1
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Azoitei N, Cobbaut M, Becher A, Van Lint J, Seufferlein T. Protein kinase D2: a versatile player in cancer biology. Oncogene 2017; 37:1263-1278. [PMID: 29259300 DOI: 10.1038/s41388-017-0052-8] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 09/14/2017] [Accepted: 09/15/2017] [Indexed: 12/23/2022]
Abstract
Protein kinase D2 (PKD2) is a serine/threonine kinase that belongs to the PKD family of calcium-calmodulin kinases, which comprises three isoforms: PKD1, PKD2, and PKD3. PKD2 is activated by many stimuli including growth factors, phorbol esters, and G-protein-coupled receptor agonists. PKD2 participation to uncontrolled growth, survival, neovascularization, metastasis, and invasion has been documented in various tumor types including pancreatic, colorectal, gastric, hepatic, lung, prostate, and breast cancer, as well as glioma multiforme and leukemia. This review discusses the versatile functions of PKD2 from the perspective of cancer hallmarks as described by Hanahan and Weinberg. The PKD2 status, signaling pathways affected in different tumor types and the molecular mechanisms that lead to tumorigenesis and tumor progression are presented. The latest developments of small-molecule inhibitors selective for PKD/PKD2, as well as the need for further chemotherapies that prevent, slow down, or eliminate tumors are also discussed in this review.
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Affiliation(s)
- Ninel Azoitei
- Center for Internal Medicine I, University of Ulm, Ulm, Germany.
| | - Mathias Cobbaut
- Laboratory for Protein Phosphorylation and Proteomics, Department of Cellular and Molecular Medicine, Leuven Cancer Institute, KU Leuven, Leuven, Belgium
| | | | - Johan Van Lint
- Laboratory for Protein Phosphorylation and Proteomics, Department of Cellular and Molecular Medicine, Leuven Cancer Institute, KU Leuven, Leuven, Belgium
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2
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Differential PKC-dependent and -independent PKD activation by G protein α subunits of the Gq family: selective stimulation of PKD Ser⁷⁴⁸ autophosphorylation by Gαq. Cell Signal 2011; 24:914-21. [PMID: 22227248 DOI: 10.1016/j.cellsig.2011.12.014] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2011] [Revised: 12/06/2011] [Accepted: 12/19/2011] [Indexed: 11/21/2022]
Abstract
Protein kinase D (PKD) is activated within cells by stimulation of multiple G protein coupled receptors (GPCR). Earlier studies demonstrated a role for PKC to mediate rapid activation loop phosphorylation-dependent PKD activation. Subsequently, a novel PKC-independent pathway in response to Gαq-coupled GPCR stimulation was identified. Here, we examined further the specificity and PKC-dependence of PKD activation using COS-7 cells cotransfected with different Gq-family Gα and stimulated with aluminum fluoride (AlF4⁻). PKD activation was measured by kinase assays, and Western blot analysis of activation loop sites Ser⁷⁴⁴, a prominent and rapid PKC transphosphorylation site, and Ser⁷⁴⁸, a site autophosphorylated in the absence of PKC signaling. Treatment with AlF4⁻ potently induced PKD activation and Ser⁷⁴⁴ and Ser⁷⁴⁸ phosphorylation, in the presence of cotransfected Gαq, Gα11, Gα14 or Gα15. These treatments achieved PKD activation loop phosphorylation similar to the maximal levels obtained by stimulation with the phorbol ester, PDBu. Preincubation with the PKC inhibitor GF1 potently blocked Gα11-, Gα14-, and Gα15-mediated enhancement of Ser⁷⁴⁸ phosphorylation induced by AlF4⁻, and largely abolished Ser⁷⁴⁴ phosphorylation. In contrast, Ser⁷⁴⁸ phosphorylation was almost completely intact, and Ser⁷⁴⁴ phosphorylation was significantly activated in cells cotransfected with Gαq. Importantly, the differential Ser⁷⁴⁸ phosphorylation was also promoted by treatment of Swiss 3T3 cells with Pasteurella multocida toxin, a selective activator of Gαq but not Gα11. Taken together, our results suggest that Gαq, but not the closely related Gα11, promotes PKD activation in response to GPCR ligands in a unique manner leading to PKD autophosphorylation at Ser⁷⁴⁸.
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3
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Sinnett-Smith J, Rozengurt N, Kui R, Huang C, Rozengurt E. Protein kinase D1 mediates stimulation of DNA synthesis and proliferation in intestinal epithelial IEC-18 cells and in mouse intestinal crypts. J Biol Chem 2010; 286:511-20. [PMID: 21051537 DOI: 10.1074/jbc.m110.167528] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We examined whether protein kinase D1 (PKD1), the founding member of a new protein kinase family, plays a critical role in intestinal epithelial cell proliferation. Our results demonstrate that PKD1 activation is sustained, whereas that of PKD2 is transient in intestinal epithelial IEC-18 stimulated with the G(q)-coupled receptor agonists angiotensin II or vasopressin. PKD1 gene silencing utilizing small interfering RNAs dramatically reduced DNA synthesis and cell proliferation in IEC-18 cells stimulated with G(q)-coupled receptor agonists. To clarify the role of PKD1 in intestinal epithelial cell proliferation in vivo, we generated transgenic mice that express elevated PKD1 protein in the intestinal epithelium. Transgenic PKD1 exhibited constitutive catalytic activity and phosphorylation at the activation loop residues Ser(744) and Ser(748) and on the autophosphorylation site, Ser(916). To examine whether PKD1 expression stimulates intestinal cell proliferation, we determined the rate of crypt cell DNA synthesis by detection of 5-bromo-2-deoxyuridine incorporated into the nuclei of crypt cells of the ileum. Our results demonstrate a significant increase (p < 0.005) in DNA-synthesizing cells in the crypts of two independent lines of PKD1 transgenic mice as compared with non-transgenic littermates. Morphometric analysis showed a significant increase in the length and in the total number of cells per crypt in the transgenic PKD1 mice as compared with the non-transgenic littermates (p < 0.01). Thus, transgenic PKD1 signaling increases the number of cells per crypt by stimulating the rate of crypt cell proliferation. Collectively, our results indicate that PKD1 plays a role in promoting cell proliferation in intestinal epithelial cells both in vitro and in vivo.
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Affiliation(s)
- James Sinnett-Smith
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095, USA
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4
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Ha CH, Jin ZG. Protein kinase D1, a new molecular player in VEGF signaling and angiogenesis. Mol Cells 2009; 28:1-5. [PMID: 19655095 PMCID: PMC4228936 DOI: 10.1007/s10059-009-0109-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2009] [Accepted: 06/29/2009] [Indexed: 01/08/2023] Open
Abstract
Vascular endothelial growth factor (VEGF) is essential for many angiogenic processes both in normal and pathological conditions. However, the signaling pathways involved in VEGF-induced angiogenesis are incompletely understood. The protein kinase D1 (PKD1), a newly described calcium/calmodulin-dependent serine/threonine kinase, has been implicated in cell migration, proliferation and membrane trafficking. Increasing evidence suggests critical roles for PKD1-mediated signaling pathways in endothelial cells, particularly in the regulation of VEGF-induced angiogenesis. Recent studies show that class IIa histone deacetylases (HDACs) are PKD1 substrates and VEGF signal-responsive repressors of myocyte enhancer factor-2 (MEF2) transcriptional activation in endothelial cells. This review provides a guide to PKD1 signaling pathways and the direct downstream targets of PKD1 in VEGF signaling, and suggests important functions of PKD1 in angiogenesis.
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Affiliation(s)
- Chang Hoon Ha
- The Aab Cardiovascular Research Institute and Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York, USA
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5
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Sinnett-Smith J, Jacamo R, Kui R, Wang YM, Young SH, Rey O, Waldron RT, Rozengurt E. Protein kinase D mediates mitogenic signaling by Gq-coupled receptors through protein kinase C-independent regulation of activation loop Ser744 and Ser748 phosphorylation. J Biol Chem 2009; 284:13434-13445. [PMID: 19289471 DOI: 10.1074/jbc.m806554200] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Rapid protein kinase D (PKD) activation and phosphorylation via protein kinase C (PKC) have been extensively documented in many cell types cells stimulated by multiple stimuli. In contrast, little is known about the role and mechanism(s) of a recently identified sustained phase of PKD activation in response to G protein-coupled receptor agonists. To elucidate the role of biphasic PKD activation, we used Swiss 3T3 cells because PKD expression in these cells potently enhanced duration of ERK activation and DNA synthesis in response to G(q)-coupled receptor agonists. Cell treatment with the preferential PKC inhibitors GF109203X or Gö6983 profoundly inhibited PKD activation induced by bombesin stimulation for <15 min but did not prevent PKD catalytic activation induced by bombesin stimulation for longer times (>60 min). The existence of sequential PKC-dependent and PKC-independent PKD activation was demonstrated in 3T3 cells stimulated with various concentrations of bombesin (0.3-10 nm) or with vasopressin, a different G(q)-coupled receptor agonist. To gain insight into the mechanisms involved, we determined the phosphorylation state of the activation loop residues Ser(744) and Ser(748). Transphosphorylation targeted Ser(744), whereas autophosphorylation was the predominant mechanism for Ser(748) in cells stimulated with G(q)-coupled receptor agonists. We next determined which phase of PKD activation is responsible for promoting enhanced ERK activation and DNA synthesis in response to G(q)-coupled receptor agonists. We show, for the first time, that the PKC-independent phase of PKD activation mediates prolonged ERK signaling and progression to DNA synthesis in response to bombesin or vasopressin through a pathway that requires epidermal growth factor receptor-tyrosine kinase activity. Thus, our results identify a novel mechanism of G(q)-coupled receptor-induced mitogenesis mediated by sustained PKD activation through a PKC-independent pathway.
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Affiliation(s)
- James Sinnett-Smith
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - Rodrigo Jacamo
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - Robert Kui
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - YunZu M Wang
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - Steven H Young
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - Osvaldo Rey
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - Richard T Waldron
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095
| | - Enrique Rozengurt
- Division of Digestive Diseases, Department of Medicine, David Geffen School of Medicine, CURE: Digestive Diseases Research Center and Molecular Biology Institute, University of California, Los Angeles, California 90095.
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6
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Chen LA, Li J, Silva SR, Jackson LN, Zhou Y, Watanabe H, Ives KL, Hellmich MR, Evers BM. PKD3 is the predominant protein kinase D isoform in mouse exocrine pancreas and promotes hormone-induced amylase secretion. J Biol Chem 2009; 284:2459-71. [PMID: 19028687 PMCID: PMC2629096 DOI: 10.1074/jbc.m801697200] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2008] [Revised: 10/14/2008] [Indexed: 11/06/2022] Open
Abstract
The protein kinase D (PKD) family of serine/threonine kinases, which can be activated by gastrointestinal hormones, consists of three distinct isoforms that modulate a variety of cellular processes including intracellular protein transport as well as constitutive and regulated secretion. Although isoform-specific functions have been identified in a variety of cell lines, the expression and function of PKD isoforms in normal, differentiated secretory tissues is unknown. Here, we demonstrate that PKD isoforms are differentially expressed in the exocrine and endocrine cells of the pancreas. Specifically, PKD3 is the predominant isoform expressed in exocrine cells of the mouse and human pancreas, whereas PKD1 and PKD2 are more abundantly expressed in the pancreatic islets. Within isolated mouse pancreatic acinar cells, PKD3 undergoes rapid membrane translocation, trans-activating phosphorylation, and kinase activation after gastrointestinal hormone or cholinergic stimulation. PKD phosphorylation in pancreatic acinar cells occurs viaaCa2+-independent, diacylglycerol- and protein kinase C-dependent mechanism. PKD phosphorylation can also be induced by physiologic concentrations of secretagogues and by in vivo stimulation of the pancreas. Furthermore, activation of PKD3 potentiates MEK/ERK/RSK (RSK, ribosomal S6 kinase) signaling and significantly enhances cholecystokinin-mediated pancreatic amylase secretion. These findings reveal a novel distinction between the exocrine and endocrine cells of the pancreas and further identify PKD3 as a signaling molecule that promotes hormone-stimulated amylase secretion.
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Affiliation(s)
- L Andy Chen
- Department of Surgery and Sealy Center for Cancer Cell Biology, The University of Texas Medical Branch, Galveston, Texas 77555-0536, USA
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7
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Jacamo R, Sinnett-Smith J, Rey O, Waldron RT, Rozengurt E. Sequential protein kinase C (PKC)-dependent and PKC-independent protein kinase D catalytic activation via Gq-coupled receptors: differential regulation of activation loop Ser(744) and Ser(748) phosphorylation. J Biol Chem 2008; 283:12877-87. [PMID: 18337243 DOI: 10.1074/jbc.m800442200] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein kinase D (PKD) is a serine/threonine protein kinase rapidly activated by G protein-coupled receptor (GPCR) agonists via a protein kinase C (PKC)-dependent pathway. Recently, PKD has been implicated in the regulation of long term cellular activities, but little is known about the mechanism(s) of sustained PKD activation. Here, we show that cell treatment with the preferential PKC inhibitors GF 109203X or Gö 6983 blocked rapid (1-5-min) PKD activation induced by bombesin stimulation, but this inhibition was greatly diminished at later times of bombesin stimulation (e.g. 45 min). These results imply that GPCR-induced PKD activation is mediated by early PKC-dependent and late PKC-independent mechanisms. Western blot analysis with site-specific antibodies that detect the phosphorylated state of the activation loop residues Ser(744) and Ser(748) revealed striking PKC-independent phosphorylation of Ser(748) as well as Ser(744) phosphorylation that remained predominantly but not completely PKC-dependent at later times of bombesin or vasopressin stimulation (20-90 min). To determine the mechanisms involved, we examined activation loop phosphorylation in a set of PKD mutants, including kinase-deficient, constitutively activated, and PKD forms in which the activation loop residues were substituted for alanine. Our results show that PKC-dependent phosphorylation of the activation loop Ser(744) and Ser(748) is the primary mechanism involved in early phase PKD activation, whereas PKD autophosphorylation on Ser(748) is a major mechanism contributing to the late phase of PKD activation occurring in cells stimulated by GPCR agonists. The present studies identify a novel mechanism induced by GPCR activation that leads to late, PKC-independent PKD activation.
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Affiliation(s)
- Rodrigo Jacamo
- Department of Medicine, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, USA
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8
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Berna MJ, Hoffmann KM, Tapia JA, Thill M, Pace A, Mantey SA, Jensen RT. CCK causes PKD1 activation in pancreatic acini by signaling through PKC-delta and PKC-independent pathways. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1773:483-501. [PMID: 17306383 PMCID: PMC1924924 DOI: 10.1016/j.bbamcr.2006.12.008] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2006] [Revised: 12/02/2006] [Accepted: 12/18/2006] [Indexed: 12/25/2022]
Abstract
Protein kinase D1 (PKD1) is involved in cellular processes including protein secretion, proliferation and apoptosis. Studies suggest PKD1 is activated by various stimulants including gastrointestinal (GI) hormones/neurotransmitters and growth factors in a protein kinase C (PKC)-dependent pathway. However, little is known about the mechanisms of PKD1 activation in physiologic GI tissues. We explored PKD1 activation by GI hormones/neurotransmitters and growth factors and the mediators involved in rat pancreatic acini. Only hormones/neurotransmitters activating phospholipase C caused PKD1 phosphorylation (S916, S744/748). CCK activated PKD1 and caused a time- and dose-dependent increase in serine phosphorylation by activation of high- and low-affinity CCK(A) receptor states. Inhibition of CCK-stimulated increases in phospholipase C, PKC activity or intracellular calcium decreased PKD1 S916 phosphorylation by 56%, 62% and 96%, respectively. PKC inhibitors GF109203X/Go6976/Go6983/PKC-zeta pseudosubstrate caused a 62/43/49/0% inhibition of PKD1 S916 phosphorylation and an 87/13/82/0% inhibition of PKD1 S744/748 phosphorylation. Expression of dominant negative PKC-delta, but not PKC-epsilon, or treatment with PKC-delta translocation inhibitor caused marked inhibition of PKD phosphorylation. Inhibition of Src/PI3K/MAPK/tyrosine phosphorylation had no effect. In unstimulated cells, PKD1 was mostly located in the cytoplasm. CCK stimulated translocation of total and phosphorylated PKD1 to the membrane. These results demonstrate that CCK(A) receptor activation leads to PKD activation by signaling through PKC-dependent and PKC-independent pathways.
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Affiliation(s)
- Marc J. Berna
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, Maryland, 20892-1804, USA
| | - K. Martin Hoffmann
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, Maryland, 20892-1804, USA
| | - Jose A. Tapia
- Departamento de Fisiología, Universidad de Extremadura, Cáceres, 10071, Spain
| | - Michelle Thill
- National Eye Institute, NIH, Bethesda, Maryland, 20892-1804, USA
| | - Andrea Pace
- Medizinische Klinik I, Universitätsklinikum Hamburg-Eppendorf, 20246 Hamburg, Germany
| | | | - Robert T. Jensen
- Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health (NIH), Bethesda, Maryland, 20892-1804, USA
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Abstract
Cholecystokinin and gastrin receptors (CCK1R and CCK2R) are G protein-coupled receptors that have been the subject of intensive research in the last 10 years with corresponding advances in the understanding of their functioning and physiology. In this review, we first describe general properties of the receptors, such as the different signaling pathways used to exert short- and long-term effects and the structural data that explain their binding properties, activation, and regulation. We then focus on peripheral cholecystokinin receptors by describing their tissue distribution and physiological actions. Finally, pathophysiological peripheral actions of cholecystokinin receptors and their relevance in clinical disorders are reviewed.
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Affiliation(s)
- Marlène Dufresne
- Institut National de la Santé et de la Recherche Médicale U. 531, Institut Louis Bugnard, Centre Hospitalier Universitaire Rangueil, France
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Jackson LN, Li J, Chen LA, Townsend CM, Evers BM. Overexpression of wild-type PKD2 leads to increased proliferation and invasion of BON endocrine cells. Biochem Biophys Res Commun 2006; 348:945-9. [PMID: 16899224 PMCID: PMC2430871 DOI: 10.1016/j.bbrc.2006.07.142] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2006] [Accepted: 07/21/2006] [Indexed: 11/25/2022]
Abstract
Carcinoid tumors are rare neuroendocrine tumors with a predilection for the gastrointestinal tract. Protein kinase D (PKD), a novel serine/threonine protein kinase, has been implicated in the regulation of transport processes in certain cell types. We have reported an important role for PKD in stimulated peptide secretion from a human (BON) carcinoid cell line; however, the role of PKD isoforms, including PKD2, in the proliferation and invasion of carcinoid tumors remains unclear. In the present study, we found that overexpression of PKD2 by stable transfection of BON cells with PKD2-wild type (PKD2WT) significantly increased proliferation and invasion compared to cells transfected with PKD2-kinase dead (PKD2KD) or pcDNA3 (control). Similarly, inhibition of PKD2 activity with small interfering RNA (siRNA) significantly decreased proliferation and invasion compared to cells transfected with non-targeting control (NTC) siRNA. These data support an important role for PKD2 in carcinoid tumor progression. Targeted inhibition of the PKD family may prove to be a novel treatment option for patients with carcinoid tumors.
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Affiliation(s)
- Lindsey N. Jackson
- Department of Surgery, The University of Texas Medical Branch, Galveston, Texas
| | - Jing Li
- Department of Surgery, The University of Texas Medical Branch, Galveston, Texas
- Sealy Center for Cancer Cell Biology, The University of Texas Medical Branch, Galveston, Texas
| | - L. Andy Chen
- Department of Surgery, The University of Texas Medical Branch, Galveston, Texas
| | | | - B. Mark Evers
- Department of Surgery, The University of Texas Medical Branch, Galveston, Texas
- Sealy Center for Cancer Cell Biology, The University of Texas Medical Branch, Galveston, Texas
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Affiliation(s)
- Enrique Rozengurt
- Department of Medicine, UCLA-CURE Digestive Diseases Research Center and Molecular Biology Institute, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA.
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12
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Rey O, Reeve JR, Zhukova E, Sinnett-Smith J, Rozengurt E. G protein-coupled receptor-mediated phosphorylation of the activation loop of protein kinase D: dependence on plasma membrane translocation and protein kinase Cepsilon. J Biol Chem 2004; 279:34361-72. [PMID: 15190080 DOI: 10.1074/jbc.m403265200] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein kinase D (PKD) is a serine/threonine protein kinase activated by G protein-coupled receptor (GPCR) agonists through an incompletely characterized mechanism that includes its reversible plasma membrane translocation and activation loop phosphorylation via a protein kinase C (PKC)-dependent pathway. To gain a better understanding of the mechanism regulating the activation of PKD in response to GPCR stimulation, we investigated the role of its rapid plasma membrane translocation on its activation loop phosphorylation and identified the endogenous PKC isozyme that mediates that event in vivo. We had found that the activation loop of a PKD mutant, with reduced affinity for diacylglycerol and phorbol esters, was only phosphorylated upon its plasma membrane association. We also found that the activation loop phosphorylation and rapid plasma membrane dissociation of PKD were inhibited either by preventing the plasma membrane translocation of PKCepsilon, through abolition of its interaction with receptor for activated C kinase, or by suppressing the expression of PKCepsilon via specific small interfering RNAs. Thus, this study demonstrates that the plasma membrane translocation of PKD, in response to GPCR stimulation, is necessary for the PKCepsilon-mediated phosphorylation of the activation loop of PKD and that this event requires the translocation of both kinases to the plasma membrane. Based on these and previous results, we propose a model of GPCR-mediated PKD regulation that integrates its changes in distribution, catalytic activity, and multisite phosphorylation.
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Affiliation(s)
- Osvaldo Rey
- Department of Medicine, UCLA-CURE Digestive Diseases Research Center and Molecular Biology Institute, David Geffen School of Medicine, University of California-Los Angeles, CA 90095, USA
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13
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Cabrera-Poch N, Sánchez-Ruiloba L, Rodríguez-Martínez M, Iglesias T. Lipid raft disruption triggers protein kinase C and Src-dependent protein kinase D activation and Kidins220 phosphorylation in neuronal cells. J Biol Chem 2004; 279:28592-602. [PMID: 15096499 DOI: 10.1074/jbc.m312242200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Kidins220 (kinase D-interacting substrate of 220 kDa) is a novel neurospecific protein recently cloned as the first substrate for the Ser/Thr kinase protein kinase D (PKD). Herein we report that Kidins220 is constitutively associated to lipid rafts in PC12 cells, rat primary cortical neurons, and brain synaptosomes. Immunocytochemistry and confocal microscopy together with sucrose gradient fractionation show co-localization of Kidins220 and lipid raft-associated proteins. In addition, cholesterol depletion of cell membranes with methyl-beta-cyclodextrin dramatically alters Kidins220 localization and detergent solubility. By studying the putative involvement of lipid rafts in PKD activation and signaling we have found that active PKD partitions in lipid raft fractions after sucrose gradient centrifugation and that green fluorescent protein-PKD translocates to lipid raft microdomains at the plasma membrane after phorbol ester treatment. Strikingly, lipid rafts disruption by methyl-beta-cyclodextrin delays green fluorescent protein-PKD translocation, as determined by live cell confocal microscopy, and activates PKD, increasing Kidins220 phosphorylation on Ser(919) by a mechanism involving PKCepsilon and the small soluble tyrosine kinase Src. Collectively, these results reveal the importance of lipid rafts on PKD activation, translocation, and downstream signaling to its substrate Kidins220.
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Affiliation(s)
- Noemí Cabrera-Poch
- Instituto de Investigaciones Biomédicas Alberto Sols, Consejo Superior de Investigaciones Científicas-Universidad Autónoma de Madrid (CSIC-UAM), C/Arturo Duperier 4, 28029-Madrid, Spain
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14
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Sinnett-Smith J, Zhukova E, Hsieh N, Jiang X, Rozengurt E. Protein kinase D potentiates DNA synthesis induced by Gq-coupled receptors by increasing the duration of ERK signaling in swiss 3T3 cells. J Biol Chem 2004; 279:16883-93. [PMID: 14963034 DOI: 10.1074/jbc.m313225200] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023] Open
Abstract
Protein kinase D (PKD) potentiates cellular DNA synthesis in response to G protein-coupled receptor (GPCR) agonists but the mechanism(s) involved has not been elucidated. Here, we examined whether PKD overexpression in Swiss 3T3 cells regulates the activation/inactivation kinetics of the extracellular-regulated protein kinase (ERK) in response to the mitogenic GPCR agonists bombesin and vasopressin. Addition of bombesin or vasopressin to Swiss 3T3 cells overexpressing PKD induced a striking increase in the duration of MEK/ERK/RSK activation as compared with cultures of either control Swiss 3T3 cells or Swiss 3T3 cells expressing a kinase-inactive PKD mutant. In contrast, the duration of ERK activation in response to epidermal growth factor, which acts via protein kinase C/PKD-independent pathways, was not increased. Furthermore, bombesin or vasopressin promoted a striking increase in phosphorylation (at Ser-374) and accumulation of c-Fos (the c-fos proto-oncogene product) in Swiss 3T3 cells overexpressing wild-type (but not kinase-inactive) PKD. Inhibition of the sustained phase of ERK/RSK activation abrogated the increase in c-Fos accumulation and DNA synthesis induced by bombesin or vasopressin in PKD-overexpressing cells. Our results demonstrate that PKD selectively potentiates mitogenesis induced by bombesin or vasopressin in Swiss 3T3 cells by increasing the duration of MEK/ERK/RSK signaling.
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Affiliation(s)
- James Sinnett-Smith
- Department of Medicine, David Geffen School of Medicine, University of California, Los Angeles, California 90095, USA
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15
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Rykx A, De Kimpe L, Mikhalap S, Vantus T, Seufferlein T, Vandenheede JR, Van Lint J. Protein kinase D: a family affair. FEBS Lett 2003; 546:81-6. [PMID: 12829240 DOI: 10.1016/s0014-5793(03)00487-3] [Citation(s) in RCA: 347] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The protein kinase D family of enzymes consists of three isoforms: PKD1/PKCmu PKD2 and PKD3/PKCnu. They all share a similar architecture with regulatory sub-domains that play specific roles in the activation, translocation and function of the enzymes. The PKD enzymes have recently been implicated in very diverse cellular functions, including Golgi organization and plasma membrane directed transport, metastasis, immune responses, apoptosis and cell proliferation.
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Affiliation(s)
- An Rykx
- Division of Biochemistry, Faculty of Medicine, Katholieke Universiteit Leuven, Herestraat 49, 3000 Leuven, Belgium
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Waldron RT, Rozengurt E. Protein kinase C phosphorylates protein kinase D activation loop Ser744 and Ser748 and releases autoinhibition by the pleckstrin homology domain. J Biol Chem 2003; 278:154-63. [PMID: 12407104 DOI: 10.1074/jbc.m208075200] [Citation(s) in RCA: 162] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Persistent activation of protein kinase D (PKD) via protein kinase C (PKC)-mediated signal transduction is accompanied by phosphorylation at Ser(744) and Ser(748) located in the catalytic domain activation loop, but whether PKC isoforms directly phosphorylate these residues, induce PKD autophosphorylation, or recruit intermediate upstream kinase(s) is unclear. Here, we explore the mechanism whereby PKC activates PKD in response to cellular stimuli. We first assessed in vitro PKC-PKD transphosphorylation and PKD activation. A PKD738-753 activation loop peptide was well phosphorylated by immunoprecipitated PKC isoforms, consistent with similarities between the loop and their known substrate specificities. A similar peptide with glutamic acid replacing Ser(748) was preferentially phosphorylated by PKCepsilon, suggesting that PKD containing phosphate at Ser(748) is rapidly targeted by this isoform at Ser(744). When incubated in the presence of phosphatidylserine, phorbol 12,13-dibutyrate and ATP, intact PKD slowly autophosphorylated in the activation loop but only at Ser(748). In contrast, addition of purified PKCepsilon to the incubation mixture induced rapid Ser(744) and Ser(748) phosphorylation, concomitant with persistent 2-3-fold increases in PKD activity, measured using reimmunoprecipitated PKD to phosphorylate an exogenous peptide, syntide-2. We also further examined pleckstrin homology domain-mediated PKD regulation to determine its relationship with activation loop phosphorylation. The high constitutive activity of the pleckstrin homology (PH) domain deletion mutant PKD-deltaPH was not abrogated by mutation of Ser(744) and Ser(748) to alanines, suggesting that one function of activation loop phosphorylation in the PKD activation mechanism is to relieve autoinhibition by the PH domain. These studies provide evidence of a direct PKCepsilon-PKD phosphorylation cascade and provide additional insight into the activation mechanism.
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Affiliation(s)
- Richard T Waldron
- Division of Digestive Diseases, Department of Medicine, The David Geffen School of Medicine at UCLA, Los Angeles, California 90095-1786, USA
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Li J, Hellmich MR, Greeley GH, Townsend CM, Evers BM. Phorbol ester-mediated neurotensin secretion is dependent on the PKC-alpha and -delta isoforms. Am J Physiol Gastrointest Liver Physiol 2002; 283:G1197-206. [PMID: 12381534 DOI: 10.1152/ajpgi.00177.2002] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Neurotensin (NT) plays an important role in gastrointestinal secretion, motility, and growth. The mechanisms regulating NT secretion are not entirely known. Our purpose was to define the role of the PKC signaling pathway in secretion of NT from BON cells, a human pancreatic carcinoid cell line that produces and secretes NT peptide. We demonstrated expression of all 11 PKC isoforms at varying levels in untreated BON cells. Expression of PKC-alpha, -beta2, -delta, and -mu isoforms was most pronounced. Immunofluorescent staining showed PKC-alpha and -mu expression throughout the cytoplasm and in the membrane. Also, significant fluorescence of PKC-delta was noted in the nucleus and cytoplasm. Treatment with PMA induced translocation of PKC-alpha, -delta, and -mu from cytosol to membrane. Activation of PKC-alpha, -delta, and -mu was further confirmed by kinase assays. Addition of PKC-alpha inhibitor Gö-6976 at a nanomolar concentration, other PKC inhibitors Gö-6983 and GF-109203X, or PKC-delta-specific inhibitor rottlerin significantly inhibited PMA-mediated NT release. Overexpression of either PKC-alpha or -delta increased PMA-mediated NT secretion compared with control cells. We demonstrated that PMA-mediated NT secretion in BON cells is associated with translocation and activation of PKC-alpha, -delta, and -mu. Furthermore, inhibition of PKC-alpha and -delta blocked PMA-stimulated NT secretion, suggesting a critical role for these isoforms in NT release.
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Affiliation(s)
- Jing Li
- Department of Surgery, The University of Texas Medical Branch, Galveston, Texas 77555-0536, USA
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Rey O, Sinnett-Smith J, Zhukova E, Rozengurt E. Regulated nucleocytoplasmic transport of protein kinase D in response to G protein-coupled receptor activation. J Biol Chem 2001; 276:49228-35. [PMID: 11641411 DOI: 10.1074/jbc.m109395200] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Protein kinase D (PKD)/protein kinase C mu is a serine/threonine protein kinase activated by growth factors, antigen-receptor engagement, and G protein-coupled receptor (GPCR) agonists via a phosphorylation-dependent mechanism that requires protein kinase C (PKC) activity. In order to investigate the dynamic mechanisms associated with GPCR signaling, the intracellular distribution of PKD was analyzed in live cells by imaging fluorescent protein-tagged PKD and in fixed cells by immunocytochemistry. We found that PKD shuttled between the cytoplasm and the nucleus in both fibroblasts and epithelial cells. Cell stimulation with mitogenic GPCR agonists that activate PKD induced a transient nuclear accumulation of PKD that was prevented by inhibiting PKC activity. The nuclear import of PKD requires its cys2 domain in conjunction with a nuclear import receptor, while its nuclear export requires its pleckstrin homology domain and a competent Crm1-dependent nuclear export pathway. This study thus characterizes the regulated nuclear transport of a signaling molecule in response to mitogenic GPCR agonists and positions PKD as a serine kinase whose kinase activity and intracellular localization is coordinated by PKC.
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Affiliation(s)
- O Rey
- Unit of Signal Transduction and Gastrointestinal Cancer, Division of Digestive Diseases, Department of Medicine, UCLA School of Medicine, Los Angeles, California 900095-1786, USA
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Zhukova E, Sinnett-Smith J, Rozengurt E. Protein kinase D potentiates DNA synthesis and cell proliferation induced by bombesin, vasopressin, or phorbol esters in Swiss 3T3 cells. J Biol Chem 2001; 276:40298-305. [PMID: 11514571 DOI: 10.1074/jbc.m106512200] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
We examined whether protein kinase D (PKD) overexpression in Swiss 3T3 cells potentiates the proliferative response to either the G protein-coupled receptor agonists bombesin and vasopressin or the biologically active phorbol ester phorbol 12,13-dibutyrate (PDBu). In order to generate Swiss 3T3 cells stably overexpressing PKD, cultures of these cells were infected with retrovirus encoding murine PKD and green fluorescent protein (GFP) expressed as two separate proteins translated from the same mRNA. GFP was used as a marker for selection of PKD-positive cells. PKD overexpressed in Swiss 3T3 cells was dramatically activated by cell treatment with bombesin or PDBu as judged by in vitro kinase autophosphorylation assays and exogenous substrate phosphorylation. Concomitantly, these stimuli induced PKD phosphorylation at Ser(744), Ser(748), and Ser(916). PKD activation and phosphorylation were prevented by exposure of the cells to protein kinase C-specific inhibitors. Addition of bombesin, vasopressin, or PDBu to cultures of Swiss 3T3 cells overexpressing PKD induced a striking increase in DNA synthesis and cell number compared with cultures of Swiss 3T3-GFP cells. In contrast, stimulation of DNA synthesis in response to epidermal growth factor, which acts via protein kinase C/PKD-independent pathways, was not enhanced. Our results demonstrate that overexpression of PKD selectively potentiates mitogenesis induced by bombesin, vasopressin, or PDBu in Swiss 3T3 cells.
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Affiliation(s)
- E Zhukova
- Department of Medicine, School of Medicine and Molecular Biology Institute, UCLA, Los Angeles, CA 90095, USA
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Waldron RT, Rey O, Iglesias T, Tugal T, Cantrell D, Rozengurt E. Activation loop Ser744 and Ser748 in protein kinase D are transphosphorylated in vivo. J Biol Chem 2001; 276:32606-15. [PMID: 11410586 DOI: 10.1074/jbc.m101648200] [Citation(s) in RCA: 140] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The importance of activation loop phosphorylation in the regulation of protein kinase D (PKD/protein kinase C (PKC) mu) activity has become controversial. In order to clarify the mechanism(s) of PKD activation, we developed a novel phosphospecific antibody recognizing phosphorylated Ser(748) in PKD (pS748). Western blot analysis with the pS748 antibody, carried out with a variety of PKD forms and in a variety of cell types including full-length PKD transfected in COS-7 and HEK 293 cells, a green fluorescent protein-PKD fusion protein transfected in either Swiss 3T3 fibroblasts or Madin-Darby canine kidney epithelial cells, and endogenous PKD expressed in A20 lymphocytes and Rat-1 fibroblasts, indicated that Ser(748) phosphorylation was absent from unstimulated cells. In contrast, dramatic increases in Ser(748) phosphorylation were induced by phorbol esters, bombesin, or cross-linking of B lymphocyte antigen receptors or by cotransfection with active PKCepsilon or PKCeta. Western analysis using a second phosphospecific antibody, which primarily recognizes PKD phosphorylated at Ser(744), revealed that Ser(744) phosphorylation accompanies Ser(748) phosphorylation during PKD activation in vivo. Ser(744)/Ser(748) phosphorylation requires PKC but not PKD activity, indicative of transphosphorylation. Our results provide new experimental evidence indicating that activation loop phosphorylation at Ser(744) and Ser(748) occurs during PKD activation in vivo and support the notion of a PKC-PKD phosphorylation cascade.
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Affiliation(s)
- R T Waldron
- Unit of Signal Transduction and Gastrointestinal Cancer, Division of Digestive Diseases, Department of Medicine, and Molecular Biology Institute, UCLA School of Medicine and UCLA-CURE Digestive Diseases Research Center, Los Angeles, California 90095, USA
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