| Structural highlights
Disease
CHIP_HUMAN Cerebellar ataxia - hypogonadism. The disease is caused by mutations affecting the gene represented in this entry.
Function
CHIP_HUMAN 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.[1] [2] [3] [4] [5] [6] [7] [8]
Publication Abstract from PubMed
Targeted protein degraders hold potential as therapeutic agents to target conventionally 'undruggable' proteins. Here, we develop a high-throughput screen, DEath FUSion Escaper (DEFUSE), to identify small-molecule protein degraders. By conjugating the protein of interest to a fast-acting triggerable death protein, this approach translates target protein degradation into a cell survival phenotype to illustrate the presence of degraders. Using this method, we discovered a small molecule (SKPer1) that triggers degradation of the oncoprotein SKP2 and specifically kills SKP2-expressing cancer cells. Mechanistically, SKPer1 acts as an induced-proximity degrader by inducing interaction between SKP2 and an E3 ligase, STUB1, resulting in SKP2 ubiquitination and degradation. SKPer1 exhibits substantial tumour suppression with good safety profiles in vivo. We further show that a sequence of ten amino acids from SKP2 can serve as a versatile degradation tag.
A rapid imaging-based screen for induced-proximity degraders identifies a potent degrader of oncoprotein SKP2.,Chu Y, Chen S, Yang M, Chen Y, Fang H, Huang P, Xie Y, Sun C, Chen Y, Zhang B, Li L, Mu H, Song D, Cheng W, Wang C, Jiang W, Xu X, He Z, Chen S, Liu M, Ma J, Yang M, Cao J, Gao J, Shen J, Zhang L, Bai Y, Liu Z, Chen J, Dai S, Zeng YA, Zhao Y, Zhou H, Chen C, Ru H, Tan L, Chi X, Wang F, Gao D, Lin M, Deng X, Jiang H Nat Biotechnol. 2025 Sep 10. doi: 10.1038/s41587-025-02793-8. PMID:40931108[9]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Ballinger CA, Connell P, Wu Y, Hu Z, Thompson LJ, Yin LY, Patterson C. Identification of CHIP, a novel tetratricopeptide repeat-containing protein that interacts with heat shock proteins and negatively regulates chaperone functions. Mol Cell Biol. 1999 Jun;19(6):4535-45. PMID:10330192
- ↑ Connell P, Ballinger CA, Jiang J, Wu Y, Thompson LJ, Hohfeld J, Patterson C. The co-chaperone CHIP regulates protein triage decisions mediated by heat-shock proteins. Nat Cell Biol. 2001 Jan;3(1):93-6. PMID:11146632 doi:https://dx.doi.org/10.1038/35050618
- ↑ Jiang J, Ballinger CA, Wu Y, Dai Q, Cyr DM, Hohfeld J, Patterson C. CHIP is a U-box-dependent E3 ubiquitin ligase: identification of Hsc70 as a target for ubiquitylation. J Biol Chem. 2001 Nov 16;276(46):42938-44. Epub 2001 Sep 13. PMID:11557750 doi:https://dx.doi.org/10.1074/jbc.M101968200
- ↑ Peng HM, Morishima Y, Jenkins GJ, Dunbar AY, Lau M, Patterson C, Pratt WB, Osawa Y. Ubiquitylation of neuronal nitric-oxide synthase by CHIP, a chaperone-dependent E3 ligase. J Biol Chem. 2004 Dec 17;279(51):52970-7. Epub 2004 Oct 4. PMID:15466472 doi:https://dx.doi.org/10.1074/jbc.M406926200
- ↑ Pabarcus MK, Hoe N, Sadeghi S, Patterson C, Wiertz E, Correia MA. CYP3A4 ubiquitination by gp78 (the tumor autocrine motility factor receptor, AMFR) and CHIP E3 ligases. Arch Biochem Biophys. 2009 Mar 1;483(1):66-74. doi: 10.1016/j.abb.2008.12.001., Epub 2008 Dec 10. PMID:19103148 doi:10.1016/j.abb.2008.12.001
- ↑ Annamalai B, Liu X, Gopal U, Isaacs JS. Hsp90 is an essential regulator of EphA2 receptor stability and signaling: implications for cancer cell migration and metastasis. Mol Cancer Res. 2009 Jul;7(7):1021-32. doi: 10.1158/1541-7786.MCR-08-0582. Epub, 2009 Jun 30. PMID:19567782 doi:https://dx.doi.org/10.1158/1541-7786.MCR-08-0582
- ↑ Parsons JL, Tait PS, Finch D, Dianova II, Edelmann MJ, Khoronenkova SV, Kessler BM, Sharma RA, McKenna WG, Dianov GL. Ubiquitin ligase ARF-BP1/Mule modulates base excision repair. EMBO J. 2009 Oct 21;28(20):3207-15. doi: 10.1038/emboj.2009.243. Epub 2009 Aug, 27. PMID:19713937 doi:10.1038/emboj.2009.243
- ↑ Matsumura Y, Sakai J, Skach WR. Endoplasmic reticulum protein quality control is determined by cooperative interactions between Hsp/c70 protein and the CHIP E3 ligase. J Biol Chem. 2013 Oct 25;288(43):31069-79. doi: 10.1074/jbc.M113.479345. Epub, 2013 Aug 29. PMID:23990462 doi:https://dx.doi.org/10.1074/jbc.M113.479345
- ↑ Chu Y, Chen S, Yang M, Chen Y, Fang H, Huang P, Xie Y, Sun C, Chen Y, Zhang B, Li L, Mu H, Song D, Cheng W, Wang C, Jiang W, Xu X, He Z, Chen S, Liu M, Ma J, Yang M, Cao J, Gao J, Shen J, Zhang L, Bai Y, Liu Z, Chen J, Dai S, Zeng YA, Zhao Y, Zhou H, Chen C, Ru H, Tan L, Chi X, Wang F, Gao D, Lin M, Deng X, Jiang H. A rapid imaging-based screen for induced-proximity degraders identifies a potent degrader of oncoprotein SKP2. Nat Biotechnol. 2025 Sep 10. PMID:40931108 doi:10.1038/s41587-025-02793-8
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