Polyamines regulate -catenin tyrosine phosphorylation via Ca during intestinal epithelial cell migration

Guo, Xin, Jaladanki N. Rao, Lan Liu, Mort Rizvi, Douglas J. Turner, and Jian-Ying Wang. Polyamines regulate -catenin tyrosine phosphorylation via Ca2 during intestinal epithelial cell migration. Am J Physiol Cell Physiol 283: C722–C734, 2002. First published April 24, 2002; 10.1152/ajpcell.00054.2002.—Polyamines are essential for early mucosal restitution that occurs by epithelial cell migration to reseal superficial wounds after injury. Normal intestinal epithelial cells are tightly bound in sheets, but they need to be rapidly disassembled during restitution. -Catenin is involved in cell-cell adhesion, and its tyrosine phosphorylation causes disassembly of adhesion junctions, enhancing the spreading of cells. The current study determined whether polyamines are required for the stimulation of epithelial cell migration by altering -catenin tyrosine phosphorylation. Migration of intestinal epithelial cells (IEC-6 line) after wounding was associated with an increase in -catenin tyrosine phosphorylation, which decreased the binding activity of -catenin to -catenin. Polyamine depletion by -difluoromethylornithine reduced cytoplasmic free Ca2 concentration ([Ca2 ]cyt), prevented induction of -catenin phosphorylation, and decreased cell migration. Elevation of [Ca2 ]cyt induced by the Ca2 ionophore ionomycin restored -catenin phosphorylation and promoted migration in polyamine-deficient cells. Decreased -catenin phosphorylation through the tyrosine kinase inhibitor herbimycin-A or genistein blocked cell migration, which was accompanied by reorganization of cytoskeletal proteins. These results indicate that -catenin tyrosine phosphorylation plays a critical role in polyamine-dependent cell migration and that polyamines induce -catenin tyrosine phosphorylation at least partially through [Ca2 ]cyt.