| Structural highlights
Disease
[TRI18_HUMAN] Defects in MID1 are the cause of Opitz GBBB syndrome 1 (OGS1) [MIM:300000]. A congenital midline malformation syndrome characterized by hypertelorism, genital-urinary defects such as hypospadias in males and splayed labia in females, lip-palate-laryngotracheal clefts, imperforate anus, developmental delay and congenital heart defects. Note=MID1 mutations produce proteins with a decreased affinity for microtubules.[1] [2] [3] [4]
Function
[TRI18_HUMAN] Has E3 ubiquitin ligase activity towards IGBP1, promoting its monoubiquitination, which results in deprotection of the catalytic subunit of protein phosphatase PP2A, and its subsequent degradation by polyubiquitination.[5] [6] [7]
Evolutionary Conservation
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The tripartite motif (TRIM) protein family, defined by N-terminal RING, B-box, and coiled-coil (RBCC) domains, consists of either a single type 2 B-box domain or tandem B-box domains of type 1 and type 2 (B1B2). Here, we report the first structure of the B-box domains in their native tandem orientation. The B-boxes are from Midline-1, a putative ubiquitin E3 ligase that is required for the proteosomal degradation of the catalytic subunit of protein phosphatase 2A (PP2Ac). This function of MID1 is facilitated by the direct binding of Alpha4, a regulatory subunit of PP2Ac, to B-box1, while B-box2 appears to influence this interaction. Both B-box1 and B-box2 bind two zinc atoms in a cross-brace motif and adopt a similar betabetaalpha structure reminiscent of the RING, PHD, ZZ, and U-box domains, although they differ from each other and with RING domains in the spacing of their zinc-binding residues. The two B-box domains pack against each other with the interface formed by residues located on the structured loop consisting of the two antiparallel beta-strands. The surface area of the interface is 188 A2 (17% of the total surface). Consistent with the globular structure, the Tm of the tandem B-box domain (59 degrees C) is higher than the individual domains, supporting a stable interaction between the B-box 1 and 2 domains. Notably, the interaction is reminiscent of the interaction of recently determined RING dimers, suggesting the possibility of an evolutionarily conserved role for B-box2 domains in regulating functional RING-type folds.
Structure of the MID1 Tandem B-Boxes Reveals an Interaction Reminiscent of Intermolecular Ring Heterodimers(,).,Tao H, Simmons BN, Singireddy S, Jakkidi M, Short KM, Cox TC, Massiah MA Biochemistry. 2008 Feb 26;47(8):2450-2457. Epub 2008 Jan 26. PMID:18220417[8]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
References
- ↑ Quaderi NA, Schweiger S, Gaudenz K, Franco B, Rugarli EI, Berger W, Feldman GJ, Volta M, Andolfi G, Gilgenkrantz S, Marion RW, Hennekam RC, Opitz JM, Muenke M, Ropers HH, Ballabio A. Opitz G/BBB syndrome, a defect of midline development, is due to mutations in a new RING finger gene on Xp22. Nat Genet. 1997 Nov;17(3):285-91. PMID:9354791 doi:10.1038/ng1197-285
- ↑ Cox TC, Allen LR, Cox LL, Hopwood B, Goodwin B, Haan E, Suthers GK. New mutations in MID1 provide support for loss of function as the cause of X-linked Opitz syndrome. Hum Mol Genet. 2000 Oct 12;9(17):2553-62. PMID:11030761
- ↑ Gaudenz K, Roessler E, Quaderi N, Franco B, Feldman G, Gasser DL, Wittwer B, Horst J, Montini E, Opitz JM, Ballabio A, Muenke M. Opitz G/BBB syndrome in Xp22: mutations in the MID1 gene cluster in the carboxy-terminal domain. Am J Hum Genet. 1998 Sep;63(3):703-10. PMID:9718340
- ↑ So J, Suckow V, Kijas Z, Kalscheuer V, Moser B, Winter J, Baars M, Firth H, Lunt P, Hamel B, Meinecke P, Moraine C, Odent S, Schinzel A, van der Smagt JJ, Devriendt K, Albrecht B, Gillessen-Kaesbach G, van der Burgt I, Petrij F, Faivre L, McGaughran J, McKenzie F, Opitz JM, Cox T, Schweiger S. Mild phenotypes in a series of patients with Opitz GBBB syndrome with MID1 mutations. Am J Med Genet A. 2005 Jan 1;132A(1):1-7. PMID:15558842 doi:10.1002/ajmg.a.30407
- ↑ Cainarca S, Messali S, Ballabio A, Meroni G. Functional characterization of the Opitz syndrome gene product (midin): evidence for homodimerization and association with microtubules throughout the cell cycle. Hum Mol Genet. 1999 Aug;8(8):1387-96. PMID:10400985
- ↑ Trockenbacher A, Suckow V, Foerster J, Winter J, Krauss S, Ropers HH, Schneider R, Schweiger S. MID1, mutated in Opitz syndrome, encodes an ubiquitin ligase that targets phosphatase 2A for degradation. Nat Genet. 2001 Nov;29(3):287-94. PMID:11685209 doi:10.1038/ng762
- ↑ Watkins GR, Wang N, Mazalouskas MD, Gomez RJ, Guthrie CR, Kraemer BC, Schweiger S, Spiller BW, Wadzinski BE. Monoubiquitination promotes calpain cleavage of the protein phosphatase 2A (PP2A) regulatory subunit alpha4, altering PP2A stability and microtubule-associated protein phosphorylation. J Biol Chem. 2012 Jul 13;287(29):24207-15. doi: 10.1074/jbc.M112.368613. Epub, 2012 May 21. PMID:22613722 doi:10.1074/jbc.M112.368613
- ↑ Tao H, Simmons BN, Singireddy S, Jakkidi M, Short KM, Cox TC, Massiah MA. Structure of the MID1 Tandem B-Boxes Reveals an Interaction Reminiscent of Intermolecular Ring Heterodimers(,). Biochemistry. 2008 Feb 26;47(8):2450-2457. Epub 2008 Jan 26. PMID:18220417 doi:10.1021/bi7018496
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