Human Caco-2 motility redistributes FAK and paxillin and activates p38 MAPK in a matrix-dependent manner

The signals involved in restitution during mucosal healing are poorly under stood. We compared focal adhesion kinase (FAK) and paxillin protein and pho sphorylation, extracellular signal-regulated kinase (ERK) 1, ERK2, and p38 activation, as well as FAK and paxillin organization in static and migratin g human intestinal Caco-2 cells on matrix proteins and anionically derivati zed polystyrene dishes (tissue culture plastic). We also studied effects of FAK, ERK, and p38 blockade in a monolayer-wounding model. Compared with st atic cells, cells migrating across matrix proteins matrix-dependently decre ased membrane/cytoskeletal FAK and paxillin and cytosolic FAK. Tyrosine pho sphorylated FAK and paxillin changed proportionately to FAK and paxillin pr otein. Conversely, cells migrating on plastic increased FAK and paxillin pr otein and phosphorylation. Migration matrix-dependently activated p38 and i nactivated ERK1 and ERK2. Total p38, ERK1, and ERK2 did not change. Caco-2 motility was inhibited by transfection of FRNK (the COOH-terminal region of FAK) and PD-98059, a mitogen-activated protein kinase-ERK kinase inhibitor , but not by SB-203580, a p38 inhibitor, suggesting that FAK and ERK modula te Caco-2 migration. In contrast to adhesion-induced phosphorylation, matri x may regulate motile intestinal epithelial cells by altering amounts and d istribution of focal adhesion plaque proteins available for phosphorylation as well as by p38 activation and ERK inactivation. Motility across plastic differs from migration across matrix.