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Araki M, Kontani K. Analysis of the Guanine Nucleotide-Bound State of KRAS by Ion-Pair Reversed-Phase High-Performance Liquid Chromatography. Methods Mol Biol 2024; 2797:227-236. [PMID: 38570463 DOI: 10.1007/978-1-0716-3822-4_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/05/2024]
Abstract
Guanine nucleotides can be quantitatively analyzed by high-performance liquid chromatography (HPLC). Here we describe an ion-pair reversed-phase HPLC (IP-RP-HPLC)-based method, which enables analyzing GDP and GTP bound to small GTPases immunoprecipitated from cells. The activation status of FLAG-KRAS expressed in HEK293T cells can be investigated with the IP-RP-HPLC method. This method also can be adapted to determine the effects of compounds such as the KRAS/G12C inhibitor sotorasib on the activation status of FLAG-KRAS in the cells.
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Affiliation(s)
- Makoto Araki
- Department of Biochemistry, Meiji Pharmaceutical University, Tokyo, Japan
| | - Kenji Kontani
- Department of Biochemistry, Meiji Pharmaceutical University, Tokyo, Japan.
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2
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GEF-H1 Transduces FcεRI Signaling in Mast Cells to Activate RhoA and Focal Adhesion Formation during Exocytosis. Cells 2023; 12:cells12040537. [PMID: 36831204 PMCID: PMC9954420 DOI: 10.3390/cells12040537] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 02/01/2023] [Accepted: 02/03/2023] [Indexed: 02/11/2023] Open
Abstract
When antigen-stimulated, mast cells release preformed inflammatory mediators stored in cytoplasmic granules. This occurs via a robust exocytosis mechanism termed degranulation. Our previous studies revealed that RhoA and Rac1 are activated during mast cell antigen stimulation and are required for mediator release. Here, we show that the RhoGEF, GEF-H1, acts as a signal transducer of antigen stimulation to activate RhoA and promote mast cell spreading via focal adhesion (FA) formation. Cell spreading, granule movement, and exocytosis were all reduced in antigen-stimulated mast cells when GEF-H1 was depleted by RNA interference. GEF-H1-depleted cells also showed a significant reduction in RhoA activation, resulting in reduced stress fiber formation without altering lamellipodia formation. Ectopic expression of a constitutively active RhoA mutant restored normal morphology in GEF-H1-depleted cells. FA formation during antigen stimulation required GEF-H1, suggesting it is a downstream target of the GEF-H1-RhoA signaling axis. GEF-H1 was activated by phosphorylation in conjunction with antigen stimulation. Syk kinase is linked to the FcεRI signaling pathway and the Syk inhibitor, GS-9973, blocked GEF-H1 activation and also suppressed cell spreading, granule movement, and exocytosis. We concluded that during FcεRI receptor stimulation, GEF-H1 transmits signals to RhoA activation and FA formation to facilitate the exocytosis mechanism.
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3
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Ramachandran RP, Nandi I, Haritan N, Zlotkin-Rivkin E, Keren Y, Danieli T, Lebendiker M, Melamed-Book N, Breuer W, Reichmann D, Aroeti B. EspH interacts with the host active Bcr related (ABR) protein to suppress RhoGTPases. Gut Microbes 2022; 14:2130657. [PMID: 36219160 PMCID: PMC9559323 DOI: 10.1080/19490976.2022.2130657] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Enteropathogenic Escherichia coli are bacterial pathogens that colonize the gut and cause severe diarrhea in humans. Upon intimate attachment to the intestinal epithelium, these pathogens translocate via a type III secretion system virulent proteins, termed effectors, into the host cells. These effectors manipulate diverse host cell organelles and functions for the pathogen's benefit. However, the precise mechanisms underlying their activities are not fully understood despite intensive research. EspH, a critical effector protein, has been previously reported to disrupt the host cell actin cytoskeleton by suppressing RhoGTPase guanine exchange factors. However, native host proteins targeted by EspH to mediate these activities remained unknown. Here, we identified the active Bcr related (ABR), a protein previously characterized to possess dual Rho guanine nucleotide exchange factor and GTPase activating protein (GAP) domains, as a native EspH interacting partner. These interactions are mediated by the effector protein's C-terminal 38 amino acid segment. The effector primarily targets the GAP domain of ABR to suppress Rac1 and Cdc42, host cell cytotoxicity, bacterial invasion, and filopodium formation at infection sites. Knockdown of ABR expression abolished the ability of EspH to suppress Rac1, Cdc42. Our studies unravel a novel mechanism by which host RhoGTPases are hijacked by bacterial effectors.
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Affiliation(s)
- Rachana Pattani Ramachandran
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ipsita Nandi
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Nir Haritan
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Efrat Zlotkin-Rivkin
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Yael Keren
- The Protein Production Facility, Wolfson Centre for Applied Structural Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Tsafi Danieli
- The Protein Production Facility, Wolfson Centre for Applied Structural Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Mario Lebendiker
- The Protein Production Facility, Wolfson Centre for Applied Structural Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Naomi Melamed-Book
- Bioimaging Unit, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - William Breuer
- Proteomics and Mass Spectrometry Unit, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Dana Reichmann
- Proteomics and Mass Spectrometry Unit, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel,Department of Biological Chemistry, The Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Benjamin Aroeti
- Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel,CONTACT Benjamin Aroeti Department of Cell and Developmental Biology, Alexander Silberman Institute of Life Sciences, The Hebrew University of Jerusalem, Jerusalem91904, Israel
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4
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Development of a versatile HPLC-based method to evaluate the activation status of small GTPases. J Biol Chem 2021; 297:101428. [PMID: 34801548 PMCID: PMC8668980 DOI: 10.1016/j.jbc.2021.101428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 11/01/2021] [Accepted: 11/04/2021] [Indexed: 11/21/2022] Open
Abstract
Small GTPases cycle between an inactive GDP-bound and an active GTP-bound state to control various cellular events, such as cell proliferation, cytoskeleton organization, and membrane trafficking. Clarifying the guanine nucleotide-bound states of small GTPases is vital for understanding the regulation of small GTPase functions and the subsequent cellular responses. Although several methods have been developed to analyze small GTPase activities, our knowledge of the activities for many small GTPases is limited, partly because of the lack of versatile methods to estimate small GTPase activity without unique probes and specialized equipment. In the present study, we developed a versatile and straightforward HPLC-based assay to analyze the activation status of small GTPases by directly quantifying the amounts of guanine nucleotides bound to them. This assay was validated by analyzing the RAS-subfamily GTPases, including HRAS, which showed that the ratios of GTP-bound forms were comparable with those obtained in previous studies. Furthermore, we applied this assay to the investigation of psychiatric disorder-associated mutations of RHEB (RHEB/P37L and RHEB/S68P), revealing that both mutations cause an increase in the ratio of the GTP-bound form in cells. Mechanistically, loss of sensitivity to TSC2 (a GTPase-activating protein for RHEB) for RHEB/P37L, as well as both decreased sensitivity to TSC2 and accelerated guanine-nucleotide exchange for RHEB/S68P, is involved in the increase of their GTP-bound forms, respectively. In summary, the HPLC-based assay developed in this study provides a valuable tool for analyzing small GTPases for which the activities and regulatory mechanisms are less well understood.
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5
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Wang Y, Gai S, Zhang W, Huang X, Ma S, Huo Y, Wu Y, Tu H, Pin JP, Rondard P, Xu C, Liu J. The GABA B receptor mediates neuroprotection by coupling to G 13. Sci Signal 2021; 14:eaaz4112. [PMID: 34665640 DOI: 10.1126/scisignal.aaz4112] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Yunyun Wang
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Siyu Gai
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Wenhua Zhang
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Xuetao Huang
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Shumin Ma
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Yujia Huo
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Yichen Wu
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Haijun Tu
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Jean-Philippe Pin
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Philippe Rondard
- Institut de Génomique Fonctionnelle (IGF), Université de Montpellier, CNRS, INSERM, 34094 Montpellier, France
| | - Chanjuan Xu
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China
| | - Jianfeng Liu
- Cellular Signaling laboratory, International Research Center for Sensory Biology and Technology of MOST, Key Laboratory of Molecular Biophysics of MOE, School of Life Science and Technology, Huazhong University of Science and Technology, 430074 Wuhan, China.,Bioland Laboratory, Guangzhou Regenerative Medicine and Health Guangdong Laboratory, 510005 Guangzhou, China
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6
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Hülsemann M, Sanchez C, Verkhusha PV, Des Marais V, Mao SPH, Donnelly SK, Segall JE, Hodgson L. TC10 regulates breast cancer invasion and metastasis by controlling membrane type-1 matrix metalloproteinase at invadopodia. Commun Biol 2021; 4:1091. [PMID: 34531530 PMCID: PMC8445963 DOI: 10.1038/s42003-021-02583-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Accepted: 08/23/2021] [Indexed: 01/12/2023] Open
Abstract
During breast cancer metastasis, cancer cell invasion is driven by actin-rich protrusions called invadopodia, which mediate the extracellular matrix degradation required for the success of the invasive cascade. In this study, we demonstrate that TC10, a member of a Cdc42 subfamily of p21 small GTPases, regulates the membrane type 1 matrix metalloproteinase (MT1-MMP)-driven extracellular matrix degradation at invadopodia. We show that TC10 is required for the plasma membrane surface exposure of MT1-MMP at these structures. By utilizing our Förster resonance energy transfer (FRET) biosensor, we demonstrate the p190RhoGAP-dependent regulation of spatiotemporal TC10 activity at invadopodia. We identified a pathway that regulates invadopodia-associated TC10 activity and function through the activation of p190RhoGAP and the downstream interacting effector Exo70. Our findings reveal the role of a previously unknown regulator of vesicular fusion at invadopodia, TC10 GTPase, in breast cancer invasion and metastasis.
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Affiliation(s)
- Maren Hülsemann
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Colline Sanchez
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Polina V Verkhusha
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Vera Des Marais
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Analytical Imaging Facility, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Serena P H Mao
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Sara K Donnelly
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Jeffrey E Segall
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Louis Hodgson
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, 10461, USA.
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7
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Rivera-Robles MJ, Medina-Velázquez J, Asencio-Torres GM, González-Crespo S, Rymond BC, Rodríguez-Medina J, Dharmawardhane S. Targeting Cdc42 with the anticancer compound MBQ-167 inhibits cell polarity and growth in the budding yeast S. cerevisiae. Small GTPases 2020; 11:430-440. [PMID: 29969362 PMCID: PMC7549613 DOI: 10.1080/21541248.2018.1495008] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
The Rho GTPase Cdc42 is highly conserved in structure and function. Mechanical or chemical cues in the microenvironment stimulate the localized activation of Cdc42 to rearrange the actin cytoskeleton and establish cell polarity. A role for Cdc42 in cell polarization was first discovered in the budding yeast Saccharomyces cerevisiae, and subsequently shown to also regulate directional motility in animal cells. Accordingly, in cancer Cdc42 promotes migration, invasion, and spread of tumor cells. Therefore, we targeted Cdc42 as a therapeutic strategy to treat metastatic breast cancer and designed the small molecule MBQ-167 as a potent inhibitor against Cdc42 and the homolog Rac. MBQ-167 inhibited cancer cell proliferation and migration in-vitro, and tumor growth and spread in-vivo in a mouse xenograft model of metastatic breast cancer. Since haploid budding yeast express a single Cdc42 gene, and do not express Rac, we used this well characterized model of polarization to define the contribution of Cdc42 inhibition to the effects of MBQ-167 in eukaryotic cells. Growth, budding pattern, and Cdc42 activity was determined in wildtype yeast or cells expressing a conditional knockdown of Cdc42 in response to vehicle or MBQ-167 treatment. As expected, growth and budding polarity were reduced by knocking-down Cdc42, with a parallel effect observed with MBQ-167. Cdc42 activity assays confirmed that MBQ-167 inhibits Cdc42 activation in yeast, and thus, bud polarity. Hence, we have validated MBQ-167 as a Cdc42 inhibitor in another biological context and present a method to screen Cdc42 inhibitors with potential as anti-metastatic cancer drugs.
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Affiliation(s)
- Michael John Rivera-Robles
- Department of Biochemistry, School of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, USA
| | - Julia Medina-Velázquez
- Department of Biochemistry, School of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, USA
| | - Gabriela M. Asencio-Torres
- Department of Biochemistry, School of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, USA
| | - Sahily González-Crespo
- Department of Biochemistry, School of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, USA
| | - Brian C. Rymond
- Department of Biology, University of Kentucky, Lexington, USA
| | - José Rodríguez-Medina
- Department of Biochemistry, School of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, USA
| | - Suranganie Dharmawardhane
- Department of Biochemistry, School of Medicine, University of Puerto Rico Medical Sciences Campus, San Juan, USA
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8
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Mitochondrial Targeting of the Enteropathogenic Escherichia coli Map Triggers Calcium Mobilization, ADAM10-MAP Kinase Signaling, and Host Cell Apoptosis. mBio 2020; 11:mBio.01397-20. [PMID: 32934081 PMCID: PMC7492733 DOI: 10.1128/mbio.01397-20] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Enteropathogenic E. coli (EPEC) is an important human diarrhea-causing bacterium. The pathogenic effects of EPEC largely depend upon its ability to inject a series of proteins, termed effectors, into the host cells. One such effector is the mitochondrion-associated protein (Map). Map has been shown to induce actin-rich projections (i.e., filopodia) on the infected cell surface and activate a Rho GTPase enzyme termed Cdc42. Nonetheless, although most injected Map localizes to host mitochondria, its functions in the mitochondria remain unknown. Here, we show that Map targeting of mitochondria stimulates the disruption of mitochondrial membrane potential to induce Ca2+ efflux into the host cytoplasm. The efflux stimulates the activity of a protein termed ADAM10, which induces activation of a mitogen-activated protein kinase cascade leading to host cell apoptosis. As apoptosis plays a central role in host-pathogen interactions, our findings provide novel insights into the functions of mitochondrial Map in promoting the EPEC disease. The ability of diarrheagenic bacterial pathogens, such as enteropathogenic Escherichia coli (EPEC), to modulate the activity of mitogen-activated protein kinases (MAPKs) and cell survival has been suggested to benefit bacterial colonization and infection. However, our understanding of the mechanisms by which EPEC modulate these functions is incomplete. In this study, we show that the EPEC type III secreted effector Map stimulates the sheddase activity of the disintegrin and metalloproteinase domain-containing protein 10 (ADAM10) and the ERK and p38 MAPK signaling cascades. Remarkably, all these activities were dependent upon the ability of Map to target host mitochondria, mainly via its mitochondrial toxicity region (MTR). Map targeting of mitochondria disrupted the mitochondrial membrane potential, causing extrusion of mitochondrial Ca2+ into the host cell cytoplasm. We also found that Map targeting of mitochondria is essential for triggering host cell apoptosis. Based on these findings, we propose a model whereby Map imported into mitochondria causes mitochondrial dysfunction and Ca2+ efflux into the host cytoplasm. Since Ca2+ has been reported to promote ADAM10 activation, the acute elevation of Ca2+ in the cytoplasm may stimulate the ADAM10 sheddase activity, resulting in the release of epidermal growth factors that stimulate the ERK signaling cascade. As p38 activity is also Ca2+ sensitive, elevation in cytoplasmic Ca2+ may independently also activate p38. We hypothesize that Map-dependent MAPK activation, combined with Map-mediated mitochondrial dysfunction, evokes mitochondrial host cell apoptosis, potentially contributing to EPEC colonization and infection of the gut.
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9
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Kang T, Lee SJ, Kwon Y, Park D. Loss of ϐPix Causes Defects in Early Embryonic Development, and Cell Spreading and PlateletDerived Growth Factor-Induced Chemotaxis in Mouse Embryonic Fibroblasts. Mol Cells 2019; 42:589-596. [PMID: 31402636 PMCID: PMC6715337 DOI: 10.14348/molcells.2019.0140] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2019] [Revised: 07/11/2019] [Accepted: 07/12/2019] [Indexed: 11/27/2022] Open
Abstract
βPix is a guanine nucleotide exchange factor for the Rho family small GTPases, Rac1 and Cdc42. It is known to regulate focal adhesion dynamics and cell migration. However, the in vivo role of βPix is currently not well understood. Here, we report the production and characterization of βPix-KO mice. Loss of βPix results in embryonic lethality accompanied by abnormal developmental features, such as incomplete neural tube closure, impaired axial rotation, and failure of allantoischorion fusion. We also generated βPix-KO mouse embryonic fibroblasts (MEFs) to examine βPix function in mouse fibroblasts. βPix-KO MEFs exhibit decreased Rac1 activity, and defects in cell spreading and platelet-derived growth factor (PDGF)-induced ruffle formation and chemotaxis. The average size of focal adhesions is increased in βPix-KO MEFs. Interestingly, βPix-KO MEFs showed increased motility in random migration and rapid wound healing with elevated levels of MLC2 phosphorylation. Taken together, our data demonstrate that βPix plays essential roles in early embryonic development, cell spreading, and cell migration in fibroblasts.
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Affiliation(s)
- TaeIn Kang
- School of Biological Sciences, Seoul National University, Seoul 08826,
Korea
| | - Seung Joon Lee
- Computational Biology & Genomics, Biogen, Cambridge, MA 02142,
USA
| | - Younghee Kwon
- School of Biological Sciences, Seoul National University, Seoul 08826,
Korea
| | - Dongeun Park
- School of Biological Sciences, Seoul National University, Seoul 08826,
Korea
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10
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Korobko IV, Shepelev MV. Mutations in the Effector Domain of RhoV GTPase Impair Its Binding to Pak1 Protein Kinase. Mol Biol 2018. [DOI: 10.1134/s002689331804009x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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11
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Clancy JW, Sheehan CS, Tricarico CJ, D'Souza-Schorey C. Aberrant endocytosis leads to the loss of normal mitotic spindle orientation during epithelial glandular morphogenesis. J Biol Chem 2018; 293:12095-12104. [PMID: 29903910 DOI: 10.1074/jbc.ra117.001640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2017] [Revised: 05/30/2018] [Indexed: 11/06/2022] Open
Abstract
Epithelial cells form tissues with many functions, including secretion and environmental separation and protection. Glandular epithelial tissues comprise cysts and tubules that are formed from a polarized, single-epithelial cell layer surrounding a central, fluid-filled lumen. The pathways regulating key processes in epithelial tissue morphogenesis such as mitotic spindle formation are incompletely understood, but are important to investigate, as their dysregulation is a signature of epithelial tumors. Here, we describe a signaling axis that manifests in a defect in mitotic spindle orientation during epithelial growth and cystogenesis. We found that activation of the small GTPase ADP-ribosylation factor 6 (ARF6) results in the sustained internalization of cell-surface components such as the cMet receptor and the cell-adhesion molecule E-cadherin. The spindle orientation defect arising from elevated levels of ARF6-GTP required an increase in cMet endocytosis, but was independent of E-cadherin internalization or elevated extracellular signal-regulated kinase (ERK) activity resulting from internalized receptor signaling on endosomes. Misorientation of the mitotic spindle resulted in the development of epithelial cysts with structural abnormalities, the most conspicuous of which was the presence of multiple intercellular lumens. Abnormal mitotic spindle orientation was necessary but insufficient to disrupt glandular development, as blocking the strong prosurvival signal resulting from ERK hyperactivation yielded structurally normal cysts despite continued manifestation of spindle orientation defects. Our findings highlight a previously unknown link between ARF6 activation, cMet receptor internalization, and mitotic spindle orientation during epithelial glandular morphogenesis.
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Affiliation(s)
- James W Clancy
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556
| | - Colin S Sheehan
- Department of Biological Sciences, University of Notre Dame, Notre Dame, Indiana 46556
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12
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Shcherbakova DM, Cox Cammer N, Huisman TM, Verkhusha VV, Hodgson L. Direct multiplex imaging and optogenetics of Rho GTPases enabled by near-infrared FRET. Nat Chem Biol 2018; 14:591-600. [PMID: 29686359 PMCID: PMC5964015 DOI: 10.1038/s41589-018-0044-1] [Citation(s) in RCA: 86] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 03/01/2018] [Indexed: 12/31/2022]
Abstract
Direct visualization and light control of several cellular processes is a challenge, owing to the spectral overlap of available genetically encoded probes. Here we report the most red-shifted monomeric near-infrared (NIR) fluorescent protein, miRFP720, and the fully NIR Förster resonance energy transfer (FRET) pair miRFP670-miRFP720, which together enabled design of biosensors compatible with CFP-YFP imaging and blue-green optogenetic tools. We developed a NIR biosensor for Rac1 GTPase and demonstrated its use in multiplexed imaging and light control of Rho GTPase signaling pathways. Specifically, we combined the Rac1 biosensor with CFP-YFP FRET biosensors for RhoA and for Rac1-GDI binding, and concurrently used the LOV-TRAP tool for upstream Rac1 activation. We directly observed and quantified antagonism between RhoA and Rac1 dependent on the RhoA-downstream effector ROCK; showed that Rac1 activity and GDI binding closely depend on the spatiotemporal coordination between these two molecules; and simultaneously observed Rac1 activity during optogenetic manipulation of Rac1.
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Affiliation(s)
- Daria M Shcherbakova
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Natasha Cox Cammer
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Tsipora M Huisman
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Vladislav V Verkhusha
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA.
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, USA.
- Department of Biochemistry and Developmental Biology, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
| | - Louis Hodgson
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA.
- Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY, USA.
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Koraïchi F, Gence R, Bouchenot C, Grosjean S, Lajoie-Mazenc I, Favre G, Cabantous S. High-content tripartite split-GFP cell-based assays to screen for modulators of small GTPase activation. J Cell Sci 2018; 131:jcs.210419. [PMID: 29192060 PMCID: PMC5818064 DOI: 10.1242/jcs.210419] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 11/28/2017] [Indexed: 01/12/2023] Open
Abstract
The human Ras superfamily of small GTPases controls essential cellular processes such as gene expression and cell proliferation. As their deregulation is widely associated with human cancer, small GTPases and their regulatory proteins have become increasingly attractive for the development of novel therapeutics. Classical methods to monitor GTPase activation include pulldown assays that limit the analysis of GTP-bound form of proteins from cell lysates. Alternatively, live-cell FRET biosensors may be used to study GTPase activation dynamics in response to stimuli, but these sensors often require further optimization for high-throughput applications. Here, we describe a cell-based approach that is suitable to monitor the modulation of small GTPase activity in a high-content analysis. The assay relies on a genetically encoded tripartite split-GFP (triSFP) system that we integrated in an optimized cellular model to monitor modulation of RhoA and RhoB GTPases. Our results indicate the robust response of the reporter, allowing the interrogation of inhibition and stimulation of Rho activity, and highlight potential applications of this method to discover novel modulators and regulators of small GTPases and related protein-binding domains. Summary: The development of a fluorescent reporter of GTPase activation based on tripartite split-GFP that enables the evaluation of GEF activity and the effect of modulators of GTPase activation in a high-content analysis.
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Affiliation(s)
- Faten Koraïchi
- Cancer Research Center of Toulouse, INSERM U1037, 31037 Toulouse, France.,Université de Toulouse, Toulouse, France
| | - Rémi Gence
- Cancer Research Center of Toulouse, INSERM U1037, 31037 Toulouse, France.,Université de Toulouse, Toulouse, France
| | - Catherine Bouchenot
- Cancer Research Center of Toulouse, INSERM U1037, 31037 Toulouse, France.,Université de Toulouse, Toulouse, France
| | - Sarah Grosjean
- Cancer Research Center of Toulouse, INSERM U1037, 31037 Toulouse, France.,Université de Toulouse, Toulouse, France
| | - Isabelle Lajoie-Mazenc
- Cancer Research Center of Toulouse, INSERM U1037, 31037 Toulouse, France.,Université de Toulouse, Toulouse, France
| | - Gilles Favre
- Cancer Research Center of Toulouse, INSERM U1037, 31037 Toulouse, France .,Université de Toulouse, Toulouse, France
| | - Stéphanie Cabantous
- Cancer Research Center of Toulouse, INSERM U1037, 31037 Toulouse, France .,Université de Toulouse, Toulouse, France
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14
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Cleghorn WM, Bulus N, Kook S, Gurevich VV, Zent R, Gurevich EV. Non-visual arrestins regulate the focal adhesion formation via small GTPases RhoA and Rac1 independently of GPCRs. Cell Signal 2018; 42:259-269. [PMID: 29133163 PMCID: PMC5732042 DOI: 10.1016/j.cellsig.2017.11.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Revised: 11/09/2017] [Accepted: 11/10/2017] [Indexed: 02/07/2023]
Abstract
Arrestins recruit a variety of signaling proteins to active phosphorylated G protein-coupled receptors in the plasma membrane and to the cytoskeleton. Loss of arrestins leads to decreased cell migration, altered cell shape, and an increase in focal adhesions. Small GTPases of the Rho family are molecular switches that regulate actin cytoskeleton and affect a variety of dynamic cellular functions including cell migration and cell morphology. Here we show that non-visual arrestins differentially regulate RhoA and Rac1 activity to promote cell spreading via actin reorganization, and focal adhesion formation via two distinct mechanisms. Arrestins regulate these small GTPases independently of G-protein-coupled receptor activation.
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Affiliation(s)
- Whitney M Cleghorn
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States
| | - Nada Bulus
- Department of Medicine, Vanderbilt University, Nashville, TN 37232, United States
| | - Seunghyi Kook
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States
| | - Vsevolod V Gurevich
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States
| | - Roy Zent
- Department of Medicine, Vanderbilt University, Nashville, TN 37232, United States; Department of Veterans Affairs Hospital, Nashville, TN, 37232, United States
| | - Eugenia V Gurevich
- Department of Pharmacology, Vanderbilt University, Nashville, TN 37232, United States.
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15
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Jaraíz-Rodríguez M, González-Sánchez A, García-Vicente L, Medina JM, Tabernero A. Biotinylated Cell-penetrating Peptides to Study Intracellular Protein-protein Interactions. J Vis Exp 2017:56457. [PMID: 29286477 PMCID: PMC5755618 DOI: 10.3791/56457] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Here we present a protocol to study intracellular protein-protein interactions that is based on the widely used biotin-avidin pull-down system. The modification presented includes the combination of this technique with cell-penetrating sequences. We propose to design cell-penetrating baits that can be incubated with living cells instead of cell lysates and therefore the interactions found will reflect those that occur within the intracellular context. Connexin43 (Cx43), a protein that forms gap junction channels and hemichannels is down-regulated in high-grade gliomas. The Cx43 region comprising amino acids 266-283 is responsible for the inhibition of the oncogenic activity of c-Src in glioma cells. Here we use TAT as the cell-penetrating sequence, biotin as the pull-down tag and the region of Cx43 comprised between amino acids 266-283 as the target to find intracellular interactions in the hard-to-transfect human glioma stem cells. One of the limitations of the proposed method is that the molecule used as bait could fail to fold properly and, consequently, the interactions found could not be associated with the effect. However, this method can be especially interesting for the interactions involved in signal transduction pathways because they are usually carried out by intrinsically disordered regions and, therefore, they do not require an ordered folding. In addition, one of the advantages of the proposed method is that the relevance of each residue on the interaction can be easily studied. This is a modular system; therefore, other cell-penetrating sequences, other tags, and other intracellular targets can be employed. Finally, the scope of this protocol is far beyond protein-protein interaction because this system can be applied to other bioactive cargoes such as RNA sequences, nanoparticles, viruses or any molecule that can be transduced with cell-penetrating sequences and fused to pull-down tags to study their intracellular mechanism of action.
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Affiliation(s)
- Myriam Jaraíz-Rodríguez
- Instituto de Neurociencias de Castilla y León (INCYL), Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca
| | - Ana González-Sánchez
- Instituto de Neurociencias de Castilla y León (INCYL), Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca; Centre for Cancer Research & Cell Biology (CCRCB), School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast
| | - Laura García-Vicente
- Instituto de Neurociencias de Castilla y León (INCYL), Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca
| | - Jose M Medina
- Instituto de Neurociencias de Castilla y León (INCYL), Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca
| | - Arantxa Tabernero
- Instituto de Neurociencias de Castilla y León (INCYL), Departamento de Bioquímica y Biología Molecular, Universidad de Salamanca;
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16
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Donnelly SK, Cabrera R, Mao SPH, Christin JR, Wu B, Guo W, Bravo-Cordero JJ, Condeelis JS, Segall JE, Hodgson L. Rac3 regulates breast cancer invasion and metastasis by controlling adhesion and matrix degradation. J Cell Biol 2017; 216:4331-4349. [PMID: 29061650 PMCID: PMC5716284 DOI: 10.1083/jcb.201704048] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/28/2017] [Accepted: 09/25/2017] [Indexed: 01/21/2023] Open
Abstract
The initial step of metastasis is the local invasion of tumor cells into the surrounding tissue. Invadopodia are actin-based protrusions that mediate the matrix degradation necessary for invasion and metastasis of tumor cells. We demonstrate that Rac3 GTPase is critical for integrating the adhesion of invadopodia to the extracellular matrix (ECM) with their ability to degrade the ECM in breast tumor cells. We identify two pathways at invadopodia important for integrin activation and delivery of matrix metalloproteinases: through the upstream recruiter CIB1 as well as the downstream effector GIT1. Rac3 activity, at and surrounding invadopodia, is controlled by Vav2 and βPIX. These guanine nucleotide exchange factors regulate the spatiotemporal dynamics of Rac3 activity, impacting GIT1 localization. Moreover, the GTPase-activating function of GIT1 toward the vesicular trafficking regulator Arf6 GTPase is required for matrix degradation. Importantly, Rac3 regulates the ability of tumor cells to metastasize in vivo. The Rac3-dependent mechanisms we show in this study are critical for balancing proteolytic activity and adhesive activity to achieve a maximally invasive phenotype.
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Affiliation(s)
- Sara K Donnelly
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY.,Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY
| | - Ramon Cabrera
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY
| | - Serena P H Mao
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY
| | - John R Christin
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY
| | - Bin Wu
- Biophysics and Biophysical Chemistry, School of Medicine, Johns Hopkins University, Baltimore, MD
| | - Wenjun Guo
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY
| | - Jose Javier Bravo-Cordero
- Department of Medicine, Division of Hematology and Medical Oncology, Icahn School of Medicine, Tisch Cancer Institute at Mount Sinai, New York, NY
| | - John S Condeelis
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY.,Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY
| | - Jeffrey E Segall
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY.,Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY
| | - Louis Hodgson
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY .,Gruss-Lipper Biophotonics Center, Albert Einstein College of Medicine, Bronx, NY
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17
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Zhao J, Stains CI. Identification of a Fragmented Small GTPase Capable of Conditional Effector Binding. RSC Adv 2017; 7:12265-12268. [PMID: 28966788 DOI: 10.1039/c6ra25575b] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
A fragmented small GTPase capable of conditional effector binding is described. The effector binding function of this split-GTPase can be modulated using a small molecule input, thus allowing for the potential design of cellular signaling pathways.
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Affiliation(s)
- Jia Zhao
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, United States
| | - Cliff I Stains
- Department of Chemistry, University of Nebraska - Lincoln, Lincoln, NE 68588, United States
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18
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Mazaki Y, Onodera Y, Higashi T, Horinouchi T, Oikawa T, Sabe H. ARF1 recruits RAC1 to leading edge in neutrophil chemotaxis. Cell Commun Signal 2017; 15:36. [PMID: 28969640 PMCID: PMC5625764 DOI: 10.1186/s12964-017-0193-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2017] [Accepted: 09/22/2017] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND The small GTPase ARF1 mediates membrane trafficking mostly from the Golgi, and is essential for the G protein-coupled receptor (GPCR)-mediated chemotaxis of neutrophils. In this process, ARF1 is activated by the guanine nucleotide exchanger GBF1, and is inactivated by the GTPase-activating protein GIT2. Neutrophils generate the Gβγ-PAK1-αPIX-GIT2 linear complex during GPCR-induced chemotaxis, in which αPIX activates RAC1/CDC42, which then employs PAK1. However, it has remained unclear as to why GIT2 is included in this complex. RESULTS We investigated the association between ARF1 and RAC1/CDC42 during the fMLP-stimulated chemotaxis of HL60 cells. We found that the silencing of GBF1 significantly impaired the recruitment of RAC1 to the leading edges, but not PAK1, αPIX, RAC2, or CDC42. A significant population of RAC1 colocalized with ARF1 at the leading edges in stimulated cells, whereas fMLP activated both ARF1 and ARF5. Consistently, the silencing of ARF1, but not ARF5, impaired the recruitment of RAC1, whereas the silencing of RAC1 did not affect the recruitment of ARF1 to the leading edges. CONCLUSIONS Our results indicated that the activation of ARF1 triggers the plasma membrane recruitment of RAC1 in GPCR-mediated chemotaxis, which is essential for cortical actin remodeling. Thus, membrane remodeling at the leading edges appears to precede actin remodeling in chemotaxis. Together with the fact that GIT2, which inactivates ARF1, is an integral component of the machinery activating RAC1, we proposed a model in which the ARF1-RAC1 linkage enables the regulation of ARF1 by repetitive on/off cycles during GPCR-mediated neutrophil chemotaxis.
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Affiliation(s)
- Yuichi Mazaki
- Department of Cellular Pharmacology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Yasuhito Onodera
- Department of Molecular Biology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Tsunehito Higashi
- Department of Cellular Pharmacology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Takahiro Horinouchi
- Department of Cellular Pharmacology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Tsukasa Oikawa
- Department of Molecular Biology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
| | - Hisataka Sabe
- Department of Molecular Biology, Graduate School of Medicine, Hokkaido University, Sapporo, Japan
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19
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Morris DC, Popp JL, Tang LK, Gibbs HC, Schmitt E, Chaki SP, Bywaters BC, Yeh AT, Porter WW, Burghardt RC, Barhoumi R, Rivera GM. Nck deficiency is associated with delayed breast carcinoma progression and reduced metastasis. Mol Biol Cell 2017; 28:3500-3516. [PMID: 28954862 PMCID: PMC5683761 DOI: 10.1091/mbc.e17-02-0106] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Revised: 09/15/2017] [Accepted: 09/20/2017] [Indexed: 12/16/2022] Open
Abstract
Nck promotes breast carcinoma progression and metastasis by directing the polarized interaction of carcinoma cells with collagen fibrils, decreasing actin turnover, and enhancing the localization and activity of MMP14 at the cell surface through modulation of the spatiotemporal activation of Cdc42 and RhoA. Although it is known that noncatalytic region of tyrosine kinase (Nck) regulates cell adhesion and migration by bridging tyrosine phosphorylation with cytoskeletal remodeling, the role of Nck in tumorigenesis and metastasis has remained undetermined. Here we report that Nck is required for the growth and vascularization of primary tumors and lung metastases in a breast cancer xenograft model as well as extravasation following injection of carcinoma cells into the tail vein. We provide evidence that Nck directs the polarization of cell–matrix interactions for efficient migration in three-dimensional microenvironments. We show that Nck advances breast carcinoma cell invasion by regulating actin dynamics at invadopodia and enhancing focalized extracellular matrix proteolysis by directing the delivery and accumulation of MMP14 at the cell surface. We find that Nck-dependent cytoskeletal changes are mechanistically linked to enhanced RhoA but restricted spatiotemporal activation of Cdc42. Using a combination of protein silencing and forced expression of wild-type/constitutively active variants, we provide evidence that Nck is an upstream regulator of RhoA-dependent, MMP14-mediated breast carcinoma cell invasion. By identifying Nck as an important driver of breast carcinoma progression and metastasis, these results lay the groundwork for future studies assessing the therapeutic potential of targeting Nck in aggressive cancers.
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Affiliation(s)
- David C Morris
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas 77843-4467
| | - Julia L Popp
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas 77843-4467
| | - Leung K Tang
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas 77843-4467
| | - Holly C Gibbs
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843-4467
| | - Emily Schmitt
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas 77843-4467
| | - Sankar P Chaki
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas 77843-4467
| | - Briana C Bywaters
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas 77843-4467
| | - Alvin T Yeh
- Department of Biomedical Engineering, Texas A&M University, College Station, Texas 77843-4467
| | - Weston W Porter
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas 77843-4467
| | - Robert C Burghardt
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas 77843-4467
| | - Rola Barhoumi
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, Texas 77843-4467
| | - Gonzalo M Rivera
- Department of Veterinary Pathobiology, Texas A&M University, College Station, Texas 77843-4467
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20
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Roggenkamp E, Giersch RM, Wedeman E, Eaton M, Turnquist E, Schrock MN, Alkotami L, Jirakittisonthon T, Schluter-Pascua SE, Bayne GH, Wasko C, Halloran M, Finnigan GC. CRISPR-UnLOCK: Multipurpose Cas9-Based Strategies for Conversion of Yeast Libraries and Strains. Front Microbiol 2017; 8:1773. [PMID: 28979241 PMCID: PMC5611381 DOI: 10.3389/fmicb.2017.01773] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2017] [Accepted: 08/31/2017] [Indexed: 11/29/2022] Open
Abstract
Saccharomyces cerevisiae continues to serve as a powerful model system for both basic biological research and industrial application. The development of genome-wide collections of individually manipulated strains (libraries) has allowed for high-throughput genetic screens and an emerging global view of this single-celled Eukaryote. The success of strain construction has relied on the innate ability of budding yeast to accept foreign DNA and perform homologous recombination, allowing for efficient plasmid construction (in vivo) and integration of desired sequences into the genome. The development of molecular toolkits and “integration cassettes” have provided fungal systems with a collection of strategies for tagging, deleting, or over-expressing target genes; typically, these consist of a C-terminal tag (epitope or fluorescent protein), a universal terminator sequence, and a selectable marker cassette to allow for convenient screening. However, there are logistical and technical obstacles to using these traditional genetic modules for complex strain construction (manipulation of many genomic targets in a single cell) or for the generation of entire genome-wide libraries. The recent introduction of the CRISPR/Cas gene editing technology has provided a powerful methodology for multiplexed editing in many biological systems including yeast. We have developed four distinct uses of the CRISPR biotechnology to generate yeast strains that utilizes the conversion of existing, commonly-used yeast libraries or strains. We present Cas9-based, marker-less methodologies for (i) N-terminal tagging, (ii) C-terminally tagging yeast genes with 18 unique fusions, (iii) conversion of fluorescently-tagged strains into newly engineered (or codon optimized) variants, and finally, (iv) use of a Cas9 “gene drive” system to rapidly achieve a homozygous state for a hypomorphic query allele in a diploid strain. These CRISPR-based methods demonstrate use of targeting universal sequences previously introduced into a genome.
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Affiliation(s)
- Emily Roggenkamp
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Rachael M Giersch
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Emily Wedeman
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Muriel Eaton
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Emily Turnquist
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Madison N Schrock
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Linah Alkotami
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Thitikan Jirakittisonthon
- Department of Anatomy and Physiology, College of Veterinary Medicine, Kansas State UniversityManhattan, KS, United States
| | | | - Gareth H Bayne
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Cory Wasko
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Megan Halloran
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
| | - Gregory C Finnigan
- Department of Biochemistry and Molecular Biophysics, Kansas State UniversityManhattan, KS, United States
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21
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Herrington KA, Trinh AL, Dang C, O'Shaughnessy E, Hahn KM, Gratton E, Digman MA, Sütterlin C. Spatial analysis of Cdc42 activity reveals a role for plasma membrane-associated Cdc42 in centrosome regulation. Mol Biol Cell 2017; 28:2135-2145. [PMID: 28539409 PMCID: PMC5509425 DOI: 10.1091/mbc.e16-09-0665] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2016] [Revised: 05/05/2017] [Accepted: 05/15/2017] [Indexed: 11/11/2022] Open
Abstract
The ability of the small GTPase Cdc42 to regulate diverse cellular processes depends on tight spatial control of its activity. Cdc42 function is best understood at the plasma membrane (PM), where it regulates cytoskeletal organization and cell polarization. Active Cdc42 has also been detected at the Golgi, but its role and regulation at this organelle are only partially understood. Here we analyze the spatial distribution of Cdc42 activity by moni-toring the dynamics of the Cdc42 FLARE biosensor using the phasor approach to FLIM-FRET. Phasor analysis revealed that Cdc42 is active at all Golgi cisternae and that this activity is controlled by Tuba and ARHGAP10, two Golgi-associated Cdc42 regulators. To our surprise, FGD1, another Cdc42 GEF at the Golgi, was not required for Cdc42 regulation at the Golgi, although its depletion decreased Cdc42 activity at the PM. Similarly, changes in Golgi morphology did not affect Cdc42 activity at the Golgi but were associated with a substantial reduction in PM-associated Cdc42 activity. Of interest, cells with reduced Cdc42 activity at the PM displayed altered centrosome morphology, suggesting that centrosome regulation may be mediated by active Cdc42 at the PM. Our study describes a novel quantitative approach to determine Cdc42 activity at specific subcellular locations and reveals new regulatory principles and functions of this small GTPase.
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Affiliation(s)
- Kari A Herrington
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697
| | - Andrew L Trinh
- Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697
| | - Carolyn Dang
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697
| | - Ellen O'Shaughnessy
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Klaus M Hahn
- Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599
| | - Enrico Gratton
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697.,Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697.,Centre for Bioactive Discovery in Health and Ageing, School of Science and Technology, University of New England, Armidale, NSW 2351, Australia
| | - Michelle A Digman
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697.,Department of Biomedical Engineering, University of California, Irvine, Irvine, CA 92697.,Centre for Bioactive Discovery in Health and Ageing, School of Science and Technology, University of New England, Armidale, NSW 2351, Australia
| | - Christine Sütterlin
- Department of Developmental and Cell Biology, University of California, Irvine, Irvine, CA 92697
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22
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Mao M, Wang L, Chang CC, Rothenberg KE, Huang J, Wang Y, Hoffman BD, Liton PB, Yuan F. Involvement of a Rac1-Dependent Macropinocytosis Pathway in Plasmid DNA Delivery by Electrotransfection. Mol Ther 2017; 25:803-815. [PMID: 28129959 PMCID: PMC5363188 DOI: 10.1016/j.ymthe.2016.12.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2016] [Revised: 12/05/2016] [Accepted: 12/07/2016] [Indexed: 12/20/2022] Open
Abstract
Electrotransfection is a widely used method for delivering genes into cells with electric pulses. Although different hypotheses have been proposed, the mechanism of electrotransfection remains controversial. Previous studies have indicated that uptake and intracellular trafficking of plasmid DNA (pDNA) are mediated by endocytic pathways, but it is still unclear which pathways are directly involved in the delivery. To this end, the present study investigated the dependence of electrotransfection on macropinocytosis. Data from the study demonstrated that electric pulses induced cell membrane ruffling and actin cytoskeleton remodeling. Using fluorescently labeled pDNA and a macropinocytosis marker (i.e., dextran), the study showed that electrotransfected pDNA co-localized with dextran in intracellular vesicles. Furthermore, electrotransfection efficiency could be decreased significantly by reducing temperature or treatment of cells with a pharmacological inhibitor of Rac1 and could be altered by changing Rac1 activity. Taken together, the findings suggested that electrotransfection of pDNA involved Rac1-dependent macropinocytosis.
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Affiliation(s)
- Mao Mao
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Liangli Wang
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Chun-Chi Chang
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | | | - Jianyong Huang
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Yingxiao Wang
- Department of Bioengineering, University of California, San Diego, La Jolla, CA 92093, USA
| | - Brenton D Hoffman
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA
| | - Paloma B Liton
- Department of Ophthalmology, Duke University, Durham, NC 27708, USA
| | - Fan Yuan
- Department of Biomedical Engineering, Duke University, Durham, NC 27708, USA; Department of Ophthalmology, Duke University, Durham, NC 27708, USA.
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23
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Chung YC, Wei WC, Hung CN, Kuo JF, Hsu CP, Chang KJ, Chao WT. Rab11 collaborates E-cadherin to promote collective cell migration and indicates a poor prognosis in colorectal carcinoma. Eur J Clin Invest 2016; 46:1002-1011. [PMID: 27696383 DOI: 10.1111/eci.12683] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 09/28/2016] [Indexed: 12/16/2022]
Abstract
BACKGROUND Collective cell migration, whereby the cell-cell contacts such as E-cadherin are maintained during migration, has only recently emerged, and its detailed mechanisms are still unclear. In this study, the role of Rab11, which functions in recycling endosomes, and its relationship to E-cadherin in colorectal carcinoma were identified, and the role of Rab11 in the collective cell migration of colon cancer cells was clarified. MATERIALS AND METHODS A total of 107 patients with surgically resected colorectal carcinoma were enrolled in this immunohistochemical study. Relationships between the overexpression of Rab11 and E-cadherin and survival were evaluated. The cell biology of Rab11 overexpression or knock-down in HT-29 colon cells was studied. RESULTS The expression of Rab11 and E-cadherin was not correlated with the stage of cancer or lymph node metastasis. However, the overall survival was poor in the group of 67 patients with duo-positive Rab11 and E-cadherin expression compared to the group (40 patients) without dual-positive expression (P = 0·038). Rab11 was demonstrated to have a physical interaction with E-cadherin, and overexpression of Rab11 was found to promote collective cell migration through the increased distribution of E-cadherin, which enhanced cell-cell connections. In addition, Rac1 activation and matrix metalloproteinase-2 expressions were upregulated upon Rab11 expression. CONCLUSIONS This study demonstrated that Rab11 and E-cadherin expressions are indicators of poor survival time in colorectal carcinoma, but that Rab11 overexpression may contribute to increased collective cell invasion in colorectal carcinoma.
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Affiliation(s)
- Yuan-Chiang Chung
- Department of Surgery, Cheng-Ching General Hospital, Chung-Kang Branch, Taichung, Taiwan.,Department of Medicinal Botanicals and Health Applications, Da-Yeh University, Dacun, Changhua, Taiwan
| | - Wan-Chen Wei
- Department of Surgery, Cheng-Ching General Hospital, Chung-Kang Branch, Taichung, Taiwan.,Department of Life Science, Tunghai University, Taichung, Taiwan
| | - Chia-Nung Hung
- Department of Life Science, Tunghai University, Taichung, Taiwan
| | - Jen-Fang Kuo
- Department of Pathology, Cheng-Ching General Hospital, Chung-Kang Branch, Taichung, Taiwan
| | - Chih-Ping Hsu
- Department of Medical Laboratory Science and Biotechnology, Yuanpei University, HsinChu, Taiwan
| | - King-Jen Chang
- Department of Surgery, Cheng-Ching General Hospital, Chung-Kang Branch, Taichung, Taiwan.,Department of Surgery, Taiwan Adventist Hospital, Taipei, Taiwan
| | - Wei-Ting Chao
- Department of Life Science, Tunghai University, Taichung, Taiwan
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24
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Girola N, Matsuo AL, Figueiredo CR, Massaoka MH, Farias CF, Arruda DC, Azevedo RA, Monteiro HP, Resende-Lara PT, Cunha RLOR, Polonelli L, Travassos LR. The Ig V H complementarity-determining region 3-containing Rb9 peptide, inhibits melanoma cells migration and invasion by interactions with Hsp90 and an adhesion G-protein coupled receptor. Peptides 2016; 85:1-15. [PMID: 27575453 DOI: 10.1016/j.peptides.2016.08.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 08/17/2016] [Accepted: 08/22/2016] [Indexed: 12/30/2022]
Abstract
The present work aims at investigating the mechanism of action of the Rb9 peptide, which contains the VHCDR 3 sequence of anti-sodium-dependent phosphate transport protein 2B (NaPi2B) monoclonal antibody RebMab200 and displayed antitumor properties. Short peptides corresponding to the hypervariable complementarity-determining regions (CDRs) of immunoglobulins have been associated with antimicrobial, antiviral, immunomodulatory and antitumor activities regardless of the specificity of the antibody. We have shown that the CDR derived peptide Rb9 induced substrate hyperadherence, inhibition of cell migration and matrix invasion in melanoma and other tumor cell lines. Rb9 also inhibited metastasis of murine melanoma in a syngeneic mouse model. We found that Rb9 binds to and interferes with Hsp90 chaperone activity causing attenuation of FAK-Src signaling and downregulation of active Rac1 in B16F10-Nex2 melanoma cells. The peptide also bound to an adhesion G-protein coupled receptor, triggering a concentration-dependent synthesis of cAMP and activation of PKA and VASP signaling as well as IP-3 dependent Ca2+ release. Hsp90 is highly expressed on the cell surface of melanoma cells, and synthetic agents that target Hsp90 are promising cancer therapeutic drugs. Based on their remarkable antitumor effects, the CDR-H3-derived peptides from RebMab200, and particularly the highly soluble and stable Rb9, are novel candidates to be further studied as potential antitumor drugs, selectively acting on cancer cell motility and invasion.
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Affiliation(s)
- Natalia Girola
- Department of Microbiology, Immunology and Parasitology, Cell Biology Division and Experimental Oncology Unit (UNONEX), Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Alisson L Matsuo
- Interdepartmental Group of Health Economics (Grides), Federal University of São Paulo, SP, Brazil
| | - Carlos R Figueiredo
- Department of Microbiology, Immunology and Parasitology, Cell Biology Division and Experimental Oncology Unit (UNONEX), Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Mariana H Massaoka
- Department of Microbiology, Immunology and Parasitology, Cell Biology Division and Experimental Oncology Unit (UNONEX), Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Camyla F Farias
- Department of Microbiology, Immunology and Parasitology, Cell Biology Division and Experimental Oncology Unit (UNONEX), Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil
| | - Denise C Arruda
- Núcleo Integrado de Biotecnologia, Universidade de Mogi das Cruzes, São Paulo, SP, Brazil
| | - Ricardo A Azevedo
- Biochemistry and Biophysics Laboratory, Butantan Institute, São Paulo, SP, Brazil
| | - Hugo P Monteiro
- Center for Cellular and Molecular Therapy (CTCMol) and Department of Biochemistry, Federal University of São Paulo, São Paulo, SP, Brazil
| | - Pedro T Resende-Lara
- Computation and Bioinformatic Biology laboratory, Federal University of ABC, Santo André, São Paulo, SP, Brazil
| | - Rodrigo L O R Cunha
- Chemical Biology Laboratory, Natural and Human Sciences Center, Federal University of ABC, Santo André, São Paulo, SP, Brazil
| | - Luciano Polonelli
- Microbiology and Virology Unit, Department of Biomedical, Biotechnological and Translational Sciences, Universitá degli Studi di Parma, Parma, Italy
| | - Luiz R Travassos
- Department of Microbiology, Immunology and Parasitology, Cell Biology Division and Experimental Oncology Unit (UNONEX), Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil; Recepta Biopharma, São Paulo, SP, Brazil.
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25
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Yen YC, Hsiao JR, Jiang SS, Chang JS, Wang SH, Shen YY, Chen CH, Chang IS, Chang JY, Chen YW. Insulin-like growth factor-independent insulin-like growth factor binding protein 3 promotes cell migration and lymph node metastasis of oral squamous cell carcinoma cells by requirement of integrin β1. Oncotarget 2016; 6:41837-55. [PMID: 26540630 PMCID: PMC4747192 DOI: 10.18632/oncotarget.5995] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Accepted: 10/05/2015] [Indexed: 12/15/2022] Open
Abstract
Frequent metastasis to the cervical lymph nodes leads to poor survival of patients with oral squamous cell carcinoma (OSCC). To understand the underlying mechanisms of lymph node metastasis, two sublines were successfully isolated from cervical lymph nodes of nude mice through in vivo selection, and identified as originating from poorly metastatic parental cells. These two sublines specifically metastasized to cervical lymph nodes in 83% of mice, whereas OEC-M1 cells did not metastasize after injection into the oral cavity. After gene expression analysis, we identified insulin-like growth factor binding protein 3 (IGFBP3) as one of the significantly up-regulated genes in the sublines in comparison with their parental cells. Consistently, meta-analysis of the public microarray datasets and IGFBP3 immunohistochemical analysis revealed increased both levels of IGFBP3 mRNA and protein in human OSCC tissues when compared to normal oral or adjacent nontumorous tissues. Interestingly, the up-regulated IGFBP3 mRNA expression was significantly associated with OSCC patients with lymph node metastasis. IGFBP3 knockdown in the sublines impaired and ectopic IGFBP3 expression in the parental cells promoted migration, transendothelial migration and lymph node metastasis of orthotopic transplantation. Additionally, ectopic expression of IGFBP3 with an IGF-binding defect sustained the IGFBP3-enhanced biological functions. Results indicated that IGFBP3 regulates metastasis-related functions of OSCC cells through an IGF-independent mechanism. Furthermore, exogenous IGFBP3 was sufficient to induce cell motility and extracellular signal-regulated kinase (ERK) activation. The silencing of integrin β1 was able to impair exogenous IGFBP3-mediated migration and ERK phosphorylation, suggesting a critical role of integrin β1 in IGFBP3-enchanced functions.
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Affiliation(s)
- Yi-Chen Yen
- National Institute of Cancer Research, National Health Research Institutes, Miaoli, Taiwan
| | - Jenn-Ren Hsiao
- Department of Otolaryngology, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Shih Sheng Jiang
- National Institute of Cancer Research, National Health Research Institutes, Miaoli, Taiwan
| | - Jeffrey S Chang
- National Institute of Cancer Research, National Health Research Institutes, Tainan, Taiwan
| | - Ssu-Han Wang
- National Institute of Cancer Research, National Health Research Institutes, Miaoli, Taiwan
| | - Ying-Ying Shen
- Pathology Core Laboratory, National Health Research Institutes, Miaoli, Taiwan
| | - Chung-Hsing Chen
- Institute of Population Health Sciences, National Health Research Institutes, Miaoli, Taiwan
| | - I-Shou Chang
- National Institute of Cancer Research, National Health Research Institutes, Miaoli, Taiwan.,Institute of Population Health Sciences, National Health Research Institutes, Miaoli, Taiwan
| | - Jang-Yang Chang
- Department of Internal Medicine, National Cheng Kung University Hospital, College of Medicine, Tainan, Taiwan
| | - Ya-Wen Chen
- National Institute of Cancer Research, National Health Research Institutes, Miaoli, Taiwan.,Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan
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26
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Ackermann KL, Florke RR, Reyes SS, Tader BR, Hamann MJ. TCL/RhoJ Plasma Membrane Localization and Nucleotide Exchange Is Coordinately Regulated by Amino Acids within the N Terminus and a Distal Loop Region. J Biol Chem 2016; 291:23604-23617. [PMID: 27660391 DOI: 10.1074/jbc.m116.750026] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2016] [Indexed: 01/16/2023] Open
Abstract
TCL/RhoJ is a Cdc42-related Rho GTPase with reported activities in endothelial cell biology and angiogenesis, metastatic melanoma, and corneal epithelial cells; however, less is known about how it is inherently regulated in comparison to its closest homologues TC10 and Cdc42. TCL has an N-terminal extension of 18 amino acids in comparison to Cdc42, but the function of this amino acid sequence has not been elucidated. A truncation mutant lacking the N terminus (ΔN) was found to alter TCL plasma membrane localization and nucleotide binding, and additional truncation and point mutants mapped the alterations of TCL biochemistry to amino acids 17-20. Interestingly, whereas the TCL ΔN mutant clearly influenced nucleotide exchange, deletion of the N terminus from its closest homologue, TC10, did not have a similar effect. Chimeras of TCL and TC10 revealed amino acids 121-129 of TCL contributed to the differences in nucleotide loading. Together, these results identify amino acids within the N terminus and a loop region distal to the nucleotide binding pocket of TCL capable of allosterically regulating nucleotide exchange and thus influence membrane association of the protein.
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Affiliation(s)
- Karly L Ackermann
- From the Biology Department, Bemidji State University, Bemidji, Minnesota 56601
| | - Rebecca R Florke
- From the Biology Department, Bemidji State University, Bemidji, Minnesota 56601
| | - Shannon S Reyes
- From the Biology Department, Bemidji State University, Bemidji, Minnesota 56601
| | - Brooke R Tader
- From the Biology Department, Bemidji State University, Bemidji, Minnesota 56601
| | - Michael J Hamann
- From the Biology Department, Bemidji State University, Bemidji, Minnesota 56601
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27
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Antkowiak A, Viaud J, Severin S, Zanoun M, Ceccato L, Chicanne G, Strassel C, Eckly A, Leon C, Gachet C, Payrastre B, Gaits-Iacovoni F. Cdc42-dependent F-actin dynamics drive structuration of the demarcation membrane system in megakaryocytes. J Thromb Haemost 2016; 14:1268-84. [PMID: 26991240 DOI: 10.1111/jth.13318] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2015] [Accepted: 03/03/2016] [Indexed: 02/04/2023]
Abstract
UNLABELLED Essentials Information about the formation of the demarcation membrane system (DMS) is still lacking. We investigated the role of the cytoskeleton in DMS structuration in megakaryocytes. Cdc42/Pak-dependent F-actin remodeling regulates DMS organization for proper megakaryopoiesis. These data highlight the mandatory role of F-actin in platelet biogenesis. SUMMARY Background Blood platelet biogenesis results from the maturation of megakaryocytes (MKs), which involves the development of a complex demarcation membrane system (DMS). Therefore, MK differentiation is an attractive model for studying membrane remodeling. Objectives We sought to investigate the mechanism of DMS structuration in relationship to the cytoskeleton. Results Using three-dimensional (3D) confocal imaging, we have identified consecutive stages of DMS organization that rely on F-actin dynamics to polarize membranes and nuclei territories. Interestingly, microtubules are not involved in this process. We found that the mechanism underlying F-actin-dependent DMS formation required the activation of the guanosine triphosphate hydrolase Cdc42 and its p21-activated kinase effectors (Pak1/2/3). Förster resonance energy transfer demonstrated that active Cdc42 was associated with endomembrane dynamics throughout terminal maturation. Inhibition of Cdc42 or Pak1/2/3 severely destructured the DMS and blocked proplatelet formation. Even though this process does not require containment within the hematopoietic niche, because DMS structuration was observed upon thrombopoietin-treatment in suspension, integrin outside-in signaling was required for Pak activation and probably resulted from secretion of extracellular matrix by MKs. Conclusions These data indicate a functional link, mandatory for MK differentiation, between actin dynamics, regulated by Cdc42/Pak1/2/3, and DMS maturation.
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Affiliation(s)
- A Antkowiak
- INSERM, UMR1048, Université Toulouse III, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - J Viaud
- INSERM, UMR1048, Université Toulouse III, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - S Severin
- INSERM, UMR1048, Université Toulouse III, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - M Zanoun
- INSERM, UMR1048, Université Toulouse III, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - L Ceccato
- INSERM, UMR1048, Université Toulouse III, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - G Chicanne
- INSERM, UMR1048, Université Toulouse III, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
| | - C Strassel
- INSERM, UMR_S949, Université de Strasbourg, Etablissement Français du Sang-Alsace, Toulouse, France
| | - A Eckly
- INSERM, UMR_S949, Université de Strasbourg, Etablissement Français du Sang-Alsace, Toulouse, France
| | - C Leon
- INSERM, UMR_S949, Université de Strasbourg, Etablissement Français du Sang-Alsace, Toulouse, France
| | - C Gachet
- INSERM, UMR_S949, Université de Strasbourg, Etablissement Français du Sang-Alsace, Toulouse, France
| | - B Payrastre
- INSERM, UMR1048, Université Toulouse III, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
- Laboratoire d'Hématologie, CHU de Toulouse, Toulouse, France
| | - F Gaits-Iacovoni
- INSERM, UMR1048, Université Toulouse III, Institut des Maladies Métaboliques et Cardiovasculaires, Toulouse, France
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28
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24-Methylenecycloartanyl ferulate, a major compound of γ-oryzanol, promotes parvin-beta expression through an interaction with peroxisome proliferator-activated receptor-gamma 2 in human breast cancer cells. Biochem Biophys Res Commun 2015; 468:574-9. [DOI: 10.1016/j.bbrc.2015.10.147] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2015] [Accepted: 10/27/2015] [Indexed: 11/19/2022]
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29
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Leyme A, Marivin A, Perez-Gutierrez L, Nguyen LT, Garcia-Marcos M. Integrins activate trimeric G proteins via the nonreceptor protein GIV/Girdin. J Cell Biol 2015; 210:1165-84. [PMID: 26391662 PMCID: PMC4586755 DOI: 10.1083/jcb.201506041] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 08/20/2015] [Indexed: 01/04/2023] Open
Abstract
Signal transduction via integrins and G protein-coupled receptors is critical to control cell behavior. These two receptor classes have been traditionally believed to trigger distinct and independent signaling cascades in response to extracellular cues. Here, we report a novel mechanism of integrin signaling that requires activation of the trimeric G protein Gαi by the nonreceptor guanine nucleotide exchange factor (GEF) GIV (also known as Girdin), a metastasis-associated protein. We demonstrate that GIV enhances integrin-dependent cell responses upon extracellular matrix stimulation and makes tumor cells more invasive. These responses include remodeling of the actin cytoskeleton and PI3K-dependent signaling, resulting in enhanced haptotaxis and invasion. We show that both GIV and its substrate Gαi3 are recruited to active integrin complexes and that tumor cells engineered to express GEF-deficient GIV fail to transduce integrin signals into proinvasive responses via a Gβγ-PI3K axis. Our discoveries delineate a novel mechanism by which integrin signaling is rewired during metastasis to result in increased tumor invasiveness.
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Affiliation(s)
- Anthony Leyme
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118
| | - Arthur Marivin
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118
| | | | - Lien T Nguyen
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118
| | - Mikel Garcia-Marcos
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118
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30
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Kim MO, Ryu JM, Suh HN, Park SH, Oh YM, Lee SH, Han HJ. cAMP Promotes Cell Migration Through Cell Junctional Complex Dynamics and Actin Cytoskeleton Remodeling: Implications in Skin Wound Healing. Stem Cells Dev 2015; 24:2513-24. [PMID: 26192163 DOI: 10.1089/scd.2015.0130] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Stem cells have attracted great interest for their therapeutic capacity in tissue regeneration. Cyclic adenosine 3',5'-monophosphate (cAMP), existing in high concentration at wound sites, mediated various signaling pathways such as cytoskeleton dynamics, cell adhesion, and cell migration in stem cells, which suggest the critical roles of cAMP in the wound healing process through functional regulation of stem cells. However, the mechanisms behind the effect of cAMP on mouse embryonic stem cell (mESC) motility and its roles on skin wound healing remain to be fully elucidated. In the present study, 8-Bromo cAMP-treated mESCs showed significant wound closure and improved neovascularization. Moreover, 8-Bromo cAMP stimulated mESC migration into the wound bed. 8-Bromo cAMP also increased ESC motility in in vitro migration assay. 8-Bromo cAMP induced myosin light chain phosphorylation through Rac1 and Cdc42 signaling, which were involved in 8-Bromo cAMP-induced decrease in expression of junction proteins (connexin 43, E-cadherin, and occludin) at the plasma membrane. Subsequently, 8-Bromo cAMP induced the disruption of cell junctions (including gap junctions, adherens junctions, and tight junctions), which reduced the function of the gap junctions and cell adhesion. In addition, 8-Bromo cAMP-induced Rac1 and Cdc42 activation increased Arp3, TOCA, PAK, and N-WASP expression, but decreased cofilin phosphorylation level, which elicited actin cytoskeleton remodeling. In contrast to the control, 8-Bromo cAMP evoked a substantial migration of cells into the denuded area, which was blocked by the small interfering RNAs of the signaling pathway-related molecules or by inhibitors. In conclusion, cAMP enhanced the migration of mESCs through effective coordination of junctional disruption and actin cytoskeleton remodeling, which increased the wound healing capacity of ESCs.
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Affiliation(s)
- Mi Ok Kim
- 1 Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University , Seoul, Republic of Korea.,2 BK21 PLUS Creative Veterinary Research Center, Seoul National University , Seoul, Republic of Korea
| | - Jung Min Ryu
- 1 Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University , Seoul, Republic of Korea.,2 BK21 PLUS Creative Veterinary Research Center, Seoul National University , Seoul, Republic of Korea
| | - Han Na Suh
- 1 Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University , Seoul, Republic of Korea.,2 BK21 PLUS Creative Veterinary Research Center, Seoul National University , Seoul, Republic of Korea
| | - Soo Hyun Park
- 3 College of Veterinary Medicine, Chonnam National University , Gwangju, Republic of Korea
| | - Yeon-Mok Oh
- 4 Department of Pulmonary and Critical Care Medicine, and Clinical Research Center for Chronic Obstructive Airway Diseases, Asan Medical Center, University of Ulsan College of Medicine , Seoul, Republic of Korea
| | - Sang Hun Lee
- 5 Medical Science Research Institute, Soonchunhyang University Seoul Hospital , Seoul, Republic of Korea
| | - Ho Jae Han
- 1 Department of Veterinary Physiology, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University , Seoul, Republic of Korea.,2 BK21 PLUS Creative Veterinary Research Center, Seoul National University , Seoul, Republic of Korea
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31
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Chaki SP, Barhoumi R, Rivera GM. Actin remodeling by Nck regulates endothelial lumen formation. Mol Biol Cell 2015; 26:3047-60. [PMID: 26157164 PMCID: PMC4551318 DOI: 10.1091/mbc.e15-06-0338] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 07/01/2015] [Indexed: 01/03/2023] Open
Abstract
Nck-dependent actin remodeling enables endothelial morphogenesis by promoting cell elongation and proper organization of VE-cadherin intercellular junctions. Nck determines spatiotemporal patterns of Cdc42/aPKC activation to regulate endothelial apical-basal polarity and lumen formation. Multiple angiogenic cues modulate phosphotyrosine signaling to promote vasculogenesis and angiogenesis. Despite its functional and clinical importance, how vascular cells integrate phosphotyrosine-dependent signaling to elicit cytoskeletal changes required for endothelial morphogenesis remains poorly understood. The family of Nck adaptors couples phosphotyrosine signals with actin dynamics and therefore is well positioned to orchestrate cellular processes required in vascular formation and remodeling. Culture of endothelial cells in three-dimensional collagen matrices in the presence of VEGF stimulation was combined with molecular genetics, optical imaging, and biochemistry to show that Nck-dependent actin remodeling promotes endothelial cell elongation and proper organization of VE-cadherin intercellular junctions. Major morphogenetic defects caused by abrogation of Nck signaling included loss of endothelial apical-basal polarity and impaired lumenization. Time-lapse imaging using a Förster resonance energy transfer biosensor, immunostaining with phospho-specific antibodies, and GST pull-down assays showed that Nck determines spatiotemporal patterns of Cdc42/aPKC activation during endothelial morphogenesis. Our results demonstrate that Nck acts as an important hub integrating angiogenic cues with cytoskeletal changes that enable endothelial apical-basal polarization and lumen formation. These findings point to Nck as an emergent target for effective antiangiogenic therapy.
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Affiliation(s)
- Sankar P Chaki
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843-4467
| | - Rola Barhoumi
- Department of Veterinary Integrative Biosciences, Texas A&M University, College Station, TX 77843-4467
| | - Gonzalo M Rivera
- Department of Veterinary Pathobiology, Texas A&M University, College Station, TX 77843-4467
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32
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Aznar N, Midde KK, Dunkel Y, Lopez-Sanchez I, Pavlova Y, Marivin A, Barbazán J, Murray F, Nitsche U, Janssen KP, Willert K, Goel A, Abal M, Garcia-Marcos M, Ghosh P. Daple is a novel non-receptor GEF required for trimeric G protein activation in Wnt signaling. eLife 2015; 4:e07091. [PMID: 26126266 PMCID: PMC4484057 DOI: 10.7554/elife.07091] [Citation(s) in RCA: 91] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 06/01/2015] [Indexed: 12/17/2022] Open
Abstract
Wnt signaling is essential for tissue homeostasis and its dysregulation causes cancer. Wnt ligands trigger signaling by activating Frizzled receptors (FZDRs), which belong to the G-protein coupled receptor superfamily. However, the mechanisms of G protein activation in Wnt signaling remain controversial. In this study, we demonstrate that FZDRs activate G proteins and trigger non-canonical Wnt signaling via the Dishevelled-binding protein, Daple. Daple contains a Gα-binding and activating (GBA) motif, which activates Gαi proteins and an adjacent domain that directly binds FZDRs, thereby linking Wnt stimulation to G protein activation. This triggers non-canonical Wnt responses, that is, suppresses the β-catenin/TCF/LEF pathway and tumorigenesis, but enhances PI3K-Akt and Rac1 signals and tumor cell invasiveness. In colorectal cancers, Daple is suppressed during adenoma-to-carcinoma transformation and expressed later in metastasized tumor cells. Thus, Daple activates Gαi and enhances non-canonical Wnt signaling by FZDRs, and its dysregulation can impact both tumor initiation and progression to metastasis.
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Affiliation(s)
- Nicolas Aznar
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Krishna K Midde
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Ying Dunkel
- Department of Medicine, University of California, San Diego, San Diego, United States
| | | | - Yelena Pavlova
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Arthur Marivin
- Department of Biochemistry, Boston University School of Medicine, Boston, United States
| | - Jorge Barbazán
- Translational Medical Oncology Laboratory, Health Research Institute of Santiago, Servizo Galego de Saúde, Santiago de Compostela, Spain
| | - Fiona Murray
- Department of Medicine, University of California, San Diego, San Diego, United States
| | - Ulrich Nitsche
- Department of Surgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Klaus-Peter Janssen
- Department of Surgery, Klinikum rechts der Isar, Technische Universität München, Munich, Germany
| | - Karl Willert
- Sanford Consortium for Regenerative Medicine, University of California, San Diego, La Jolla, California, United States
| | - Ajay Goel
- Division of Gastroenterology, Department of Internal Medicine and Charles A Sammons Cancer Center and Baylor Research Institute, Baylor University Medical Center, Dallas, Texas, United States
| | - Miguel Abal
- Translational Medical Oncology Laboratory, Health Research Institute of Santiago, Servizo Galego de Saúde, Santiago de Compostela, Spain
| | - Mikel Garcia-Marcos
- Department of Biochemistry, Boston University School of Medicine, Boston, United States
| | - Pradipta Ghosh
- Department of Medicine, University of California, San Diego, San Diego, United States
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33
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Schroeder B, Schulze RJ, Weller SG, Sletten AC, Casey CA, McNiven MA. The small GTPase Rab7 as a central regulator of hepatocellular lipophagy. Hepatology 2015; 61:1896-907. [PMID: 25565581 PMCID: PMC4441591 DOI: 10.1002/hep.27667] [Citation(s) in RCA: 205] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2014] [Accepted: 12/17/2014] [Indexed: 12/13/2022]
Abstract
UNLABELLED Autophagy is a central mechanism by which hepatocytes catabolize lipid droplets (LDs). Currently, the regulatory mechanisms that control this important process are poorly defined. The small guanosine triphosphatase (GTPase) Rab7 has been implicated in the late endocytic pathway and is known to associate with LDs, although its role in LD breakdown has not been tested. In this study, we demonstrate that Rab7 is indispensable for LD breakdown ("lipophagy") in hepatocytes subjected to nutrient deprivation. Importantly, Rab7 is dramatically activated in cells placed under nutrient stress; this activation is required for the trafficking of both multivesicular bodies and lysosomes to the LD surface during lipophagy, resulting in the formation of a lipophagic "synapse." Depletion of Rab7 leads to gross morphological changes of multivesicular bodies, lysosomes, and autophagosomes, consequently leading to attenuation of hepatocellular lipophagy. CONCLUSION These findings provide additional support for the role of autophagy in hepatocellular LD catabolism while implicating the small GTPase Rab7 as a key regulatory component of this essential process.
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Affiliation(s)
- Barbara Schroeder
- Department of Biochemistry and Molecular Biology and the Center for Digestive Diseases, Mayo Clinic, 200 1 Street SW, Rochester, MN, 55905, USA
| | - Ryan J. Schulze
- Department of Biochemistry and Molecular Biology and the Center for Digestive Diseases, Mayo Clinic, 200 1 Street SW, Rochester, MN, 55905, USA
| | - Shaun G. Weller
- Department of Biochemistry and Molecular Biology and the Center for Digestive Diseases, Mayo Clinic, 200 1 Street SW, Rochester, MN, 55905, USA
| | - Arthur C. Sletten
- Department of Biochemistry and Molecular Biology and the Center for Digestive Diseases, Mayo Clinic, 200 1 Street SW, Rochester, MN, 55905, USA
| | - Carol A. Casey
- Department of Internal Medicine, University of Nebraska Medical Center, 988090 Nebraska Medical Center, Omaha, NE, 68198, USA
| | - Mark A. McNiven
- Department of Biochemistry and Molecular Biology and the Center for Digestive Diseases, Mayo Clinic, 200 1 Street SW, Rochester, MN, 55905, USA
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Mense SM, Barrows D, Hodakoski C, Steinbach N, Schoenfeld D, Su W, Hopkins BD, Su T, Fine B, Hibshoosh H, Parsons R. PTEN inhibits PREX2-catalyzed activation of RAC1 to restrain tumor cell invasion. Sci Signal 2015; 8:ra32. [PMID: 25829446 DOI: 10.1126/scisignal.2005840] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The tumor suppressor PTEN restrains cell migration and invasion by a mechanism that is independent of inhibition of the PI3K pathway and decreased activation of the kinase AKT. PREX2, a widely distributed GEF that activates the GTPase RAC1, binds to and inhibits PTEN. We used mouse embryonic fibroblasts and breast cancer cell lines to show that PTEN suppresses cell migration and invasion by blocking PREX2 activity. In addition to metabolizing the phosphoinositide PIP₃, PTEN inhibited PREX2-induced invasion by a mechanism that required the tail domain of PTEN, but not its lipid phosphatase activity. Fluorescent nucleotide exchange assays revealed that PTEN inhibited the GEF activity of PREX2 toward RAC1. PREX2 is a frequently mutated GEF in cancer, and examination of human tumor data showed that PREX2 mutation was associated with high PTEN expression. Therefore, we tested whether cancer-derived somatic PREX2 mutants, which accelerate tumor formation of immortalized melanocytes, were inhibited by PTEN. The three stably expressed, somatic PREX2 cancer mutants that we tested were resistant to PTEN-mediated inhibition of invasion but retained the ability to inhibit the lipid phosphatase activity of PTEN. In vitro analysis showed that PTEN did not block the GEF activity of two PREX2 cancer mutants and had a reduced binding affinity for the third. Thus, PTEN antagonized migration and invasion by restraining PREX2 GEF activity, and PREX2 mutants are likely selected in cancer to escape PTEN-mediated inhibition of invasion.
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Affiliation(s)
- Sarah M Mense
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY 10029, USA
| | - Douglas Barrows
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY 10029, USA. Department of Pharmacology, Columbia University, New York, NY 10032, USA
| | - Cindy Hodakoski
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY 10029, USA
| | - Nicole Steinbach
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY 10029, USA. Integrated Program in Cellular, Molecular, Structural, and Genetic Studies, Columbia University, New York, NY 10032, USA
| | - David Schoenfeld
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY 10029, USA. Integrated Program in Cellular, Molecular, Structural, and Genetic Studies, Columbia University, New York, NY 10032, USA
| | - William Su
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY 10029, USA
| | - Benjamin D Hopkins
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY 10029, USA
| | - Tao Su
- Herbert Irving Comprehensive Cancer Center, Columbia University, 1130 St. Nicholas Avenue, New York, NY 10032, USA
| | - Barry Fine
- Department of Medicine, Columbia University, 630 West 168th Street, New York, NY 10032, USA
| | - Hanina Hibshoosh
- Herbert Irving Comprehensive Cancer Center, Columbia University, 1130 St. Nicholas Avenue, New York, NY 10032, USA. Department of Pathology and Cell Biology, Columbia University, 630 West 168th Street, New York, NY 10032, USA
| | - Ramon Parsons
- Department of Oncological Sciences, Icahn School of Medicine at Mount Sinai, 1470 Madison Avenue, New York, NY 10029, USA.
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Rac1 GTPase-deficient HeLa cells present reduced DNA repair, proliferation, and survival under UV or gamma irradiation. Mol Cell Biochem 2015; 404:281-97. [DOI: 10.1007/s11010-015-2388-0] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2014] [Accepted: 03/05/2015] [Indexed: 12/21/2022]
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Son K, Smith TC, Luna EJ. Supervillin binds the Rac/Rho-GEF Trio and increases Trio-mediated Rac1 activation. Cytoskeleton (Hoboken) 2015; 72:47-64. [PMID: 25655724 DOI: 10.1002/cm.21210] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 01/21/2015] [Indexed: 01/06/2023]
Abstract
We investigated cross-talk between the membrane-associated, myosin II-regulatory protein supervillin and the actin-regulatory small GTPases Rac1, RhoA, and Cdc42. Supervillin knockdown reduced Rac1-GTP loading, but not the GTP loading of RhoA or Cdc42, in HeLa cells with normal levels of the Rac1-activating protein Trio. No reduction in Rac1-GTP loading was observed when supervillin levels were reduced in Trio-depleted cells. Conversely, overexpression of supervillin isoform 1 (SV1) or, especially, isoform 4 (SV4) increased Rac1 activation. Inhibition of the Trio-mediated Rac1 guanine nucleotide exchange activity with ITX3 partially blocked the SV4-mediated increase in Rac1-GTP. Both SV4 and SV1 co-localized with Trio at or near the plasma membrane in ruffles and cell surface projections. Two sequences within supervillin bound directly to Trio spectrin repeats 4-7: SV1-171, which contains N-terminal residues found in both SV1 and SV4 and the SV4-specific differentially spliced coding exons 3, 4, and 5 within SV4 (SV4-E345; SV4 amino acids 276-669). In addition, SV4-E345 interacted with the homologous sequence in rat kalirin (repeats 4-7, amino acids 531-1101). Overexpressed SV1-174 and SV4-E345 affected Rac1-GTP loading, but only in cells with endogenous levels of Trio. Trio residues 771-1057, which contain both supervillin-interaction sites, exerted a dominant-negative effect on cell spreading. Supervillin and Trio knockdowns, separately or together, inhibited cell spreading, suggesting that supervillin regulates the Rac1 guanine nucleotide exchange activity of Trio, and potentially also kalirin, during cell spreading and lamellipodia extension.
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Affiliation(s)
- Kyonghee Son
- Department of Cell and Developmental Biology, Program in Cell & Developmental Dynamics, University of Massachusetts Medical School, Worcester, Massachusetts
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Miskolci V, Spiering D, Cox D, Hodgson L. A mix-and-measure assay for determining the activation status of endogenous Cdc42 in cytokine-stimulated macrophage cell lysates. Methods Mol Biol 2014; 1172:173-84. [PMID: 24908304 DOI: 10.1007/978-1-4939-0928-5_15] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/16/2023]
Abstract
Cytokine stimulations of leukocytes many times result in transient activation of the p21 Rho family of small GTPases. The role of these molecules during cell migration and chemotaxis is well established. The traditional approach to study the activation dynamics of these proteins involves affinity pull-downs that are often cumbersome and prone to errors. Here, we describe a reagent and a method of simple "mix-and-measure" approach useful for determining the activation status of endogenous Cdc42 GTPase from cell lysates.
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Affiliation(s)
- Veronika Miskolci
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine of Yeshiva University, 1300 Morris Park Ave, Bronx, NY, 10461, USA,
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Phosphatidylinositol 5-phosphate regulates invasion through binding and activation of Tiam1. Nat Commun 2014; 5:4080. [PMID: 24905281 DOI: 10.1038/ncomms5080] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Accepted: 05/09/2014] [Indexed: 12/13/2022] Open
Abstract
PtdIns5P is a lipid messenger acting as a stress-response mediator in the nucleus, and known to maintain cell activation through traffic alterations upon bacterial infection. Here, we show that PtdIns5P regulates actin dynamics and invasion via recruitment and activation of the exchange factor Tiam1 and Rac1. Restricted Rac1 activation results from the binding of Tiam1 DH-PH domains to PtdIns5P. Using an assay that mimics Rac1 membrane anchoring by using Rac1-His and liposomes containing Ni(2+)-NTA modified lipids, we demonstrate that intrinsic Tiam1 DH-PH activity increases when Rac1 is anchored in a PtdIns5P-enriched environment. This pathway appears to be general since it is valid in different pathophysiological models: receptor tyrosine kinase activation, bacterial phosphatase IpgD expression and the invasive NPM-ALK(+) lymphomas. The discovery that PtdIns5P could be a keystone of GTPases and cytoskeleton spatiotemporal regulation opens important research avenues towards unravelling new strategies counteracting cell invasion.
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Carter AM, Gutowski S, Sternweis PC. Regulated localization is sufficient for hormonal control of regulator of G protein signaling homology Rho guanine nucleotide exchange factors (RH-RhoGEFs). J Biol Chem 2014; 289:19737-46. [PMID: 24855647 DOI: 10.1074/jbc.m114.564930] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The regulator of G protein signaling homology (RH) Rho guanine nucleotide exchange factors (RhoGEFs) (p115RhoGEF, leukemia-associated RhoGEF, and PDZ-RhoGEF) contain an RH domain and are specific GEFs for the monomeric GTPase RhoA. The RH domains interact specifically with the α subunits of G12 heterotrimeric GTPases. Activated Gα13 modestly stimulates the exchange activity of both p115RhoGEF and leukemia-associated RhoGEF but not PDZ-RhoGEF. Because all three RH-RhoGEFs can localize to the plasma membrane upon expression of activated Gα13, cellular localization of these RhoGEFs has been proposed as a mechanism for controlling their activity. We use a small molecule-regulated heterodimerization system to rapidly control the localization of RH-RhoGEFs. Acute localization of the proteins to the plasma membrane activates RhoA within minutes and to levels that are comparable with activation of RhoA by hormonal stimulation of G protein-coupled receptors. The catalytic activity of membrane-localized RhoGEFs is not dependent on activated Gα13. We further show that the conserved RH domains can rewire two different RacGEFs to activate Rac1 in response to a traditional activator of RhoA. Thus, RH domains act as independent detectors for activated Gα13 and are sufficient to modulate the activity of RhoGEFs by hormones via mediating their localization to substrate, membrane-associated RhoA.
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Affiliation(s)
- Angela M Carter
- From the Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Stephen Gutowski
- From the Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
| | - Paul C Sternweis
- From the Department of Pharmacology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390
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40
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Filamin-A regulates neutrophil uropod retraction through RhoA during chemotaxis. PLoS One 2013; 8:e79009. [PMID: 24205360 PMCID: PMC3808352 DOI: 10.1371/journal.pone.0079009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Accepted: 09/18/2013] [Indexed: 11/19/2022] Open
Abstract
Filamin-A (FLNa) has been shown to be a key cross-linker of actin filaments in the leading edge of a motile melanoma cell line, however its role in neutrophils undergoing chemotaxis is unknown. Using a murine transgenic model in which FLNa is selectively deleted in granulocytes, we report that, while neutrophils lacking FLNa show normal polarization and pseudopod extension, they exhibit obvious defects in uropod retraction. This uropod retraction defect was found to be a direct result of reduced FLNa mediated activation of the small GTPase RhoA and myosin mediated actin contraction in the FLNa null cells. This results in a neutrophil recruitment defect in FLNa null mice. The compensatory increase in FLNb levels that was observed in the FLNa null neutrophils may be sufficient to compensate for the lack of FLNa at the leading edge allowing for normal polarization, however this compensation is unable to regulate RhoA activated tail retraction at the rear of the cell.
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41
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Karuppaiya P, Satheeshkumar E, Chao WT, Kao LY, Chen ECF, Tsay HS. Anti-metastatic activity of biologically synthesized gold nanoparticles on human fibrosarcoma cell line HT-1080. Colloids Surf B Biointerfaces 2013; 110:163-70. [DOI: 10.1016/j.colsurfb.2013.04.037] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 04/12/2013] [Accepted: 04/15/2013] [Indexed: 01/30/2023]
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Anliker B, Choi JW, Lin ME, Gardell SE, Rivera RR, Kennedy G, Chun J. Lysophosphatidic acid (LPA) and its receptor, LPA1 , influence embryonic schwann cell migration, myelination, and cell-to-axon segregation. Glia 2013; 61:2009-22. [PMID: 24115248 DOI: 10.1002/glia.22572] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2013] [Revised: 07/31/2013] [Accepted: 08/13/2013] [Indexed: 01/08/2023]
Abstract
Schwann cell (SC) migration is an important step preceding myelination and remyelination in the peripheral nervous system, and can be promoted by peptide factors like neuregulins. Here we present evidence that a lipid factor, lysophosphatidic acid (LPA), influences both SC migration and peripheral myelination through its cognate G protein-coupled receptor (GPCR) known as LPA1 . Ultrastructural analyses of peripheral nerves in mouse null-mutants for LPA1 showed delayed SC-to-axon segregation, polyaxonal myelination by single SCs, and thinner myelin sheaths. In primary cultures, LPA promoted SC migration through LPA1 , while analysis of conditioned media from purified dorsal root ganglia neurons using HPLC/MS supported the production of LPA by these neurons. The heterotrimeric G-alpha protein, Gαi , and the small GTPase, Rac1, were identified as important downstream signaling components of LPA1 . These results identify receptor mediated LPA signaling between neurons and SCs that promote SC migration and contribute to the normal development of peripheral nerves through effects on SC-axon segregation and myelination.
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Affiliation(s)
- Brigitte Anliker
- Molecular and Cellular Neuroscience Department, Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, California
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43
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Atkins BD, Yoshida S, Saito K, Wu CF, Lew DJ, Pellman D. Inhibition of Cdc42 during mitotic exit is required for cytokinesis. ACTA ACUST UNITED AC 2013; 202:231-40. [PMID: 23878274 PMCID: PMC3718968 DOI: 10.1083/jcb.201301090] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
A decrease in Cdc42 activation during mitotic exit is necessary to allow localization of key cytokinesis regulators and proper septum formation. The role of Cdc42 and its regulation during cytokinesis is not well understood. Using biochemical and imaging approaches in budding yeast, we demonstrate that Cdc42 activation peaks during the G1/S transition and during anaphase but drops during mitotic exit and cytokinesis. Cdc5/Polo kinase is an important upstream cell cycle regulator that suppresses Cdc42 activity. Failure to down-regulate Cdc42 during mitotic exit impairs the normal localization of key cytokinesis regulators—Iqg1 and Inn1—at the division site, and results in an abnormal septum. The effects of Cdc42 hyperactivation are largely mediated by the Cdc42 effector p21-activated kinase Ste20. Inhibition of Cdc42 and related Rho guanosine triphosphatases may be a general feature of cytokinesis in eukaryotes.
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Affiliation(s)
- Benjamin D Atkins
- Department of Pediatric Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA 02115, USA
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44
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PLEKHG2 promotes heterotrimeric G protein βγ-stimulated lymphocyte migration via Rac and Cdc42 activation and actin polymerization. Mol Cell Biol 2013; 33:4294-307. [PMID: 24001768 DOI: 10.1128/mcb.00879-13] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PLEKHG2 is a Dbl family Rho guanine nucleotide exchange factor (RhoGEF) whose gene was originally identified as being upregulated in a leukemia mouse model and was later shown to be activated by heterotrimeric G protein βγ (Gβγ) subunits. However, its function and activation mechanisms remain elusive. Here we show that, compared to its expression in primary human T cells, its expression is upregulated in several leukemia cell lines, including Jurkat T cells. Downregulation of PLEKHG2 in Jurkat T cells by small interfering RNAs (siRNAs) specifically inhibited Gβγ-stimulated Rac and Cdc42, but not RhoA, activation. Consequently, suppressing PLEKHG2 expression blocked actin polymerization and SDF1α-stimulated lymphocyte migration. Additional studies indicate that Gβγ likely activates PLEKHG2, in part by binding the N terminus of PLEKHG2 to release an autoinhibition imposed by its C terminus, which interacts with a region encompassing the catalytic Dbl homology (DH) domain. As a result, overexpressing either the N terminus or the C terminus of PLEKHG2 blocked Gβγ-stimulated Rac and Cdc42 activation and prevented Jurkat T cells from forming membrane protrusions and migrating. Together, our studies have provided the first evidence for the endogenous function of PLEKHG2, which may serve as a key Gβγ-stimulated RhoGEF that regulates lymphocyte chemotaxis via Rac and Cdc42 activation and actin polymerization.
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Abstract
The Rac inhibitor EHop-016 was developed as a compound with the potential to inhibit cancer metastasis. Inhibition of the first step of metastasis, migration, is an important strategy for metastasis prevention. The small GTPase Rac acts as a pivotal binary switch that is turned "on" by guanine nucleotide exchange factors (GEFs) via a myriad of cell surface receptors, to regulate cancer cell migration, survival, and proliferation. Unlike the related GTPase Ras, Racs are not usually mutated, but overexpressed or overactivated in cancer. Therefore, a rational Rac inhibitor should block the activation of Rac by its upstream effectors, GEFs, and the Rac inhibitor NSC23766 was developed using this rationale. However, this compound is ineffective at inhibiting the elevated Rac activity of metastatic breast cancer cells. Therefore, a panel of small molecule compounds were derived from NSC23766 and screened for Rac activity inhibition in metastatic cancer cells. EHop-016 was identified as a compound that blocks the interaction of Rac with the GEF Vav in metastatic human breast cancer cells with an IC50 of ~1μM. At higher concentrations (10μM), EHop-016 inhibits the related Rho GTPase Cdc42, but not Rho, and also reduces cell viability. Moreover, EHop-016 inhibits the activation of the Rac downstream effector p21-activated kinase, extension of motile actin-based structures, and cell migration. Future goals are to develop EHop-016 as a therapeutic to inhibit cancer metastasis, either individually or in combination with current anticancer compounds. The next generation of EHop-016-based Rac inhibitors is also being developed.
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Affiliation(s)
- Suranganie Dharmawardhane
- Department of Biochemistry, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico, USA.
| | - Eliud Hernandez
- Department of Biochemistry, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico, USA
| | - Cornelis Vlaar
- Department of Biochemistry, University of Puerto Rico Medical Sciences Campus, San Juan, Puerto Rico, USA
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Hajas G, Bacsi A, Aguilera-Aguirre L, Hegde ML, Tapas KH, Sur S, Radak Z, Ba X, Boldogh I. 8-Oxoguanine DNA glycosylase-1 links DNA repair to cellular signaling via the activation of the small GTPase Rac1. Free Radic Biol Med 2013; 61:384-94. [PMID: 23612479 PMCID: PMC3795866 DOI: 10.1016/j.freeradbiomed.2013.04.011] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2012] [Revised: 02/24/2013] [Accepted: 04/09/2013] [Indexed: 12/20/2022]
Abstract
8-Oxo-7,8-dihydroguanine (8-oxoG) is one of the most abundant DNA base lesions induced by reactive oxygen species (ROS). Accumulation of 8-oxoG in the mammalian genome is considered a marker of oxidative stress, to be causally linked to inflammation, and is thought to contribute to aging processes and various aging-related diseases. Unexpectedly, mice that lack 8-oxoguanine DNA glycosylase-1 (OGG1) activity and accumulate 8-oxoG in their genome have a normal phenotype and longevity; in fact, they show increased resistance to both inflammation and oxidative stress. OGG1 excises and generates free 8-oxoG base during DNA base-excision repair (BER) processes. In the present study, we report that in the presence of the 8-oxoG base, OGG1 physically interacts with guanine nucleotide-free and GDP-bound Rac1 protein. This interaction results in rapid GDP→GTP, but not GTP→GDP, exchange in vitro. Importantly, a rise in the intracellular 8-oxoG base levels increases the proportion of GTP-bound Rac1. In turn Rac1-GTP mediates an increase in ROS levels via nuclear membrane-associated NADPH oxidase type 4. These results show a novel mechanism by which OGG1 in complex with 8-oxoG is linked to redox signaling and cellular responses.
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Affiliation(s)
- Gyorgy Hajas
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | - Attila Bacsi
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | - Leopoldo Aguilera-Aguirre
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | - Muralidhar L Hegde
- Department of Biochemistry & Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | - K Hazra Tapas
- Department of Internal Medicine, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; Sealy Center for Molecular Medicine, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; Department of Biochemistry & Molecular Biology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | - Sanjiv Sur
- Department of Internal Medicine, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; Sealy Center for Molecular Medicine, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | - Zsolt Radak
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | - Xueqing Ba
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA
| | - Istvan Boldogh
- Department of Microbiology and Immunology, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA; Sealy Center for Molecular Medicine, University of Texas Medical Branch at Galveston, Galveston, TX 77555, USA.
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p16 Stimulates CDC42-dependent migration of hepatocellular carcinoma cells. PLoS One 2013; 8:e69389. [PMID: 23894465 PMCID: PMC3722281 DOI: 10.1371/journal.pone.0069389] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Accepted: 06/08/2013] [Indexed: 02/07/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is a leading cause of cancer-related deaths worldwide. Tumor dissemination to the extra-hepatic region of the portal vein, lymph nodes, lungs or bones contributes to the high mortality seen in HCC; yet, the molecular mechanisms responsible for HCC metastasis remain unclear. Prior studies have suggested a potential link between accumulated cytoplasm-localized p16 and tumor progression. Here we report that p16 enhances metastasis-associated phenotypes in HCC cells – ectopic p16 expression increased cell migration in vitro, and lung colonization after intravenous injection, whereas knockdown of endogenous p16 reduced cell migration. Interestingly, analysis of p16 mutants indicated that the Cdk4 interaction domain is required for stimulation of HCC cell migration; however, knockdown of Cdk4 and Cdk6 showed that these proteins are dispensable for this phenomenon. Intriguingly, we found that in p16-positive HCC samples, p16 protein is predominantly localized in the cytoplasm. In addition, we identified a potential role for nuclear-cytoplasmic shuttling in p16-stimulated migration, consistent with the predominantly cytoplasmic localization of p16 in IHC-positive HCC samples. Finally, we determined that p16-stimulated cell migration requires the Cdc42 GTPase. Our results demonstrate for the first time a pro-migratory role for p16, and suggest a potential mechanism for the observed association between cytoplasmic p16 and tumor progression in diverse tumor types.
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Inositol kinase and its product accelerate wound healing by modulating calcium levels, Rho GTPases, and F-actin assembly. Proc Natl Acad Sci U S A 2013; 110:11029-34. [PMID: 23776233 DOI: 10.1073/pnas.1217308110] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Wound healing is essential for survival. We took advantage of the Xenopus embryo, which exhibits remarkable capacities to repair wounds quickly and efficiently, to investigate the mechanisms responsible for wound healing. Previous work has shown that injury triggers a rapid calcium response, followed by the activation of Ras homolog (Rho) family guanosine triphosphatases (GTPases), which regulate the formation and contraction of an F-actin purse string around the wound margin. How these processes are coordinated following wounding remained unclear. Here we show that inositol-trisphosphate 3-kinase B (Itpkb) via its enzymatic product inositol 1,3,4,5-tetrakisphosphate (InsP4) plays an essential role during wound healing by modulating the activity of Rho family GTPases and F-actin ring assembly. Furthermore, we show that Itpkb and InsP4 modulate the speed of the calcium wave, which propagates from the site of injury into neighboring uninjured cells. Strikingly, both overexpression of itpkb and exogenous application of InsP4 accelerate the speed of wound closure, a finding that has potential implications in our quest to find treatments that improve wound healing in patients with acute or chronic wounds.
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Goicoechea SM, García-Mata R, Staub J, Valdivia A, Sharek L, McCulloch CG, Hwang RF, Urrutia R, Yeh JJ, Kim HJ, Otey CA. Palladin promotes invasion of pancreatic cancer cells by enhancing invadopodia formation in cancer-associated fibroblasts. Oncogene 2013; 33:1265-73. [PMID: 23524582 DOI: 10.1038/onc.2013.68] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 12/17/2012] [Accepted: 01/25/2013] [Indexed: 12/29/2022]
Abstract
The stromal compartment surrounding epithelial-derived pancreatic tumors is thought to have a key role in the aggressive phenotype of this malignancy. Emerging evidence suggests that cancer-associated fibroblasts (CAFs), the most abundant cells in the stroma of pancreatic tumors, contribute to the tumor's invasion, metastasis and resistance to therapy, but the precise molecular mechanisms that regulate CAFs behavior are poorly understood. In this study, we utilized immortalized human pancreatic CAFs to investigate molecular pathways that control the matrix-remodeling and invasion-promoting activity of CAFs. We showed previously that palladin, an actin-associated protein, is expressed at high levels in CAFs of pancreatic tumors and other solid tumors, and also in an immortalized line of human CAFs. In this study, we found that short-term exposure of CAFs to phorbol esters reduced the number of stress fibers and triggered the appearance of individual invadopodia and invadopodial rosettes in CAFs. Molecular analysis of invadopodia revealed that their composition resembled that of similar structures (that is, invadopodia and podosomes) described in other cell types. Pharmacological inhibition and small interfering RNA knockdown experiments demonstrated that protein kinase C, the small GTPase Cdc42 and palladin were necessary for the efficient assembly of invadopodia by CAFs. In addition, GTPase activity assays showed that palladin contributes to the activation of Cdc42. In mouse xenograft experiments using a mixture of CAFs and tumor cells, palladin expression in CAFs promoted the rapid growth and metastasis of human pancreatic tumor cells. Overall, these results indicate that high levels of palladin expression in CAFs enhance their ability to remodel the extracellular matrix by regulating the activity of Cdc42, which in turn promotes the assembly of matrix-degrading invadopodia in CAFs and tumor cell invasion. Together, these results identify a novel molecular signaling pathway that may provide new molecular targets for the inhibition of pancreatic cancer metastasis.
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Affiliation(s)
- S M Goicoechea
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - R García-Mata
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - J Staub
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - A Valdivia
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - L Sharek
- Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - C G McCulloch
- CIHR Group in Matrix Dynamics, Faculty of Dentistry, University of Toronto, Toronto, Ontario, Canada
| | - R F Hwang
- Department of Surgical Oncology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - R Urrutia
- Department of Biochemistry and Molecular Biology, Epigenetics and Chromatin Dynamics Laboratory, Division of Gastroenterology and Hepatology, Translational Epigenomics Program, Center for Individualized Medicine (CIM), Mayo Clinic, Rochester, MN, USA
| | - J J Yeh
- 1] Department of Pharmacology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA [3] Department of Surgery, UNC School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - H J Kim
- 1] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA [2] Department of Surgery, UNC School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
| | - C A Otey
- 1] Department of Cell Biology and Physiology, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA [2] Lineberger Comprehensive Cancer Center, University of North Carolina at Chapel Hill, Chapel Hill, NC, USA
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Lévay M, Bartos B, Ligeti E. p190RhoGAP has cellular RacGAP activity regulated by a polybasic region. Cell Signal 2013; 25:1388-94. [PMID: 23499677 DOI: 10.1016/j.cellsig.2013.03.004] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2012] [Revised: 02/19/2013] [Accepted: 03/06/2013] [Indexed: 01/09/2023]
Abstract
p190RhoGAP is a GTPase-activating protein (GAP) known to regulate actin cytoskeleton dynamics by decreasing RhoGTP levels through activation of the intrinsic GTPase activity of Rho. Although the GAP domain of p190RhoGAP stimulates the intrinsic' GTPase activity of several Rho family members (Rho, Rac, Cdc42) under in vitro conditions, p190RhoGAP is generally regarded as a GAP for RhoA in the cell. The cellular RacGAP activity of the protein has not been proven directly. We have previously shown that the in vitro RacGAP and RhoGAP activity of p190RhoGAP was inversely regulated through a polybasic region of the protein. Here we provide evidence that p190RhoGAP shows remarkable GAP activity toward Rac also in the cell. The cellular RacGAP activity of p190RhoGAP requires an intact polybasic region adjacent to the GAP domain whereas the RhoGAP activity is inhibited by the same domain. Our data indicate that through its alternating RacGAP and RhoGAP activity, p190RhoGAP plays a more complex role in the Rac-Rho antagonism than it was realized earlier.
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Affiliation(s)
- Magdolna Lévay
- Department of Physiology, Semmelweis University, Budapest, Hungary
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