6v7q
Crystal structure of SUMO1 in complex with phosphorylated PIAS-SIM2
Structural highlights
DiseaseSUMO1_HUMAN Defects in SUMO1 are the cause of non-syndromic orofacial cleft type 10 (OFC10) [MIM:613705; also called non-syndromic cleft lip with or without cleft palate 10. OFC10 is a birth defect consisting of cleft lips with or without cleft palate. Cleft lips are associated with cleft palate in two-third of cases. A cleft lip can occur on one or both sides and range in severity from a simple notch in the upper lip to a complete opening in the lip extending into the floor of the nostril and involving the upper gum. Note=A chromosomal aberation involving SUMO1 is the cause of OFC10. Translocation t(2;8)(q33.1;q24.3). The breakpoint occurred in the SUMO1 gene and resulted in haploinsufficiency confirmed by protein assays.[1] FunctionSUMO1_HUMAN Ubiquitin-like protein that can be covalently attached to proteins as a monomer or a lysine-linked polymer. Covalent attachment via an isopeptide bond to its substrates requires prior activation by the E1 complex SAE1-SAE2 and linkage to the E2 enzyme UBE2I, and can be promoted by E3 ligases such as PIAS1-4, RANBP2 or CBX4. This post-translational modification on lysine residues of proteins plays a crucial role in a number of cellular processes such as nuclear transport, DNA replication and repair, mitosis and signal transduction. Involved for instance in targeting RANGAP1 to the nuclear pore complex protein RANBP2. Polymeric SUMO1 chains are also susceptible to polyubiquitination which functions as a signal for proteasomal degradation of modified proteins. May also regulate a network of genes involved in palate development.[2] [3] [4] [5] Publication Abstract from PubMedThe human PIAS proteins are small ubiquitin-like modifier (SUMO) E3 ligases that participate in important cellular functions. Several of these functions depend on a conserved SUMO-interacting motif (SIM) located in the central region of all PIAS proteins (SIM1). Recently, it was determined that Siz2, a yeast homolog of PIAS proteins, possesses a second SIM at its C terminus (SIM2). Sequence alignment indicates that a SIM2 is also present in PIAS1-3, but not PIAS4. Using biochemical and structural studies, we demonstrate PIAS-SIM2 binds to SUMO1, but that phosphorylation of the PIAS-SIM2 or acetylation of SUMO1 alter this interaction in a manner distinct from what is observed for the PIAS-SIM1. We also show that the PIAS-SIM2 plays a key role in formation of a UBC9-PIAS1-SUMO1 complex. These results provide insights into how post-translational modifications selectively regulate the specificity of multiple SIMs found in the PIAS proteins by exploiting the plasticity built into the SUMO-SIM binding interface. Characterization of a C-Terminal SUMO-Interacting Motif Present in Select PIAS-Family Proteins.,Lussier-Price M, Mascle XH, Cappadocia L, Kamada R, Sakaguchi K, Wahba HM, Omichinski JG Structure. 2020 May 5;28(5):573-585.e5. doi: 10.1016/j.str.2020.04.002. Epub 2020, Apr 28. PMID:32348746[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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