Physicochemical Control of Adult Stem Cell Differentiation: Shedding Light on Potential Molecular Mechanisms
Figure 3
Two alternate coupling molecular mechanisms. The soluble factors are known to play an important role in stem cells differentiation (thicker arrows). (a) A physical stimulus may affect cell differentiation synergistically in the presence of the soluble factors via integrins and the MAP kinase signaling system. The physical stimulus causes integrin redistribution, clustering, activation, and assembly of some focal adhesion proteins such as FAK, paxillin, vinculin, src, and others. Enzymatic activity of assembled proteins (e.g., FAK or src) causes further MAP kinase activation. In effect, the MAP kinase cascade is amplified and cell differentiation may be accelerated. (b) Alternative mechanism involves activation of other receptors (e.g., G-proteins receptors) in the cell membrane. This leads to the PLC enzyme-mediated signaling through Ca2+ and protein kinase C (PKC) in multiple pathways. Not all intricate signaling effects of these secondary messengers are shown. However, PKC activation can be effectively coupled to the MAP kinase cascades.
