Transcriptional corepressor which facilitates transcriptional repression via its association with DNA-binding transcription factors and recruitment of other corepressors and histone-modifying enzymes (PubMed:12559562, PubMed:15203199). Can repress the expression of MMP7 in a ZBTB33-dependent manner (PubMed:23251453). Reduces the protein levels and stability of the transcriptinal regulator HIF1A; interacts with EGLN1 and promotes the HIF1A prolyl hydroxylation-dependent ubiquitination and proteasomal degradation pathway (PubMed:25974097). Contributes to inhibition of glycolysis and stimulation of mitochondrial respiration by down-regulating the expression of glycolytic genes including PFKFB3, PFKFB4, PDK1, PFKP, LDHA and HK1 which are direct targets of HIF1A (PubMed:23840896, PubMed:25974097). Regulates the proliferation and the differentiation of erythroid progenitors by repressing the expression of TAL1 target genes (By similarity). Plays a role in granulocyte differentiation (PubMed:15231665). Isoform 2 functions as an A-kinase-anchoring protein (PubMed:11823486). Homooligomer. Homotetramerization is mediated by nervy homology region 2 (NRH2) (By similarity). Can interact with RUNX1T1 and CBFA2T2; heterotetramerization between members of the CBFA2T family is proposed (PubMed:12242670). Component of a TAL-1 complex composed at least of CBFA2T3, LDB1, TAL1 and TCF3 (By similarity). Interacts with ERBB4, HDAC1, HDAC2, HDAC3, HDAC6, HDAC8, NCOR1, NCOR2, and ZNF652. According to PubMed:12242670, may not interact with HDAC6. Interacts with PLXNA1, PLXNA3 and PRKAR1A. Isoform 2 interacts with PRKAR2A, PDE7A and probably PDE4A. Interacts with ZBTB4, ZBTB38 and ZBTB33. Interacts with HIF1A and EGLN1. Interacts with the AML1-MTG8/ETO fusion protein. The RUNX1-CBFA2T3 fusion protein localizes to the nucleoplasm. Widely expressed with higher expression in heart, pancreas, skeletal muscle, spleen, thymus and peripheral blood leukocytes. Expressed in hematopoietic cells (at protein level). Down-regulated by all-trans retinoic acid (ATRA). Nervy homology region 2 (NHR2) mediates homo- and possibly heterotypic oligomerization by forming a four-helix bundle tetrameric structure. A chromosomal aberration involving CBFA2T3 is found in therapy-related myeloid malignancies. Translocation t(16;21)(q24;q22) that forms a RUNX1-CBFA2T3 fusion protein. Belongs to the CBFA2T family. Aberrant splicing.