Diacylglycerol kinase-alpha mediates hepatocyte growth factor-induced epithelial cell scatter by regulating Rac activation and membrane ruffling.
Diacylglycerol kinases (Dgk) phosphorylate diacylglycerol (DG) to phosphatidic acid (PA), thus turning off and on, respectively, DG-mediated and PA-mediated signaling pathways. We previously showed that hepatocyte growth factor (HGF), vascular endothelial growth factor, and anaplastic lymphoma kinase activate Dgkalpha in endothelial and leukemia cells through a Src-mediated mechanism and that activation of Dgkalpha is required for chemotactic, proliferative, and angiogenic signaling in vitro. Here, we investigate the downstream events and signaling pathways regulated by Dgkalpha, leading to cell scatter and migration upon HGF treatment and v-Src expression in epithelial cells. We report that specific inhibition of Dgkalpha, obtained either pharmacologically by R59949 treatment, or by expression of Dgkalpha dominant-negative mutant, or by small interfering RNA-mediated down-regulation of endogenous Dgkalpha, impairs 1) HGF- and v-Src-induced cell scatter and migration, without affecting the loss of intercellular adhesions; 2) HGF-induced cell spreading, lamellipodia formation, membrane ruffling, and focal adhesions remodeling; and 3) HGF-induced Rac activation and membrane targeting. In summary, we provide evidence that Dgkalpha, activated downstream of tyrosine kinase receptors and Src, regulates crucial steps directing Rac activation and Rac-dependent remodeling of actin cytoskeleton and focal contacts in migrating epithelial cells.
Chianale
Federica
F
Department of Medical Sciences, University of Piemonte Orientale "A. Avogadro," 28100 Novara, Italy.
Cutrupi
Santina
S
Rainero
Elena
E
Baldanzi
Gianluca
G
Porporato
Paolo E
PE
Traini
Sara
S
Filigheddu
Nicoletta
N
Gnocchi
Viola F
VF
Santoro
Massimo M
MM
Parolini
Ornella
O
van Blitterswijk
Wim J
WJ
Sinigaglia
Fabiola
F
Graziani
Andrea
A
D000818:Animals; D015820:Cadherins / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects*; D002460:Cell Line; D002462:Cell Membrane / Q000187:drug effects / Q000201:enzymology*; D002465:Cell Movement / Q000187:drug effects; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism; D019852:Diacylglycerol Kinase / Q000235:genetics / Q000378:metabolism*; D015536:Down-Regulation / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology*; D017228:Hepatocyte Growth Factor / Q000494:pharmacology*; D006801:Humans; D011485:Protein Binding; D020744:rac GTP-Binding Proteins / Q000378:metabolism*
D015820:Cadherins; D017228:Hepatocyte Growth Factor; D019852:Diacylglycerol Kinase; D020744:rac GTP-Binding Proteins