MAP2K1 and neoplasm: Further, in addition to stabilizing tumor/endothelial cell adhesive interactions, endothelial α3β1 engagement triggers the formation of the focal adhesion type macromolecular signaling complexes at the endothelial cell membrane and time-dependent phosphorylation of Src, p38, and MEK1/2 in endothelial cells downstream of α3β1 indicative of the activation of p38 and ERK1/2 signal transduction pathways.