|Human, Monkey, Mouse|
Application Methods: Immunofluorescence (Immunocytochemistry), Immunohistochemistry (Paraffin), Immunoprecipitation, Western Blotting
Background: CtBP1 (C-terminal binding protein 1) was first recognized as a cellular factor that interacts with the C-terminal portion of adenovirus E1A, a protein involved in the transcriptional regulation of key cellular genes (1). CtBP1 is able to regulate gene activity through its intrinsic dehydrogenase activity (2,3) and by interacting with Polycomb Group (PcG) proteins during development (4). Along with its homologue, CtBP2, it acts as a transcriptional corepressor of zinc-finger homeodomain factor deltaEF1 to regulate a wide range of cellular processes through transrepression mechanisms (5). Through its direct interaction with PRDM16, CtBP1 has been shown to be involved in brown adipose tissue differentiation by mediating the repression of white fat genes and directing differentiation toward the brown fat gene program (6). CtBP1 also plays a role in lipid metabolic pathways and membrane fission by regulating the fission machinery operating Golgi tubular networks (7). CtBP1 has recently been shown to repress transcription of BRCA1 via a redox regulated mechanism (8). Furthermore, it is thought that downregulation of BRCA1 and E-cadherin in invasive ductal breast carcinoma correlates directly with activation of CtBP1 (9).
|Human, Monkey, Mouse, Rat|
Application Methods: Immunoprecipitation, Western Blotting
Background: CtBP2 (carboxy-terminal binding protein-2) and its homolog CtBP1 are transcriptional co-repressors originally identified as proteins that bind the carboxy-terminus of the human adenovirus E1A protein (1-3). CtBP proteins are thought to play important roles in regulating various developmental pathways because deletion of CtBP2 leads to embryonic lethality at E10.5 and is correlated with axial patterning defects (4). CtBP proteins regulate various oncogenic signaling pathways as promoters of epithelial-mesenchymal transition, apoptosis antagonists, and tumor suppressor genes repressors (1,5). The CtBP protein transcription co-repression activity results from interactions with numerous transcription factors and chromatin modulators, including the polycomb group proteins (1,6,7). Depending on the context, CtBP proteins interact with a short amino acid sequence motif (PXDLS) to mediate repression of target genes through both histone deacetylase-dependent and independent mechanisms (6,8,9). CtBP proteins display a high sequence homology to the bacterial D-isomer-specific 2-hydroxyacid dehydrogenase enzymes. Research studies indicate that nuclear NADH levels regulate CtBP transcription repression activities, as NADH binding is required for CtBP2 homodimerization and transcription co-repressor activity (6,9-11).