Figure 3

Proposed mechanisms for how p107 can control neuronal differentiation and endochondral bone formation. p107 can bind to E2Fs and potentially inhibit the transcription of Hes1 and Fgf2, two genes involved in cell cycle control, survival, and cell fate decisions during neurogenesis (left panel). During endochondral bone formation in mesenchymal progenitors, FGF signaling can induce the direct binding and de-phosphorylation is p107 by PP2A, which then leads to p107-mediated repression of target genes. Although the direct targets of p107 in this context have yet to be identified, candidates such as E2F1 and Cbfa1 have both shown to be critical mediators of bone and chondrocyte development and are deregulated in the absence of p107 and p130 [138, 139].