5fqd
From Proteopedia
Structural basis of Lenalidomide induced CK1a degradation by the crl4crbn ubiquitin ligase
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 PubMedThalidomide and its derivatives, lenalidomide and pomalidomide, are immune modulatory drugs (IMiDs) used in the treatment of haematologic malignancies. IMiDs bind CRBN, the substrate receptor of the CUL4-RBX1-DDB1-CRBN (also known as CRL4CRBN) E3 ubiquitin ligase, and inhibit ubiquitination of endogenous CRL4CRBN substrates. Unexpectedly, IMiDs also repurpose the ligase to target new proteins for degradation. Lenalidomide induces degradation of the lymphoid transcription factors Ikaros and Aiolos (also known as IKZF1 and IKZF3), and casein kinase 1alpha (CK1alpha), which contributes to its clinical efficacy in the treatment of multiple myeloma and 5q-deletion associated myelodysplastic syndrome (del(5q) MDS), respectively. How lenalidomide alters the specificity of the ligase to degrade these proteins remains elusive. Here we present the 2.45 A crystal structure of DDB1-CRBN bound to lenalidomide and CK1alpha. CRBN and lenalidomide jointly provide the binding interface for a CK1alpha beta-hairpin-loop located in the kinase N-lobe. We show that CK1alpha binding to CRL4CRBN is strictly dependent on the presence of an IMiD. Binding of IKZF1 to CRBN similarly requires the compound and both, IKZF1 and CK1alpha, use a related binding mode. Our study provides a mechanistic explanation for the selective efficacy of lenalidomide in del(5q) MDS therapy. We anticipate that high-affinity protein-protein interactions induced by small molecules will provide opportunities for drug development, particularly for targeted protein degradation. Structural basis of lenalidomide-induced CK1alpha degradation by the CRL4 ubiquitin ligase.,Petzold G, Fischer ES, Thoma NH Nature. 2016 Feb 24. doi: 10.1038/nature16979. PMID:26909574[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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