Runt-related transcription factor 2 (RUNX2), also know as CBFA1, is a 56 kDa DNA-binding protein that belongs to the Runt-related family of transcription factors. It is synthesized as a 521 amino acid (aa) protein with multiple domains. From the N-terminus, there is a 19 aa activation domain (AD1), a 41 aa glutamine/alanine (Q/A) repeat segment (AD2), a 128 aa Runt/DNA-binding region, a 9 aa NLS and a 285 aa ProSerThr (PST)-rich sequence that is needed for gene activation. Two isoforms exist, one with a truncated AD1 domain and another with a 22 aa deletion in the AD3 section of PST-rich sequence. Human CBFA1 is 98% aa identical to mouse CBFA1.
RUNX2 is marker for Mesenchymal Stem Cells/Osteoblast Differentiation.