TY - JOUR
T1 - The distinct roles of Ras and Rac in PI 3-kinase-dependent protrusion during EGF-stimulated cell migration
AU - Yip, Shu Chin
AU - El-Sibai, Mirvat
AU - Coniglio, Salvatore J.
AU - Mouneimne, Ghassan
AU - Eddy, Robert J.
AU - Drees, Beth E.
AU - Neilsen, Paul O.
AU - Goswami, Sumanta
AU - Symons, Marc
AU - Condeelis, John S.
AU - Backer, Jonathan M.
PY - 2007/9/1
Y1 - 2007/9/1
N2 - Cell migration involves the localized extension of actin-rich protrusions, a process that requires Class I phosphoinositide 3-kinases (PI 3-kinases). Both Rac and Ras have been shown to regulate actin polymerization and activate PI 3-kinase. However, the coordination of Rac, Ras and PI 3-kinase activation during epidermal growth factor (EGF)-stimulated protrusion has not been analyzed. We examined PI 3-kinase-dependent protrusion in MTLn3 rat adenocarcinoma cells. EGF-stimulated phosphatidyl-inositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P3] levels showed a rapid and persistent response, as PI 3-kinase activity remained elevated up to 3 minutes. The activation kinetics of Ras, but not Rac, coincided with those of leading-edge PtdIns(3,4,5)P3 production. Small interfering RNA (siRNA) knockdown of K-Ras but not Rac1 abolished PtdIns(3,4,5)P3 production at the leading edge and inhibited EGF-stimulated protrusion. However, Rac1 knockdown did inhibit cell migration, because of the inhibition of focal adhesion formation in Rac1 siRNA-treated cells. Our data show that in EGF-stimulated MTLn3 carcinoma cells, Ras is required for both PtdIns(3,4,5)P3 production and lamellipod extension, whereas Rac1 is required for formation of adhesive structures. These data suggest an unappreciated role for Ras during protrusion, and a crucial role for Rac in the stabilization of protrusions required for cell motility.
AB - Cell migration involves the localized extension of actin-rich protrusions, a process that requires Class I phosphoinositide 3-kinases (PI 3-kinases). Both Rac and Ras have been shown to regulate actin polymerization and activate PI 3-kinase. However, the coordination of Rac, Ras and PI 3-kinase activation during epidermal growth factor (EGF)-stimulated protrusion has not been analyzed. We examined PI 3-kinase-dependent protrusion in MTLn3 rat adenocarcinoma cells. EGF-stimulated phosphatidyl-inositol (3,4,5)-trisphosphate [PtdIns(3,4,5)P3] levels showed a rapid and persistent response, as PI 3-kinase activity remained elevated up to 3 minutes. The activation kinetics of Ras, but not Rac, coincided with those of leading-edge PtdIns(3,4,5)P3 production. Small interfering RNA (siRNA) knockdown of K-Ras but not Rac1 abolished PtdIns(3,4,5)P3 production at the leading edge and inhibited EGF-stimulated protrusion. However, Rac1 knockdown did inhibit cell migration, because of the inhibition of focal adhesion formation in Rac1 siRNA-treated cells. Our data show that in EGF-stimulated MTLn3 carcinoma cells, Ras is required for both PtdIns(3,4,5)P3 production and lamellipod extension, whereas Rac1 is required for formation of adhesive structures. These data suggest an unappreciated role for Ras during protrusion, and a crucial role for Rac in the stabilization of protrusions required for cell motility.
KW - Cdc42
KW - Lamellipodia
KW - Rac
KW - Ras
KW - Rho
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U2 - 10.1242/jcs.005298
DO - 10.1242/jcs.005298
M3 - Article
C2 - 17698922
AN - SCOPUS:34948904831
SN - 0021-9533
VL - 120
SP - 3138
EP - 3146
JO - Journal of cell science
JF - Journal of cell science
IS - 17
ER -