6m2d
MUL1-RING domain
Structural highlights
FunctionMUL1_HUMAN Exhibits weak E3 ubiquitin-protein ligase activity (PubMed:18591963, PubMed:19407830, PubMed:22410793). E3 ubiquitin ligases accept ubiquitin from an E2 ubiquitin-conjugating enzyme in the form of a thioester and then directly transfer the ubiquitin to targeted substrates (PubMed:18591963, PubMed:19407830, PubMed:22410793). Can ubiquitinate AKT1 preferentially at 'Lys-284' involving 'Lys-48'-linked polyubiquitination and seems to be involved in regulation of Akt signaling by targeting phosphorylated Akt to proteosomal degradation (PubMed:22410793). Proposed to preferentially act as a SUMO E3 ligase at physiological concentrations (PubMed:19407830). Plays a role in the control of mitochondrial morphology by promoting mitochondrial fragmentation, and influences mitochondrial localization (PubMed:19407830, PubMed:18207745, PubMed:18213395). Likely to promote mitochondrial fission through negatively regulating the mitochondrial fusion proteins MFN1 and MFN2, acting in a pathway that is parallel to the PRKN/PINK1 regulatory pathway (PubMed:24898855). May also be involved in the sumoylation of the membrane fission protein DNM1L (PubMed:18207745, PubMed:19407830). Inhibits cell growth (PubMed:18591963, PubMed:22410793). When overexpressed, activates JNK through MAP3K7/TAK1 and induces caspase-dependent apoptosis (PubMed:23399697). Involved in the modulation of innate immune defense against viruses by inhibiting DDX58-dependent antiviral response (PubMed:23399697). Can mediate DDX58 sumoylation and disrupt its polyubiquitination (PubMed:23399697).[1] [2] [3] [4] [5] [6] [7] Publication Abstract from PubMedThe RING domain of MUL1 (RINGMUL1 ) alone mediates ubiquitylation of the p53-transactivation domain (TADp53 ). To elucidate the mechanism underlying the simultaneous recruitment of UBE2D2 and the substrate TADp53 by RINGMUL1 , we determined the complex structure of RINGMUL1 :UBE2D2 and studied the interaction between RINGMUL1 and TADp53 in the presence of UBE2D2-UB thioester (UBE2D2~UB) mimetics. The RINGMUL1 -binding induced the closed conformation of UBE2D2(S22R/C85S) -UB(K48R) oxyester (UBE2D2(RS) -UB(R) OE ), and strongly accelerated its hydrolysis, which was suppressed by the additional N77A-mutation of UBE2D2. Interestingly, UBE2D2(S22R/N77A/C85S) -UB(K48R) oxyester (UBE2D2(RAS) -UB(R) OE ) already formed a closed conformation in the absence of RINGMUL1 . Although TADp53 exhibited weak binding for RINGMUL1 or UBE2D2 alone, its binding affinity was enhanced and even further for RINGMUL1 :UBE2D2 and RINGMUL1 :UBE2D2(RAS) -UB(R) OE , respectively. The recognition of TADp53 by RINGMUL1 as a complex with UBE2D2~UB is related to the multivalency of the binding events and underlies the ability of RINGMUL1 to ubiquitylate the intrinsically disordered protein, TADp53 . MUL1-RING recruits the substrate, p53-TAD as a complex with UBE2D2-UB conjugate.,Lee MS, Lee SO, Choi J, Ryu M, Lee MK, Kim JH, Hwang E, Lee CK, Chi SW, Ryu KS FEBS J. 2022 Jan 19. doi: 10.1111/febs.16360. PMID:35048531[8] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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