title: Protein kinase D2 potentiates MEK/ERK/RSK signaling, c-Fos accumulation and DNA synthesis induced by bombesin in Swiss 3T3 cells.
abstract: Protein kinase D (PKD) plays an important role in mediating cellular DNA synthesis in response to G protein-coupled receptor (GPCR) agonists but the function of other isoforms of the PKD family has been much less explored. Here, we examined whether PKD2 overexpression in Swiss 3T3 cells facilitates DNA synthesis and the activation of the extracellular regulated protein kinase (ERK) pathway in response to the mitogenic GPCR agonist bombesin. We show that PKD2 overexpression markedly potentiated the ability of this agonist to induce DNA synthesis. Addition of bombesin to Swiss 3T3 cells overexpressing PKD2 also induced a striking increase in the duration of MEK/ERK/RSK activation as compared with cultures of control cells. In contrast, neither DNA synthesis nor the duration of ERK activation in response to epidermal growth factor, which acts via protein kinase C/PKD2-independent pathways, was increased. Furthermore, bombesin promoted a striking accumulation of c-Fos protein in cells overexpressing PKD2. Our study demonstrates that PKD2, like PKD, facilitates mitogenesis and supports the hypothesis that an increase in the duration of the ERK signaling leading to accumulation of immediate gene products is one of the mechanisms by which isoforms of the PKD family enhance re-initiation of DNA synthesis by Gq-coupled receptor activation.
authors.affiliation: Division of Digestive Diseases, Department of Medicine, School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095, USA.
authors.forename: James
authors.initials: J
authors.lastname: Sinnett-Smith
authors.forename: Elena
authors.initials: E
authors.lastname: Zhukova
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Rey
authors.forename: Enrique
authors.initials: E
authors.lastname: Rozengurt
mesh_terms: D016475:3T3 Cells; D000818:Animals; D001839:Bombesin / Q000494:pharmacology*; D002455:Cell Division / Q000187:drug effects / Q000502:physiology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000378:metabolism; D043802:GTP-Binding Protein alpha Subunits, Gq-G11 / Q000378:metabolism; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D049452:Green Fluorescent Proteins / Q000235:genetics; D020935:MAP Kinase Signaling System / Q000187:drug effects* / Q000502:physiology*; D051379:Mice; D020929:Mitogen-Activated Protein Kinase Kinases / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000494:pharmacology*; D000091283:Protein Kinase D2; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism*; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism; D019893:Ribosomal Protein S6 Kinases; D014162:Transfection
chemical_list: D018377:Neurotransmitter Agents; D000091283:Protein Kinase D2; D016760:Proto-Oncogene Proteins c-fos; D049452:Green Fluorescent Proteins; D011494:Protein Kinases; D019893:Ribosomal Protein S6 Kinases; D048049:Extracellular Signal-Regulated MAP Kinases; D020929:Mitogen-Activated Protein Kinase Kinases; D043802:GTP-Binding Protein alpha Subunits, Gq-G11; D001839:Bombesin