The CtBP1 protein was originally identified as a human protein that bound a PLDLS motif in the C-terminus of adenovirus E1A proteins. It and the related protein CTBP2 were later shown to function as transcriptional corepressors.[2] That is, regulatory proteins that bind to sequence-specific DNA-binding proteins and help turn genes off. CtBPs do this by recruiting histone modifying enzymes that add repressive histone marks and remove activating marks. CtBP proteins can also self-associate and presumably bring together gene regulatory complexes.[3]
CtBP1 is broadly expressed from embryo to adult, while CtBP2 has a somewhat more restricted pattern of expression. CtBPs have multiple biological roles and appear to be most important in regulating the epithelial to mesenchymal transition, as well as influencing metabolism. They do the latter by binding NADH in preference to NAD+, thereby sensing the NADH/NAD+ ratio. When bound it undergoes a conformational change that allows it to dimerize and associate with its partner proteins and silence specific genes.
During skeletal and T cell development, CtBP1 and CtBP2 associate with the PLDLSL domain of δEF1, a cellular zinc finger-homeodomain protein, and thereby enhances δEF1-induced transcriptional silencing. CtBP also binds the Kruppel-like factors family of zinc finger proteins KLF3, KLF8 and KLF12. In addition, CtBP complexes with CtIP, a 125 kDa protein that recognizes distinctly different protein motifs from CtBP. CtIP binds to the BRCT repeats within the breast cancer gene BRCA1 and enables CtBP to influence BRCA1 activity. Both proteins can also interact with a polycomb group protein complex which participates in regulation of gene expression during development. Alternative splicing of transcripts from this gene results in multiple transcript variants.[4]
↑ 1.01.1Schaeper U, Subramanian T, Lim L, Boyd JM, Chinnadurai G (April 1998). "Interaction between a cellular protein that binds to the C-terminal region of adenovirus E1A (CtBP) and a novel cellular protein is disrupted by E1A through a conserved PLDLS motif". J. Biol. Chem. 273 (15): 8549–52. doi:10.1074/jbc.273.15.8549. PMID9535825.
↑Chinnadurai G (2002). "CtBP, an unconventional transcriptional corepressor in development and oncogenesis". Mol. Cell. 9 (2): 213–24. doi:10.1016/S1097-2765(02)00443-4. PMID11864595.
↑Oma Y, Nishimori K, Harata M (February 2003). "The brain-specific actin-related protein ArpN alpha interacts with the transcriptional co-repressor CtBP". Biochem. Biophys. Res. Commun. 301 (2): 521–8. doi:10.1016/S0006-291X(02)03073-5. PMID12565893.
↑Chakraborty S, Senyuk V, Sitailo S, Chi Y, Nucifora G (November 2001). "Interaction of EVI1 with cAMP-responsive element-binding protein-binding protein (CBP) and p300/CBP-associated factor (P/CAF) results in reversible acetylation of EVI1 and in co-localization in nuclear speckles". J. Biol. Chem. 276 (48): 44936–43. doi:10.1074/jbc.M106733200. PMID11568182.
↑Izutsu K, Kurokawa M, Imai Y, Maki K, Mitani K, Hirai H (May 2001). "The corepressor CtBP interacts with Evi-1 to repress transforming growth factor beta signaling". Blood. 97 (9): 2815–22. doi:10.1182/blood.V97.9.2815. PMID11313276.
↑Zhang CL, McKinsey TA, Lu JR, Olson EN (January 2001). "Association of COOH-terminal-binding protein (CtBP) and MEF2-interacting transcription repressor (MITR) contributes to transcriptional repression of the MEF2 transcription factor". J. Biol. Chem. 276 (1): 35–9. doi:10.1074/jbc.M007364200. PMID11022042.
↑ 11.011.1Melhuish TA, Wotton D (December 2000). "The interaction of the carboxyl terminus-binding protein with the Smad corepressor TGIF is disrupted by a holoprosencephaly mutation in TGIF". J. Biol. Chem. 275 (50): 39762–6. doi:10.1074/jbc.C000416200. PMID10995736.
↑Sundqvist A, Sollerbrant K, Svensson C (June 1998). "The carboxy-terminal region of adenovirus E1A activates transcription through targeting of a C-terminal binding protein-histone deacetylase complex". FEBS Lett. 429 (2): 183–8. doi:10.1016/S0014-5793(98)00588-2. PMID9650586.
↑Koipally J, Georgopoulos K (June 2000). "Ikaros interactions with CtBP reveal a repression mechanism that is independent of histone deacetylase activity". J. Biol. Chem. 275 (26): 19594–602. doi:10.1074/jbc.M000254200. PMID10766745.
↑Perdomo J, Crossley M (December 2002). "The Ikaros family protein Eos associates with C-terminal-binding protein corepressors". Eur. J. Biochem. 269 (23): 5885–92. doi:10.1046/j.1432-1033.2002.03313.x. PMID12444977.
↑Li S, Chen PL, Subramanian T, Chinnadurai G, Tomlinson G, Osborne CK, Sharp ZD, Lee WH (April 1999). "Binding of CtIP to the BRCT repeats of BRCA1 involved in the transcription regulation of p21 is disrupted upon DNA damage". J. Biol. Chem. 274 (16): 11334–8. doi:10.1074/jbc.274.16.11334. PMID10196224.
Chinnadurai G (2002). "CtBP, an unconventional transcriptional corepressor in development and oncogenesis". Mol. Cell. 9 (2): 213–24. doi:10.1016/S1097-2765(02)00443-4. PMID11864595.
Schaeper U, Subramanian T, Lim L, et al. (1998). "Interaction between a cellular protein that binds to the C-terminal region of adenovirus E1A (CtBP) and a novel cellular protein is disrupted by E1A through a conserved PLDLS motif". J. Biol. Chem. 273 (15): 8549–52. doi:10.1074/jbc.273.15.8549. PMID9535825.
Sundqvist A, Sollerbrant K, Svensson C (1998). "The carboxy-terminal region of adenovirus E1A activates transcription through targeting of a C-terminal binding protein-histone deacetylase complex". FEBS Lett. 429 (2): 183–8. doi:10.1016/S0014-5793(98)00588-2. PMID9650586.
Fuks F, Milner J, Kouzarides T (1998). "BRCA2 associates with acetyltransferase activity when bound to P/CAF". Oncogene. 17 (19): 2531–4. doi:10.1038/sj.onc.1202475. PMID9824164.
Li S, Chen PL, Subramanian T, et al. (1999). "Binding of CtIP to the BRCT repeats of BRCA1 involved in the transcription regulation of p21 is disrupted upon DNA damage". J. Biol. Chem. 274 (16): 11334–8. doi:10.1074/jbc.274.16.11334. PMID10196224.
Holmes M, Turner J, Fox A, et al. (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. PMID10438528.
Yu X, Baer R (2000). "Nuclear localization and cell cycle-specific expression of CtIP, a protein that associates with the BRCA1 tumor suppressor". J. Biol. Chem. 275 (24): 18541–9. doi:10.1074/jbc.M909494199. PMID10764811.
Koipally J, Georgopoulos K (2000). "Ikaros interactions with CtBP reveal a repression mechanism that is independent of histone deacetylase activity". J. Biol. Chem. 275 (26): 19594–602. doi:10.1074/jbc.M000254200. PMID10766745.
Melhuish TA, Wotton D (2001). "The interaction of the carboxyl terminus-binding protein with the Smad corepressor TGIF is disrupted by a holoprosencephaly mutation in TGIF". J. Biol. Chem. 275 (50): 39762–6. doi:10.1074/jbc.C000416200. PMID10995736.
Zhang CL, McKinsey TA, Lu JR, Olson EN (2001). "Association of COOH-terminal-binding protein (CtBP) and MEF2-interacting transcription repressor (MITR) contributes to transcriptional repression of the MEF2 transcription factor". J. Biol. Chem. 276 (1): 35–9. doi:10.1074/jbc.M007364200. PMID11022042.
Izutsu K, Kurokawa M, Imai Y, et al. (2001). "The corepressor CtBP interacts with Evi-1 to repress transforming growth factor beta signaling". Blood. 97 (9): 2815–22. doi:10.1182/blood.V97.9.2815. PMID11313276.
Palmer S, Brouillet JP, Kilbey A, et al. (2001). "Evi-1 transforming and repressor activities are mediated by CtBP co-repressor proteins". J. Biol. Chem. 276 (28): 25834–40. doi:10.1074/jbc.M102343200. PMID11328817.
Schuierer M, Hilger-Eversheim K, Dobner T, et al. (2001). "Induction of AP-2alpha expression by adenoviral infection involves inactivation of the AP-2rep transcriptional corepressor CtBP1". J. Biol. Chem. 276 (30): 27944–9. doi:10.1074/jbc.M100070200. PMID11373277.