RUNX2, presumably in complex with at least CBFB, binds to at least two of the three RUNX2-binding sites in the promoter of the CDKN1A (p21) gene. CDK4-mediated phosphorylation of RUNX2 enhances binding of RUNX2 to the CDKN1A promoter (Pierce et al. 2012). The complex of RUNX2 and HDAC6 is also implicated in regulation of the CDKN1A promoter (Westendorf et al. 2002).