TY - JOUR
T1 - Ca2+-RhoA signaling pathway required for polyamine-dependent intestinal epithelial cell migration
AU - Rao, Jaladanki N.
AU - Li, Li
AU - Golovina, Vera A.
AU - Platoshyn, Oleksandr
AU - Strauch, Eric D.
AU - Yuan, Jason Xiao Jian
AU - Wang, Jian Ying
PY - 2001
Y1 - 2001
N2 - 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.
AB - 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.
KW - Guanosine 5′-triphosphate-binding protein
KW - Intestinal epithelial cells
KW - Intracellular calcium
KW - Polyamines
KW - Potassium channels
KW - Restitution
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U2 - 10.1152/ajpcell.2001.280.4.c993
DO - 10.1152/ajpcell.2001.280.4.c993
M3 - Article
C2 - 11245616
AN - SCOPUS:0035016998
SN - 0363-6143
VL - 280
SP - C993-C1007
JO - American Journal of Physiology - Cell Physiology
JF - American Journal of Physiology - Cell Physiology
IS - 4 49-4
ER -