7lps
From Proteopedia
Crystal structure of DDB1-CRBN-ALV1 complex bound to Helios (IKZF2 ZF2)
Structural highlights
FunctionDDB1_HUMAN Required for DNA repair. Binds to DDB2 to form the UV-damaged DNA-binding protein complex (the UV-DDB complex). The UV-DDB complex may recognize UV-induced DNA damage and recruit proteins of the nucleotide excision repair pathway (the NER pathway) to initiate DNA repair. The UV-DDB complex preferentially binds to cyclobutane pyrimidine dimers (CPD), 6-4 photoproducts (6-4 PP), apurinic sites and short mismatches. Also appears to function as a component of numerous distinct DCX (DDB1-CUL4-X-box) E3 ubiquitin-protein ligase complexes which mediate the ubiquitination and subsequent proteasomal degradation of target proteins. The functional specificity of the DCX E3 ubiquitin-protein ligase complex is determined by the variable substrate recognition component recruited by DDB1. DCX(DDB2) (also known as DDB1-CUL4-ROC1, CUL4-DDB-ROC1 and CUL4-DDB-RBX1) may ubiquitinate histone H2A, histone H3 and histone H4 at sites of UV-induced DNA damage. The ubiquitination of histones may facilitate their removal from the nucleosome and promote subsequent DNA repair. DCX(DDB2) also ubiquitinates XPC, which may enhance DNA-binding by XPC and promote NER. DCX(DTL) plays a role in PCNA-dependent polyubiquitination of CDT1 and MDM2-dependent ubiquitination of TP53 in response to radiation-induced DNA damage and during DNA replication. DCX(ERCC8) (the CSA complex) plays a role in transcription-coupled repair (TCR). May also play a role in ubiquitination of CDKN1B/p27kip when associated with CUL4 and SKP2.[1] [2] [3] [4] [5] [6] [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] Publication Abstract from PubMedThe zinc-finger transcription factor Helios is critical for maintaining the identity, anergic phenotype and suppressive activity of regulatory T (T(reg)) cells. While it is an attractive target to enhance the efficacy of currently approved immunotherapies, no existing approaches can directly modulate Helios activity or abundance. Here, we report the structure-guided development of small molecules that recruit the E3 ubiquitin ligase substrate receptor cereblon to Helios, thereby promoting its degradation. Pharmacological Helios degradation destabilized the anergic phenotype and reduced the suppressive activity of T(reg) cells, establishing a route towards Helios-targeting therapeutics. More generally, this study provides a framework for the development of small-molecule degraders for previously unligandable targets by reprogramming E3 ligase substrate specificity. Acute pharmacological degradation of Helios destabilizes regulatory T cells.,Wang ES, Verano AL, Nowak RP, Yuan JC, Donovan KA, Eleuteri NA, Yue H, Ngo KH, Lizotte PH, Gokhale PC, Gray NS, Fischer ES Nat Chem Biol. 2021 Jun;17(6):711-717. doi: 10.1038/s41589-021-00802-w. Epub 2021 , May 25. PMID:34035522[17] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. Loading citation details.. Citations No citations found See AlsoReferences
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