2kqs

Structural highlights

Disease

[SUMO1_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]

Function

[SUMO1_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]} [DAXX_HUMAN] Transcription corepressor known to repress transcriptional potential of several sumoylated transcription factors. Acts as an adapter protein in a MDM2-DAXX-USP7 complex by regulating the RING-finger E3 ligase MDM2 ubiquitination activity. Under non-stress condition, in association with the deubiquitinating USP7, prevents MDM2 self-ubiquitination and enhances the intrinsic E3 ligase activity of MDM2 towards TP53, thereby promoting TP53 ubiquitination and subsequent proteasomal degradation. Upon DNA damage, its association with MDM2 and USP7 is disrupted, resulting in increased MDM2 autoubiquitination and consequently, MDM2 degradation, which leads to TP53 stabilization. Proposed to mediate activation of the JNK pathway and apoptosis via MAP3K5 in response to signaling from TNFRSF6 and TGFBR2. Interaction with HSPB1/HSP27 may prevent interaction with TNFRSF6 and MAP3K5 and block DAXX-mediated apoptosis. In contrast, in lymphoid cells JNC activation and TNFRSF6-mediated apoptosis may not involve DAXX. Seems to regulate transcription in PML/POD/ND10 nuclear bodies together with PML and may influence TNFRSF6-dependent apoptosis thereby. Down-regulates basal and activated transcription. Seems to act as a transcriptional corepressor and inhibits PAX3 and ETS1 through direct protein-protein interaction. Modulates PAX5 activity. Its transcription repressor activity is modulated by recruiting it to subnuclear compartments like the nucleolus or PML/POD/ND10 nuclear bodies through interactions with MCSR1 and PML, respectively.^{[6] [7] [8] [9]}

See Also

• SUMO

References

1. ↑ Alkuraya FS, Saadi I, Lund JJ, Turbe-Doan A, Morton CC, Maas RL. SUMO1 haploinsufficiency leads to cleft lip and palate. Science. 2006 Sep 22;313(5794):1751. PMID:16990542 doi:10.1126/science.1128406
2. ↑ Mahajan R, Delphin C, Guan T, Gerace L, Melchior F. A small ubiquitin-related polypeptide involved in targeting RanGAP1 to nuclear pore complex protein RanBP2. Cell. 1997 Jan 10;88(1):97-107. PMID:9019411
3. ↑ Kamitani T, Nguyen HP, Yeh ET. Preferential modification of nuclear proteins by a novel ubiquitin-like molecule. J Biol Chem. 1997 May 30;272(22):14001-4. PMID:9162015
4. ↑ Meulmeester E, Kunze M, Hsiao HH, Urlaub H, Melchior F. Mechanism and consequences for paralog-specific sumoylation of ubiquitin-specific protease 25. Mol Cell. 2008 Jun 6;30(5):610-9. doi: 10.1016/j.molcel.2008.03.021. PMID:18538659 doi:10.1016/j.molcel.2008.03.021
5. ↑ Tatham MH, Geoffroy MC, Shen L, Plechanovova A, Hattersley N, Jaffray EG, Palvimo JJ, Hay RT. RNF4 is a poly-SUMO-specific E3 ubiquitin ligase required for arsenic-induced PML degradation. Nat Cell Biol. 2008 May;10(5):538-46. doi: 10.1038/ncb1716. Epub 2008 Apr 13. PMID:18408734 doi:10.1038/ncb1716
6. ↑ Hollenbach AD, McPherson CJ, Mientjes EJ, Iyengar R, Grosveld G. Daxx and histone deacetylase II associate with chromatin through an interaction with core histones and the chromatin-associated protein Dek. J Cell Sci. 2002 Aug 15;115(Pt 16):3319-30. PMID:12140263
7. ↑ Zhao LY, Liu J, Sidhu GS, Niu Y, Liu Y, Wang R, Liao D. Negative regulation of p53 functions by Daxx and the involvement of MDM2. J Biol Chem. 2004 Nov 26;279(48):50566-79. Epub 2004 Sep 10. PMID:15364927 doi:10.1074/jbc.M406743200
8. ↑ Lin DY, Huang YS, Jeng JC, Kuo HY, Chang CC, Chao TT, Ho CC, Chen YC, Lin TP, Fang HI, Hung CC, Suen CS, Hwang MJ, Chang KS, Maul GG, Shih HM. Role of SUMO-interacting motif in Daxx SUMO modification, subnuclear localization, and repression of sumoylated transcription factors. Mol Cell. 2006 Nov 3;24(3):341-54. PMID:17081986 doi:10.1016/j.molcel.2006.10.019
9. ↑ Tang J, Qu LK, Zhang J, Wang W, Michaelson JS, Degenhardt YY, El-Deiry WS, Yang X. Critical role for Daxx in regulating Mdm2. Nat Cell Biol. 2006 Aug;8(8):855-62. Epub 2006 Jul 16. PMID:16845383 doi:10.1038/ncb1442
10. ↑ Chang CC, Naik MT, Huang YS, Jeng JC, Liao PH, Kuo HY, Ho CC, Hsieh YL, Lin CH, Huang NJ, Naik NM, Kung CC, Lin SY, Chen RH, Chang KS, Huang TH, Shih HM. Structural and functional roles of Daxx SIM phosphorylation in SUMO paralog-selective binding and apoptosis modulation. Mol Cell. 2011 Apr 8;42(1):62-74. PMID:21474068 doi:10.1016/j.molcel.2011.02.022