Ca2+-RhoA signaling pathway required for polyamine-dependent intestinal epithelial cell migration

Jaladanki N. Rao, Li Li, Vera A. Golovina, Oleksandr Platoshyn, Eric D. Strauch, Jason Xiao Jian Yuan, Jian Ying Wang

Research output: Contribution to journalArticlepeer-review

72 Scopus citations


Expression of voltage-gated K+ (Kv) channel genes is regulated by polyamines in intestinal epithelial cells (IEC-6 line), and Kv channel activity is involved in the regulation of cell migration during early restitution by controlling membrane potential (Em) and cytosolic free Ca2+ concentration ([Ca2+]cyt). This study tests the hypothesis that RhoA of small GTPases is a downstream target of elevated [Ca2+]cyt following activation of K+ channels by increased polyamines in IEC-6 cells. Depletion of cellular polyamines by α-difluoromethylornithine (DFMO) reduced whole cell K+ currents [IK(v)] through Kv channels and caused membrane depolarization, which was associated with decreases in [Ca2+]cyt, RhoA protein, and cell migration. Exogenous polyamine spermidine reversed the effects of DFMO on IK(v), Em, [Ca2+]cyt, and RhoA protein and restored cell migration to normal. Elevation of [Ca2+]cyt induced by the Ca2+ ionophore ionomycin increased RhoA protein synthesis and stimulated cell migration, while removal of extracellular Ca2+ decreased RhoA protein synthesis, reduced protein stability, and inhibited cell motility. Decreased RhoA activity due to Clostridium botulinum exoenzyme C3 transferase inhibited formation of myosin II stress fibers and prevented restoration of cell migration by exogenous spermidine in polyamine-deficient cells. These findings suggest that polyamine-dependent cell migration is partially initiated by the formation of myosin II stress fibers as a result of Ca2+-activated RhoA activity.

Original languageEnglish (US)
Pages (from-to)C993-C1007
JournalAmerican Journal of Physiology - Cell Physiology
Issue number4 49-4
StatePublished - 2001
Externally publishedYes


  • Guanosine 5′-triphosphate-binding protein
  • Intestinal epithelial cells
  • Intracellular calcium
  • Polyamines
  • Potassium channels
  • Restitution

ASJC Scopus subject areas

  • Physiology
  • Cell Biology


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