4tse
Crystal Structure of the Mib Repeat Domain of Mind bomb 1
Structural highlights
DiseaseMIB1_HUMAN Left ventricular noncompaction. The disease is caused by mutations affecting the gene represented in this entry. FunctionMIB1_HUMAN E3 ubiquitin-protein ligase that mediates ubiquitination of Delta receptors, which act as ligands of Notch proteins. Positively regulates the Delta-mediated Notch signaling by ubiquitinating the intracellular domain of Delta, leading to endocytosis of Delta receptors. Probably mediates ubiquitination and subsequent proteasomal degradation of DAPK1, thereby antagonizing anti-apoptotic effects of DAPK1 to promote TNF-induced apoptosis (By similarity). Involved in ubiquitination of centriolar satellite CEP131, CEP290 and PCM1 proteins and hence inhibits primary cilium formation in proliferating cells. Mediates 'Lys-63'-linked polyubiquitination of TBK1, which probably participates in kinase activation.[1] Publication Abstract from PubMedMind bomb (Mib) proteins are large, multi-domain E3 ligases that promote ubiquitination of the cytoplasmic tails of Notch ligands. This ubiquitination step marks the ligand proteins for epsin-dependent endocytosis, which is critical for in vivo Notch receptor activation. We present here crystal structures of the substrate recognition domains of Mib1, both in isolation and in complex with peptides derived from Notch ligands. The structures, in combination with biochemical, cellular, and in vivo assays, show that Mib1 contains two independent substrate recognition domains that engage two distinct epitopes from the cytoplasmic tail of the ligand Jagged1, one in the intracellular membrane proximal region and the other near the C terminus. Together, these studies provide insights into the mechanism of ubiquitin transfer by Mind bomb E3 ligases, illuminate a key event in ligand-induced activation of Notch receptors, and identify a potential target for therapeutic modulation of Notch signal transduction in disease. A tail of two sites: a bipartite mechanism for recognition of notch ligands by mind bomb e3 ligases.,McMillan BJ, Schnute B, Ohlenhard N, Zimmerman B, Miles L, Beglova N, Klein T, Blacklow SC Mol Cell. 2015 Mar 5;57(5):912-24. doi: 10.1016/j.molcel.2015.01.019. PMID:25747658[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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