1
|
Duewell BR, Wilson NE, Bailey GM, Peabody SE, Hansen SD. Molecular dissection of PI3Kβ synergistic activation by receptor tyrosine kinases, GβGγ, and Rho-family GTPases. eLife 2024; 12:RP88991. [PMID: 38713746 PMCID: PMC11076043 DOI: 10.7554/elife.88991] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2024] Open
Abstract
Phosphoinositide 3-kinase (PI3K) beta (PI3Kβ) is functionally unique in the ability to integrate signals derived from receptor tyrosine kinases (RTKs), G-protein coupled receptors, and Rho-family GTPases. The mechanism by which PI3Kβ prioritizes interactions with various membrane-tethered signaling inputs, however, remains unclear. Previous experiments did not determine whether interactions with membrane-tethered proteins primarily control PI3Kβ localization versus directly modulate lipid kinase activity. To address this gap in our knowledge, we established an assay to directly visualize how three distinct protein interactions regulate PI3Kβ when presented to the kinase in a biologically relevant configuration on supported lipid bilayers. Using single molecule Total Internal Reflection Fluorescence (TIRF) Microscopy, we determined the mechanism controlling PI3Kβ membrane localization, prioritization of signaling inputs, and lipid kinase activation. We find that auto-inhibited PI3Kβ prioritizes interactions with RTK-derived tyrosine phosphorylated (pY) peptides before engaging either GβGγ or Rac1(GTP). Although pY peptides strongly localize PI3Kβ to membranes, stimulation of lipid kinase activity is modest. In the presence of either pY/GβGγ or pY/Rac1(GTP), PI3Kβ activity is dramatically enhanced beyond what can be explained by simply increasing membrane localization. Instead, PI3Kβ is synergistically activated by pY/GβGγ and pY/Rac1 (GTP) through a mechanism consistent with allosteric regulation.
Collapse
Affiliation(s)
- Benjamin R Duewell
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Naomi E Wilson
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Gabriela M Bailey
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Sarah E Peabody
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of OregonEugeneUnited States
| | - Scott D Hansen
- Department of Chemistry and Biochemistry, Institute of Molecular Biology, University of OregonEugeneUnited States
| |
Collapse
|
2
|
Duewell BR, Wilson NE, Bailey GM, Peabody SE, Hansen SD. Molecular dissection of PI3Kβ synergistic activation by receptor tyrosine kinases, GβGγ, and Rho-family GTPases. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.01.538969. [PMID: 37205345 PMCID: PMC10187233 DOI: 10.1101/2023.05.01.538969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The class 1A phosphoinositide 3-kinase (PI3K) beta (PI3Kβ) is functionally unique in the ability to integrate signals derived from receptor tyrosine kinases (RTKs), heterotrimeric guanine nucleotide-binding protein (G-protein)-coupled receptors (GPCRs), and Rho-family GTPases. The mechanism by which PI3Kβ prioritizes interactions with various membrane tethered signaling inputs, however, remains unclear. Previous experiments have not been able to elucidate whether interactions with membrane-tethered proteins primarily control PI3Kβ localization versus directly modulate lipid kinase activity. To address this gap in our understanding of PI3Kβ regulation, we established an assay to directly visualize and decipher how three distinct protein interactions regulate PI3Kβ when presented to the kinase in a biologically relevant configuration on supported lipid bilayers. Using single molecule Total Internal Reflection Fluorescence (TIRF) Microscopy, we determined the mechanism controlling membrane localization of PI3Kβ, prioritization of signaling inputs, and lipid kinase activation. We find that auto-inhibited PI3Kβ prioritizes interactions with RTK-derived tyrosine phosphorylated (pY) peptides before engaging either GβGγ or Rac1(GTP). Although pY peptides strongly localize PI3Kβ to membranes, stimulation of lipid kinase activity is modest. In the presence of either pY/GβGγ or pY/Rac1(GTP), PI3Kβ activity is dramatically enhanced beyond what can be explained by simply increasing the strength of membrane localization. Instead, PI3Kβ is synergistically activated by pY/GβGγ and pY/Rac1(GTP) through a mechanism consistent with allosteric regulation.
Collapse
|
3
|
Wen X, Zhang X, Hu Y, Xu J, Wang T, Yin S. iTRAQ-based quantitative proteomic analysis of Takifugu fasciatus liver in response to low-temperature stress. J Proteomics 2019; 201:27-36. [PMID: 30954612 DOI: 10.1016/j.jprot.2019.04.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2018] [Revised: 03/25/2019] [Accepted: 04/03/2019] [Indexed: 10/27/2022]
Abstract
Low temperatures profoundly influence the physiological and behavioural processes of ectotherms, especially teleosts, which have made them the subjects of strong interest over time. However, the characteristics of fish cold-tolerance at the protein level remain unclear. Therefore, to shed further light on the molecular mechanisms of low temperature adaptation in fish, we conducted quantitative proteomics on the T. fasciatus liver using iTRAQ. Comparing the proteomic profiles of the T. fasciatus liver at 12 °C and 26 °C, a total of 3741 proteins were identified, and 160 were differentially abundant proteins (DAPs). Among the DAPs, the most significant changes were noted in proteins involved in oxidative stress (nine proteins), mitochondrial enzymes (eleven proteins) and signal transduction (thirteen proteins). The KEGG enrichment analysis indicated significant enhancement of D-arginine and D-ornithine metabolism, MAPK signalling, Wnt signalling and Gap junction pathway. Subsequently, three significantly up-regulated proteins (CIRB, HSP90 and GST) and two significantly down-regulated proteins (FLNB and A2ML1) were validated with parallel reaction monitoring (PRM) assays. Furthermore, the changes in abundance of proteins that are involved in oxidative stress, mitochondrial enzymes and signal transduction were validated at the transcriptional level with qPCR. These verification results show that the experimental data of iTRAQ are reliable. Our results not only deepen the understanding of the mechanisms underlying low-temperature tolerance in fish, but they also may contribute to the enhancement of cold tolerance during its breeding process. SIGNIFICANCE OF THE STUDY: The study focused on a comparative quantitative proteomics analysis of the T. fasciatus liver in response to low temperatures using iTRAQ, which has not yet been reported in the literatures. The results showed that the effect of low temperature on T. fasciatus is significant, including a detoxification of metabolic by-products and oxidative stress, an activation of the mitochondrial enzyme to strengthen energy metabolism, and a negative effect on signal transduction, which result in dysfunction or suboptimal performance. These low-temperature-related changes in the liver proteome of T. fasciatus can facilitate the understanding of the low temperature-related response that takes place in similar conditions in the liver and may contribute to the breeding of cold-resistant strains.
Collapse
Affiliation(s)
- Xin Wen
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Xinyu Zhang
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Yadong Hu
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Jiejie Xu
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China
| | - Tao Wang
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China.
| | - Shaowu Yin
- College of Life Sciences, College of Marine Science and Engineering, Nanjing Normal University, Nanjing 210023, China; Co-Innovation Center for Marine Bio-Industry Technology of Jiangsu Province, Lianyungang, Jiangsu 222005, China.
| |
Collapse
|
4
|
Houslay DM, Anderson KE, Chessa T, Kulkarni S, Fritsch R, Downward J, Backer JM, Stephens LR, Hawkins PT. Coincident signals from GPCRs and receptor tyrosine kinases are uniquely transduced by PI3Kβ in myeloid cells. Sci Signal 2016; 9:ra82. [PMID: 27531651 PMCID: PMC5417692 DOI: 10.1126/scisignal.aae0453] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Class I phosphoinositide 3-kinases (PI3Ks) catalyze production of the lipid messenger phosphatidylinositol 3,4,5-trisphosphate (PIP3), which plays a central role in a complex signaling network regulating cell growth, survival, and movement. This network is overactivated in cancer and inflammation, and there is interest in determining the PI3K catalytic subunit (p110α, p110β, p110γ, or p110δ) that should be targeted in different therapeutic contexts. Previous studies have defined unique regulatory inputs for p110β, including direct interaction with Gβγ subunits, Rac, and Rab5. We generated mice with knock-in mutations of p110β that selectively blocked the interaction with Gβγ and investigated its contribution to the PI3K isoform dependency of receptor tyrosine kinase (RTK) and G protein (heterotrimeric guanine nucleotide-binding protein)-coupled receptor (GPCR) responses in primary macrophages and neutrophils. We discovered a unique role for p110β in supporting synergistic PIP3 formation in response to the coactivation of macrophages by macrophage colony-stimulating factor (M-CSF) and the complement protein C5a. In contrast, we found partially redundant roles for p110α, p110β, and p110δ downstream of M-CSF alone and a nonredundant role for p110γ downstream of C5a alone. This role for p110β completely depended on direct interaction with Gβγ, suggesting that p110β transduces GPCR signals in the context of coincident activation by an RTK. The p110β-Gβγ interaction was also required for neutrophils to generate reactive oxygen species in response to the Fcγ receptor-dependent recognition of immune complexes and for their β2 integrin-mediated adhesion to fibrinogen or poly-RGD+, directly implicating heterotrimeric G proteins in these two responses.
Collapse
Affiliation(s)
- Daniel M Houslay
- Inositide Laboratory, Babraham Institute, Babraham Research Campus, Babraham, Cambridge CB223AT, UK
| | - Karen E Anderson
- Inositide Laboratory, Babraham Institute, Babraham Research Campus, Babraham, Cambridge CB223AT, UK
| | - Tamara Chessa
- Inositide Laboratory, Babraham Institute, Babraham Research Campus, Babraham, Cambridge CB223AT, UK
| | - Suhasini Kulkarni
- Inositide Laboratory, Babraham Institute, Babraham Research Campus, Babraham, Cambridge CB223AT, UK
| | - Ralph Fritsch
- Department of Hematology and Oncology, Freiburg University Medical Centre, Albert-Ludwigs-Universität, Freiburg, Hugstetter Str. 55 79106, Germany
| | - Julian Downward
- Signal Transduction Laboratory, Francis Crick Institute, Lincoln's Inn Fields, London WC2A 3LY, UK
| | - Jonathan M Backer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Forchheimer 230, Bronx, NY 10461, USA
| | - Len R Stephens
- Inositide Laboratory, Babraham Institute, Babraham Research Campus, Babraham, Cambridge CB223AT, UK.
| | - Phillip T Hawkins
- Inositide Laboratory, Babraham Institute, Babraham Research Campus, Babraham, Cambridge CB223AT, UK.
| |
Collapse
|
5
|
Zhu LA, Fang NY, Gao PJ, Jin X, Wang HY, Liu Z. Differential ERK1/2 Signaling and Hypertrophic Response to Endothelin-1 in Cardiomyocytes from SHR and Wistar-Kyoto Rats: A Potential Target for Combination Therapy of Hypertension. Curr Vasc Pharmacol 2016; 13:467-74. [PMID: 25360842 PMCID: PMC4997939 DOI: 10.2174/1570161112666141014150007] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2014] [Revised: 04/29/2014] [Accepted: 05/21/2014] [Indexed: 11/26/2022]
Abstract
Extracellular signal regulated kinase½ (ERK1/2) signaling is critical to endothelin-1 (ET-1)-induced cardiomyocyte hypertrophy. This study was to investigate ERK1/2 signaling and hypertrophic response to ET-1 stimulation in cardiomyocytes (CMs) from spontaneous hypertensive rats (SHR) and normotensive Wistar-Kyoto rats (WKY). Primary neonatal SHR and WKY CMs were exposed to ET-1 for up to 24 hrs. Minimal basal ERK1/2 phosphorylation was present in WKY CMs, while a significant baseline ERK1/2 phosphorylation was observed in SHR CMs. ET-1 induced a time- and dose-dependent increase in ERK1/2 phosphorylation in both SHR and WKY CMs. However, ET-1-induced ERK1/2 activation occurred much earlier with significantly higher peak phosphorylation level, and stayed elevated for longer duration in SHR CMs than that in WKY CMs. ET-1-induced hypertrophic response was more prominent in SHR CMs than that in WKY CMs as reflected by increased cell surface area, intracellular actin density, and protein synthesis. Pre-treatment with ERK1/2 phosphorylation inhibitor PD98059 completely prevented ET-1-induced ERK1/2 phosphorylation and increases in cell surface area and protein synthesis in SHR and WKY CMs. The specific PI3 kinase inhibitor LY294002 blocked ET-1-induced Akt and ERK1/2 phosphorylation, and protein synthesis in CMs. These data indicated that ERK1/2 signaling was differentially enhanced in CMs, and was associated with increased cardiac hypertrophic response to ET-1 in SHR. ET-1-induced ERK1/2 activation and cardiac hypertrophy appeared to be mediated via PI3 kinase/Akt signaling in SHR and WKY. The differential ERK1/2 activation in SHR CMs by ET-1 might represent a potential target for combination therapy of hypertension.
Collapse
Affiliation(s)
| | - Ning-Yuan Fang
- Department of Geriatrics, Renji Hospital, Shanghai Jiao Tong University School of Medicine, 145 Shan-Dong Middle Road, Shanghai 200001, China.
| | | | | | | | - Zhenguo Liu
- Davis Heart & Lung Research Institute, the Ohio State University Medical Center, DHLRI Suite 200; 473 West 12th Ave, Columbus, OH 43210, USA.
| |
Collapse
|
6
|
Kitamura Y, Koide M, Akakabe Y, Matsuo K, Shimoda Y, Soma Y, Ogata T, Ueyama T, Matoba S, Yamada H, Ikeda K. Manipulation of cardiac phosphatidylinositol 3-kinase (PI3K)/Akt signaling by apoptosis regulator through modulating IAP expression (ARIA) regulates cardiomyocyte death during doxorubicin-induced cardiomyopathy. J Biol Chem 2013; 289:2788-800. [PMID: 24338479 DOI: 10.1074/jbc.m113.508143] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
PI3K/Akt signaling plays an important role in the regulation of cardiomyocyte death machinery, which can cause stress-induced cardiac dysfunction. Here, we report that apoptosis regulator through modulating IAP expression (ARIA), a recently identified transmembrane protein, regulates the cardiac PI3K/Akt signaling and thus modifies the progression of doxorubicin (DOX)-induced cardiomyopathy. ARIA is highly expressed in the mouse heart relative to other tissues, and it is also expressed in isolated rat cardiomyocytes. The stable expression of ARIA in H9c2 cardiac muscle cells increased the levels of membrane-associated PTEN and subsequently reduced the PI3K/Akt signaling and the downstream phosphorylation of Bad, a proapoptotic BH3-only protein. When challenged with DOX, ARIA-expressing H9c2 cells exhibited enhanced apoptosis, which was reversed by the siRNA-mediated silencing of Bad. ARIA-deficient mice exhibited normal heart morphology and function. However, DOX-induced cardiac dysfunction was significantly ameliorated in conjunction with reduced cardiomyocyte death and cardiac fibrosis in ARIA-deficient mice. Phosphorylation of Akt and Bad was substantially enhanced in the heart of ARIA-deficient mice even after treatment with DOX. Moreover, repressing the PI3K by cardiomyocyte-specific expression of dominant-negative PI3K (p110α) abolished the cardioprotective effects of ARIA deletion. Notably, targeted activation of ARIA in cardiomyocytes but not in endothelial cells reduced the cardiac PI3K/Akt signaling and exacerbated the DOX-induced cardiac dysfunction. These studies, therefore, revealed a previously undescribed mode of manipulating cardiac PI3K/Akt signaling by ARIA, thus identifying ARIA as an attractive new target for the prevention of stress-induced myocardial dysfunction.
Collapse
Affiliation(s)
- Youhei Kitamura
- From the Department of Cardiology, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kyoto 602-8566, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
7
|
McLean BA, Kienesberger PC, Wang W, Masson G, Zhabyeyev P, Dyck JRB, Oudit GY. Enhanced recovery from ischemia-reperfusion injury in PI3Kα dominant negative hearts: investigating the role of alternate PI3K isoforms, increased glucose oxidation and MAPK signaling. J Mol Cell Cardiol 2012; 54:9-18. [PMID: 23142539 DOI: 10.1016/j.yjmcc.2012.10.015] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/15/2012] [Revised: 10/16/2012] [Accepted: 10/29/2012] [Indexed: 11/24/2022]
Abstract
Classical ischemia-reperfusion (IR) preconditioning relies on phosphatidylinositol 3-kinase (PI3K) for protective signaling. Surprisingly, inhibition of PI3Kα activity using a dominant negative (DN) strategy protected the murine heart from IR injury. It has been proposed that increased signaling through PI3Kγ may contribute to the improved recovery of PI3KαDN hearts following IR. To investigate the mechanism by which PI3KαDN hearts are protected from IR injury, we created a double mutant (PI3KDM) model by crossing p110γ(-/-) (PI3KγKO) with cardiac-specific PI3KαDN mice. The PI3KDM model has morphological and hemodynamic features that are characteristic of both PI3Kγ(-/-) and PI3KαDN mice. Interestingly, when subjected to IR using ex vivo Langendorff perfusion, PI3KDM hearts showed significantly enhanced functional recovery when compared to wildtype (WT) hearts. However, signaling downstream of PI3K through Akt and GSK3β, which has been associated with IR protection, was reduced in PI3KDM hearts. Using ex vivo working heart perfusion, we found no difference in functional recovery after IR between PI3KDM and PI3KαDN; also, glucose oxidation rates were significantly increased in PI3KαDN hearts when compared to WT, and this metabolic shift has been associated with enhanced IR recovery. However, we found that PI3KαDN hearts still had enhanced recovery when perfused exclusively with fatty acids (FA). We then investigated parallel signaling pathways, and found that mitogen-activated protein kinase signaling was increased in PI3KαDN hearts, possibly through the inhibition of negative feedback loops downstream of PI3Kα.
Collapse
Affiliation(s)
- Brent A McLean
- Department of Physiology, Department of Medicine, University of Alberta, Edmonton, Canada
| | | | | | | | | | | | | |
Collapse
|
8
|
Ngkelo A, Meja K, Yeadon M, Adcock I, Kirkham PA. LPS induced inflammatory responses in human peripheral blood mononuclear cells is mediated through NOX4 and Giα dependent PI-3kinase signalling. J Inflamm (Lond) 2012; 9:1. [PMID: 22239975 PMCID: PMC3293082 DOI: 10.1186/1476-9255-9-1] [Citation(s) in RCA: 136] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2011] [Accepted: 01/12/2012] [Indexed: 11/10/2022] Open
Abstract
COPD is a disease of innate immunity and bacterial infections are a dominant cause of exacerbations in the later stages resulting in poor health and high mortality. The pathogen-associated molecular pattern (PAMP) lipopolysaccharide (LPS) is sensed by immune cells through activation of the toll-like receptor 4 (TLR4). This leads to the activation of NADPH oxidase (NOX) and NF-κB which together drive COPD inflammation. In this study we show in human PBMCs that LPS stimulated proinflammatory cytokine release (CXCL8 and IL6) was inhibited by approximately 50% by the broad specificity phosphatidylinositol 3-kinase (PI3K) inhibitor, wortmannin. Our results also demonstrate that activation of PI3K following LPS stimulation is mediated by a NOX4 dependent mechanism releasing endogenous H2O2, as the NOX4 inhibitor apocynin blocked LPS induced AKT phosphorylation. Moreover, LPS-induced PI3K activation was inhibited by the anti-oxidant N-acetylcysteine in a concentration dependent manner (IC50 ~100 μM). In addition, our data demonstrated that inhibition of small G proteins, by pre-treatment with pertussis toxin, inhibited LPS-induced AKT phosphorylation. Furthermore, the G-protein inhibitors pertussis toxin and mastoparan both inhibited LPS-induced CXCL8 and IL-6 release by approximately 50%. Together, these data indicate there is a mechanism in human PBMCs where TLR4 activation by LPS leads to ROS generation through NOX4 and activation of the PI3K pathway. This effect is apparently mediated through small G proteins facilitating the release of pro-inflammatory cytokines.
Collapse
Affiliation(s)
- Anta Ngkelo
- Airways Disease Section, National Heart and Lung Institute, Imperial College London, London, UK
| | - Koremu Meja
- University College London, Cancer Institute, London, UK
| | - Mike Yeadon
- Allergy and Respiratory, Pfizer, Sandwich, Kent, UK
| | - Ian Adcock
- Airways Disease Section, National Heart and Lung Institute, Imperial College London, London, UK
| | - Paul A Kirkham
- Airways Disease Section, National Heart and Lung Institute, Imperial College London, London, UK
| |
Collapse
|
9
|
O'Neill C. Phosphatidylinositol 3-kinase signaling in mammalian preimplantation embryo development. Reproduction 2008; 136:147-56. [PMID: 18515313 DOI: 10.1530/rep-08-0105] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The development of the preimplantation mammalian embryo is an autopoietic process; once initiated development proceeds without an absolute requirement for external information or growth cues. This developmental autonomy is partly explained by the generation of autocrine trophic ligands that are released and act back on the embryo via specific receptors. Several embryotrophic ligands cause receptor-dependent activation of 1-o-phosphatidylinositol 3-kinase. This enzyme phosphorylates phosphatidylinositol-4,5-bisphosphate to form phosphatidylinositol-3,4,5-trisphosphate. Genetic or pharmacological ablation of this enzyme activity disrupts normal development of preimplantation embryos. Phosphatidylinositol-3,4,5-trisphosphate is a membrane lipid that acts as a docking site for a wide range of proteins possessing the pleckstrin homology (PH) domain. Such proteins are important regulators of cell survival, proliferation, and differentiation. RAC-alpha serine/threonine protein kinase is an important PH domain protein and its activity is required for normal preimplantation embryo development and survival. The activity of a range of PH domain proteins is also implicated in the normal development of the embryo. This review critically examines the evidence for the activation of 1-o-phosphatidylinositol 3-kinase in the generation of pleiotypic trophic response to embryotrophins in the autopoietic development of the preimplantation embryo.
Collapse
Affiliation(s)
- Chris O'Neill
- Disciplines of Medicine and Physiology, Human Reproduction Unit, Royal North Shore Hospital, University of Sydney, St Leonards, New South Wales 2065, Australia.
| |
Collapse
|
10
|
Bolitho C, Bayl P, Hou JY, Lynch G, Hassel AJ, Wall AJ, Zoellner H. The Anti-Apoptotic Activity of Albumin for Endothelium Is Mediated by a Partially Cryptic Protein Domain and Reduced by Inhibitors of G-Coupled Protein and PI-3 Kinase, but Is Independent of Radical Scavenging or Bound Lipid. J Vasc Res 2007; 44:313-24. [PMID: 17438360 DOI: 10.1159/000101777] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2006] [Accepted: 02/18/2007] [Indexed: 12/18/2022] Open
Abstract
Increased vascular disease occurs with low albumin (human serum albumin, HSA), possibly reflecting specific inhibition of endothelial apoptosis reported for tissue culture. Despite the reported specificity for endothelial protection by HSA, the high but physiological concentrations needed appear more consistent with non-specific low-affinity interactions. We reconcile this contradiction by demonstrating protection is mediated by a partially cryptic HSA protein domain, which becomes more exposed and active following cyanogen bromide fragmentation (p < 0.001). Also, although others reported HSA radical scavenging and bound lipids as important for inhibiting apoptosis in non-endothelial cell types, we demonstrate the protective effect for endothelium is unaffected when HSA radical scavenging is blocked by alkylation, or following delipidation. Further probing the mechanism responsible, we found that the G-coupled protein inhibitors pertussis toxin and suramin reduced protection of endothelium by HSA (p < 0.005), while the tyrosine kinase inhibitor genistein had no effect. Consistent with a role for phosphoinositide 3 kinase (PI3K) was inhibition by both wortmannin and LY294002 (p < 0.05), as well as phosphorylation of Akt, while MAP kinase inhibitors had no effect. We conclude the active site in HSA inhibiting endothelial apoptosis is partially cryptic, and acts via a G-coupled protein PI3K-dependent mechanism.
Collapse
Affiliation(s)
- Christine Bolitho
- Cellular and Molecular Pathology Research Unit, Department of Oral Pathology and Oral Medicine, University of Sydney, Westmead Centre for Oral Health, Westmead, Australia
| | | | | | | | | | | | | |
Collapse
|
11
|
Ishibashi K, Okazaki S, Hiramatsu M. Simultaneous measurement of superoxide generation and intracellular Ca2+ concentration reveals the effect of extracellular Ca2+ on rapid and transient contents of superoxide generation in differentiated THP-1 cells. Biochem Biophys Res Commun 2006; 344:571-80. [PMID: 16630555 DOI: 10.1016/j.bbrc.2006.02.173] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2006] [Accepted: 02/21/2006] [Indexed: 11/25/2022]
Abstract
We invented a simultaneous measuring instrument of fluorescence and chemiluminescence, realizing the analysis of chronological correlation between change in intracellular Ca2+ concentration ([Ca2+]i) and superoxide generation. A human monocytic cell line, THP-1, differentiated to be neutrophil-like cells generated superoxide with increase in intracellular Ca2+ concentration when stimulated with formyl-methionyl-leucyl-phenylalanine (fMLP) whereas PMA, phorbol ester-stimulated superoxide response occurred without change in [Ca2+]i. The cells treated with TMB-8, an intracellular Ca2+ antagonist, generated superoxide rapidly as well as transiently with transient [Ca2+]i elevation after stimulation with fMLP, whereas EGTA-treated cells generated superoxide slowly as well as persistently with transient [Ca2+]i elevation after the stimulation. These results suggest that the rapid and transient contents of superoxide generation are specific for Ca2+ influx from the extracellular domain. Verapamil, voltage-dependent Ca2+ channel blocker, dose-dependently inhibited fMLP-stimulated extracellular Ca2+ influx and superoxide generation without affecting PMA-stimulated superoxide generation. Other channel blockers tested, nifedipine and diltiazem, similarly inhibited these fMLP-stimulated responses. Numerical analysis of the values of the response curves elucidated that TMB-8 or the channel blocker reveals or eliminates the same contents of superoxide generation by the antagonism of intracellular Ca2+ release or extracellular Ca2+ influx, respectively. Taking these results together, the characteristic extracellular Ca2+ influx essential for superoxide generation was first revealed by the simultaneous measurement of superoxide generation and change in [Ca2+]i.
Collapse
Affiliation(s)
- Kaname Ishibashi
- Laboratory of Molecular Biophotonics, 5000 Hirakuchi, Hamamatsu 434-8555, Japan.
| | | | | |
Collapse
|
12
|
Kim SK, Wang KC, Hong SJ, Chung CK, Lim SY, Kim YY, Chi JG, Kim CJ, Chung YN, Kim HJ, Cho BK. Gene expression profile analyses of cortical dysplasia by cDNA arrays. Epilepsy Res 2004; 56:175-83. [PMID: 14643002 DOI: 10.1016/j.eplepsyres.2003.09.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Cortical dysplasia (CD) is a well-recognized cause of intractable epilepsy, especially in children and is characterized histologically by derangements in cortical development and organization. The objective of this study was to expand the current knowledge of altered gene expression in CD as a first step towards in the identification of additional genes operative in the evolution of CD. Surgical specimens were obtained from eight patients (4 males and 4 females; age range 2-38 years; mean 15 years) with a pathologic diagnosis of CD. Nondysplastic temporal neocortex was obtained from a 2-year-old boy with intractable epilepsy and medial temporal lobe ganglioglioma. After total RNA isolation from frozen brain tissues, we carried out gene expression profiling using a cDNA expression array. Differences in gene expressions between CD and the nondysplastic neocortex were confirmed by semi-quantitative conventional reverse transcription-PCR. Three genes (recombination activating gene 1 (RAG1), heat shock 60 kDa protein 1 (HSP-60), and transforming growth factor beta1 (TGF beta1)) were found to be up-regulated more than two-fold in CD, whereas four genes (phosphoinositide-3-kinase regulatory subunit polypeptide 1 [p85 alpha] (PI3K), frizzled homolog 2 [Drosophila], Bcl-2/adenovirus E1B 19 kDa interacting protein (NIP3), and glia maturation factor beta (GMF beta)) were down-regulated to less than 50% of their normal levels. Interestingly, the majority of genes showing altered expression were associated with apoptosis. Our study demonstrates diverse changes in gene expression in CD. However, it remains to be shown which of these are causally related to the evolution of CD.
Collapse
Affiliation(s)
- Seung-Ki Kim
- Division of Pediatric Neurosurgery, Department of Neurosurgery, Seoul National University College of Medicine, Neurological Research Institute, SNUMRC, 28 Yongon-dong, Chongno-gu, Seoul 110-744, South Korea
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Xiong Y, Miyamoto N, Shibata K, Valasek MA, Motoike T, Kedzierski RM, Yanagisawa M. Short-chain fatty acids stimulate leptin production in adipocytes through the G protein-coupled receptor GPR41. Proc Natl Acad Sci U S A 2004; 101:1045-50. [PMID: 14722361 PMCID: PMC327148 DOI: 10.1073/pnas.2637002100] [Citation(s) in RCA: 511] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Leptin is an adipose-derived hormone that regulates a wide variety of physiological processes, including feeding behavior, metabolic rate, sympathetic nerve activity, reproduction, and immune response. Circulating leptin levels are tightly regulated according to energy homeostasis in vivo. Although mechanisms for the regulation of leptin production in adipocytes are not well understood, G protein-coupled receptors may play an important role in this adipocyte function. Here we report that C2-C6 short-chain fatty acids, ligands of an orphan G protein-coupled receptor GPR41, stimulate leptin expression in both a mouse adipocyte cell line and mouse adipose tissue in primary culture. Acute oral administration of propionate increases circulating leptin levels in mice. The concentrations of short-chain fatty acids required to stimulate leptin production are within physiological ranges, suggesting the relevance of this pathway in vivo.
Collapse
Affiliation(s)
- Yumei Xiong
- Howard Hughes Medical Institute and Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390-9050, USA
| | | | | | | | | | | | | |
Collapse
|
14
|
Wang M, Vogel I, Kalthoff H. Correlation between metastatic potential and variants from colorectal tumor cell line HT-29. World J Gastroenterol 2003; 9:2627-31. [PMID: 14606113 PMCID: PMC4656557 DOI: 10.3748/wjg.v9.i11.2627] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
AIM: To evaluate the relationship between uPA, PAI-1, CEA, PI3K and metastatic potential in three colorectal tumor cell lines.
METHODS: Metastatic model in nude rats was established by variants HT-29c and HT-29d cell lines and the metastatic potential of two tumor cell variants was compared. Urokinase-type plasminogen activator (uPA) and plasminogen activator inhibitor type 1 (PAI-1) were determined using ELISA in colorectal carcinoma WiDr, HT-29 and HT-29d cell lines with different metastatic potentials. Expression of carcinoembryonic antigen (CEA) and phosphoinositide 3-kinase (PI3-Kinase) was analyzed using immunohistochemistry (IHC) in these cell lines in vitro and in vivo. CEA expression was compared using fluorescence activated cell sorter (FACS) in vitro.
RESULTS: The number of HT-29d cells arrested in liver dramatically decreased within the initial 24 h after injection. The taking rate of liver metastases in the variant HT-29d increased as compared with parental HT-29 cells (70% versus 50%) and a variant HT-29b cells (70% versus 60%), and extensive organs were synchronously involved in metastases. The uPA concentration of variant HT-29d cell line was significantly higher than that of the non-metastatic WiDr and the low metastatic HT-29 cell lines. The variant HT-29d cells produced stronger PI3-kinase expression as compared with the non-metastatic WiDr cells and the low metastatic HT-29 cells in vivo.
CONCLUSION: The selected variant HT-29d cell exhibited an enhanced metastatic potential. The level of uPA and PAI-1 is positively correlated with the metastatic capacity of tumor cells. The expression of PI3-kinase correlates with tumor development and metastasis.
Collapse
Affiliation(s)
- Min Wang
- Department of Surgical Oncology, First Affiliated Hospital of Medical College, Zhejiang University, Hangzhou 310003, Zhejiang Province, China.
| | | | | |
Collapse
|
15
|
Dzimiri N. Receptor crosstalk. Implications for cardiovascular function, disease and therapy. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:4713-30. [PMID: 12354102 DOI: 10.1046/j.1432-1033.2002.03181.x] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
There are at least three well-defined signalling cascades engaged directly in the physiological regulation of cardiac circulatory function: the beta1-adrenoceptors that control the cardiac contractile apparatus, the renin-angiotensin-aldosterone system involved in regulating blood pressure and the natriuretic peptides contributing at least to the factors determining circulating volume. Apart from these pathways, other cardiac receptor systems, particularly the alpha1-adrenoceptors, adenosine, endothelin and opioid receptors, whose physiological role may not be immediately evident, are also important with respect to regulating cardiovascular function especially in disease. These and the majority of other cardiovascular receptors identified to date belong to the guanine nucleotide binding (G) protein-coupled receptor families that mediate signalling by coupling primarily to three G proteins, the stimulatory (Gs), inhibitory (Gi) and Gq/11 proteins to stimulate the adenylate cyclases and phospholipases, activating a small but diverse subset of effectors and ion channels. These receptor pathways are engaged in crosstalk utilizing second messengers and protein kinases as checkpoints and hubs for diverting, converging, sieving and directing the G protein-mediated messages resulting in different signalling products. Besides, the heart itself is endowed with the means to harmonize these signalling mechanisms and to fend off potentially fatal consequences of functional loss of the essential signalling pathways via compensatory reserve pathways, or by inducing some adaptive mechanisms to be turned on, if and when required. This receptor crosstalk constitutes the underlying basis for sustaining a coherently functional circulatory entity comprising mechanisms controlling the contractile apparatus, blood pressure and circulating volume, both in normal physiology and in disease.
Collapse
Affiliation(s)
- Nduna Dzimiri
- Cardiovascular Pharmacology Laboratory, Biological and Medical Research Department, King Faisal Specialist Hospital & Research Centre, Riyadh, Saudi Arabia.
| |
Collapse
|
16
|
|
17
|
Bi L, Okabe I, Bernard DJ, Nussbaum RL. Early embryonic lethality in mice deficient in the p110beta catalytic subunit of PI 3-kinase. Mamm Genome 2002; 13:169-72. [PMID: 11919689 DOI: 10.1007/bf02684023] [Citation(s) in RCA: 127] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2001] [Accepted: 10/31/2001] [Indexed: 11/25/2022]
Affiliation(s)
- Lei Bi
- Genetic Diseases Research Branch, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892-4472, USA
| | | | | | | |
Collapse
|
18
|
Gosmanov AR, Thomason DB. Insulin and isoproterenol differentially regulate mitogen-activated protein kinase-dependent Na(+)-K(+)-2Cl(-) cotransporter activity in skeletal muscle. Diabetes 2002; 51:615-23. [PMID: 11872658 DOI: 10.2337/diabetes.51.3.615] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Recent studies have demonstrated that p44/42(MAPK) extracellular signal-regulated kinase (ERK)1 and -2-dependent Na(+)-K(+)-2Cl(-) co-transporter (NKCC) activity may contribute to total potassium uptake by skeletal muscle. To study the precise mechanisms regulating NKCC activity, rat soleus and plantaris muscles were stimulated ex vivo by insulin or isoproterenol (ISO). Both hormones stimulated total uptake of the potassium congener (86)Rb by 25--70%. However, only ISO stimulated the NKCC-mediated (86)Rb uptake. Insulin inhibited the ISO-stimulated NKCC activity, and this counteraction was sensitive to the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580 in the predominantly slow-twitch soleus muscle. Pretreatment of the soleus muscle with the phosphatidylinositol (PI) 3-kinase inhibitors wortmannin and LY294002 or with SB203580 uncovered an insulin-stimulated NKCC activity and also increased the insulin-stimulated phosphorylation of ERK. In the predominantly fast-twitch plantaris muscle, insulin-stimulated NKCC activity became apparent only after inhibition of PI 3-kinase activity, accompanied by an increase in ERK phosphorylation. PI 3-kinase inhibitors also abolished insulin-stimulated p38 MAPK phosphorylation in the plantaris muscle and Akt phosphorylation in both muscles. These data demonstrated that insulin inhibits NKCC-mediated transport in skeletal muscle through PI 3-kinase-sensitive and SB203580-sensitive mechanisms. Furthermore, differential activation of signaling cascade elements after hormonal stimulation may contribute to fiber-type specificity in the control of potassium transport by skeletal muscle.
Collapse
Affiliation(s)
- Aidar R Gosmanov
- Department of Physiology, College of Medicine, University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
| | | |
Collapse
|
19
|
Mamoon AM, Baker RC, Farley JM. Activation of phospholipase D in porcine tracheal smooth muscle: role of phosphatidylinositol 3-kinase and RhoA activation. Eur J Pharmacol 2001; 433:7-16. [PMID: 11755129 DOI: 10.1016/s0014-2999(01)01439-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Muscarinic receptor agonists transiently activate phospholipase D in tracheal smooth muscle. Muscarinic activation of phospholipase D in this tissue is dependent on activation of protein kinase C and an unidentified pathway that is not protein kinase C dependent. Cholinergic agents have also been shown to activate phospholipase D by pathways linked to the small G protein, RhoA. This study explores the relationship between muscarinic activation of phophatidylinositol 3-kinase and activation of RhoA, and examines whether phospholipase D activation is dependent on either pathway in tracheal smooth muscle. Wortmannin or 2-(4-morphonyl)-8-phenyl-4H-1-benzopyran-4-one (LY-294002), putative specific inhibitors of phophatidylinositol 3-kinase, significantly inhibit acetylcholine-induced formation of phosphatidylethanol and also block acetylcholine-induced translocation of RhoA to the membrane. In previous experiments calphostin C, a protein kinase C inhibitor, partially inhibited both acetylcholine-induced and phorbol-12-myristate-13-acetate (PMA)-induced phosphatidylethanol formation. In the present study calphostin C did not block acetylcholine-induced RhoA translocation to the membrane. However, the Rho kinase inhibitor, N-(4-pyridyl)-4-(1-aminoethyl)-cyclohexanecarboxamide (Y-27632), significantly inhibited acetylcholine-induced phosphatidylethanol formation, but had no effect on activation of phospholipase D by PMA. Acetylcholine treatment also stimulated the phosphorylation of the 110-kDa subunit of phosphatidylinositol 3-kinase. Phosphorylation of phosphatidylinositol 3-kinase 110-kDa subunit could be blocked by wortmannin in a concentration-dependent manner, and acetylcholine-induced phosphatidylinositol 3-kinase activity was significantly inhibited by wortmannin. LY-294002 also inhibited acetylcholine-induced phosphorylation of 110-kDa subunit and activation of phosphatidylinositol 3-kinase. These results suggest that acetylcholine stimulation translocates RhoA to the membrane by a phosphatidylinositol 3-kinase-dependent mechanism and acetylcholine-induced phospholipase D stimulation is at least partly mediated via phosphatidylinositol 3-kinase, however, protein kinase C appears to activate phospholipase D independent of phosphatidylinositol 3-kinase or RhoA activation in porcine tracheal smooth muscle.
Collapse
Affiliation(s)
- A M Mamoon
- Department of Pharmacology and Toxicology, University of Mississippi Medical Center, 2500 North State Street, Jackson, MS 39216-4505, USA
| | | | | |
Collapse
|
20
|
Corvera S. Phosphatidylinositol 3-kinase and the control of endosome dynamics: new players defined by structural motifs. Traffic 2001; 2:859-66. [PMID: 11737823 DOI: 10.1034/j.1600-0854.2001.21201.x] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Phosphatidylinositol (PtdIns) 3-kinase (PI 3-kinase) activity has been implicated in fundamental cellular functions such as endosomal trafficking, growth-factor receptor signal transduction, and cell survival. This multiplicity of actions can be attributed to the existence of three classes of PI 3-kinases in mammalian cells, which can together lead to the production of four known distinct end products: PtdIns(3)P, PtdIns(3,4)P2, PtdIns(3,4,5)P3 and PtdIns(3,5)P2. The challenge of deciphering the connection between PI 3-kinase activity, the production of specific phosphoinositides and the control of specific cellular events is being met with the discovery of novel structural motifs that interact specifically with distinct PI 3-kinase products.
Collapse
Affiliation(s)
- S Corvera
- Program in Molecular Medicine, University of Massachusetts Medical School, 373 Plantation Street, Worcester, MA 01615, USA.
| |
Collapse
|
21
|
El Mabrouk M, Touyz RM, Schiffrin EL. Differential ANG II-induced growth activation pathways in mesenteric artery smooth muscle cells from SHR. Am J Physiol Heart Circ Physiol 2001; 281:H30-9. [PMID: 11406465 DOI: 10.1152/ajpheart.2001.281.1.h30] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Angiotensin II-induced growth signaling mechanisms were investigated in vascular smooth muscle cells (VSMCs) from mesenteric arteries of spontaneously hypertensive (SHR) and Wistar-Kyoto rats (WKY). In WKY, angiotensin II significantly increased protein synthesis ([(3)H]leucine incorporation) but not DNA synthesis ([(3)H]thymidine incorporation). In SHR, angiotensin II increased protein and DNA synthesis. VSMCs from both strains expressed angiotensin type 1 (AT(1)) and type 2 (AT(2)) receptors. Losartan (an AT(1) receptor antagonist) but not PD-123319 (an AT(2) receptor antagonist) attenuated angiotensin II-stimulated protein synthesis in WKY VSMCs. In SHR, losartan and PD-123319 partially inhibited angiotensin II-induced VSMC proliferation. The mitogen-activated protein kinase or extracellular signal-regulated protein kinase (ERK) kinase inhibitor PD-98059 blocked VSMC growth responses to angiotensin II in both strains. Angiotensin II increased ERK1/2 activation more in SHR than WKY, an effect inhibited by losartan but not PD-123319. LY-294002 [a phosphatidylinositol-3 (PI3) kinase inhibitor] blocked angiotensin II-stimulated ERK1/2 activation in SHR but not in WKY, whereas bisindolylmaleimide [a protein kinase C (PKC) inhibitor] was ineffective. In conclusion, angiotensin II stimulates VSMC proliferation via AT(1) and AT(2) receptors in SHR. In WKY, angiotensin II induces VSMC hypertrophy via AT(1) receptors. ERK1/2-dependent pathways regulated by intracellular Ca(2+) but not PKC mediate these effects. In SHR VSMCs, PI3 kinase plays a role in augmented angiotensin II-induced ERK1/2 phosphorylation. These angiotensin II-mediated signaling events could contribute to vascular remodeling in SHR.
Collapse
MESH Headings
- Angiotensin II/pharmacology
- Animals
- Calcium/physiology
- Cell Division/drug effects
- Cells, Cultured
- Enzyme Activation
- Hypertension/pathology
- Intracellular Membranes/metabolism
- Mesenteric Arteries/drug effects
- Mesenteric Arteries/metabolism
- Mesenteric Arteries/pathology
- Mitogen-Activated Protein Kinase 1/metabolism
- Mitogen-Activated Protein Kinase 3
- Mitogen-Activated Protein Kinases/metabolism
- Muscle, Smooth, Vascular/drug effects
- Muscle, Smooth, Vascular/metabolism
- Muscle, Smooth, Vascular/pathology
- Phosphatidylinositol 3-Kinases/physiology
- Phosphorylation
- Protein Kinase C/physiology
- Rats
- Rats, Inbred SHR/anatomy & histology
- Rats, Inbred WKY
- Receptor, Angiotensin, Type 1
- Receptor, Angiotensin, Type 2
- Receptors, Angiotensin/metabolism
- Receptors, Angiotensin/physiology
- Reference Values
Collapse
Affiliation(s)
- M El Mabrouk
- Multidisciplinary Research Group on Hypertension, Clinical Research Institute of Montreal, University of Montreal, Montreal, Quebec, Canada H2W 1R7
| | | | | |
Collapse
|
22
|
Gulli MP, Peter M. Temporal and spatial regulation of Rho-type guanine-nucleotide exchange factors: the yeast perspective. Genes Dev 2001; 15:365-79. [PMID: 11230144 DOI: 10.1101/gad.876901] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- M P Gulli
- Swiss Institute for Experimental Cancer Research (ISREC), 1066 Epalinges/VD, Switzerland
| | | |
Collapse
|
23
|
Belisle B, Abo A. N-Formyl peptide receptor ligation induces rac-dependent actin reorganization through Gbeta gamma subunits and class Ia phosphoinositide 3-kinases. J Biol Chem 2000; 275:26225-32. [PMID: 10843992 DOI: 10.1074/jbc.m002743200] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The N-formyl peptide receptor is a G protein-coupled transmembrane receptor involved in stimulating a variety of differential responses in neutrophils including chemotaxis, degranulation, superoxide production, transcriptional activation, and actin reorganization. Although it is known that N-formyl-Met-Leu-Phe induces actin reorganization, the sequence of events from the receptor to the actin cytoskeleton is not well characterized. To study the signaling pathway from the N-formyl peptide receptor to the actin cytoskeleton, we developed a model system utilizing microinjection techniques with a nonhematopoietic cell line. An expression vector coding for the N-formyl peptide receptor was microinjected into porcine aortic endothelial cells and stimulated with N-formyl-Met-Leu-Phe to induce actin reorganization and membrane ruffling. The receptor-mediated signal was blocked by pertussis toxin and by a dominant negative Rac-N17, indicating the involvement of G(i)alpha subunit and the small guanosine triphosphatase Rac, respectively. Moreover, Gbetagamma subunits and membrane targeted forms of phosphatidylinositol (PI) 3-kinase alpha were sufficient to induce similar actin reorganization, and coexpression of various mutants of PI 3-kinase with the N-formyl peptide receptor identified a link to class Ia PI-3 kinase-mediated actin reorganization.
Collapse
MESH Headings
- Actins/metabolism
- Animals
- DNA, Complementary/administration & dosage
- Endothelium, Vascular/cytology
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- GTP-Binding Protein beta Subunits
- GTP-Binding Protein gamma Subunits
- GTP-Binding Proteins/metabolism
- Heterotrimeric GTP-Binding Proteins
- Microinjections
- N-Formylmethionine Leucyl-Phenylalanine/metabolism
- Pertussis Toxin
- Phosphatidylinositol 3-Kinases/metabolism
- Plasmids
- Receptors, Formyl Peptide
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Receptors, Peptide/genetics
- Receptors, Peptide/metabolism
- Swine
- Virulence Factors, Bordetella/pharmacology
- rac GTP-Binding Proteins/metabolism
Collapse
Affiliation(s)
- B Belisle
- Onyx Pharmaceuticals, Richmond, California 94806, USA
| | | |
Collapse
|
24
|
Yamboliev IA, Wiesmann KM, Singer CA, Hedges JC, Gerthoffer WT. Phosphatidylinositol 3-kinases regulate ERK and p38 MAP kinases in canine colonic smooth muscle. Am J Physiol Cell Physiol 2000; 279:C352-60. [PMID: 10913001 DOI: 10.1152/ajpcell.2000.279.2.c352] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In canine colon, M2/M3 muscarinic receptors are coupled to extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein (MAP) kinases. We tested the hypothesis that this coupling is mediated by enzymes of the phosphatidylinositol (PI) 3-kinase family. RT-PCR and Western blotting demonstrated expression of two isoforms, PI 3-kinase-alpha and PI 3-kinase-gamma. Muscarinic stimulation of intact muscle strips (10 microM ACh) activated PI 3-kinase-gamma, ERK and p38 MAP kinases, and MAP kinase-activated protein kinase-2, whereas PI 3-kinase-alpha activation was not detected. Wortmannin (25 microM) abolished the activation of PI 3-kinase-gamma, ERK, and p38 MAP kinases. MAP kinase inhibition was a PI 3-kinase-gamma-specific effect, since wortmannin did not inhibit recombinant activated murine ERK2 MAP kinase, protein kinase C, Raf-1, or MAP kinase kinase. In cultured muscle cells, newborn calf serum (3%) activated PI 3-kinase-alpha and PI 3-kinase-gamma isoforms, ERK and p38 MAP kinases, and stimulated chemotactic cell migration. Using wortmannin and LY-294002 to inhibit PI 3-kinase activity and PD-098059 and SB-203580 to inhibit ERK and p38 MAP kinases, we established that these enzymes are functionally important for regulation of chemotactic migration of colonic myocytes.
Collapse
Affiliation(s)
- I A Yamboliev
- Department of Pharmacology, University of Nevada School of Medicine, Reno 89557-0046, USA.
| | | | | | | | | |
Collapse
|
25
|
Yokogawa T, Nagata S, Nishio Y, Tsutsumi T, Ihara S, Shirai R, Morita K, Umeda M, Shirai Y, Saitoh N, Fukui Y. Evidence that 3'-phosphorylated polyphosphoinositides are generated at the nuclear surface: use of immunostaining technique with monoclonal antibodies specific for PI 3,4-P(2). FEBS Lett 2000; 473:222-6. [PMID: 10812079 DOI: 10.1016/s0014-5793(00)01535-0] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Phosphatidylinositol (PI) 3,4-P(2) is a phosphoinositide that has been shown to be important for signal transduction in growth factor stimulation. We have produced monoclonal antibodies specific for PI 3,4-P(2), which were able to detect PI 3,4-P(2) generated in 293T cells treated with H(2)O(2), or in MKN45/BD110 cells expressing activated PI 3-kinase in immunostaining. Prolonged treatment with 0.05% Tween 20 resulted in detection of staining not only at the plasma membrane, but also at the nuclear surface, indicating that 3'-phosphorylated phosphoinositides can be generated and function in the nucleus.
Collapse
Affiliation(s)
- T Yokogawa
- Department of Applied Biological Chemistry, Graduate School of Agriculture and Life Science, University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|