Schematic diagram of possible key signaling components in the force-mediated stem cell differentiation. These mechanotransduction components include focal adhesion (FA), cytoskeletal contractility, Rho GTPase signaling and nuclear regulation. Simplified schematic diagram showing the components involved in (A) FAs in mechanotransduction, (B) the RhoA pathways in the regulation and differentiation of (i) embryonic stem cells and (ii) adult stem cells, and (C) nuclear regulation. (B) Pharmaceutical inhibitors are indicated in green text. Dotted lines, signaling pathway with intermediate steps not shown; dashed lines, signaling pathway with intermediate steps yet to be identified.(?), examples of questions under active research. Arrow, activation; block-ended line, inhibitions. B-Cat, beta-catenin; BMP, bone morphogenetic protein; Cad, cadherin; CCMT, continuous cyclic mechanical tension; ESC, embryonic stem cell; FAK, focal adhesion kinase; GEF, guanine exchange factor; KASH, Klarsicht, Anc-1, and Syne homology; LPA, lysophosphatidic acid; MLCK, myosin light-chain kinase; MSC, mesenchymal stem cell; NPC, neural progenitor cell; PPAR, peroxisome proliferator-activated receptor; ROCK, Rho-associated kinase; SMAD, SMA/mothers against decapentaplegic; SUN, Sad1p and UNc-84; VASP, vasodilator-stimulated phosphoprotein.