Anti-RUNX family transcription factor 2 antibodies are used for the immunodetection of the protein encoded by the RUNX2 gene. In humans, the canonical protein has a reported length of 521 amino acid residues and a mass of 56.6 kDa. Its subcellular localization is in the nucleus. Alternative splicing is reported to yield 3 different isoforms for this protein. It is notably expressed in osteoblasts. It is a reported transcription factor involved in osteoblastic differentiation and skeletal morphogenesis. Post-translational modifications have been described, including phosphorylation. The gene encoding this protein is implicated in Cleidocranial dysplasia. Other names for this target antigen include CBF-alpha-1, CBFA1, CCD, CCD1, CLCD, OSF-2, OSF2, and AML3. Gene orthologs have been identified in the mouse, rat, bovine, frog, zebrafish, chimpanzee and chicken species.