FIGURE 7.

Model of RhoGDIβ-regulated MSC commitment to adipocyte or SMC lineage. BMP4 signaling increases the expression of Lox, which down-regulates the expression of RhoGDIβ. The enhanced Rac1 activation due to the lowering of RhoGDIβ leads to actin filament disruption by decreasing the phosphorylation of MLC, facilitating adipocyte lineage commitment. Knockdown of Lox prevents BMP4-induced RhoGDIβ down-regulation and Rac1 activation, resulting in enhanced phosphorylation of MLC and formation of stress fibers, which drive commitment to the smooth muscle-like cell lineage.