Transcription factor involved in osteoblastic differentiation and skeletal morphogenesis. Essential for the maturation of osteoblasts and both intramembranous and endochondral ossification. CBF binds to the core site, 5'-PYGPYGGT-3', of a number of enhancers and promoters, including murine leukemia virus, polyomavirus enhancer, T-cell receptor enhancers, osteocalcin, osteopontin, bone sialoprotein, alpha 1(I) collagen, LCK, IL-3 and GM-CSF promoters. Inhibits KAT6B-dependent transcriptional activation. In osteoblasts, supports transcription activation: synergizes with SPEN/MINT to enhance FGFR2-mediated activation of the osteocalcin FGF-responsive element (OCFRE). Heterodimer of an alpha and a beta subunit. The alpha subunit binds DNA as a monomer and through the Runt domain. DNA-binding is increased by heterodimerization (By similarity). Interacts with XRCC6 (Ku70) and XRCC5 (Ku80). Interacts with CCNB1, KAT6A and KAT6B. Interacts with HIVEP3. Interacts with IFI204. Interaction with SATB2; the interaction results in enhanced DNA binding and transactivation by these transcription factors. Binds to HIPK3. Interacts (isoform 3) with DDX5. Interacts with FOXO1 (via a C-terminal region); the interaction inhibits RUNX2 transcriptional activity towards BGLAP. This interaction is prevented on insulin or IGF1 stimulation as FOXO1 is exported from the nucleus. Interacts with FOXP3. Interacts with TMEM119. Interacts with OLFM2 (By similarity). Phosphorylated; probably by MAP kinases (MAPK). Phosphorylation by HIPK3 is required for the SPEN/MINT and FGF2 transactivation during osteoblastic differentiation (By similarity).