MEK1 restores migration of polyamine-depleted cells by retention and activation of Rac1 in the cytoplasm
Open Access
- 1 February 2005
- journal article
- Published by American Physiological Society in American Journal of Physiology-Cell Physiology
- Vol. 288 (2), C350-C359
- https://doi.org/10.1152/ajpcell.00290.2004
Abstract
We previously showed that polyamines are required for proliferation and migration both in vivo and in a cultured intestinal epithelial cell (IEC-6) model. Wounding of the IEC-6 monolayer induced transient ERK activation, which was further enhanced by EGF. EGF stimulated migration in control and polyamine-depleted cells, but the degree of stimulation was significantly less in polyamine-depleted cells. Inhibition of MEK1 inhibited basal as well as EGF-induced ERK activation and migration. Expression of constitutively active (CA)-MEK and dominant-negative (DN)-MEK had significant effects on F-actin structure. CA-MEK increased stress fiber and lamellipodia formation, while DN-MEK showed loss of stress fibers and abnormal actin cytoskeletal structure. Unlike EGF, CA-MEK significantly increased migration of both control and polyamine-depleted cells. The most important and significant finding in this study was that polyamine depletion caused localization of Rac1 and RhoA to the nuclear as well as perinuclear regions. Interestingly, CA-MEK completely reversed the subcellular distribution of Rac1 and RhoA proteins in polyamine-depleted cells. Polyamine depletion increased Rac1 in the nuclear fraction and decreased it in the cytoplasmic and membrane fractions of vector-transfected cells. CA-MEK prevented accumulation of Rac1 in the nucleus. Polyamine depletion significantly decreased Rac1 activity during 6-h migration in vector-transfected cells. Cells transfected with CA-MEK had almost identical levels of activated Rac1 in all three groups. These results suggest that polyamine depletion prevents activation of Rac1 and RhoA by sequestering them to the nucleus and that expression of constitutively active MEK reverses this effect, creating the cellular localization required for activation.Keywords
This publication has 50 references indexed in Scilit:
- Prevention of TNF-α-induced apoptosis in polyamine-depleted IEC-6 cells is mediated through the activation of ERK1/2American Journal of Physiology-Gastrointestinal and Liver Physiology, 2004
- The Requirement for Polyamines for Intestinal Epithelial Cell Migration Is Mediated through Rac1Online Journal of Public Health Informatics, 2003
- Cell scattering of SK-N-MC neuroepithelioma cells in response to Ret and FGF receptor tyrosine kinase activation is correlated with sustained ERK2 activationOncogene, 1997
- Epidermal growth factor promotes rapid response to epithelial injury in rabbit duodenum in vitroGastroenterology, 1996
- Expression of Epidermal Growth Factor and Transforming Growth Factor-α after Exposure of Rat Gastric Mucosa to StressScandinavian Journal of Gastroenterology, 1996
- Relative distribution of actin, myosin I, and myosin II during the wound healing response of fibroblasts.The Journal of cell biology, 1993
- Epidermal growth factor, polyamines, and prostaglandins in healing of stress-induced gastric lesions in ratsDigestive Diseases and Sciences, 1993
- The small GTP-binding protein rac regulates growth factor-induced membrane rufflingCell, 1992
- The small GTP-binding protein rho regulates the assembly of focal adhesions and actin stress fibers in response to growth factorsCell, 1992
- ELECTRON MICROSCOPIC EVIDENCE FOR EPIDERMAL GROWTH FACTOR RECEPTOR (EGF‐R)‐LIKE IMMUNOREACTIVITY ASSOCIATED WITH THE BASOLATERAL SURFACE OF GASTRIC PARIETAL CELLSActa Pathologica Japonica, 1987