Skip to main content
. 2006 Jun 23;50(1-3):181–190. doi: 10.1007/s10616-005-3862-4

Figure 1.

Figure 1

A hypothetical model of the action of different ligands in maintaining hESC pluripotency. BMP4 which is present in serum and produced by hESC binds to BMPR I and II receptors to activate Smad 1/5/8 leading to differentiation. Noggin produced by feeders can sequester BMP preventing its action. Alternatively Activin A, which belongs to the BMP family can compete for the BMPR I and II receptors to activate Smad 2/3/4 leading to self-renewal and block the actions of Smad 1/5/8 via Smad 6/7. FGF-2 is postulated to bind to FGFR1 receptors and activate the Akt/PI3K pathway which is required for self-renewal.