Rho family small GTPases are essential for the formation of adherens junctions in epithelial cells. Here, we found that FilGAP (also known as ARHGAP24), a Rac-specific Rho GTPase-activating protein, promoted the formation of adherens junctions in Madin-Darby canine kidney (MDCK) cells. Knockdown of FilGAP by siRNA stimulated the disassembly and migration of MDCK cells induced by hepatocyte growth factor (HGF). By contrast, forced expression of FilGAP induced accumulation of E-cadherin at adherens junctions. Endogenous FilGAP colocalized with E-cadherin at adherens junctions, and depletion of FilGAP reduced the amount of E-cadherin expressed at the surface. The Rac GAP domain of FilGAP was necessary for the suppression of cell scattering induced by HGF. In agreement with this, siRNA-mediated knockdown of both Rac1 and FilGAP suppressed cell scattering induced by HGF. Forced expression of Rho kinase (ROCK, of which there are two isoforms ROCK1 and ROCK2) induced the accumulation of E-cadherin at the adherens junction, and depletion of FilGAP prevented the accumulation of E-cadherin. Moreover, wild-type FilGAP but not a non-phosphorylatable FilGAP mutant rescued the accumulation of E-cadherin at adherens junctions. These results suggest that FilGAP might regulate cell-cell adhesion through inactivation of Rac downstream of Rho-ROCK-signaling in MDCK cells.

In general, it is supposed that the construction of the new roads in rural areas is a major factor to induce the landuse conversion of farms located adjacent to the construction sites. However, the substantial factors of farm conversion and its relationship of road construction are not yet clarified. This study aims to analyze the pattern of the farmland conversion around the new road construction sites and to realize the influence of road construction and other factors through the case study in Ukiha Region, Fukuoka Prefecture. As the results of the discriminant analysis on the previous examples of farm conversion, we clarify the relationship between pattern of farm conversion and road construction factor and that the influence multiplied with the location factor strengthens the trend of farm conversion.