The C-terminal-binding protein (CtBP) was originally identified as a cellular protein that interacts with a C-terminal motif of adenovirus E1A oncoproteins. CtBP is highly conserved in higher eukaryotes. Vertebrates contain two highly homologous CtBP proteins (CtBP1 and CtBP2) while invertebrates contain a single CtBP. CtBP family proteins share significant sequence homology with D-2-hydroxy acid dehydrogenases. Also, CtBP proteins associate with various proteins and functions as a co-repressor of transcription.Synonyms: C-terminal-binding protein 1, CTBP