SUMO-conjugating enzyme UBC9 is an enzyme that in humans is encoded by the UBE2Igene.[1] It is also sometimes referred to as "ubiquitin conjugating enzyme E2I" or "ubiquitin carrier protein 9", even though these names do not accurately describe its function.
Four alternatively spliced transcript variants encoding the same protein have been found for this gene.[2]
Function
The UBC9 protein encoded by the UBE2I gene constitutes a core machinery in the cell's sumoylation pathway. Sumoylation is a process in which a Small Ubiquitin-like MOdifier (SUMO) is covalently attached to other proteins in order to modify their behaviour. For example, sumoylation may affect a protein's localization in the cell, its ability to interact with other proteins or DNA.
UBC9 performs the third step in the sumoylation life cycle: the conjugation step. When SUMO protein precursors are first expressed, they first undergo a maturation step in which the four C-terminal amino acids are removed, revealing a di-glycine motif. In a second step, an E1 activating complex binds to SUMO at its di-glycine and passes it on to the E2 protein Ubc9, where it forms a thioester bond with a cysteine residue within Ubc9's catalytic pocket. The loaded Ubc9 is now ready to perform the sumoylation of its various target proteins (also called substrates). It recognizes a particular motif of amino acid residues in these substrates: A large hydrophobic residue, followed by a lysine, followed by a spacer, followed by an acidic residue. This motif is usually described in shorthand as ΨKxD/E. The central lysine within the substrate's recognition motif is inserted into the catalytic pocket. There the carbolxyl terminus of SUMO's di-glycine forms a peptide bond with the ε-amino group of the lysine. This process can be assisted by an E3 ligase protein.
The sumoylation process is reversible. SENP proteases can remove SUMO from sumoylated proteins, freeing it to be used in further sumoylation reactions.
Clinical significance relevance
The protein UBC9 encoded by the UBE2I gene has been shown to be targeted by multiple viruses, including HIV and HPV. It has been hypothesized that these viruses hijack UBC9 to serve their own purposes.[3]
↑Watanabe TK, Fujiwara T, Kawai A, Shimizu F, Takami S, Hirano H, Okuno S, Ozaki K, Takeda S, Shimada Y, Nagata M, Takaichi A, Takahashi E, Nakamura Y, Shin S (March 1996). "Cloning, expression, and mapping of UBE2I, a novel gene encoding a human homologue of yeast ubiquitin-conjugating enzymes which are critical for regulating the cell cycle". Cytogenet Cell Genet. 72 (1): 86–9. doi:10.1159/000134169. PMID8565643.
↑Varadaraj A, Mattoscio D, Chiocca S (Jan 2014). "SUMO Ubc9 enzyme as a viral target". IUBMB Life. 66 (1): 27–33. doi:10.1002/iub.1240. PMID24395713.
↑Firestein R, Feuerstein N (March 1998). "Association of activating transcription factor 2 (ATF2) with the ubiquitin-conjugating enzyme hUBC9. Implication of the ubiquitin/proteasome pathway in regulation of ATF2 in T cells". J. Biol. Chem. 273 (10): 5892–902. doi:10.1074/jbc.273.10.5892. PMID9488727.
↑Poukka H, Aarnisalo P, Karvonen U, Palvimo JJ, Jänne OA (July 1999). "Ubc9 interacts with the androgen receptor and activates receptor-dependent transcription". J. Biol. Chem. 274 (27): 19441–6. doi:10.1074/jbc.274.27.19441. PMID10383460.
↑Koldamova RP, Lefterov IM, DiSabella MT, Lazo JS (Dec 1998). "An evolutionarily conserved cysteine protease, human bleomycin hydrolase, binds to the human homologue of ubiquitin-conjugating enzyme 9". Mol. Pharmacol. 54 (6): 954–61. PMID9855622.
↑ 7.07.1Rual JF, Venkatesan K, Hao T, Hirozane-Kishikawa T, Dricot A, Li N, Berriz GF, Gibbons FD, Dreze M, Ayivi-Guedehoussou N, Klitgord N, Simon C, Boxem M, Milstein S, Rosenberg J, Goldberg DS, Zhang LV, Wong SL, Franklin G, Li S, Albala JS, Lim J, Fraughton C, Llamosas E, Cevik S, Bex C, Lamesch P, Sikorski RS, Vandenhaute J, Zoghbi HY, Smolyar A, Bosak S, Sequerra R, Doucette-Stamm L, Cusick ME, Hill DE, Roth FP, Vidal M (October 2005). "Towards a proteome-scale map of the human protein-protein interaction network". Nature. 437 (7062): 1173–8. doi:10.1038/nature04209. PMID16189514.
↑Machon O, Backman M, Julin K, Krauss S (October 2000). "Yeast two-hybrid system identifies the ubiquitin-conjugating enzyme mUbc9 as a potential partner of mouse Dac". Mech. Dev. 97 (1–2): 3–12. doi:10.1016/s0925-4773(00)00402-0. PMID11025202.
↑Kang ES, Park CW, Chung JH (Dec 2001). "Dnmt3b, de novo DNA methyltransferase, interacts with SUMO-1 and Ubc9 through its N-terminal region and is subject to modification by SUMO-1". Biochem. Biophys. Res. Commun. 289 (4): 862–8. doi:10.1006/bbrc.2001.6057. PMID11735126.
↑ 11.011.111.2Knipscheer P, Flotho A, Klug H, Olsen JV, van Dijk WJ, Fish A, Johnson ES, Mann M, Sixma TK, Pichler A (August 2008). "Ubc9 sumoylation regulates SUMO target discrimination". Mol. Cell. 31 (3): 371–82. doi:10.1016/j.molcel.2008.05.022. PMID18691969.
↑Ryu SW, Chae SK, Kim E (Dec 2000). "Interaction of Daxx, a Fas binding protein, with sentrin and Ubc9". Biochem. Biophys. Res. Commun. 279 (1): 6–10. doi:10.1006/bbrc.2000.3882. PMID11112409.
↑Hahn SL, Wasylyk B, Criqui-Filipe P, Criqui P (September 1997). "Modulation of ETS-1 transcriptional activity by huUBC9, a ubiquitin-conjugating enzyme". Oncogene. 15 (12): 1489–95. doi:10.1038/sj.onc.1201301. PMID9333025.
↑ 16.016.1Saltzman A, Searfoss G, Marcireau C, Stone M, Ressner R, Munro R, Franks C, D'Alonzo J, Tocque B, Jaye M, Ivashchenko Y (April 1998). "hUBC9 associates with MEKK1 and type I TNF-alpha receptor and stimulates NFkappaB activity". FEBS Lett. 425 (3): 431–5. doi:10.1016/s0014-5793(98)00287-7. PMID9563508.
↑Xu W, Gong L, Haddad MM, Bischof O, Campisi J, Yeh ET, Medrano EE (March 2000). "Regulation of microphthalmia-associated transcription factor MITF protein levels by association with the ubiquitin-conjugating enzyme hUBC9". Exp. Cell Res. 255 (2): 135–43. doi:10.1006/excr.2000.4803. PMID10694430.
↑ 18.018.118.2Shen Z, Pardington-Purtymun PE, Comeaux JC, Moyzis RK, Chen DJ (October 1996). "Associations of UBE2I with RAD52, UBL1, p53, and RAD51 proteins in a yeast two-hybrid system". Genomics. 37 (2): 183–6. doi:10.1006/geno.1996.0540. PMID8921390.
↑ 19.019.1Minty A, Dumont X, Kaghad M, Caput D (November 2000). "Covalent modification of p73alpha by SUMO-1. Two-hybrid screening with p73 identifies novel SUMO-1-interacting proteins and a SUMO-1 interaction motif". J. Biol. Chem. 275 (46): 36316–23. doi:10.1074/jbc.M004293200. PMID10961991.
↑Gallagher WM, Argentini M, Sierra V, Bracco L, Debussche L, Conseiller E (June 1999). "MBP1: a novel mutant p53-specific protein partner with oncogenic properties". Oncogene. 18 (24): 3608–16. doi:10.1038/sj.onc.1202937. PMID10380882.
↑Bernier-Villamor V, Sampson DA, Matunis MJ, Lima CD (February 2002). "Structural basis for E2-mediated SUMO conjugation revealed by a complex between ubiquitin-conjugating enzyme Ubc9 and RanGAP1". Cell. 108 (3): 345–56. doi:10.1016/s0092-8674(02)00630-x. PMID11853669.
↑ 22.022.1Lee BH, Yoshimatsu K, Maeda A, Ochiai K, Morimatsu M, Araki K, Ogino M, Morikawa S, Arikawa J (Dec 2003). "Association of the nucleocapsid protein of the Seoul and Hantaan hantaviruses with small ubiquitin-like modifier-1-related molecules". Virus Res. 98 (1): 83–91. doi:10.1016/j.virusres.2003.09.001. PMID14609633.
↑Kahyo T, Nishida T, Yasuda H (September 2001). "Involvement of PIAS1 in the sumoylation of tumor suppressor p53". Mol. Cell. 8 (3): 713–8. doi:10.1016/s1097-2765(01)00349-5. PMID11583632.
↑ 28.028.1Tatham MH, Kim S, Yu B, Jaffray E, Song J, Zheng J, Rodriguez MS, Hay RT, Chen Y (August 2003). "Role of an N-terminal site of Ubc9 in SUMO-1, -2, and -3 binding and conjugation". Biochemistry. 42 (33): 9959–69. doi:10.1021/bi0345283. PMID12924945.
↑Netzer C, Bohlander SK, Rieger L, Müller S, Kohlhase J (August 2002). "Interaction of the developmental regulator SALL1 with UBE2I and SUMO-1". Biochem. Biophys. Res. Commun. 296 (4): 870–6. doi:10.1016/s0006-291x(02)02003-x. PMID12200128.
↑Huggins GS, Chin MT, Sibinga NE, Lee SL, Haber E, Lee ME (October 1999). "Characterization of the mUBC9-binding sites required for E2A protein degradation". J. Biol. Chem. 274 (40): 28690–6. doi:10.1074/jbc.274.40.28690. PMID10497239.
Jiang W, Koltin Y (1996). "Two-hybrid interaction of a human UBC9 homolog with centromere proteins of Saccharomyces cerevisiae". Mol. Gen. Genet. 251 (2): 153–60. doi:10.1007/s004380050152. PMID8668125.
Göttlicher M, Heck S, Doucas V, Wade E, Kullmann M, Cato AC, Evans RM, Herrlich P (1996). "Interaction of the Ubc9 human homologue with c-Jun and with the glucocorticoid receptor". Steroids. 61 (4): 257–62. doi:10.1016/0039-128X(96)00032-3. PMID8733011.
Schneikert J, Peterziel H, Defossez PA, Klocker H, de Launoit Y, Cato AC (1996). "Androgen receptor-Ets protein interaction is a novel mechanism for steroid hormone-mediated down-modulation of matrix metalloproteinase expression". J. Biol. Chem. 271 (39): 23907–13. doi:10.1074/jbc.271.39.23907. PMID8798622.
Wang ZY, Qiu QQ, Seufert W, Taguchi T, Testa JR, Whitmore SA, Callen DF, Welsh D, Shenk T, Deuel TF (1996). "Molecular cloning of the cDNA and chromosome localization of the gene for human ubiquitin-conjugating enzyme 9". J. Biol. Chem. 271 (40): 24811–6. doi:10.1074/jbc.271.40.24811. PMID8798754.
Hateboer G, Hijmans EM, Nooij JB, Schlenker S, Jentsch S, Bernards R (1996). "mUBC9, a novel adenovirus E1A-interacting protein that complements a yeast cell cycle defect". J. Biol. Chem. 271 (42): 25906–11. doi:10.1074/jbc.271.42.25906. PMID8824223.
Shen Z, Pardington-Purtymun PE, Comeaux JC, Moyzis RK, Chen DJ (1997). "Associations of UBE2I with RAD52, UBL1, p53, and RAD51 proteins in a yeast two-hybrid system". Genomics. 37 (2): 183–6. doi:10.1006/geno.1996.0540. PMID8921390.
Tachibana M, Iwata N, Watanabe A, Nobukuni Y, Ploplis B, Kajigaya S (1997). "Assignment of the gene for a ubiquitin-conjugating enzyme (UBE2I) to human chromosome band 16p13.3 by in situ hybridization". Cytogenet. Cell Genet. 75 (4): 222–3. doi:10.1159/000134487. PMID9067428.
Masson M, Menissier-de Murcia J, Mattei MG, de Murcia G, Niedergang CP (1997). "Poly(ADP-ribose) polymerase interacts with a novel human ubiquitin conjugating enzyme: hUbc9". Gene. 190 (2): 287–96. doi:10.1016/S0378-1119(97)00015-2. PMID9197546.
Becker K, Schneider P, Hofmann K, Mattmann C, Tschopp J (1997). "Interaction of Fas(Apo-1/CD95) with proteins implicated in the ubiquitination pathway". FEBS Lett. 412 (1): 102–6. doi:10.1016/S0014-5793(97)00758-8. PMID9257699.
Tong H, Hateboer G, Perrakis A, Bernards R, Sixma TK (1997). "Crystal structure of murine/human Ubc9 provides insight into the variability of the ubiquitin-conjugating system". J. Biol. Chem. 272 (34): 21381–7. doi:10.1074/jbc.272.34.21381. PMID9261152.
Hahn SL, Wasylyk B, Criqui-Filipe P, Criqui P (1997). "Modulation of ETS-1 transcriptional activity by huUBC9, a ubiquitin-conjugating enzyme". Oncogene. 15 (12): 1489–95. doi:10.1038/sj.onc.1201301. PMID9333025.
Firestein R, Feuerstein N (1998). "Association of activating transcription factor 2 (ATF2) with the ubiquitin-conjugating enzyme hUBC9. Implication of the ubiquitin/proteasome pathway in regulation of ATF2 in T cells". J. Biol. Chem. 273 (10): 5892–902. doi:10.1074/jbc.273.10.5892. PMID9488727.
Joanisse DR, Inaguma Y, Tanguay RM (1998). "Cloning and developmental expression of a nuclear ubiquitin-conjugating enzyme (DmUbc9) that interacts with small heat shock proteins in Drosophila melanogaster". Biochem. Biophys. Res. Commun. 244 (1): 102–9. doi:10.1006/bbrc.1998.8214. PMID9514881.
Saltzman A, Searfoss G, Marcireau C, Stone M, Ressner R, Munro R, Franks C, D'Alonzo J, Tocque B, Jaye M, Ivashchenko Y (1998). "hUBC9 associates with MEKK1 and type I TNF-alpha receptor and stimulates NFkappaB activity". FEBS Lett. 425 (3): 431–5. doi:10.1016/S0014-5793(98)00287-7. PMID9563508.
Koldamova RP, Lefterov IM, DiSabella MT, Lazo JS (1999). "An evolutionarily conserved cysteine protease, human bleomycin hydrolase, binds to the human homologue of ubiquitin-conjugating enzyme 9". Mol. Pharmacol. 54 (6): 954–61. PMID9855622.