1
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Salloum G, Bresnick AR, Backer JM. Macropinocytosis: mechanisms and regulation. Biochem J 2023; 480:335-362. [PMID: 36920093 DOI: 10.1042/bcj20210584] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2022] [Revised: 02/22/2023] [Accepted: 02/27/2023] [Indexed: 03/16/2023]
Abstract
Macropinocytosis is defined as an actin-dependent but coat- and dynamin-independent endocytic uptake process, which generates large intracellular vesicles (macropinosomes) containing a non-selective sampling of extracellular fluid. Macropinocytosis provides an important mechanism of immune surveillance by dendritic cells and macrophages, but also serves as an essential nutrient uptake pathway for unicellular organisms and tumor cells. This review examines the cell biological mechanisms that drive macropinocytosis, as well as the complex signaling pathways - GTPases, lipid and protein kinases and phosphatases, and actin regulatory proteins - that regulate macropinosome formation, internalization, and disposition.
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Affiliation(s)
- Gilbert Salloum
- Department of Molecular Pharamacology, Albert Einstein College of Medicine, Bronx, NY, U.S.A
| | - Anne R Bresnick
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, U.S.A
| | - Jonathan M Backer
- Department of Molecular Pharamacology, Albert Einstein College of Medicine, Bronx, NY, U.S.A
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, U.S.A
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2
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Wang Y, Jiang L, Zhao Y, Ju X, Wang L, Jin L, Fine RD, Li M. Biological characteristics and pathogenicity of Acanthamoeba. Front Microbiol 2023; 14:1147077. [PMID: 37089530 PMCID: PMC10113681 DOI: 10.3389/fmicb.2023.1147077] [Citation(s) in RCA: 19] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/21/2023] [Indexed: 04/25/2023] Open
Abstract
Acanthamoeba is an opportunistic protozoa, which exists widely in nature and is mainly distributed in soil and water. Acanthamoeba usually exists in two forms, trophozoites and cysts. The trophozoite stage is one of growth and reproduction while the cyst stage is characterized by cellular quiescence, commonly resulting in human infection, and the lack of effective monotherapy after initial infection leads to chronic disease. Acanthamoeba can infect several human body tissues such as the skin, cornea, conjunctiva, respiratory tract, and reproductive tract, especially when the tissue barriers are damaged. Furthermore, serious infections can cause Acanthamoeba keratitis, granulomatous amoebic encephalitis, skin, and lung infections. With an increasing number of Acanthamoeba infections in recent years, the pathogenicity of Acanthamoeba is becoming more relevant to mainstream clinical care. This review article will describe the etiological characteristics of Acanthamoeba infection in detail from the aspects of biological characteristic, classification, disease, and pathogenic mechanism in order to provide scientific basis for the diagnosis, treatment, and prevention of Acanthamoeba infection.
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Affiliation(s)
- Yuehua Wang
- College of Laboratory Medicine, Jilin Medical University, Jilin City, China
| | - Linzhe Jiang
- General Surgery, Jilin People’s Hospital, Jilin City, China
| | - Yitong Zhao
- College of Laboratory Medicine, Jilin Medical University, Jilin City, China
| | - Xiaohong Ju
- College of Laboratory Medicine, Jilin Medical University, Jilin City, China
| | - Le Wang
- Department of Laboratory Medicine, Jilin Hospital of Integrated Chinese and Western Medicine, Jilin City, China
| | - Liang Jin
- Department of Laboratory Medicine, Jilin Hospital of Integrated Chinese and Western Medicine, Jilin City, China
| | - Ryan D. Fine
- Center for Human Genetics and Genomics, New York University Grossman School of Medicine, New York City, NY, United States
| | - Mingguang Li
- College of Laboratory Medicine, Jilin Medical University, Jilin City, China
- *Correspondence: Mingguang Li,
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3
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Abstract
Macropinocytosis is an evolutionarily conserved endocytic pathway that mediates the nonselective acquisition of extracellular material via large endocytic vesicles known as macropinosomes. In addition to other functions, this uptake pathway supports cancer cell metabolism through the uptake of nutrients. Cells harboring oncogene or tumor suppressor mutations are known to display heightened macropinocytosis, which confers to the cancer cells the ability to survive and proliferate despite the nutrient-scarce conditions of the tumor microenvironment. Thus, macropinocytosis is associated with cancer malignancy. Macropinocytic uptake can be induced in cancer cells by different stress stimuli, acting as an adaptive mechanism for the cells to resist stresses in the tumor milieu. Here, we review the cellular stresses that are known to promote macropinocytosis, as well as the underlying molecular mechanisms that drive this process.
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Affiliation(s)
- Guillem Lambies
- Cell and Molecular Biology of Cancer Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA
| | - Cosimo Commisso
- Cell and Molecular Biology of Cancer Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, USA.
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4
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Soriano O, Alcón-Pérez M, Vicente-Manzanares M, Castellano E. The Crossroads between RAS and RHO Signaling Pathways in Cellular Transformation, Motility and Contraction. Genes (Basel) 2021; 12:genes12060819. [PMID: 34071831 PMCID: PMC8229961 DOI: 10.3390/genes12060819] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2021] [Revised: 05/25/2021] [Accepted: 05/26/2021] [Indexed: 02/07/2023] Open
Abstract
Ras and Rho proteins are GTP-regulated molecular switches that control multiple signaling pathways in eukaryotic cells. Ras was among the first identified oncogenes, and it appears mutated in many forms of human cancer. It mainly promotes proliferation and survival through the MAPK pathway and the PI3K/AKT pathways, respectively. However, the myriad proteins close to the plasma membrane that activate or inhibit Ras make it a major regulator of many apparently unrelated pathways. On the other hand, Rho is weakly oncogenic by itself, but it critically regulates microfilament dynamics; that is, actin polymerization, disassembly and contraction. Polymerization is driven mainly by the Arp2/3 complex and formins, whereas contraction depends on myosin mini-filament assembly and activity. These two pathways intersect at numerous points: from Ras-dependent triggering of Rho activators, some of which act through PI3K, to mechanical feedback driven by actomyosin action. Here, we describe the main points of connection between the Ras and Rho pathways as they coordinately drive oncogenic transformation. We emphasize the biochemical crosstalk that drives actomyosin contraction driven by Ras in a Rho-dependent manner. We also describe possible routes of mechanical feedback through which myosin II activation may control Ras/Rho activation.
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Affiliation(s)
- Olga Soriano
- Tumor Biophysics Laboratory, Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-University of Salamanca, 37007 Salamanca, Spain;
| | - Marta Alcón-Pérez
- Tumour-Stroma Signalling Laboratory, Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-University of Salamanca, 37007 Salamanca, Spain;
| | - Miguel Vicente-Manzanares
- Tumor Biophysics Laboratory, Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-University of Salamanca, 37007 Salamanca, Spain;
- Correspondence: (M.V.-M.); (E.C.)
| | - Esther Castellano
- Tumour-Stroma Signalling Laboratory, Centro de Investigación del Cáncer and Instituto de Biología Molecular y Celular del Cáncer, Consejo Superior de Investigaciones Científicas (CSIC)-University of Salamanca, 37007 Salamanca, Spain;
- Correspondence: (M.V.-M.); (E.C.)
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5
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Immune complex-induced apoptosis and concurrent immune complex clearance are anti-inflammatory neutrophil functions. Cell Death Dis 2021; 12:296. [PMID: 33741905 PMCID: PMC7979711 DOI: 10.1038/s41419-021-03528-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 02/09/2021] [Accepted: 02/12/2021] [Indexed: 12/12/2022]
Abstract
Persistent neutrophilic inflammation drives host damage in autoimmune diseases that are characterized by abundant immune complexes. Insoluble immune complexes (iICs) potently activate pro-inflammatory neutrophil effector functions. We and others have shown that iICs also promote resolution of inflammation via stimulation of neutrophil apoptosis. We demonstrate here that iICs trigger FcγRIIa-dependent neutrophil macropinocytosis, leading to the rapid uptake, and subsequent degradation of iICs. We provide evidence that concurrent iIC-induced neutrophil apoptosis is distinct from phagocytosis-induced cell death. First, uptake of iICs occurs by FcγRII-stimulated macropinocytosis, rather than phagocytosis. Second, production of reactive oxygen species, but not iIC-internalization is a pre-requisite for iIC-induced neutrophil apoptosis. Our findings identify a previously unknown mechanism by which neutrophils can remove pro-inflammatory iICs from the circulation. Together iIC clearance and iIC-induced neutrophil apoptosis may act to prevent the potential escalation of neutrophilic inflammation in response to iICs.
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6
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Lin XP, Mintern JD, Gleeson PA. Macropinocytosis in Different Cell Types: Similarities and Differences. MEMBRANES 2020; 10:membranes10080177. [PMID: 32756454 PMCID: PMC7463864 DOI: 10.3390/membranes10080177] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 12/14/2022]
Abstract
Macropinocytosis is a unique pathway of endocytosis characterised by the nonspecific internalisation of large amounts of extracellular fluid, solutes and membrane in large endocytic vesicles known as macropinosomes. Macropinocytosis is important in a range of physiological processes, including antigen presentation, nutrient sensing, recycling of plasma proteins, migration and signalling. It has become apparent in recent years from the study of specialised cells that there are multiple pathways of macropinocytosis utilised by different cell types, and some of these pathways are triggered by different stimuli. Understanding the physiological function of macropinocytosis requires knowledge of the regulation and fate of the macropinocytosis pathways in a range of cell types. Here, we compare the mechanisms of macropinocytosis in different primary and immortalised cells, identify the gaps in knowledge in the field and discuss the potential approaches to analyse the function of macropinocytosis in vivo.
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7
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Bennison SA, Blazejewski SM, Smith TH, Toyo-Oka K. Protein kinases: master regulators of neuritogenesis and therapeutic targets for axon regeneration. Cell Mol Life Sci 2020; 77:1511-1530. [PMID: 31659414 PMCID: PMC7166181 DOI: 10.1007/s00018-019-03336-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Revised: 09/16/2019] [Accepted: 10/08/2019] [Indexed: 12/25/2022]
Abstract
Proper neurite formation is essential for appropriate neuronal morphology to develop and defects at this early foundational stage have serious implications for overall neuronal function. Neuritogenesis is tightly regulated by various signaling mechanisms that control the timing and placement of neurite initiation, as well as the various processes necessary for neurite elongation to occur. Kinases are integral components of these regulatory pathways that control the activation and inactivation of their targets. This review provides a comprehensive summary of the kinases that are notably involved in regulating neurite formation, which is a complex process that involves cytoskeletal rearrangements, addition of plasma membrane to increase neuronal surface area, coupling of cytoskeleton/plasma membrane, metabolic regulation, and regulation of neuronal differentiation. Since kinases are key regulators of these functions during neuromorphogenesis, they have high potential for use as therapeutic targets for axon regeneration after injury or disease where neurite formation is disrupted.
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Affiliation(s)
- Sarah A Bennison
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - Sara M Blazejewski
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - Trevor H Smith
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA
| | - Kazuhito Toyo-Oka
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, PA, 19129, USA.
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8
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Salloum G, Jakubik CT, Erami Z, Heitz SD, Bresnick AR, Backer JM. PI3Kβ is selectively required for growth factor-stimulated macropinocytosis. J Cell Sci 2019; 132:jcs.231639. [PMID: 31409694 DOI: 10.1242/jcs.231639] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 07/16/2019] [Indexed: 12/16/2022] Open
Abstract
Macropinocytosis is an actin-dependent but clathrin-independent endocytic process by which cells nonselectively take up large aliquots of extracellular material. Macropinocytosis is used for immune surveillance by dendritic cells, as a route of infection by viruses and protozoa, and as a nutrient uptake pathway in tumor cells. In this study, we explore the role of class I phosphoinositide 3-kinases (PI3Ks) during ligand-stimulated macropinocytosis. We find that macropinocytosis in response to receptor tyrosine kinase activation is strikingly dependent on a single class I PI3K isoform, namely PI3Kβ (containing the p110β catalytic subunit encoded by PIK3CB). Loss of PI3Kβ expression or activity blocks macropinocytosis at early steps, before the formation of circular dorsal ruffles, but also plays a role in later steps, downstream from Rac1 activation. PI3Kβ is also required for the elevated levels of constitutive macropinocytosis found in tumor cells that are defective for the PTEN tumor suppressor. Our data shed new light on PI3K signaling during macropinocytosis, and suggest new therapeutic uses for pharmacological inhibitors of PI3Kβ.
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Affiliation(s)
- Gilbert Salloum
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Charles T Jakubik
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Zahra Erami
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Samantha D Heitz
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Anne R Bresnick
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | - Jonathan M Backer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY 10461, USA .,Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY 10461, USA
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9
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Amplification of PIP3 signalling by macropinocytic cups. Biochem J 2018; 475:643-648. [PMID: 29444849 PMCID: PMC5813501 DOI: 10.1042/bcj20170785] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Revised: 01/12/2018] [Accepted: 01/14/2018] [Indexed: 01/22/2023]
Abstract
In a role distinct from and perhaps more ancient than that in signal transduction, PIP3 and Ras help to spatially organize the actin cytoskeleton into macropinocytic cups. These large endocytic structures are extended by actin polymerization from the cell surface and have at their core an intense patch of active Ras and PIP3, around which actin polymerizes, creating cup-shaped projections. We hypothesize that active Ras and PIP3 self-amplify within macropinocytic cups, in a way that depends on the structural integrity of the cup. Signalling that triggers macropinocytosis may therefore be amplified downstream in a way that depends on macropinocytosis. This argument provides a context for recent findings that signalling to Akt (an effector of PIP3) is sensitive to cytoskeletal and macropinocytic inhibitors.
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10
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Reyhani V, Tsioumpekou M, van Wieringen T, Rask L, Lennartsson J, Rubin K. PDGF-BB enhances collagen gel contraction through a PI3K-PLCγ-PKC-cofilin pathway. Sci Rep 2017; 7:8924. [PMID: 28827622 PMCID: PMC5566449 DOI: 10.1038/s41598-017-08411-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2017] [Accepted: 07/11/2017] [Indexed: 01/11/2023] Open
Abstract
Cell-mediated contraction of collagenous matrices is modulated by various growth factors and cytokines, such as platelet-derived growth factor-BB (PDGF-BB). Here we used a genetic cell model to delineate defined signaling pathways that enhance collagen gel contraction downstream of ligand-stimulated platelet-derived growth factor receptor-β (PDGF-Rβ). Our data show that PDGF BB-enhanced activations of phosphatidylinositol 3′-kinase (PI3K) and phospholipase Cγ (PLCγ) were necessary for PDGF-enhanced collagen gel contraction. Importantly, other defined signaling pathways down-stream of PDGF-Rβ were, however, dispensable. The decisive roles for PI3K and PLCγ were corroborated by experiments using selective inhibitors. Furthermore, we show that de-phosphorylation and thereby activation of cofilin that is important for the turnover of actin filaments, is depended on PI3K and PLCγ down-stream of PDGF-Rβ. Moreover, inhibition of protein kinase C (PKC) by GÖ6976 and bisindolylmaleimide-II abolished cofilin de-phosphorylation, as well as PDGF-enhanced contraction. In contrast, activation of the PKC protein family by 4β-phorbol 12-myristate 13-acetate (PMA) did not accelerate collagen gel contraction although it induced long-term cofilin de-phosphorylation, showing the need of a dynamic control of cofilin de-phosphorylation for PDGF-enhanced collagen gel contraction. Taken together, our data point to the involvement of a PI3K/PLCγ-PKC-cofilin pathway in both PDGF-enhanced cofilin de-phosphorylation and PDGF-enhanced collagen gel contraction.
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Affiliation(s)
- Vahid Reyhani
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, BMC Box 582, SE-751 23, Uppsala, Sweden.
| | - Maria Tsioumpekou
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, BMC Box 582, SE-751 23, Uppsala, Sweden.,Ludwig Institute for Cancer Research, Science for Life Laboratory, Uppsala University, Box 595, SE-751 24, Uppsala, Sweden
| | - Tijs van Wieringen
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, BMC Box 582, SE-751 23, Uppsala, Sweden
| | - Lars Rask
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, BMC Box 582, SE-751 23, Uppsala, Sweden
| | - Johan Lennartsson
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, BMC Box 582, SE-751 23, Uppsala, Sweden.,Ludwig Institute for Cancer Research, Science for Life Laboratory, Uppsala University, Box 595, SE-751 24, Uppsala, Sweden
| | - Kristofer Rubin
- Department of Medical Biochemistry and Microbiology, Science for Life Laboratory, Uppsala University, BMC Box 582, SE-751 23, Uppsala, Sweden.
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11
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Buckley CM, King JS. Drinking problems: mechanisms of macropinosome formation and maturation. FEBS J 2017; 284:3778-3790. [DOI: 10.1111/febs.14115] [Citation(s) in RCA: 93] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 04/25/2017] [Accepted: 05/17/2017] [Indexed: 11/30/2022]
Affiliation(s)
- Catherine M. Buckley
- Department of Biomedical Sciences Centre for Membrane Interactions and Dynamics University of Sheffield UK
- Bateson Centre University of Sheffield UK
| | - Jason S. King
- Department of Biomedical Sciences Centre for Membrane Interactions and Dynamics University of Sheffield UK
- Bateson Centre University of Sheffield UK
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12
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Kim H, Kim DH, Jeong B, Kim JH, Lee SR, Sonn JK. Blebbistatin induces chondrogenesis of single mesenchymal cells via PI3K/PDK1/mTOR/p70S6K pathway. Biologia (Bratisl) 2017. [DOI: 10.1515/biolog-2017-0078] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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13
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Valdivia A, Goicoechea SM, Awadia S, Zinn A, Garcia-Mata R. Regulation of circular dorsal ruffles, macropinocytosis, and cell migration by RhoG and its exchange factor, Trio. Mol Biol Cell 2017; 28:1768-1781. [PMID: 28468978 PMCID: PMC5491185 DOI: 10.1091/mbc.e16-06-0412] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 04/20/2017] [Accepted: 04/25/2017] [Indexed: 11/11/2022] Open
Abstract
The small GTPase RhoG and its exchange factor, Trio, regulate the formation and size of circular dorsal ruffles and associated functions, including macropinocytosis and cell migration. Circular dorsal ruffles (CDRs) are actin-rich structures that form on the dorsal surface of many mammalian cells in response to growth factor stimulation. CDRs represent a unique type of structure that forms transiently and only once upon stimulation. The formation of CDRs involves a drastic rearrangement of the cytoskeleton, which is regulated by the Rho family of GTPases. So far, only Rac1 has been consistently associated with CDR formation, whereas the role of other GTPases in this process is either lacking or inconclusive. Here we show that RhoG and its exchange factor, Trio, play a role in the regulation of CDR dynamics, particularly by modulating their size. RhoG is activated by Trio downstream of PDGF in a PI3K- and Src-dependent manner. Silencing RhoG expression decreases the number of cells that form CDRs, as well as the area of the CDRs. The regulation of CDR area by RhoG is independent of Rac1 function. In addition, our results show the RhoG plays a role in the cellular functions associated with CDR formation, including macropinocytosis, receptor internalization, and cell migration. Taken together, our results reveal a novel role for RhoG in the regulation of CDRs and the cellular processes associated with their formation.
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Affiliation(s)
- Alejandra Valdivia
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606.,Division of Cardiology, School of Medicine, Emory University, Atlanta, GA 30322
| | | | - Sahezeel Awadia
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Ashtyn Zinn
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
| | - Rafael Garcia-Mata
- Department of Biological Sciences, University of Toledo, Toledo, OH 43606
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14
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Recouvreux MV, Commisso C. Macropinocytosis: A Metabolic Adaptation to Nutrient Stress in Cancer. Front Endocrinol (Lausanne) 2017; 8:261. [PMID: 29085336 PMCID: PMC5649207 DOI: 10.3389/fendo.2017.00261] [Citation(s) in RCA: 150] [Impact Index Per Article: 21.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/22/2017] [Accepted: 09/20/2017] [Indexed: 12/28/2022] Open
Abstract
Oncogenic mutations, such as Ras mutations, drive not only enhanced proliferation but also the metabolic adaptations that confer to cancer cells the ability to sustain cell growth in a harsh tumor microenvironment. These adaptations might represent metabolic vulnerabilities that can be exploited to develop novel and more efficient cancer therapies. Macropinocytosis is an evolutionarily conserved endocytic pathway that permits the internalization of extracellular fluid via large endocytic vesicles known as macropinosomes. Recently, macropinocytosis has been determined to function as a nutrient-scavenging pathway in Ras-driven cancer cells. Macropinocytic uptake of extracellular proteins, and their further degradation within endolysosomes, provides the much-needed amino acids that fuel cancer cell metabolism and tumor growth. Here, we review the molecular mechanisms that govern the process of macropinocytosis, as well as discuss recent work that provides evidence of the important role of macropinocytosis as a nutrient supply pathway in cancer cells.
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Affiliation(s)
- Maria Victoria Recouvreux
- Tumor Initiation and Maintenance Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
| | - Cosimo Commisso
- Tumor Initiation and Maintenance Program, NCI-Designated Cancer Center, Sanford Burnham Prebys Medical Discovery Institute, La Jolla, CA, United States
- *Correspondence: Cosimo Commisso,
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15
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Yang Z, Wu F, Yang H, Zhou P. Endocytosis mechanism of a novel proteoglycan, extracted from Ganoderma lucidum, in HepG2 cells. RSC Adv 2017. [DOI: 10.1039/c7ra07520k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A novel protein tyrosine phosphatase 1B (PTP1B) inhibitor,FYGL, extracted fromGanoderma lucidum, was first reported to have an efficient hypoglycemic effect and high safetyin vivoin our previous study.
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Affiliation(s)
- Zhou Yang
- State Key Laboratory of Molecular Engineering of Polymers
- Department of Macromolecular Science
- Fudan University
- Shanghai 200433
- P. R. China
| | - Fan Wu
- State Key Laboratory of Molecular Engineering of Polymers
- Department of Macromolecular Science
- Fudan University
- Shanghai 200433
- P. R. China
| | - Hongjie Yang
- Yueyang Hospital of Integrated Traditional Chinese and Western Medicine
- Shanghai University of Traditional Chinese Medicine
- Shanghai 200437
- P. R. China
| | - Ping Zhou
- State Key Laboratory of Molecular Engineering of Polymers
- Department of Macromolecular Science
- Fudan University
- Shanghai 200433
- P. R. China
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16
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Tanimura S, Hashizume J, Arichika N, Watanabe K, Ohyama K, Takeda K, Kohno M. ERK signaling promotes cell motility by inducing the localization of myosin 1E to lamellipodial tips. J Cell Biol 2016; 214:475-89. [PMID: 27502487 PMCID: PMC4987290 DOI: 10.1083/jcb.201503123] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 07/14/2016] [Indexed: 12/31/2022] Open
Abstract
Tanimura et al. demonstrate that SH3P2 binds to and functions as a cytosolic anchor for myosin 1E (Myo1E). ERK signaling–dependent phosphorylation of SH3P2 induces the dissociation of bound Myo1E and its consequent localization to the tips of lamellipodia, where it promotes cell motility. Signaling by extracellular signal–regulated kinase (ERK) plays an essential role in the induction of cell motility, but the precise mechanism underlying such regulation has remained elusive. We recently identified SH3P2 as a negative regulator of cell motility whose function is inhibited by p90 ribosomal S6 kinase (RSK)–mediated phosphorylation downstream of ERK. We here show that myosin 1E (Myo1E) is a binding partner of SH3P2 and that the interaction of the two proteins in the cytosol prevents the localization of Myo1E to the plasma membrane. Serum-induced phosphorylation of SH3P2 at Ser202 by RSK results in dissociation of Myo1E from SH3P2 in the cytosol and the subsequent localization of Myo1E to the tips of lamellipodia mediated by binding of its TH2 domain to F-actin. This translocation of Myo1E is essential for lamellipodium extension and consequent cell migration. The ERK signaling pathway thus promotes cell motility through regulation of the subcellular localization of Myo1E.
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Affiliation(s)
- Susumu Tanimura
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan Nagasaki University Research Centre for Genomic Instability and Carcinogenesis, Nagasaki 852-8523, Japan
| | - Junya Hashizume
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Naoya Arichika
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Kazushi Watanabe
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Kaname Ohyama
- Department of Pharmacy Practice, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan Nagasaki University Research Centre for Genomic Instability and Carcinogenesis, Nagasaki 852-8523, Japan
| | - Kohsuke Takeda
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
| | - Michiaki Kohno
- Department of Cell Regulation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki 852-8521, Japan
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The H1047R point mutation in p110 alpha changes the morphology of human colon HCT116 cancer cells. Cell Death Discov 2015; 1:15044. [PMID: 27551473 PMCID: PMC4979441 DOI: 10.1038/cddiscovery.2015.44] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 08/07/2015] [Indexed: 02/07/2023] Open
Abstract
The class IA phosphatidylinositol 3-kinases (PI3K) is involved in controlling changes in cell morphology, which is a highly coordinated cellular event. This event is powered by actin filament polymerization and remodeling. The gain-of-function mutations in the catalytic subunit of p110α of class IA PI3K, which occur in up to one-third of human colorectal cancers (CRCs), are capable of causing dysregulation of cell signaling and thus may result in the alteration in cell morphology and motility and in turn cause cancer metastasis. In vivo studies have demonstrated that cell lines bearing the H1047R point mutation, the most frequent cancer-specific mutation in the kinase domain of p110α, are more metastatic than cells carrying wild-type p110α. In the current study, we show that the H1047R in p110α of PI3K decreases F-actin polymerization, increases the formation of filopodia and significantly changes the cell morphology in HCT116 cancer cells. The anti-apoptotic protein B-cell lymphoma 2 (Bcl-2), which is also involved in actin polymerization and cell migration, is downregulated by the H1047R mutation in p110α. Our data suggest that the H1047R mutation in PI3K is responsible for the rearrangement of the cytoskeleton, alteration in cell morphology and enhancing cell motility, and that Bcl-2 may be involved in the H1047R mutation-mediated morphological changes and increased migratory capability.
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18
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Posor Y, Eichhorn-Grünig M, Haucke V. Phosphoinositides in endocytosis. Biochim Biophys Acta Mol Cell Biol Lipids 2015; 1851:794-804. [DOI: 10.1016/j.bbalip.2014.09.014] [Citation(s) in RCA: 124] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2014] [Revised: 08/21/2014] [Accepted: 09/17/2014] [Indexed: 02/04/2023]
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Abstract
Rac and PI3Ks are intracellular signal transducers able to regulate multiple signaling pathways fundamental for cell behavior. PI3Ks are lipid kinases that produce phosphorylated lipids which, in turn, transduce extracellular cues within the cell, while Rac is a small G protein that impacts on actin organization. Compelling evidence indicates that in multiple circumstances the 2 signaling pathways appear intermingled. For instance, phosphorylated lipids produced by PI3Ks recruit and activate GEF and GAP proteins, key modulators of Rac function. Conversely, PI3Ks interact with activated Rac, leading to Rac signaling amplification. This review summarizes the molecular mechanisms underlying the cross-talk between Rac and PI3K signaling in 2 different processes, cell migration and ROS production.
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Affiliation(s)
- Carlo C Campa
- a Molecular Biotechnology Center; Department of Molecular Biotechnology and Health Sciences; University of Torino ; Torino , Italy
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20
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Abstract
PURPOSE Prostate cancer cells are responsive to multiple hormones and growth factors that can affect cell function. These effects may include modulating cell proliferation and apoptosis, but the ability to impinge on the metastatic potential of prostate cancer cells by affecting cell motility should also be considered, as prostate tumor metastasis correlates with limited therapeutic options and poor prognosis. Human growth hormone (hGH) can affect the growth and survival of prostate cancer cells, but the effect of hGH on prostate cancer cell motility is unknown. In the present study, the potential for exogenous and autocrine hGH to directly affect prostate cancer cell motility was addressed. MATERIALS AND METHODS The effects of exogenous and autocrine hGH on the chemokinesis and chemotaxis of LNCaP prostate cancer cells were tested using cell monolayer wound healing and Boyden chamber invasion assays. The signaling pathways underlying these effects were resolved with chemical inhibitors and the correlation with cytoskeletal actin reorganization evaluated microscopically by staining cells with fluor-conjugated phalloidin. RESULTS Both exogenous and autocrine hGH augmented the migration and invasion of LNCaP cells, and hGH itself acted as a chemoattractant. This activity was dependent upon the STAT5, MEK1/2 and PI3K signaling pathways, and was accompanied by an alteration in cellular actin organization. CONCLUSIONS hGH may enhance the metastatic potential of prostate cancer cells, both as a stimulant of cellular motility and invasiveness and as a chemoattractant.
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Affiliation(s)
- Alona O Nakonechnaya
- Department of Biochemistry and Molecular Biology, Brody School of Medicine at East Carolina University , Greenville, NC , USA
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21
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Abstract
The phosphoinositide 3-kinase (PI 3-K) signal relay pathway represents arguably one of the most intensely studied mechanisms by which extracellular signals elicit cellular responses through the generation of second messengers that are associated with cell growth and transformation. This chapter reviews the many landmark discoveries in the PI 3-K signaling pathway in biology and disease, from the identification of a novel phosphoinositide kinase activity associated with transforming oncogenes in the 1980s, to the identification of oncogenic mutations in the catalytic subunit of PI 3-K in the mid 2000s. Two and a half decades of intense research have provided clear evidence that the PI 3-K pathway controls virtually all aspects of normal cellular physiology, and that deregulation of one or more proteins that regulate or transduce the PI 3-K signal ultimately leads to human pathology. The most recent efforts have focused on the development of specific PI 3-K inhibitors that are currently being evaluated in clinical trials for a range of disease states.This chapter is devoted to a historical review of the landmark findings in the PI 3-K from its relatively humble beginnings in the early to mid 1980s up until the present day. When considering the key findings in the history of PI 3-K, it is essential to recognize the landmark studies by Lowell and Mabel Hokin in the 1950s who were the first to describe that extracellular agonists such as acetylcholine could stimulate the incorporation of radiolabeled phosphate into phospholipids (Hokin and Hokin 1953). Their work initiated an entirely new field of lipid signaling, and subsequent studies in the 1970s by Michell and Lapetina who linked phosphoinositide turnover to membrane-associated receptors that initiate intracellular calcium mobilization (Lapetina and Michell 1973). Later studies revealed that the phospholipase-mediated breakdown of the same minor membrane phospholipids such as PtdIns-4,5-P(2) (phosphatidylinositol-4,5-bisphosphate) is responsible for the release of two additional key second messengers, diacylglycerol (DG) and IP(3) (inositol-1,4,5-trisphosphate) (Kirk et al. 1981; Berridge 1983; Berridge et al. 1983). Berridge, Irvine and Schulz then revealed that one of the byproducts of this lipid signal relay pathway is the release of calcium from intracellular stores such as the endoplasmic reticulum (Streb et al. 1983). Finally, pioneering studies by Nishizuka in the late 1970s identified PKC (protein kinase C) as a phospholipid and diacylglycerol-activated serine/threonine protein kinase (Inoue et al. 1977; Takai et al. 1977). At this point, it probably seemed to most at the time that the story was complete, such that hydrolysis of phosphoinositides such as PtdIns-4,5-P(2) and PtdIns-4-P would account for the major mechanisms of agonist-stimulated lipid signaling leading to physiological responses. On the contrary, the story was far from complete and was about to become a lot more complex.
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Affiliation(s)
- Alex Toker
- Department of Pathology, Beth Israel Deaconess Medical Center, Harvard Medical School, 330 Brookline Avenue, EC/CLS-633A, 02130, Boston, MA, USA,
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Murakami S, Sakurai-Yageta M, Maruyama T, Murakami Y. Trans-homophilic interaction of CADM1 activates PI3K by forming a complex with MAGuK-family proteins MPP3 and Dlg. PLoS One 2014; 9:e82894. [PMID: 24503895 PMCID: PMC3913574 DOI: 10.1371/journal.pone.0082894] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2013] [Accepted: 11/07/2013] [Indexed: 11/25/2022] Open
Abstract
CADM1 (Cell adhesion molecule 1), a cell adhesion molecule belonging to the immunoglobulin superfamily, is involved in cell-cell interaction and the formation and maintenance of epithelial structure. Expression of CADM1 is frequently down-regulated in various tumors derived from epithelial cells. However, the intracellular signaling pathways activated by CADM1-mediated cell adhesion remain unknown. Here, we established a cell-based spreading assay to analyze the signaling pathway specifically activated by the trans-homophilic interaction of CADM1. In the assay, MDCK cells expressing exogenous CADM1 were incubated on the glass coated with a recombinant extracellular fragment of CADM1, and the degree of cell spreading was quantified by measuring their surface area. Assay screening of 104 chemical inhibitors with known functions revealed that LY294002, an inhibitor of phosphoinositide 3-kinase (PI3K), efficiently suppressed cell spreading in a dose-dependent manner. Inhibitors of Akt and Rac1, downstream effectors of PI3K, also partially suppressed cell spreading, while the addition of both inhibitors blocked cell spreading to the same extent as did LY294002. Furthermore, MPP3 and Dlg, membrane-associated guanylate kinase homologs (MAGuK) proteins, connect CADM1 with p85 of PI3K by forming a multi-protein complex at the periphery of cells. These results suggest that trans-homophilic interaction mediated by CADM1 activates the PI3K pathway to reorganize the actin cytoskeleton and form epithelial cell structure.
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Affiliation(s)
- Shigefumi Murakami
- Division of Molecular Pathology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Mika Sakurai-Yageta
- Division of Molecular Pathology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Tomoko Maruyama
- Division of Molecular Pathology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
| | - Yoshinori Murakami
- Division of Molecular Pathology, Institute of Medical Science, The University of Tokyo, Tokyo, Japan
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Interference with the contractile machinery of the fibroblastic chondrocyte cytoskeleton induces re-expression of the cartilage phenotype through involvement of PI3K, PKC and MAPKs. Exp Cell Res 2013; 320:175-87. [PMID: 24246223 DOI: 10.1016/j.yexcr.2013.11.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2013] [Revised: 11/04/2013] [Accepted: 11/08/2013] [Indexed: 12/20/2022]
Abstract
Chondrocytes rapidly lose their phenotypic expression of collagen II and aggrecan when grown on 2D substrates. It has generally been observed that a fibroblastic morphology with strong actin-myosin contractility inhibits chondrogenesis, whereas chondrogenesis may be promoted by depolymerization of the stress fibers and/or disruption of the physical link between the actin stress fibers and the ECM, as is the case in 3D hydrogels. Here we studied the relationship between the actin-myosin cytoskeleton and expression of chondrogenic markers by culturing fibroblastic chondrocytes in the presence of cytochalasin D and staurosporine. Both drugs induced collagen II re-expression; however, renewed glycosaminoglycan synthesis could only be observed upon treatment with staurosporine. The chondrogenic effect of staurosporine was augmented when blebbistatin, an inhibitor of myosin/actin contractility, was added to the staurosporine-stimulated cultures. Furthermore, in 3D alginate cultures, the amount of staurosporine required to induce chondrogenesis was much lower compared to 2D cultures (0.625 nM vs. 2.5 nM). Using a selection of specific signaling pathway inhibitors, it was found that PI3K-, PKC- and p38-MAPK pathways positively regulated chondrogenesis while the ERK-pathway was found to be a negative regulator in staurosporine-induced re-differentiation, whereas down-regulation of ILK by siRNA indicated that ILK is not determining for chondrocyte re-differentiation. Furthermore, staurosporine analog midostaurin displayed only a limited chondrogenic effect, suggesting that activation/deactivation of a specific set of key signaling molecules can control the expression of the chondrogenic phenotype. This study demonstrates the critical importance of mechanobiological factors in chondrogenesis suggesting that the architecture of the actin cytoskeleton and its contractility control key signaling molecules that determine whether the chondrocyte phenotype will be directed along a fibroblastic or chondrogenic path.
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Juvin V, Malek M, Anderson KE, Dion C, Chessa T, Lecureuil C, Ferguson GJ, Cosulich S, Hawkins PT, Stephens LR. Signaling via class IA Phosphoinositide 3-kinases (PI3K) in human, breast-derived cell lines. PLoS One 2013; 8:e75045. [PMID: 24124465 PMCID: PMC3790768 DOI: 10.1371/journal.pone.0075045] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2013] [Accepted: 08/08/2013] [Indexed: 02/01/2023] Open
Abstract
We have addressed the differential roles of class I Phosphoinositide 3-kinases (PI3K) in human breast-derived MCF10a (and iso-genetic derivatives) and MDA-MB 231 and 468 cells. Class I PI3Ks are heterodimers of p110 catalytic (α, β, δ and γ) and p50-101 regulatory subunits and make the signaling lipid, phosphatidylinositol (3,4,5)-trisphosphate (PtdIns(3,4,5)P3) that can activate effectors, eg protein kinase B (PKB), and responses, eg migration. The PtdIns(3,4,5)P3-3-phosphatase and tumour-suppressor, PTEN inhibits this pathway. p110α, but not other p110s, has a number of onco-mutant variants that are commonly found in cancers. mRNA-seq data shows that MCF10a cells express p110β>>α>δ with undetectable p110γ. Despite this, EGF-stimulated phosphorylation of PKB depended upon p110α-, but not β- or δ- activity. EGF-stimulated chemokinesis, but not chemotaxis, was also dependent upon p110α, but not β- or δ- activity. In the presence of single, endogenous alleles of onco-mutant p110α (H1047R or E545K), basal, but not EGF-stimulated, phosphorylation of PKB was increased and the effect of EGF was fully reversed by p110α inhibitors. Cells expressing either onco-mutant displayed higher basal motility and EGF-stimulated chemokinesis.This latter effect was, however, only partially-sensitive to PI3K inhibitors. In PTEN(-/-) cells, basal and EGF-stimulated phosphorylation of PKB was substantially increased, but the p110-dependency was variable between cell types. In MDA-MB 468s phosphorylation of PKB was significantly dependent on p110β, but not α- or δ- activity; in PTEN(-/-) MCF10a it remained, like the parental cells, p110α-dependent. Surprisingly, loss of PTEN suppressed basal motility and EGF-stimulated chemokinesis. These results indicate that; p110α is required for EGF signaling to PKB and chemokinesis, but not chemotaxis; onco-mutant alleles of p110α augment signaling in the absence of EGF and may increase motility, in part, via acutely modulating PI3K-activity-independent mechanisms. Finally, we demonstrate that there is not a universal mechanism that up-regulates p110β function in the absence of PTEN.
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Affiliation(s)
| | | | | | - Carine Dion
- The Babraham Institute, Babraham, Cambridge, United Kingdom
| | - Tamara Chessa
- The Babraham Institute, Babraham, Cambridge, United Kingdom
| | | | | | - Sabina Cosulich
- The Babraham Institute, Babraham, Cambridge, United Kingdom
- Astrazeneca, Macclesfield United Kingdom
| | | | - Len R. Stephens
- The Babraham Institute, Babraham, Cambridge, United Kingdom
- * E-mail:
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25
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Fyffe C, Falasca M. 3-Phosphoinositide-dependent protein kinase-1 as an emerging target in the management of breast cancer. Cancer Manag Res 2013; 5:271-80. [PMID: 24039447 PMCID: PMC3771848 DOI: 10.2147/cmar.s35026] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
It should be noted that 3-phosphoinositide-dependent protein kinase-1 (PDK1) is a protein encoded by the PDPK1 gene, which plays a key role in the signaling pathways activated by several growth factors and hormones. PDK1 is a crucial kinase that functions downstream of phosphoinositide 3-kinase activation and activates members of the AGC family of protein kinases, such as protein kinase B (Akt), protein kinase C (PKC), p70 ribosomal protein S6 kinases, and serum glucocorticoid-dependent kinase, by phosphorylating serine/threonine residues in the activation loop. AGC kinases are known to play crucial roles in regulating physiological processes relevant to metabolism, growth, proliferation, and survival. Changes in the expression and activity of PDK1 and several AGC kinases have been linked to human diseases including cancer. Recent data have revealed that the alteration of PDK1 is a critical component of oncogenic phosphoinositide 3-kinase signaling in breast cancer, suggesting that inhibition of PDK1 can inhibit breast cancer progression. Indeed, PDK1 is highly expressed in a majority of human breast cancer cell lines and both PDK1 protein and messenger ribonucleic acid are overexpressed in a majority of human breast cancers. Furthermore, overexpression of PDK1 is sufficient to transform mammary epithelial cells. PDK1 plays an essential role in regulating cell migration, especially in the context of phosphatase and tensin homologue deficiency. More importantly, downregulation of PDK1 levels inhibits migration and experimental metastasis of human breast cancer cells. Thus, targeting PDK1 may be a valuable anticancer strategy that may improve the efficacy of chemotherapeutic strategies in breast cancer patients. In this review, we summarize the evidence that has been reported to support the idea that PDK1 may be a key target in breast cancer management.
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Affiliation(s)
- Chanse Fyffe
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Blizard Institute, Inositide Signallling Group, London, UK
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26
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Abstract
Remodeling of extracellular matrix (ECM) is a fundamental cell property that allows cells to alter their microenvironment and move through tissues. Invadopodia and podosomes are subcellular actin-rich structures that are specialized for matrix degradation and are formed by cancer and normal cells, respectively. Although initial studies focused on defining the core machinery of these two structures, recent studies have identified inputs from both growth factor and adhesion signaling as crucial for invasive activity. This Commentary will outline the current knowledge on the upstream signaling inputs to invadopodia and podosomes and their role in governing distinct stages of these invasive structures. We discuss invadopodia and podosomes as adhesion structures and highlight new data showing that invadopodia-associated adhesion rings promote the maturation of already-formed invadopodia. We present a model in which growth factor stimulation leads to phosphoinositide 3-kinase (PI3K) activity and formation of invadopodia, whereas adhesion signaling promotes exocytosis of proteinases at invadopodia.
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Affiliation(s)
- Daisuke Hoshino
- Department of Cancer Biology, Vanderbilt University Medical Center, 2220 Pierce Avenue, Nashville, TN 37232-6840, USA
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Hoeller O, Bolourani P, Clark J, Stephens LR, Hawkins PT, Weiner OD, Weeks G, Kay RR. Two distinct functions for PI3-kinases in macropinocytosis. J Cell Sci 2013; 126:4296-307. [PMID: 23843627 DOI: 10.1242/jcs.134015] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Class-1 PI3-kinases are major regulators of the actin cytoskeleton, whose precise contributions to chemotaxis, phagocytosis and macropinocytosis remain unresolved. We used systematic genetic ablation to examine this question in growing Dictyostelium cells. Mass spectroscopy shows that a quintuple mutant lacking the entire genomic complement of class-1 PI3-kinases retains only 10% of wild-type PtdIns(3,4,5)P3 levels. Chemotaxis to folate and phagocytosis of bacteria proceed normally in the quintuple mutant but macropinocytosis is abolished. In this context PI3-kinases show specialized functions, only one of which is directly linked to gross PtdIns(3,4,5)P3 levels: macropinosomes originate in patches of PtdIns(3,4,5)P3, with associated F-actin-rich ruffles, both of which depend on PI3-kinase 1/2 (PI3K1/2) but not PI3K4, whereas conversion of ruffles into vesicles requires PI3K4. A biosensor derived from the Ras-binding domain of PI3K1 suggests that Ras is activated throughout vesicle formation. Binding assays show that RasG and RasS interact most strongly with PI3K1/2 and PI3K4, and single mutants of either Ras have severe macropinocytosis defects. Thus, the fundamental function of PI3-kinases in growing Dictyostelium cells is in macropinocytosis where they have two distinct functions, supported by at least two separate Ras proteins.
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Affiliation(s)
- Oliver Hoeller
- Cardiovascular Research Institute and Department of Biochemistry and Biophysics, University of California San Francisco, San Francisco, CA, USA
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28
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Pall ML. Electromagnetic fields act via activation of voltage-gated calcium channels to produce beneficial or adverse effects. J Cell Mol Med 2013; 17:958-65. [PMID: 23802593 PMCID: PMC3780531 DOI: 10.1111/jcmm.12088] [Citation(s) in RCA: 246] [Impact Index Per Article: 22.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2013] [Accepted: 05/20/2013] [Indexed: 12/27/2022] Open
Abstract
The direct targets of extremely low and microwave frequency range electromagnetic fields (EMFs) in producing non-thermal effects have not been clearly established. However, studies in the literature, reviewed here, provide substantial support for such direct targets. Twenty-three studies have shown that voltage-gated calcium channels (VGCCs) produce these and other EMF effects, such that the L-type or other VGCC blockers block or greatly lower diverse EMF effects. Furthermore, the voltage-gated properties of these channels may provide biophysically plausible mechanisms for EMF biological effects. Downstream responses of such EMF exposures may be mediated through Ca2+/calmodulin stimulation of nitric oxide synthesis. Potentially, physiological/therapeutic responses may be largely as a result of nitric oxide-cGMP-protein kinase G pathway stimulation. A well-studied example of such an apparent therapeutic response, EMF stimulation of bone growth, appears to work along this pathway. However, pathophysiological responses to EMFs may be as a result of nitric oxide-peroxynitrite-oxidative stress pathway of action. A single such well-documented example, EMF induction of DNA single-strand breaks in cells, as measured by alkaline comet assays, is reviewed here. Such single-strand breaks are known to be produced through the action of this pathway. Data on the mechanism of EMF induction of such breaks are limited; what data are available support this proposed mechanism. Other Ca2+-mediated regulatory changes, independent of nitric oxide, may also have roles. This article reviews, then, a substantially supported set of targets, VGCCs, whose stimulation produces non-thermal EMF responses by humans/higher animals with downstream effects involving Ca2+/calmodulin-dependent nitric oxide increases, which may explain therapeutic and pathophysiological effects.
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Affiliation(s)
- Martin L Pall
- Professor Emeritus of Biochemistry and Basic Medical Sciences, Washington State University, Portland, OR, USA.
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29
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Koutsioumpa M, Polytarchou C, Courty J, Zhang Y, Kieffer N, Mikelis C, Skandalis SS, Hellman U, Iliopoulos D, Papadimitriou E. Interplay between αvβ3 integrin and nucleolin regulates human endothelial and glioma cell migration. J Biol Chem 2013; 288:343-54. [PMID: 23161541 PMCID: PMC3537032 DOI: 10.1074/jbc.m112.387076] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2012] [Revised: 11/14/2012] [Indexed: 11/06/2022] Open
Abstract
The multifunctional protein nucleolin (NCL) is overexpressed on the surface of activated endothelial and tumor cells and mediates the stimulatory actions of several angiogenic growth factors, such as pleiotrophin (PTN). Because α(v)β(3) integrin is also required for PTN-induced cell migration, the aim of the present work was to study the interplay between NCL and α(v)β(3) by using biochemical, immunofluorescence, and proximity ligation assays in cells with genetically altered expression of the studied molecules. Interestingly, cell surface NCL localization was detected only in cells expressing α(v)β(3) and depended on the phosphorylation of β(3) at Tyr(773) through receptor protein-tyrosine phosphatase β/ζ (RPTPβ/ζ) and c-Src activation. Downstream of α(v)β(3,) PI3K activity mediated this phenomenon and cell surface NCL was found to interact with both α(v)β(3) and RPTPβ/ζ. Positive correlation of cell surface NCL and α(v)β(3) expression was also observed in human glioblastoma tissue arrays, and inhibition of cell migration by cell surface NCL antagonists was observed only in cells expressing α(v)β(3). Collectively, these data suggest that both expression and β(3) integrin phosphorylation at Tyr(773) determine the cell surface localization of NCL downstream of the RPTPβ/ζ/c-Src signaling cascade and can be used as a biomarker for the use of cell surface NCL antagonists as anticancer agents.
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Affiliation(s)
- Marina Koutsioumpa
- From the Department of Pharmacy, Laboratory of Molecular Pharmacology, University of Patras, Greece
| | - Christos Polytarchou
- the Department of Cancer Immunology & AIDS, Dana Farber Cancer Institute, Boston, Massachusetts 02215
- the Department of Immunobiology and Microbiology, Harvard Medical School, Boston, Massachusetts 02115
| | - José Courty
- the Laboratoire CRRET, Universite Paris Est Creteil Val de Marne, avenue du General de Gaulle, 94010 Creteil Cedex
| | - Yue Zhang
- the Sino-French Research Centre for Life Sciences and Genomics, CNRS/LIA124, Rui Jin Hospital, Jiao Tong University Medical School, 197 Rui Jin Er Road, Shanghai 200025, China, and
| | - Nelly Kieffer
- the Sino-French Research Centre for Life Sciences and Genomics, CNRS/LIA124, Rui Jin Hospital, Jiao Tong University Medical School, 197 Rui Jin Er Road, Shanghai 200025, China, and
| | - Constantinos Mikelis
- From the Department of Pharmacy, Laboratory of Molecular Pharmacology, University of Patras, Greece
| | - Spyros S. Skandalis
- the Ludwig Institute for Cancer Research, Uppsala University, Uppsala SE-751-05, Sweden
| | - Ulf Hellman
- the Ludwig Institute for Cancer Research, Uppsala University, Uppsala SE-751-05, Sweden
| | - Dimitrios Iliopoulos
- the Department of Cancer Immunology & AIDS, Dana Farber Cancer Institute, Boston, Massachusetts 02215
- the Department of Immunobiology and Microbiology, Harvard Medical School, Boston, Massachusetts 02115
| | - Evangelia Papadimitriou
- From the Department of Pharmacy, Laboratory of Molecular Pharmacology, University of Patras, Greece
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30
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Ras Guanine Nucleotide Releasing Factor 1 (RasGrf1) Enhancement of Trk Receptor-Mediated Neurite Outgrowth Requires Activation of Both H-Ras and Rac. J Mol Neurosci 2012; 49:38-51. [DOI: 10.1007/s12031-012-9847-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2011] [Accepted: 05/31/2012] [Indexed: 10/28/2022]
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Abstract
Over the past two decades, our understanding of phospoinositide 3-kinases (PI3Ks) has progressed from the identification of an enzymatic activity associated with growth factors, GPCRs and certain oncogene products to a disease target in cancer and inflammation, with PI3K inhibitors currently in clinical trials. Elucidation of PI3K-dependent networks led to the discovery of the phosphoinositide-binding PH, PX and FYVE domains as conduits of intracellular lipid signalling, the determination of the molecular function of the tumour suppressor PTEN and the identification of AKT and mTOR protein kinases as key regulators of cell growth. Here we look back at the main discoveries that shaped the PI3K field.
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32
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Abstract
Phosphatidylinositol lipids generated through the action of phosphinositide 3-kinase (PI3K) are key mediators of a wide array of biological responses. In particular, their role in the regulation of cell migration has been extensively studied and extends to amoeboid as well as mesenchymal migration. Through the emergence of fluorescent probes that target PI3K products as well as the use of specific inhibitors and knockout technologies, the spatio-temporal distribution of PI3K products in chemotaxing cells has been shown to represent a key anterior polarity signal that targets downstream effectors to actin polymerization. In addition, through intricate cross-talk networks PI3K products have been shown to regulate signals that control posterior effectors. Yet, in more complex environments or in conditions where chemoattractant gradients are steep, a variety of cell types can still chemotax in the absence of PI3K signals. Indeed, parallel signal transduction pathways have been shown to coordinately regulate cell polarity and directed movement. In this chapter, we will review the current role PI3K products play in the regulation of directed cell migration in various cell types, highlight the importance of mathematical modeling in the study of chemotaxis, and end with a brief overview of other signaling cascades known to also regulate chemotaxis.
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Affiliation(s)
- Michael C Weiger
- Laboratory of Cellular and Molecular Biology, National Cancer Institute, National Institutes of Health, 37 Convent Drive, Bldg.37/Rm2066, 20892-4256, Bethesda, MD, USA
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Dubielecka PM, Machida K, Xiong X, Hossain S, Ogiue-Ikeda M, Carrera AC, Mayer BJ, Kotula L. Abi1/Hssh3bp1 pY213 links Abl kinase signaling to p85 regulatory subunit of PI-3 kinase in regulation of macropinocytosis in LNCaP cells. FEBS Lett 2010; 584:3279-86. [PMID: 20598684 DOI: 10.1016/j.febslet.2010.06.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Revised: 06/09/2010] [Accepted: 06/13/2010] [Indexed: 12/25/2022]
Abstract
Macropinocytosis is regulated by Abl kinase via an unknown mechanism. We previously demonstrated that Abl kinase activity is, itself, regulated by Abi1 subsequent to Abl kinase phosphorylation of Abi1 tyrosine 213 (pY213) [1]. Here we show that blocking phosphorylation of Y213 abrogated the ability of Abl to regulate macropinocytosis, implicating Abi1 pY213 as a key regulator of macropinocytosis. Results from screening the human SH2 domain library and mapping the interaction site between Abi1 and the p85 regulatory domain of PI-3 kinase, coupled with data from cells transfected with loss-of-function p85 mutants, support the hypothesis that macropinocytosis is regulated by interactions between Abi1 pY213 and the C-terminal SH2 domain of p85-thereby linking Abl kinase signaling to p85-dependent regulation of macropinocytosis.
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Messmer-Blust AF, Balasubramanian S, Gorbacheva VY, Jeyaratnam JA, Vestal DJ. The interferon-gamma-induced murine guanylate-binding protein-2 inhibits rac activation during cell spreading on fibronectin and after platelet-derived growth factor treatment: role for phosphatidylinositol 3-kinase. Mol Biol Cell 2010; 21:2514-28. [PMID: 20505078 PMCID: PMC2903678 DOI: 10.1091/mbc.e09-04-0344] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Exposure of cells to certain cytokines can alter how these same cells respond to later cues from other agents, such as extracellular matrix or growth factors. Interferon (IFN)-gamma pre-exposure inhibits the spreading of fibroblasts on fibronectin. Expression of the IFN-gamma-induced GTPase murine guanylate-binding protein-2 (mGBP-2) can phenocopy this inhibition and small interfering RNA knockdown of mGBP-2 prevents IFN-gamma-mediated inhibition of cell spreading. Either IFN-gamma treatment or mGBP-2 expression inhibits Rac activation during cell spreading. Rac is required for cell spreading. mGBP-2 also inhibits the activation of Akt during cell spreading on fibronectin. mGBP-2 is incorporated into a protein complex containing the catalytic subunit of phosphatidylinositol 3-kinase (PI3-K), p110. The association of mGBP-2 with p110 seems important for the inhibition of cell spreading because S52N mGBP-2, which does not incorporate into the protein complex with p110, is unable to inhibit cell spreading. PI3-K activation during cell spreading on fibronectin was inhibited in the presence of mGBP-2. Both IFN-gamma and mGBP-2 also inhibit cell spreading initiated by platelet-derived growth factor treatment, which is also accompanied by inhibition of Rac activation by mGBP-2. This is the first report of a novel mechanism by which IFN-gamma can alter how cells respond to subsequent extracellular signals, by the induction of mGBP-2.
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35
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Abella JV, Vaillancourt R, Frigault MM, Ponzo MG, Zuo D, Sangwan V, Larose L, Park M. The Gab1 scaffold regulates RTK-dependent dorsal ruffle formation through the adaptor Nck. J Cell Sci 2010; 123:1306-19. [PMID: 20332103 DOI: 10.1242/jcs.062570] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
The polarised distribution of signals downstream from receptor tyrosine kinases (RTKs) regulates fundamental cellular processes that control cell migration, growth and morphogenesis. It is poorly understood how RTKs are involved in the localised signalling and actin remodelling required for these processes. Here, we show that the Gab1 scaffold is essential for the formation of a class of polarised actin microdomain, namely dorsal ruffles, downstream from the Met, EGF and PDGF RTKs. Gab1 associates constitutively with the actin-nucleating factor N-WASP. Following RTK activation, Gab1 recruits Nck, an activator of N-WASP, into a signalling complex localised to dorsal ruffles. Formation of dorsal ruffles requires interaction between Gab1 and Nck, and also requires functional N-WASP. Epithelial cells expressing Gab1DeltaNck (Y407F) exhibit decreased Met-dependent Rac activation, fail to induce dorsal ruffles, and have impaired cell migration and epithelial remodelling. These data show that a Gab1-Nck signalling complex interacts with several RTKs to promote polarised actin remodelling and downstream biological responses.
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Affiliation(s)
- Jasmine V Abella
- Department of Biochemistry, McGill University, Montréal, Québec H3A 1A1, Canada
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36
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Desai LP, White SR, Waters CM. Cyclic mechanical stretch decreases cell migration by inhibiting phosphatidylinositol 3-kinase- and focal adhesion kinase-mediated JNK1 activation. J Biol Chem 2010; 285:4511-9. [PMID: 20018857 PMCID: PMC2836056 DOI: 10.1074/jbc.m109.084335] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2009] [Revised: 11/30/2009] [Indexed: 01/11/2023] Open
Abstract
Epithelial cell migration during wound healing requires coordinated signaling pathways that direct polarization of the leading and trailing ends of the cells, cytoskeletal organization, and remodeling of focal adhesions. These inherently mechanical processes are disrupted by cyclic stretch (CS), but the specific signaling molecules involved in this disruption are not well understood. In this study, we demonstrate that inhibition of phosphatidylinositol 3-kinase (PI3K) or expression of a dominant-negative form of PI3K caused inhibition of airway epithelial cell wound closure. CS caused a sustained decrease in activation of PI3K and inhibited wound healing. Expression of constitutively active PI3K stimulated translocation of Tiam1 to the membrane, increased Rac1 activity, and increased wound healing of airway epithelial cells. Increased Rac1 activity resulted in increased phosphorylation of JNK1. PI3K activation was not regulated by association with focal adhesion kinase. Restoration of efficient cell migration during CS required coexpression of constitutively active PI3K, focal adhesion kinase, and JIP3.
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Affiliation(s)
| | - Steven R. White
- the Section of Pulmonary and Critical Care Medicine, University of Chicago, Chicago, Illinois 60637
| | - Christopher M. Waters
- From the Departments of Physiology
- Medicine, and
- Biomedical Engineering, University of Tennessee Health Science Center, Memphis, Tennessee 38163 and
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37
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Affiliation(s)
- C.B. SHUSTER
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA, USA
| | - I.M. HERMAN
- Department of Physiology, Tufts University School of Medicine, Boston, MA, USA
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38
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Zhou L, Takayama Y, Boucher P, Tallquist MD, Herz J. LRP1 regulates architecture of the vascular wall by controlling PDGFRbeta-dependent phosphatidylinositol 3-kinase activation. PLoS One 2009; 4:e6922. [PMID: 19742316 PMCID: PMC2734324 DOI: 10.1371/journal.pone.0006922] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 08/07/2009] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Low density lipoprotein receptor-related protein 1 (LRP1) protects against atherosclerosis by regulating the activation of platelet-derived growth factor receptor beta (PDGFRbeta) in vascular smooth muscle cells (SMCs). Activated PDGFRbeta undergoes tyrosine phosphorylation and subsequently interacts with various signaling molecules, including phosphatidylinositol 3-kinase (PI3K), which binds to the phosphorylated tyrosine 739/750 residues in mice, and thus regulates actin polymerization and cell movement. METHODS AND PRINCIPAL FINDINGS In this study, we found disorganized actin in the form of membrane ruffling and enhanced cell migration in LRP1-deficient (LRP1-/-) SMCs. Marfan syndrome-like phenotypes such as tortuous aortas, disrupted elastic layers and abnormally activated transforming growth factor beta (TGFbeta) signaling are present in smooth muscle-specific LRP1 knockout (smLRP1-/-) mice. To investigate the role of LRP1-regulated PI3K activation by PDGFRbeta in atherogenesis, we generated a strain of smLRP1-/- mice in which tyrosine 739/750 of the PDGFRbeta had been mutated to phenylalanines (PDGFRbeta F2/F2). Spontaneous atherosclerosis was significantly reduced in the absence of hypercholesterolemia in these mice compared to smLRP1-/- animals that express wild type PDGFR. Normal actin organization was restored and spontaneous SMC migration as well as PDGF-BB-induced chemotaxis was dramatically reduced, despite continued overactivation of TGFbeta signaling, as indicated by high levels of nuclear phospho-Smad2. CONCLUSIONS AND SIGNIFICANCE Our data suggest that LRP1 regulates actin organization and cell migration by controlling PDGFRbeta-dependent activation of PI3K. TGFbeta activation alone is not sufficient for the expression of the Marfan-like vascular phenotype. Thus, regulation of PI3 Kinase by PDGFRbeta is essential for maintaining vascular integrity, and for the prevention of atherosclerosis as well as Marfan syndrome.
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Affiliation(s)
- Li Zhou
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Yoshiharu Takayama
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Philippe Boucher
- Department of Pharmacology, University of Strasbourg, Strasbourg, France
| | - Michelle D. Tallquist
- Molecular Biology, UT Southwestern Medical Center, Dallas, Texas, United States of America
| | - Joachim Herz
- Department of Molecular Genetics, UT Southwestern Medical Center, Dallas, Texas, United States of America
- * E-mail:
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Ruusala A, Pawson T, Heldin CH, Aspenström P. Nck adapters are involved in the formation of dorsal ruffles, cell migration, and Rho signaling downstream of the platelet-derived growth factor beta receptor. J Biol Chem 2008; 283:30034-44. [PMID: 18765673 DOI: 10.1074/jbc.m800913200] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The SH3 and SH2 domain-containing adapter proteins Nck1 and Nck2 are known to function downstream of activated tyrosine kinase receptors, such as the platelet-derived growth factor (PDGF) receptors. The SH2 domain of Nck1 binds to phosphorylated tyrosine residue 751 in PDGFbeta receptor and has been suggested to have a role in the PDGF-induced mobilization of the actin filament system. Because Tyr-751 is a site for additional receptor interactors, it has been difficult to discriminate the signaling from Nck from signaling via other molecules. For this reason we have used mouse embryonic fibroblasts derived from mice in which the genes for Nck1 and Nck2 have been inactivated by gene targeting (knock-out (KO) cells). The mutant cells had a reduced ability to form edge ruffles in response to PDGF, and the presence of Nck was obligatory for the formation of dorsal ruffles. In addition, the KO cells had a reduced chemotactic and migratory potential. Importantly, KO cells had reduced cell attachment properties and a reduced ability to form focal adhesions in response to serum stimulation. Moreover, signaling involving the Rho GTPases was defective in KO cells. In summary, our observations suggest that the Nck adapters are needed for signaling to Rho GTPases and actin dynamics downstream of the PDGFbeta receptor.
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Affiliation(s)
- Aino Ruusala
- Ludwig Institute for Cancer Research, Biomedical Center, Uppsala University, SE-751 24 Uppsala, Sweden
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40
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Abstract
The ingestion of particles or cells by phagocytosis and of fluids by macropinocytosis requires the formation of large endocytic vacuolar compartments inside cells by the organized movements of membranes and the actin cytoskeleton. Fc-receptor-mediated phagocytosis is guided by the zipper-like progression of local, receptor-initiated responses that conform to particle geometry. By contrast, macropinosomes and some phagosomes form with little or no guidance from receptors. The common organizing structure is a cup-shaped invagination of the plasma membrane that becomes the phagosome or macropinosome. Recent studies, focusing on the physical properties of forming cups, indicate that a feedback mechanism regulates the signal transduction of phagocytosis and macropinocytosis.
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Affiliation(s)
- Joel A Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan 48109-5620, USA.
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41
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Kim EK, Tucker DF, Yun SJ, Do KH, Kim MS, Kim JH, Kim CD, Birnbaum MJ, Bae SS. Linker region of Akt1/protein kinase Balpha mediates platelet-derived growth factor-induced translocation and cell migration. Cell Signal 2008; 20:2030-7. [PMID: 18700164 DOI: 10.1016/j.cellsig.2008.07.012] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2008] [Revised: 06/23/2008] [Accepted: 07/17/2008] [Indexed: 02/04/2023]
Abstract
The phosphatidylinositol 3-kinase (PI3K) signaling pathway(s) is activated by a variety of agonists to regulate cell migration. Here, we show that the stimulation of mouse embryonic fibroblasts with platelet-derived growth factor (PDGF) induces migration in a PI3K-dependent manner. Cells lacking Akt1/PKBalpha exhibit impaired migration and peripheral ruffling in response to PDGF stimulation, whereas cells lacking Akt2/PKBbeta are normal. In addition, over-expression of Akt1/PKBalpha but not Akt2/PKBbeta is sufficient to restore PDGF-induced cell migration in an Akt1/PKBalpha and Akt2/PKBbeta deficient background. In response to PDGF stimulation, Akt1/PKBalpha selectively translocates to membrane ruffles, however, this localization is abrogated by substituting the linker region of Akt2/PKBbeta. Similarly, expression of an Akt2/PKBalpha chimera containing the linker region of Akt1/PKBalpha restored PDGF-induced migration in cells lacking both Akt1/PKBalpha and Akt2/PKBbeta. Finally, over-expression of constitutively active Rac rescues PDGF-induced migration defects in cells lacking Akt1/PKBalpha. Given these results, we suggest that Akt1/PKBalpha controls cell migration by selectively translocating to the leading edge and activating Rac.
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Affiliation(s)
- Eun Kyoung Kim
- MRC for Ischemic Tissue Regeneration, Medical Research Institute, Department of Pharmacology, School of Medicine, Pusan National University, Ami-dong 1-ga 10, Seo-gu, Pusan 602-739, Republic of Korea
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42
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Ho KJ, Owens CD, Longo T, Sui XX, Ifantides C, Conte MS. C-reactive protein and vein graft disease: evidence for a direct effect on smooth muscle cell phenotype via modulation of PDGF receptor-beta. Am J Physiol Heart Circ Physiol 2008; 295:H1132-H1140. [PMID: 18621860 DOI: 10.1152/ajpheart.00079.2008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Plasma C-reactive protein (CRP) concentration is a biomarker of systemic atherosclerosis and may also be associated with vein graft disease. It remains unclear whether CRP is also an important modulator of biological events in the vessel wall. We hypothesized that CRP influences vein graft healing by stimulating smooth muscle cells (SMCs) to undergo a phenotypic switch. Distribution of CRP was examined by immunohistochemistry in prebypass human saphenous veins (HSVs, n = 21) and failing vein grafts (n = 18, 25-4,400 days postoperatively). Quiescent HSV SMCs were stimulated with human CRP (5-50 microg/ml). SMC migration was assessed in modified Boyden chambers with platelet-derived growth factor (PDGF)-BB (5-10 ng/ml) as the chemoattractant. SMC viability and proliferation were assessed by trypan blue exclusion and reduction of Alamar Blue substrate, respectively. Expression of PDGF ligand and receptor (PDGFR) genes was examined at RNA and protein levels after 24-72 h of CRP exposure. CRP staining was present in 13 of 18 diseased vein grafts, where it localized to the deep media and adventitia, but it was minimally detectable in most prebypass veins. SMCs pretreated with CRP demonstrated a dose-dependent increase in migration to PDGF-BB (P = 0.02), which was inhibited by a PDGF-neutralizing antibody. SMCs treated with CRP showed a dose-dependent increase in PDGFRbeta expression and phosphorylation after 24-48 h. Exogenous CRP had no effect on SMC viability or proliferation. These data suggest that CRP is detectable within the wall of most diseased vein grafts, where it may exert local effects. Clinically relevant levels of CRP can stimulate SMC migration by a mechanism that may involve upregulation and activation of PDGFRbeta.
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Affiliation(s)
- Karen J Ho
- Division of Vascular and Endovascular Surgery, Brigham and Women's Hospital, Boston, Massachusetts, USA
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43
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Hershenson MB, Brown M, Camoretti-Mercado B, Solway J. Airway smooth muscle in asthma. ANNUAL REVIEW OF PATHOLOGY-MECHANISMS OF DISEASE 2008; 3:523-55. [PMID: 18039134 DOI: 10.1146/annurev.pathmechdis.1.110304.100213] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Airway smooth muscle plays a multifaceted role in the pathogenesis of asthma. We review the current understanding of the contribution of airway myocytes to airway inflammation, airway wall remodeling, and airflow obstruction in this prevalent disease syndrome. Together, these roles make airway smooth muscle an attractive target for asthma therapy.
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Affiliation(s)
- Marc B Hershenson
- Department of Pediatrics and Communicable Diseases, University of Michigan, Ann Arbor, MI 48109, USA.
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44
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Pickett EA, Olsen GS, Tallquist MD. Disruption of PDGFRalpha-initiated PI3K activation and migration of somite derivatives leads to spina bifida. Development 2008; 135:589-98. [PMID: 18192285 DOI: 10.1242/dev.013763] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Spina bifida, or failure of the vertebrae to close at the midline, is a common congenital malformation in humans that is often synonymous with neural tube defects (NTDs). However, it is likely that other etiologies exist. Genetic disruption of platelet-derived growth factor receptor (PDGFR) alpha results in spina bifida, but the underlying mechanism has not been identified. To elucidate the cause of this birth defect in PDGFRalpha mutant embryos, we examined the developmental processes involved in vertebrae formation. Exposure of chick embryos to the PDGFR inhibitor imatinib mesylate resulted in spina bifida in the absence of NTDs. We next examined embryos with a tissue-specific deletion of the receptor. We found that loss of the receptor from chondrocytes did not recapitulate the spina bifida phenotype. By contrast, loss of the receptor from all sclerotome and dermatome derivatives or disruption of PDGFRalpha-driven phosphatidyl-inositol 3' kinase (PI3K) activity resulted in spina bifida. Furthermore, we identified a migration defect in the sclerotome as the cause of the abnormal vertebral development. We found that primary cells from these mice exhibited defects in PAK1 activation and paxillin localization. Taken together, these results indicate that PDGFRalpha downstream effectors, especially PI3K, are essential for cell migration of a somite-derived dorsal mesenchyme and disruption of receptor signaling in these cells leads to spina bifida.
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Affiliation(s)
- Elizabeth A Pickett
- Department of Molecular Biology, The University of Texas Southwestern Medical Center at Dallas, Dallas, TX 75390, USA
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45
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Ikegami Y, Inukai K, Awata T, Asano T, Katayama S. SH3 domain of the phosphatidylinositol 3-kinase regulatory subunit is responsible for the formation of a sequestration complex with insulin receptor substrate-1. Biochem Biophys Res Commun 2007; 365:433-8. [PMID: 17991427 DOI: 10.1016/j.bbrc.2007.10.187] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2007] [Accepted: 10/29/2007] [Indexed: 11/30/2022]
Abstract
Class IA phosphatidylinositol 3-kinase (PI 3-kinase), which is composed of a 110kDa catalytic subunit and a regulatory subunit, plays a key role in most insulin dependent cellular responses. To date, five mammalian regulatory subunit isoforms have been identified, including two 85kDa proteins (p85alpha and p85beta), two 55kDa proteins (p55gamma and p55alpha), and one 50kDa protein (p50alpha). In the present study, we overexpressed these recombinant proteins, tagged with green fluorescent proteins (GFP), in CHO-IR cells and investigated intracellular localizations in both the presence and the absence of insulin stimulation. Interestingly, in response to insulin, only p85alpha and p85beta redistributed to isolated foci in the cells, while both were present throughout the cytoplasm in quiescent cells. In contrast, p55s accumulated in the perinuclear region irrespective of insulin stimulation, while p50alpha behaved similarly to control GFP. Immunofluorescent antibodies against endogenous IRS-1 revealed IRS-1 to be co-localized in the p85 foci in response to insulin. As both insulin receptors and p110alpha catalytic subunits were absent from these foci on immunofluorescence study, only p85 and IRS-1 were suggested to form a sequestration complex in response to insulin. To determine the domain responsible for IRS-1 complex formation, we prepared and overexpressed the SH3 domain deletion mutant of p85alpha in CHO-IR cells. This mutant failed to form foci, suggesting the SH3 domain of regulatory subunits to be responsible for formation of the p85-IRS-1 sequestration complex. In conclusion, our study revealed the SH3 domain of PI 3-kinase to play a critical role in intracellular localizations, including formation of foci with IRS-1 in response to insulin.
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Affiliation(s)
- Yuichi Ikegami
- Division of Endocrinology and Diabetes, Department of Medicine, Saitama Medical University, Morohongo 38, Moroyama, Iruma-gun, Saitama 350-0495, Japan
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46
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Chaigne-Delalande B, Anies G, Kramer I, Genot E. Nonadherent cells switch to a Rac-mediated, SHIP regulated, Akt activation mode for survival. Oncogene 2007; 27:1876-85. [PMID: 17906692 DOI: 10.1038/sj.onc.1210830] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Constitutively active Rac stimulates Akt activity in T lymphocytes cultured in suspension. This regulation contrasts with findings obtained in fibroblasts, endothelial or neuronal cells grown on substrate, where Akt stimulation occurs independently of Rac. We now show that V12Rac-mediated stimulation of Akt is not restricted to the hematopoietic lineage but is dependent on the adherence status of the cell. V12Rac-mediated stimulation of Akt as well as molecular association between Rac and Akt occurred exclusively in cells kept in suspension. Stimulation and complex formation are dependent on SHIP but in a manner that differs from its role in dephosphorylation of phosphoinositide lipids. Adherent cells lacking SHIP, but not those lacking PTEN, are able to activate Akt through the Rac pathway. Our data reveal the existence of a bona fide Rac to Akt signaling pathway, tightly regulated by SHIP and operational in suspended cells only. This pathway may point to an alternative survival signal that is called into action when cells lose contact with the substrate and/or with other cells.
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Affiliation(s)
- B Chaigne-Delalande
- European Institute of Chemistry and Biology, University of Bordeaux I, Pessac, France
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47
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Farini D, La Sala G, Tedesco M, De Felici M. Chemoattractant action and molecular signaling pathways of Kit ligand on mouse primordial germ cells. Dev Biol 2007; 306:572-83. [PMID: 17467686 DOI: 10.1016/j.ydbio.2007.03.031] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2006] [Revised: 03/22/2007] [Accepted: 03/23/2007] [Indexed: 02/05/2023]
Abstract
Using a Transwell chamber as migration assay for mouse primordial germ cells (PGCs), we show here that these cells posses directional migration in the absence of somatic cell and defined matrix support and in response to a Kit ligand (KL) gradient or medium conditioned by Aorta/Gonad/Mesonephros and gonadal ridges. Other putative PGC chemoattractants such as SDF1 and TGFbeta did not exert any attractive action on PGCs. The chemoattractant activity of KL and conditioned medium was also evidenced by their ability to stimulate actin reorganization in PGCs. In the aim to identify downstream signaling pathways governing KL chemoattraction on PGCs, we demonstrated that in such cells KL rapidly (5 min) increased autophosphorylation of its receptor c-Kit and caused phosphorylation of the serine-threonine kinase AKT through the action of PI3K. 740Y-P peptide, a direct activator of PI3 kinase, stimulated PGC migration at levels similar to those elicited by KL. LY294002 (a specific inhibitor of PI3K) abolished KL-dependent PGC migration or the chemoattractant activity of the conditioned medium and inhibited AKT phosphorylation; Src kinase inhibitors PP2 and SU6656, caused significant reduction of the KL-dependent PGC migration and AKT phosphorylation, while U0126, a selective inhibitor of the MEK/ERK protein kinase cascade, reduced PGC migration and AKT phosphorylation at lesser extent. SU6656 completely abolished the chemoattractant activity of the conditioned medium. Finally, SB202190 (a p38 inhibitor) and rapamycin (mTOR inhibitor) did not affect PGC migration. In addition, to demonstrate that somatic cells are not essential for PGC motility and directional migration, we evidenced a novel role for KL as PGC chemoattractant and for PI3K/AKT and Src kinase, as players involved in the activation of the PGC migratory machinery and likely important for their directional movement towards the gonadal ridges.
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Affiliation(s)
- Donatella Farini
- Department of Public Health and Cell Biology, Section of Histology and Embryology, University of Rome Tor Vergata, Via Montpellier 1, 00173 Rome, Italy
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48
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Grabalska M, Malec P. Blue Light-induced Chloroplast Reorientations in Lemna trisulca L. (Duckweed) are Controlled by Two Separable Cellular Mechanisms as Suggested by Different Sensitivity to Wortmannin¶. Photochem Photobiol 2007. [DOI: 10.1111/j.1751-1097.2004.tb00019.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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49
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Araki N, Egami Y, Watanabe Y, Hatae T. Phosphoinositide metabolism during membrane ruffling and macropinosome formation in EGF-stimulated A431 cells. Exp Cell Res 2007; 313:1496-507. [PMID: 17368443 DOI: 10.1016/j.yexcr.2007.02.012] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2006] [Revised: 01/30/2007] [Accepted: 02/13/2007] [Indexed: 11/30/2022]
Abstract
Inhibitors of phosphoinositide 3-kinase (PI3K) were found to perturb macropinosome formation without affecting the membrane ruffling and actin polymerization in epidermal growth factor-stimulated A431 cells. Live-cell imaging and quantitative image analysis of the fluorescence intensity ratio of the YFP-tagged phospholipase Cdelta1-pleckstrin homology domain (YFP-PLC-PH) relative to membrane-targeted CFP (CFP-Mem) demonstrated that the concentration of PI(4,5)P(2) in the membrane ruffles forming macropinocytic cups increased to more than double that in planar plasma membranes. The PI(4,5)P(2) level in the membrane reached its maximum just before macropinosome closure and rapidly fell as the macropinocytic cups closed. In contrast, the PI(3,4,5)P(3) concentrations visualized based on the YFP-Akt-PH or YFP-Bruton's tyrosine kinase (Btk)-PH/CFP-Mem ratio increased locally at the site of macropinosome formation and peaked at the time of macropinosome closure. The kinetics of PI(4,5)P(2) and PI(3,4,5)P(3) appeared to be mechanistically linked to actin remodeling during macropinocytosis. From the pharmacological data using inhibitors and synthetic phosphoinositides and other data, it could be concluded that both PI(4,5)P(2) elimination and PI(3,4,5)P(3) production by PI3K might be crucial for macropinosome formation from membrane ruffles. This study emphasizes that locally controlled levels of phosphoinositides are important for regulating the function of actin-binding proteins which effect changes in the membrane architecture.
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Affiliation(s)
- Nobukazu Araki
- Department of Histology and Cell Biology, School of Medicine, Kagawa University, Miki, Kagawa 761-0793, Japan.
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50
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Liu J, Li D, Cao B, Li YX, Herva R, Piao YS, Wang YL. Expression and localization of SWAP-70 in human fetomaternal interface and placenta during tubal pregnancy and normal placentation. J Histochem Cytochem 2007; 55:701-8. [PMID: 17371938 DOI: 10.1369/jhc.6a7151.2007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
SWAP-70 has been demonstrated as a multiple functional signaling protein involved in formation of membrane ruffling induced by signal cascade of tyrosine kinase growth factor receptors. In the present study, the spatial and temporal expression pattern of SWAP-70 on human fetomaternal interface was investigated using specimens collected from tubal and normal pregnancies by in situ hybridization, immunohistochemistry, and Western blotting. Data showed an intense expression of SWAP-70 in trophoblasts at weeks 3-6 of fallopian implantation and at weeks 6-7 of normal pregnancy. The most intense expression was exhibited by those highly motile and invasive extravillous trophoblasts. From gestational week 8 on, the level of SWAP-70 in trophoblasts decreased significantly, and the signal was restricted in villous cytotrophoblast cells. In the in vitro cultured human trophoblast cell line, B6Tert-1, colocalization of SWAP-70 with F-actin was verified. Data in human placenta were similar to what we recently reported on rhesus monkey fetomaternal interface. Our results suggest that SWAP-70 may be involved in regulating migration and invasion of trophoblast cells during the processes of embryonic implantation and placentation in primates.
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Affiliation(s)
- Jing Liu
- State Key Laboratory of Reproductive Biology, Institute of Zoology, Chinese Academy of Sciences, 25 Bei Si Huan Xi Road, Beijing 100080, China
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