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C-terminal-binding protein 2 also known as CtBP2 is a protein that in humans is encoded by the CTBP2 gene.[1][2][3]


The CtBPs - CtBP1 and CtBP2 in mammals - are among the best characterized transcriptional corepressors.[4] They typically turn their target genes off. They do this by binding to sequence-specific DNA-binding proteins that carry a short motif of the general form Proline-Isoleucine-Aspartate-Leucine-Serine (the PIDLS motif). They then recruit histone modifying enzymes, histone deacetylases, histone methylases and histone demethylases. These enzymes are thought to work together to remove activating and add repressive histone marks. For example, histone deacetylase 1 (HDAC1) and HDAC2 can remove the activating mark histone 3 acetyl lysine 9 (H3K9Ac), then the histone methylase G9a can add methyl groups, while the histone demethylase lysine specific demethylase 1 (LSD1) can remove the activating mark H3K4me.[5]

The CtBPs bind to many different DNA-binding proteins and also bind to co-repressors that are themselves bound to DNA-binding proteins, such as Friend of GATA (Fog).[6] CtBPs can also dimerize and multimerize to bridge larger transcriptional complexes. They appear to be primarily scaffold proteins that allow the assembly of gene repression complexes.

One interesting aspect of CtBPs is their ability to bind to NADH and to a lesser extent NAD+. It has been proposed that this will enable them to sense the metabolic status of the cell and to regulate genes in response to changes in the NADH/NAD+ ratio. Accordingly, CtBPs have been found to be important in fat biology, binding to key proteins such as PRDM16, NRIP, and FOG2.[7]

The full functional roles of CtBP proteins in mammals have been difficult to evaluate because of partial redundancy between CtBP1 and CtBP2.[8] Similarly, the early lethality of the CtBP2 knockout and of double knockout mice has precluded detailed analysis of the cellular effects of deleting these proteins. Important results have emerged from model organisms where there is only a single CtBP gene. In Drosophila CtBP is involved in development and in circadian rhythms.[9] In the worm C. elegans CtBP is involved in life span.[10] Both circadian rhythms and life span appear to be linked to metabolism supporting the role for CtBPs in metabolic sensing.

The mammalian CtBP2 gene produces alternative transcripts encoding two distinct proteins. In addition to the transcriptional repressor (corepressor) discussed above, there is a longer isoform that is a major component of specialized synapses known as synaptic ribbons. Both proteins contain a NAD+ binding domain similar to NAD+-dependent 2-hydroxyacid dehydrogenases. A portion of the 3'-untranslated region was used to map this gene to chromosome 21q21.3; however, it was noted that similar loci elsewhere in the genome are likely. Blast analysis shows that this gene is present on chromosome 10.[3]


CTBP2 has been shown to interact with:


  1. 1.0 1.1 Turner J, Crossley M (September 1998). "Cloning and characterization of mCtBP2, a co-repressor that associates with basic Krüppel-like factor and other mammalian transcriptional regulators". EMBO J. 17 (17): 5129–40. doi:10.1093/emboj/17.17.5129. PMC 1170841. PMID 9724649.
  2. Chinnadurai G (February 2002). "CtBP, an unconventional transcriptional corepressor in development and oncogenesis". Mol. Cell. 9 (2): 213–24. doi:10.1016/S1097-2765(02)00443-4. PMID 11864595.
  3. 3.0 3.1 "Entrez Gene: CTBP2 C-terminal binding protein 2".
  4. Turner J, Crossley M (August 2001). "The CtBP family: enigmatic and enzymatic transcriptional co-repressors". BioEssays. 23 (8): 683–90. doi:10.1002/bies.1097. PMID 11494316.
  5. Shi Y, Lan F, Matson C, Mulligan P, Whetstine JR, Cole PA, Casero RA, Shi Y (December 2004). "Histone demethylation mediated by the nuclear amine oxidase homolog LSD1". Cell. 119 (7): 941–53. doi:10.1016/j.cell.2004.12.012. PMID 15620353.
  6. Fox AH, Liew C, Holmes M, Kowalski K, Mackay J, Crossley M (May 1999). "Transcriptional cofactors of the FOG family interact with GATA proteins by means of multiple zinc fingers". EMBO J. 18 (10): 2812–22. doi:10.1093/emboj/18.10.2812. PMC 1171362. PMID 10329627.
  7. Jack BH, Pearson RC, Crossley M (May 2011). "C-terminal binding protein: A metabolic sensor implicated in regulating adipogenesis". Int. J. Biochem. Cell Biol. 43 (5): 693–6. doi:10.1016/j.biocel.2011.01.017. PMID 21281737.
  8. Hildebrand JD, Soriano P (August 2002). "Overlapping and unique roles for C-terminal binding protein 1 (CtBP1) and CtBP2 during mouse development". Mol. Cell. Biol. 22 (15): 5296–307. doi:10.1128/mcb.22.15.5296-5307.2002. PMC 133942. PMID 12101226.
  9. Itoh TQ, Matsumoto A, Tanimura T (2013). "C-terminal binding protein (CtBP) activates the expression of E-box clock genes with CLOCK/CYCLE in Drosophila". PLoS ONE. 8 (4): e63113. doi:10.1371/journal.pone.0063113. PMC 3640014. PMID 23646183.
  10. Chen S, Whetstine JR, Ghosh S, Hanover JA, Gali RR, Grosu P, Shi Y (February 2009). "The conserved NAD(H)-dependent corepressor CTBP-1 regulates Caenorhabditis elegans life span". Proc. Natl. Acad. Sci. U.S.A. 106 (5): 1496–501. doi:10.1073/pnas.0802674106. PMC 2635826. PMID 19164523.
  11. 11.0 11.1 Turner J, Nicholas H, Bishop D, Matthews JM, Crossley M (2003). "The LIM protein FHL3 binds basic Krüppel-like factor/Krüppel-like factor 3 and its co-repressor C-terminal-binding protein 2". J. Biol. Chem. 278 (15): 12786–95. doi:10.1074/jbc.M300587200. PMID 12556451.
  12. van Vliet J, Turner J, Crossley M (2000). "Human Krüppel-like factor 8: a CACCC-box binding protein that associates with CtBP and represses transcription". Nucleic Acids Res. 28 (9): 1955–62. doi:10.1093/nar/28.9.1955. PMC 103308. PMID 10756197.
  13. Mirnezami AH, Campbell SJ, Darley M, Primrose JN, Johnson PW, Blaydes JP (2003). "Hdm2 recruits a hypoxia-sensitive corepressor to negatively regulate p53-dependent transcription". Curr. Biol. 13 (14): 1234–9. doi:10.1016/S0960-9822(03)00454-8. PMID 12867035.
  14. Rual 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 (2005). "Towards a proteome-scale map of the human protein-protein interaction network". Nature. 437 (7062): 1173–8. doi:10.1038/nature04209. PMID 16189514.
  15. Castet A, Boulahtouf A, Versini G, Bonnet S, Augereau P, Vignon F, Khochbin S, Jalaguier S, Cavaillès V (2004). "Multiple domains of the Receptor-Interacting Protein 140 contribute to transcription inhibition". Nucleic Acids Res. 32 (6): 1957–66. doi:10.1093/nar/gkh524. PMC 390375. PMID 15060175.
  16. Murakami A, Ishida S, Thurlow J, Revest JM, Dickson C (2001). "SOX6 binds CtBP2 to repress transcription from the Fgf-3 promoter". Nucleic Acids Res. 29 (16): 3347–55. doi:10.1093/nar/29.16.3347. PMC 55854. PMID 11504872.
  17. Holmes M, Turner J, Fox A, Chisholm O, Crossley M, Chong B (1999). "hFOG-2, a novel zinc finger protein, binds the co-repressor mCtBP2 and modulates GATA-mediated activation". J. Biol. Chem. 274 (33): 23491–8. doi:10.1074/jbc.274.33.23491. PMID 10438528.

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