Directional cell migration regulation by small G proteins, nectin-like molecule-5, and afadin.

Cell movement is a complex and dynamic process that causes changes in cell morphology by reorganizing the actin cytoskeleton and modulating cell adhesions. For directional cell migration, cells must continuously receive the polarized environmental signals and transmit the polarized intracellular signals from a fixed direction, which orient protrusion of the leading edge. The dynamic regulation of cyclical activation and inactivation of the Rho family small G proteins as a result of the crosstalk between small G protein signaling pathways is particularly important for the formation and disassembly of leading edge structures. However, the regulatory mechanisms of directionality and small G protein dynamics have not been fully understood. Recently, it has been found that nectin, an immunoglobulin-like cell adhesion molecule, implicated in a wide variety of fundamental cellular events including cell adhesion, proliferation, movement, and polarity, and its related proteins such as nectin-like molecule-5 and afadin regulate directionality and small G protein dynamics during directional cell movement.