“…These signaling mechanisms may occur between stem cells, between support cells and stem cells, and between stem cells and differentiating cells. Cell/cell and cell/ECM adhesion and signaling in adult niches is mediated through cell adhesion receptors such as cadherins (Song et al, 2002;Zhang et al, 2003) and integrins (Jones and Watt, 1993;Shinohara et al, 1999;Suzuki et al, 2000;Fujimoto et al, 2002;Frye et al, 2003;Scott et al, 2003;Blanpain et al, 2004;Chen et al, 2004;Deb et al, 2004;Hidalgo et al, 2004;Corbel et al, 2005;Priestley et al, 2005;Wagers and Weissman, 2005;Bajanca et al, 2006;Pajoohesh-Ganji et al, 2006;Lawson et al, 2007;Yang et al, 2007). In this model, as a cell moves away from the niche and thus away from some regulatory signals, it adopts a differentiated phenotype as shown in the pair of cells to the right.…”