[Mechanism of transcriptional regulation by Runx2 in osteoblasts].

Runt-related transcription factor 2 (Runx2) is an essential transcription factor for osteoblast differentiation, and the expression is regulated by many factors including bone morphogenetic protein (BMP). Core binding factorbeta (Cbf beta) is required for DNA binding of Runx2 and Runx2-dependent transcription, and Cbf beta regulates Runx2 function isoform-dependently. Further, ability of Runx2 for transcriptional activation is regulated by many molecules. Phosphoinositide 3-kinase (PI3K)-Akt signaling enhances DNA binding of Runx2 and Runx2-dependent transcription, and Runx2 upregulates PI3K subunits (p85 and p110 beta) and Akt. Therefore, Runx2 and PI3K-Akt signaling are mutually dependent each other in the regulation of osteoblast and chondrocyte differentiation and their migration.