal level of SMAD3 via ubiquitin-mediated degradation (By similarity). May regulate myosin assembly in striated muscles together with UBE4B and VCP/p97 by targeting myosin chaperone UNC45B for proteasomal degradation (By similarity). Mediates ubiquitination of RIPK3 leading to its subsequent proteasome-dependent degradation (By similarity).
Subcellular location: Cytoplasm {ECO:0000269|PubMed:11435423}. Nucleus {ECO:0000250|UniProtKB:Q9UNE7}. Mitochondrion {ECO:0000250|UniProtKB:A6HD62}. Note=Translocates to the nucleus in response to inflammatory signals in regulatory T-cells (Treg). Localizes to mitochondria following oxygen and glucose deprivation-induced cellular stress (By similarity). {ECO:0000250|UniProtKB:A6HD62, ECO:0000250|UniProtKB:Q9UNE7}.
Interaction partners:
- Heat shock protein HSP 90-beta
- Heat shock cognate 71 kDa protein
- Heat shock protein HSP 90-alpha
- Heat shock 70 kDa protein 1B
- BAG family molecular chaperone regulator 3
- Ubiquitin-conjugating enzyme E2 D1
- Ubiquitin-conjugating enzyme E2 N
- BAG family molecular chaperone regulator 2
- Heat shock protein beta-8
- Heat shock 70 kDa protein 4
Sequence:
MKGKEEKEGGARLGTGGGGSPDKSPSAQELKEQGNRLFVGRKYPEAAACYGRAITRNPLVAVYYTNRALCYLKMQQPEQALADCRRALELDGQSVKAHFFLGQCQLEMESYDEAIANLQRAYSLAKEQRLNFGDDIPSALRIAKKKRWNSIEERRIHQESELHSYLTRLIAAERERELEECQRNHEGHEDDGHIRAQQACIEAKHDKYMADMDELFSQVDEKRKKRDIPDYLCGKISFELMREPCITPSGITYDRKDIEEHLQRVGHFDPVTRSPLTQEQLIPNLAMKEVIDAFISENGWVEDY