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López-García S, López-Merino E, Fernández-Rodrigo A, Zamorano-González P, Gutiérrez-Eisman S, Jiménez-Sánchez R, Esteban JA. PI3K couples long-term synaptic potentiation with cofilin recruitment and actin polymerization in dendritic spines via its regulatory subunit p85α. Cell Mol Life Sci 2024; 81:358. [PMID: 39158722 PMCID: PMC11335278 DOI: 10.1007/s00018-024-05394-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 07/16/2024] [Accepted: 08/02/2024] [Indexed: 08/20/2024]
Abstract
Long-term synaptic plasticity is typically associated with morphological changes in synaptic connections. However, the molecular mechanisms coupling functional and structural aspects of synaptic plasticity are still poorly defined. The catalytic activity of type I phosphoinositide-3-kinase (PI3K) is required for specific forms of synaptic plasticity, such as NMDA receptor-dependent long-term potentiation (LTP) and mGluR-dependent long-term depression (LTD). On the other hand, PI3K signaling has been linked to neuronal growth and synapse formation. Consequently, PI3Ks are promising candidates to coordinate changes in synaptic strength with structural remodeling of synapses. To investigate this issue, we targeted individual regulatory subunits of type I PI3Ks in hippocampal neurons and employed a combination of electrophysiological, biochemical and imaging techniques to assess their role in synaptic plasticity. We found that a particular regulatory isoform, p85α, is selectively required for LTP. This specificity is based on its BH domain, which engages the small GTPases Rac1 and Cdc42, critical regulators of the actin cytoskeleton. Moreover, cofilin, a key regulator of actin dynamics that accumulates in dendritic spines after LTP induction, failed to do so in the absence of p85α or when its BH domain was overexpressed as a dominant negative construct. Finally, in agreement with this convergence on actin regulatory mechanisms, the presence of p85α in the PI3K complex determined the extent of actin polymerization in dendritic spines during LTP. Therefore, this study reveals a molecular mechanism linking structural and functional synaptic plasticity through the coordinate action of PI3K catalytic activity and a specific isoform of the regulatory subunits.
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Affiliation(s)
- Sergio López-García
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - Esperanza López-Merino
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - Alba Fernández-Rodrigo
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - Pablo Zamorano-González
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
- Current address: Universidad de Málaga, Málaga, Spain
| | - Silvia Gutiérrez-Eisman
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - Raquel Jiménez-Sánchez
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain
| | - José A Esteban
- Department of Molecular Neuropathology, Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Madrid, Spain.
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2
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Fung SYS, Xǔ XJ, Wu M. Nonlinear dynamics in phosphoinositide metabolism. Curr Opin Cell Biol 2024; 88:102373. [PMID: 38797149 PMCID: PMC11186694 DOI: 10.1016/j.ceb.2024.102373] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2024] [Revised: 04/26/2024] [Accepted: 05/01/2024] [Indexed: 05/29/2024]
Abstract
Phosphoinositides broadly impact membrane dynamics, signal transduction and cellular physiology. The orchestration of signaling complexity by this seemingly simple metabolic pathway remains an open question. It is increasingly evident that comprehending the complexity of the phosphoinositides metabolic network requires a systems view based on nonlinear dynamics, where the products of metabolism can either positively or negatively modulate enzymatic function. These feedback and feedforward loops may be paradoxical, leading to counterintuitive effects. In this review, we introduce the framework of nonlinear dynamics, emphasizing distinct dynamical regimes such as the excitable state, oscillations, and mixed-mode oscillations-all of which have been experimentally observed in phosphoinositide metabolisms. We delve into how these dynamical behaviors arise from one or multiple network motifs, including positive and negative feedback loops, coherent and incoherent feedforward loops. We explore the current understanding of the molecular circuits responsible for these behaviors. While mapping these circuits presents both conceptual and experimental challenges, redefining cellular behavior based on dynamical state, lipid fluxes, time delay, and network topology is likely essential for a comprehensive understanding of this fundamental metabolic network.
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Affiliation(s)
- Suet Yin Sarah Fung
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520-8002, USA
| | - X J Xǔ
- Department of Physics, Yale University, New Haven, CT, 06511, USA
| | - Min Wu
- Department of Cell Biology, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06520-8002, USA.
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3
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Bement WM, Goryachev AB, Miller AL, von Dassow G. Patterning of the cell cortex by Rho GTPases. Nat Rev Mol Cell Biol 2024; 25:290-308. [PMID: 38172611 DOI: 10.1038/s41580-023-00682-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2023] [Indexed: 01/05/2024]
Abstract
The Rho GTPases - RHOA, RAC1 and CDC42 - are small GTP binding proteins that regulate basic biological processes such as cell locomotion, cell division and morphogenesis by promoting cytoskeleton-based changes in the cell cortex. This regulation results from active (GTP-bound) Rho GTPases stimulating target proteins that, in turn, promote actin assembly and myosin 2-based contraction to organize the cortex. This basic regulatory scheme, well supported by in vitro studies, led to the natural assumption that Rho GTPases function in vivo in an essentially linear matter, with a given process being initiated by GTPase activation and terminated by GTPase inactivation. However, a growing body of evidence based on live cell imaging, modelling and experimental manipulation indicates that Rho GTPase activation and inactivation are often tightly coupled in space and time via signalling circuits and networks based on positive and negative feedback. In this Review, we present and discuss this evidence, and we address one of the fundamental consequences of coupled activation and inactivation: the ability of the Rho GTPases to self-organize, that is, direct their own transition from states of low order to states of high order. We discuss how Rho GTPase self-organization results in the formation of diverse spatiotemporal cortical patterns such as static clusters, oscillatory pulses, travelling wave trains and ring-like waves. Finally, we discuss the advantages of Rho GTPase self-organization and pattern formation for cell function.
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Affiliation(s)
- William M Bement
- Center for Quantitative Cell Imaging, Department of Integrative Biology, University of Wisconsin-Madison, Madison, WI, USA.
| | - Andrew B Goryachev
- Center for Engineering Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
| | - Ann L Miller
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI, USA.
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4
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Poku R, Amissah F, Alan JK. PI3K Functions Downstream of Cdc42 to Drive Cancer phenotypes in a Melanoma Cell Line. Small GTPases 2023; 14:1-13. [PMID: 37114375 PMCID: PMC10150613 DOI: 10.1080/21541248.2023.2202612] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023] Open
Abstract
Rho proteins are part of the Ras superfamily, which function to modulate cytoskeletal dynamics including cell adhesion and motility. Recently, an activating mutation in Cdc42, a Rho family GTPase, was found in a patient sample of melanoma. Previously, our work had shown the PI3K was important downstream of mutationally active Cdc42. Our present study sought to determine whether PI3K was a crucial downstream partner for Cdc42 in a melanoma cells line with a BRAF mutation, which is the most common mutation in cutaneous melanoma. In this work we were able to show that Cdc42 contributes to proliferation, anchorage-independent growth, cell motility and invasion. Treatment with a pan-PI3K inhibitor was able to effectively ameliorate all these cancer phenotypes. These data suggest that PI3K may be an important target downstream of Cdc42 in melanoma.
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Affiliation(s)
- Rosemary Poku
- College of Medicine, Central Michigan University, Mt. Pleasant, MI, USA
| | - Felix Amissah
- Department of Pharmaceutical Science, Ferris State University, Big Rapids, MI, USA
| | - Jamie K Alan
- Department of Pharmacology and Toxicology, College of Human Medicine, Michigan State University, East Lansing, MI, USA
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5
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Tsay A, Wang JC. The Role of PIK3R1 in Metabolic Function and Insulin Sensitivity. Int J Mol Sci 2023; 24:12665. [PMID: 37628845 PMCID: PMC10454413 DOI: 10.3390/ijms241612665] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 08/04/2023] [Accepted: 08/08/2023] [Indexed: 08/27/2023] Open
Abstract
PIK3R1 (also known as p85α) is a regulatory subunit of phosphoinositide 3-kinases (PI3Ks). PI3K, a heterodimer of a regulatory subunit and a catalytic subunit, phosphorylates phosphatidylinositol into secondary signaling molecules involved in regulating metabolic homeostasis. PI3K converts phosphatidylinositol 4,5-bisphosphate (PIP2) to phosphatidylinositol 3,4,5-triphosphate (PIP3), which recruits protein kinase AKT to the inner leaflet of the cell membrane to be activated and to participate in various metabolic functions. PIK3R1 stabilizes and inhibits p110 catalytic activity and serves as an adaptor to interact with insulin receptor substrate (IRS) proteins and growth factor receptors. Thus, mutations in PIK3R1 or altered expression of PIK3R1 could modulate the activity of PI3K and result in significant metabolic outcomes. Interestingly, recent studies also found PI3K-independent functions of PIK3R1. Overall, in this article, we will provide an updated review of the metabolic functions of PIK3R1 that includes studies of PIK3R1 in various metabolic tissues using animal models, the mechanisms modulating PIK3R1 activity, and studies on the mutations of human PIK3R1 gene.
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Affiliation(s)
- Ariel Tsay
- Metabolic Biology Graduate Program, University of California Berkeley, Berkeley, CA 94720, USA;
- Department of Nutritional Sciences & Toxicology, University of California Berkeley, Berkeley, CA 94720, USA
| | - Jen-Chywan Wang
- Metabolic Biology Graduate Program, University of California Berkeley, Berkeley, CA 94720, USA;
- Department of Nutritional Sciences & Toxicology, University of California Berkeley, Berkeley, CA 94720, USA
- Endocrinology Graduate Program, University of California Berkeley, Berkeley, CA 94720, USA
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6
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Nesson ET, McDowell SA. Innovations in Evaluating Statin Benefit and Efficacy in Staphylococcus aureus Intracellular Infection Management. Int J Mol Sci 2022; 23:ijms232113006. [PMID: 36361794 PMCID: PMC9657138 DOI: 10.3390/ijms232113006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 10/21/2022] [Accepted: 10/22/2022] [Indexed: 11/23/2022] Open
Abstract
An emerging therapeutic approach in the treatment of infectious disease is to augment the host response through repurposing of well-tolerated, non-antibiotic, host-directed therapeutics. Earlier retrospective studies identify a positive association between statin use and a decreased risk of death due to sepsis or bacteremia. However, more recent randomized control trials fail to detect a therapeutic benefit in these complex infection settings. It is postulated that unrecognized biases in certain observational studies may have led to an overestimation of benefit and that statin use is instead a marker for health status, wealth, and demographic characteristics which may separately affect death due to infection. What remains unresolved is that in vitro and in vivo evidence reproducibly indicates that statin pharmacology limits infection and augments immunomodulatory responses, suggesting that therapeutic benefits may be attainable in certain infection settings, such as intracellular infection by S. aureus. Carefully considering the biological mechanisms capable of driving the relationship between statins and infections and constructing a methodology to avoid potential biases in observational studies would enable the examination of protective effects against infection and limit the risk of underestimating statin efficacy. Such an approach would rely on the examination of statin use in defined infection settings based on an underlying mode-of-action and pharmacology, where the inhibition of HMG-CoA-reductase at the rate-limiting step in cholesterol biosynthesis diminishes not only cholesterol levels but also isoprenoid intermediates central to host cell invasion by S. aureus. Therapeutic benefit in such settings, if existent, may be of clinical importance.
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Affiliation(s)
- Erik T. Nesson
- Department of Economics, Ball State University, Muncie, IN 47306, USA
| | - Susan A. McDowell
- Office of Research and Innovation, Miami University, Oxford, OH 45056, USA
- Correspondence:
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7
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Pleiotropic Effects of Statins: New Therapeutic Approaches to Chronic, Recurrent Infection by Staphylococcus aureus. Pharmaceutics 2021; 13:pharmaceutics13122047. [PMID: 34959329 PMCID: PMC8706520 DOI: 10.3390/pharmaceutics13122047] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 11/25/2021] [Accepted: 11/28/2021] [Indexed: 01/01/2023] Open
Abstract
An emergent approach to bacterial infection is the use of host rather than bacterial-directed strategies. This approach has the potential to improve efficacy in especially challenging infection settings, including chronic, recurrent infection due to intracellular pathogens. For nearly two decades, the pleiotropic effects of statin drugs have been examined for therapeutic usefulness beyond the treatment of hypercholesterolemia. Interest originated after retrospective studies reported decreases in the risk of death due to bacteremia or sepsis for those on a statin regimen. Although subsequent clinical trials have yielded mixed results and earlier findings have been questioned for biased study design, in vitro and in vivo studies have provided clear evidence of protective mechanisms that include immunomodulatory effects and the inhibition of host cell invasion. Ultimately, the benefits of statins in an infection setting appear to require attention to the underlying host response and to the timing of the dosage. From this examination of statin efficacy, additional novel host-directed strategies may produce adjunctive therapeutic approaches for the treatment of infection where traditional antimicrobial therapy continues to yield poor outcomes. This review focuses on the opportunistic pathogen, Staphylococcus aureus, as a proof of principle in examining the promise and limitations of statins in recalcitrant infection.
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8
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Class IA PI3K regulatory subunits: p110-independent roles and structures. Biochem Soc Trans 2021; 48:1397-1417. [PMID: 32677674 PMCID: PMC7458397 DOI: 10.1042/bst20190845] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 12/12/2022]
Abstract
The phosphatidylinositol 3-kinase (PI3K) pathway is a critical regulator of many cellular processes including cell survival, growth, proliferation and motility. Not surprisingly therefore, the PI3K pathway is one of the most frequently mutated pathways in human cancers. In addition to their canonical role as part of the PI3K holoenzyme, the class IA PI3K regulatory subunits undertake critical functions independent of PI3K. The PI3K regulatory subunits exist in excess over the p110 catalytic subunits and therefore free in the cell. p110-independent p85 is unstable and exists in a monomer-dimer equilibrium. Two conformations of dimeric p85 have been reported that are mediated by N-terminal and C-terminal protein domain interactions, respectively. The role of p110-independent p85 is under investigation and it has been found to perform critical adaptor functions, sequestering or influencing compartmentalisation of key signalling proteins. Free p85 has roles in glucose homeostasis, cellular stress pathways, receptor trafficking and cell migration. As a regulator of fundamental pathways, the amount of p110-independent p85 in the cell is critical. Factors that influence the monomer-dimer equilibrium of p110-independent p85 offer additional control over this system, disruption to which likely results in disease. Here we review the current knowledge of the structure and functions of p110-independent class IA PI3K regulatory subunits.
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9
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Silva PM, Puerner C, Seminara A, Bassilana M, Arkowitz RA. Secretory Vesicle Clustering in Fungal Filamentous Cells Does Not Require Directional Growth. Cell Rep 2020; 28:2231-2245.e5. [PMID: 31433995 DOI: 10.1016/j.celrep.2019.07.062] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Revised: 04/22/2019] [Accepted: 07/18/2019] [Indexed: 11/27/2022] Open
Abstract
During symmetry breaking, the highly conserved Rho GTPase Cdc42 becomes stabilized at a defined site via an amplification process. However, little is known about how a new polarity site is established in an already asymmetric cell-a critical process in a changing environment. The human fungal pathogen Candida albicans switches from budding to filamentous growth in response to external cues, a transition controlled by Cdc42. Here, we have used optogenetic manipulation of cell polarity to reset growth in asymmetric filamentous C. albicans cells. We show that increasing the level of active Cdc42 on the plasma membrane results in disruption of the exocyst subunit Sec3 localization and a striking de novo clustering of secretory vesicles. This new cluster of secretory vesicles is highly dynamic, moving by hops and jumps, until a new growth site is established. Our results reveal that secretory vesicle clustering can occur in the absence of directional growth.
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Affiliation(s)
- Patrícia M Silva
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), Parc Valrose, Nice, France
| | - Charles Puerner
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), Parc Valrose, Nice, France
| | - Agnese Seminara
- Université Côte d'Azur, CNRS, Institute Physics of Nice (INPHYNI), Ave. J. Vallot, Nice, France
| | - Martine Bassilana
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), Parc Valrose, Nice, France
| | - Robert A Arkowitz
- Université Côte d'Azur, CNRS, INSERM, Institute of Biology Valrose (iBV), Parc Valrose, Nice, France.
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10
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Humphries BA, Wang Z, Yang C. MicroRNA Regulation of the Small Rho GTPase Regulators-Complexities and Opportunities in Targeting Cancer Metastasis. Cancers (Basel) 2020; 12:E1092. [PMID: 32353968 PMCID: PMC7281527 DOI: 10.3390/cancers12051092] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 04/24/2020] [Accepted: 04/25/2020] [Indexed: 02/07/2023] Open
Abstract
The small Rho GTPases regulate important cellular processes that affect cancer metastasis, such as cell survival and proliferation, actin dynamics, adhesion, migration, invasion and transcriptional activation. The Rho GTPases function as molecular switches cycling between an active GTP-bound and inactive guanosine diphosphate (GDP)-bound conformation. It is known that Rho GTPase activities are mainly regulated by guanine nucleotide exchange factors (RhoGEFs), GTPase-activating proteins (RhoGAPs), GDP dissociation inhibitors (RhoGDIs) and guanine nucleotide exchange modifiers (GEMs). These Rho GTPase regulators are often dysregulated in cancer; however, the underlying mechanisms are not well understood. MicroRNAs (miRNAs), a large family of small non-coding RNAs that negatively regulate protein-coding gene expression, have been shown to play important roles in cancer metastasis. Recent studies showed that miRNAs are capable of directly targeting RhoGAPs, RhoGEFs, and RhoGDIs, and regulate the activities of Rho GTPases. This not only provides new evidence for the critical role of miRNA dysregulation in cancer metastasis, it also reveals novel mechanisms for Rho GTPase regulation. This review summarizes recent exciting findings showing that miRNAs play important roles in regulating Rho GTPase regulators (RhoGEFs, RhoGAPs, RhoGDIs), thus affecting Rho GTPase activities and cancer metastasis. The potential opportunities and challenges for targeting miRNAs and Rho GTPase regulators in treating cancer metastasis are also discussed. A comprehensive list of the currently validated miRNA-targeting of small Rho GTPase regulators is presented as a reference resource.
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Affiliation(s)
- Brock A. Humphries
- Center for Molecular Imaging, Department of Radiology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI 48109, USA
| | - Zhishan Wang
- Department of Toxicology and Cancer Biology, College of Medicine, University of Kentucky, 1095 V A Drive, Lexington, KY 40536, USA;
| | - Chengfeng Yang
- Department of Toxicology and Cancer Biology, College of Medicine, University of Kentucky, 1095 V A Drive, Lexington, KY 40536, USA;
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11
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Ferrandon S, DeVecchio J, Duraes L, Chouhan H, Karagkounis G, Davenport J, Orloff M, Liska D, Kalady MF. CoA Synthase ( COASY) Mediates Radiation Resistance via PI3K Signaling in Rectal Cancer. Cancer Res 2019; 80:334-346. [PMID: 31704889 DOI: 10.1158/0008-5472.can-19-1161] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 09/11/2019] [Accepted: 11/05/2019] [Indexed: 12/18/2022]
Abstract
Neoadjuvant radiation is standard of care for locally advanced rectal cancer. Response to radiation is highly variable and directly linked with survival. However, there currently are no validated biomarkers or molecular targets to predict or improve radiation response, which would help develop personalized treatment and ideally targeted therapies. Here, we identified a novel biomarker, coenzyme A synthase (COASY), whose mRNA expression was consistently elevated in radioresistant human rectal cancers. This observation was validated in independent patient cohorts and further confirmed in colorectal cancer cell lines. Importantly, genetic overexpression and knockdown yielded radioresistant and sensitive phenotypes, respectively, in vitro and in vivo. COASY-knockdown xenografts were more vulnerable to radiation, showing delayed tumor growth, decreased proliferation, and increased apoptosis. Mechanistically, COASY protein directly interacted with the PI3K regulatory subunit PI3K-P85α, which increased AKT and mTOR phosphorylation, enhancing cell survival. Furthermore, shRNA COASY knockdown disrupted downstream PI3K pathway activation and also hindered DNA double-strand break repair, which both led to improved radiosensitivity. Collectively, this work reveals for the first time the biological relevance of COASY as a predictive rectal cancer biomarker for radiation response and offers mechanistic evidence to support COASY as a potential therapeutic target. SIGNIFICANCE: COASY is a novel radiotherapy response modulator in rectal cancer that regulates PI3K activation and DNA repair. Furthermore, COASY levels directly correlate with radiation response and serve as a predictive biomarker.
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Affiliation(s)
- Sylvain Ferrandon
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Jennifer DeVecchio
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Leonardo Duraes
- Department of Colorectal Surgery, Digestive Disease and Surgery Institute, Cleveland Clinic, Cleveland, Ohio
| | - Hanumant Chouhan
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Georgios Karagkounis
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
- Department of Colorectal Surgery, Digestive Disease and Surgery Institute, Cleveland Clinic, Cleveland, Ohio
| | - Jacqueline Davenport
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - Matthew Orloff
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
| | - David Liska
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio
- Department of Colorectal Surgery, Digestive Disease and Surgery Institute, Cleveland Clinic, Cleveland, Ohio
| | - Matthew F Kalady
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio.
- Department of Colorectal Surgery, Digestive Disease and Surgery Institute, Cleveland Clinic, Cleveland, Ohio
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12
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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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13
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Aguilar BJ, Zhao Y, Zhou H, Huo S, Chen YH, Lu Q. Inhibition of Cdc42-intersectin interaction by small molecule ZCL367 impedes cancer cell cycle progression, proliferation, migration, and tumor growth. Cancer Biol Ther 2019; 20:740-749. [PMID: 30849276 PMCID: PMC6606017 DOI: 10.1080/15384047.2018.1564559] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2018] [Revised: 10/19/2018] [Accepted: 12/25/2018] [Indexed: 10/27/2022] Open
Abstract
Cdc42 is a member of the Rho family of small GTPases that are at the crossroads of major oncogenic signaling pathways involved in both lung and prostate cancers. However, the therapeutic potential of Cdc42 regulation is still unclear due to the lack of pharmacological tools. Herein, we report that ZCL367 is a bona fide Cdc42 inhibitor that suppressed cancer development and ZCL278 can act as a partial Cdc42 agonist. In lung cancer cell lines with varying EGFR and Ras mutations as well as both androgen-independent and androgen-dependent prostate cancer cell lines, ZCL367 impeded cell cycle progression, reduced proliferation, and suppressed migration. ZCL367 decreased Cdc42-intersectin interactions and reduced Cdc42-mediated filopodia formation. ZCL367 showed increased potency and selectivity for Cdc42 when compared to Rac1 and RhoA. ZCL367 reduced A549 tumorigenesis in a xenograft mouse model. Altogether, ZCL367 is a selective Cdc42 inhibitor and an excellent candidate for lead compound optimization for further anticancer studies.
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Affiliation(s)
- Byron J. Aguilar
- Department of Anatomy & Cell Biology, The Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Yaxue Zhao
- State Key Laboratory of Microbial Metabolism, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
| | - Huchen Zhou
- State Key Laboratory of Microbial Metabolism, School of Pharmacy, Shanghai Jiao Tong University, Shanghai 200240, People’s Republic of China
| | - Shouquan Huo
- Department of Chemistry, Harriot College of Arts and Sciences, East Carolina University, Greenville, NC, USA
| | - Yan-Hua Chen
- Department of Anatomy & Cell Biology, The Brody School of Medicine, East Carolina University, Greenville, NC, USA
| | - Qun Lu
- Department of Anatomy & Cell Biology, The Brody School of Medicine, East Carolina University, Greenville, NC, USA
- The Harriet and John Wooten Laboratory for Alzheimer’s and Neurodegenerative Diseases Research, The Brody School of Medicine, East Carolina University, Greenville, NC, USA
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14
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Heitz SD, Hamelin DJ, Hoffmann RM, Greenberg N, Salloum G, Erami Z, Khalil BD, Shymanets A, Steidle EA, Gong GQ, Nürnberg B, Burke JE, Flanagan JU, Bresnick AR, Backer JM. A single discrete Rab5-binding site in phosphoinositide 3-kinase β is required for tumor cell invasion. J Biol Chem 2019; 294:4621-4633. [DOI: 10.1074/jbc.ra118.006032] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Revised: 01/15/2019] [Indexed: 11/06/2022] Open
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15
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Kalailingam P, Tan HB, Pan JY, Tan SH, Thanabalu T. Overexpression of CDC42SE1 in A431 Cells Reduced Cell Proliferation by Inhibiting the Akt Pathway. Cells 2019; 8:cells8020117. [PMID: 30717410 PMCID: PMC6406378 DOI: 10.3390/cells8020117] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Revised: 01/25/2019] [Accepted: 01/30/2019] [Indexed: 12/28/2022] Open
Abstract
Cell division cycle 42 (CDC42), a small Rho GTPase, plays a critical role in many cellular processes, including cell proliferation and survival. CDC42 interacts with the CRIB (Cdc42- and Rac-interactive binding) domain of CDC42SE1, a small effector protein of 9 kDa. We found that the expression of CDC42SE1 was reduced in human skin cancer samples relative to matched perilesional control. Exogenous expression of CDC42SE1 but not CDC42SE1H38A (mutation within CRIB domain) in A431 cells (A431SE1, A431SE1-H38A) reduced cell proliferation. Antibody microarray analysis of A431Ctrl and A431SE1 lysate suggested that reduced A431SE1 cells proliferation was due to inhibition of Akt pathway, which was confirmed by the reduced P-Akt and P-mTOR levels in A431SE1 cells compared to A431Ctrl cells. This suggests that CDC42SE1 modulates the CDC42-mediated Akt pathway by competing with other effector proteins to bind CDC42. A431SE1 cells formed smaller colonies in soft agar compared to A431Ctrl and A431SE1-H38A cells. These findings correlate with nude mice xenograft assays, where A431SE1 cells formed tumors with significantly-reduced volume compared to the tumors formed by A431Ctrl cells. Our results suggest that CDC42SE1 is downregulated in skin cancer to promote tumorigenesis, and thus CDC42SE1 might be an important marker of skin cancer progression.
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Affiliation(s)
- Pazhanichamy Kalailingam
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
| | - Hui Bing Tan
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
| | - Jiun Yit Pan
- National Skin Centre, Singapore 308205, Singapore.
| | | | - Thirumaran Thanabalu
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
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16
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Marshall JDS, Mellor P, Ruan X, Whitecross DE, Moore SA, Anderson DH. Insight into the PTEN - p85α interaction and lipid binding properties of the p85α BH domain. Oncotarget 2018; 9:36975-36992. [PMID: 30651929 PMCID: PMC6319338 DOI: 10.18632/oncotarget.26432] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2018] [Accepted: 11/26/2018] [Indexed: 12/24/2022] Open
Abstract
The phosphatidylinositol 3-kinase (PI3K) pathway plays a key role in regulating cell growth and cell survival and is frequently deregulated in cancer cells. p85α regulates the p110α lipid kinase, and also stabilizes and stimulates PTEN, the lipid phosphatase that downregulates this pathway. In this report, we determined that the p85α BH domain binds several phosphorylated phosphoinositide lipids, an interaction that could help localize p85α to membranes rich in these lipids. We also identified key residues responsible for mediating PTEN – p85α complex formation. Based on these experimental results, a docking model for the PTEN – p85α BH domain complex was developed that is consistent with the known binding interactions for both PTEN and p85α. This model involves extensive side-chain and peptide backbone contacts between both the PASE and C2 domains of PTEN with the p85α BH domains. The p85α BH domain residues shown to be important for PTEN binding were p85α residues E212, Q221, K225, R228 and H234. We also verified experimentally the importance of PTEN-E91 in mediating the interaction with the p85α BH domain. These results shed new light on the mechanism of PTEN regulation by p85α.
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Affiliation(s)
- Jeremy D S Marshall
- Cancer Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E5, Canada.,Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E5, Canada
| | - Paul Mellor
- Cancer Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E5, Canada
| | - Xuan Ruan
- Cancer Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E5, Canada
| | - Dielle E Whitecross
- Cancer Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E5, Canada
| | - Stanley A Moore
- Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E5, Canada
| | - Deborah H Anderson
- Cancer Research Group, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E5, Canada.,Department of Biochemistry, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5E5, Canada.,Cancer Research, Saskatchewan Cancer Agency, Saskatoon, Saskatchewan, S7N 5E5, Canada
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17
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Ito Y, Hart JR, Vogt PK. Isoform-specific activities of the regulatory subunits of phosphatidylinositol 3-kinases - potentially novel therapeutic targets. Expert Opin Ther Targets 2018; 22:869-877. [PMID: 30205700 DOI: 10.1080/14728222.2018.1522302] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
INTRODUCTION The main regulatory subunits of Class IA phosphatidylinositol 3-kinase (PI3K), p85α and p85β, initiate diverse cellular activities independent of binding to the catalytic subunit p110. Several of these signaling processes directly or indirectly contribute to a regulation of PI3K and could become targets for therapeutic efforts. Areas covered: This review will highlight two general areas of p85 activity: (1) direct interaction with regulatory proteins and with determinants of the cytoskeleton, and (2) a genetic analysis by deletion and domain switches identifying new functions for p85 domains. Expert Opinion: Isoform-specific activities of regulatory subunits have long been at the periphery of the PI3K field. Our understanding of these unique functions of the regulatory subunits is fragmentary and raises many important questions. At this time, there is insufficient information to translate this knowledge into the clinic, but some tempting targets have emerged that could move the field forward with the help of novel technologies in drug design and identification.
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Affiliation(s)
- Yoshihiro Ito
- a Department of Molecular Medicine , The Scripps Research Institute , La Jolla , CA , USA
| | - Jonathan R Hart
- a Department of Molecular Medicine , The Scripps Research Institute , La Jolla , CA , USA
| | - Peter K Vogt
- a Department of Molecular Medicine , The Scripps Research Institute , La Jolla , CA , USA
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18
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Hung KC, Lin ML, Hsu SW, Lee CC, Huang RY, Wu TS, Chen SS. Suppression of Akt-mediated HDAC3 expression and CDK2 T39 phosphorylation by a bichalcone analog contributes to S phase retardation of cancer cells. Eur J Pharmacol 2018; 829:141-150. [DOI: 10.1016/j.ejphar.2018.04.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2017] [Revised: 04/13/2018] [Accepted: 04/13/2018] [Indexed: 12/23/2022]
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19
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Mellor P, Marshall JDS, Ruan X, Whitecross DE, Ross RL, Knowles MA, Moore SA, Anderson DH. Patient-derived mutations within the N-terminal domains of p85α impact PTEN or Rab5 binding and regulation. Sci Rep 2018; 8:7108. [PMID: 29740032 PMCID: PMC5940657 DOI: 10.1038/s41598-018-25487-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2018] [Accepted: 04/20/2018] [Indexed: 12/11/2022] Open
Abstract
The p85α protein regulates flux through the PI3K/PTEN signaling pathway, and also controls receptor trafficking via regulation of Rab-family GTPases. In this report, we determined the impact of several cancer patient-derived p85α mutations located within the N-terminal domains of p85α previously shown to bind PTEN and Rab5, and regulate their respective functions. One p85α mutation, L30F, significantly reduced the steady state binding to PTEN, yet enhanced the stimulation of PTEN lipid phosphatase activity. Three other p85α mutations (E137K, K288Q, E297K) also altered the regulation of PTEN catalytic activity. In contrast, many p85α mutations reduced the binding to Rab5 (L30F, I69L, I82F, I177N, E217K), and several impacted the GAP activity of p85α towards Rab5 (E137K, I177N, E217K, E297K). We determined the crystal structure of several of these p85α BH domain mutants (E137K, E217K, R262T E297K) for bovine p85α BH and found that the mutations did not alter the overall domain structure. Thus, several p85α mutations found in human cancers may deregulate PTEN and/or Rab5 regulated pathways to contribute to oncogenesis. We also engineered several experimental mutations within the p85α BH domain and identified L191 and V263 as important for both binding and regulation of Rab5 activity.
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Affiliation(s)
- Paul Mellor
- Cancer Research Group, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan, S7N 5E5, Canada
| | - Jeremy D S Marshall
- Cancer Research Group, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan, S7N 5E5, Canada.,Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan, S7N 5E5, Canada
| | - Xuan Ruan
- Cancer Research Group, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan, S7N 5E5, Canada
| | - Dielle E Whitecross
- Cancer Research Group, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan, S7N 5E5, Canada
| | - Rebecca L Ross
- Section of Experimental Oncology, Leeds Institute of Cancer and Pathology, St James's University Hospital, Leeds, United Kingdom
| | - Margaret A Knowles
- Section of Experimental Oncology, Leeds Institute of Cancer and Pathology, St James's University Hospital, Leeds, United Kingdom
| | - Stanley A Moore
- Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan, S7N 5E5, Canada
| | - Deborah H Anderson
- Cancer Research Group, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan, S7N 5E5, Canada. .,Department of Biochemistry, University of Saskatchewan, 107 Wiggins Road, Saskatoon, Saskatchewan, S7N 5E5, Canada. .,Cancer Research, Saskatchewan Cancer Agency, 107 Wiggins Road, Saskatoon, Saskatchewan, S7N 5E5, Canada.
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20
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Establishing Neuronal Polarity with Environmental and Intrinsic Mechanisms. Neuron 2017; 96:638-650. [DOI: 10.1016/j.neuron.2017.10.021] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2017] [Revised: 10/14/2017] [Accepted: 10/15/2017] [Indexed: 12/31/2022]
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21
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Neuronal polarization: From spatiotemporal signaling to cytoskeletal dynamics. Mol Cell Neurosci 2017; 84:11-28. [PMID: 28363876 DOI: 10.1016/j.mcn.2017.03.008] [Citation(s) in RCA: 76] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/24/2017] [Accepted: 03/26/2017] [Indexed: 12/20/2022] Open
Abstract
Neuronal polarization establishes distinct molecular structures to generate a single axon and multiple dendrites. Studies over the past years indicate that this efficient separation is brought about by a network of feedback loops. Axonal growth seems to play a major role in fueling those feedback loops and thereby stabilizing neuronal polarity. Indeed, various effectors involved in feedback loops are pivotal for axonal growth by ultimately acting on the actin and microtubule cytoskeleton. These effectors have key roles in interconnecting actin and microtubule dynamics - a mechanism crucial to commanding the growth of axons. We propose a model connecting signaling with cytoskeletal dynamics and neurite growth to better describe the underlying processes involved in neuronal polarization. We will discuss the current views on feedback loops and highlight the current limits of our understanding.
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22
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Amin E, Jaiswal M, Derewenda U, Reis K, Nouri K, Koessmeier KT, Aspenström P, Somlyo AV, Dvorsky R, Ahmadian MR. Deciphering the Molecular and Functional Basis of RHOGAP Family Proteins: A SYSTEMATIC APPROACH TOWARD SELECTIVE INACTIVATION OF RHO FAMILY PROTEINS. J Biol Chem 2016; 291:20353-71. [PMID: 27481945 PMCID: PMC5034035 DOI: 10.1074/jbc.m116.736967] [Citation(s) in RCA: 77] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2016] [Revised: 07/15/2016] [Indexed: 12/30/2022] Open
Abstract
RHO GTPase-activating proteins (RHOGAPs) are one of the major classes of regulators of the RHO-related protein family that are crucial in many cellular processes, motility, contractility, growth, differentiation, and development. Using database searches, we extracted 66 distinct human RHOGAPs, from which 57 have a common catalytic domain capable of terminating RHO protein signaling by stimulating the slow intrinsic GTP hydrolysis (GTPase) reaction. The specificity of the majority of the members of RHOGAP family is largely uncharacterized. Here, we comprehensively investigated the sequence-structure-function relationship between RHOGAPs and RHO proteins by combining our in vitro data with in silico data. The activity of 14 representatives of the RHOGAP family toward 12 RHO family proteins was determined in real time. We identified and structurally verified hot spots in the interface between RHOGAPs and RHO proteins as critical determinants for binding and catalysis. We have found that the RHOGAP domain itself is nonselective and in some cases rather inefficient under cell-free conditions. Thus, we propose that other domains of RHOGAPs confer substrate specificity and fine-tune their catalytic efficiency in cells.
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Affiliation(s)
- Ehsan Amin
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Mamta Jaiswal
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Urszula Derewenda
- the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908, and
| | - Katarina Reis
- the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Kazem Nouri
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Katja T Koessmeier
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany
| | - Pontus Aspenström
- the Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Avril V Somlyo
- the Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, Virginia 22908, and
| | - Radovan Dvorsky
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany,
| | - Mohammad R Ahmadian
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty, Heinrich-Heine-University, 40225 Düsseldorf, Germany,
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23
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Miranda F, Mannion D, Liu S, Zheng Y, Mangala LS, Redondo C, Herrero-Gonzalez S, Xu R, Taylor C, Chedom DF, Carrami EM, Albukhari A, Jiang D, Pradeep S, Rodriguez-Aguayo C, Lopez-Berestein G, Salah E, Abdul Azeez KR, Elkins JM, Campo L, Myers KA, Klotz D, Bivona S, Dhar S, Bast RC, Saya H, Choi HG, Gray NS, Fischer R, Kessler BM, Yau C, Sood AK, Motohara T, Knapp S, Ahmed AA. Salt-Inducible Kinase 2 Couples Ovarian Cancer Cell Metabolism with Survival at the Adipocyte-Rich Metastatic Niche. Cancer Cell 2016; 30:273-289. [PMID: 27478041 DOI: 10.1016/j.ccell.2016.06.020] [Citation(s) in RCA: 121] [Impact Index Per Article: 15.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 12/24/2015] [Accepted: 06/23/2016] [Indexed: 02/08/2023]
Abstract
The adipocyte-rich microenvironment forms a niche for ovarian cancer metastasis, but the mechanisms driving this process are incompletely understood. Here we show that salt-inducible kinase 2 (SIK2) is overexpressed in adipocyte-rich metastatic deposits compared with ovarian primary lesions. Overexpression of SIK2 in ovarian cancer cells promotes abdominal metastasis while SIK2 depletion prevents metastasis in vivo. Importantly, adipocytes induce calcium-dependent activation and autophosphorylation of SIK2. Activated SIK2 plays a dual role in augmenting AMPK-induced phosphorylation of acetyl-CoA carboxylase and in activating the PI3K/AKT pathway through p85α-S154 phosphorylation. These findings identify SIK2 at the apex of the adipocyte-induced signaling cascades in cancer cells and make a compelling case for targeting SIK2 for therapy in ovarian cancer.
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Affiliation(s)
- Fabrizio Miranda
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - David Mannion
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Shujuan Liu
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Yiyan Zheng
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Lingegowda S Mangala
- Gynecologic Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA; Center for RNAi and Non-Coding RNA, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Clara Redondo
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK; Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Sandra Herrero-Gonzalez
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Ruoyan Xu
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Charlotte Taylor
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Donatien Fotso Chedom
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Eli M Carrami
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Ashwag Albukhari
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK; Biochemistry Department, Faculty of Science, King Abdulaziz University, Jeddah 21551, Saudi Arabia
| | - Dahai Jiang
- Gynecologic Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA; Center for RNAi and Non-Coding RNA, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Sunila Pradeep
- Gynecologic Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Cristian Rodriguez-Aguayo
- Center for RNAi and Non-Coding RNA, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA; Department of Experimental Therapeutics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Gabriel Lopez-Berestein
- Center for RNAi and Non-Coding RNA, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA; Department of Experimental Therapeutics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Eidarus Salah
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Kamal R Abdul Azeez
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Jonathan M Elkins
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK
| | - Leticia Campo
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Kevin A Myers
- Department of Oncology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ, UK
| | - Daniel Klotz
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Serena Bivona
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK
| | - Sunanda Dhar
- Department of Histopathology, Oxford University Hospitals, Oxford OX3 9DU, UK
| | - Robert C Bast
- Department of Experimental Therapeutics, University of Texas M.D. Anderson Cancer Center, Houston, TX 77030, USA
| | - Hideyuki Saya
- Division of Gene Regulation, Institute for Advanced Medical Research, School of Medicine, Keio University, Tokyo 160-8582, Japan
| | - Hwan Geun Choi
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology, Dana Farber Cancer Institute, Boston, MA 02215, USA
| | - Nathanael S Gray
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, MA 02115, USA; Department of Cancer Biology, Dana Farber Cancer Institute, Boston, MA 02215, USA
| | - Roman Fischer
- Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Benedikt M Kessler
- Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK
| | - Christopher Yau
- Wellcome Trust Centre for Human Genetics, NIHR Biomedical Research Centre, Roosevelt Drive, Oxford OX3 7BN, UK; Department of Statistics, University of Oxford, 1 South Parks Road, Oxford OX1 3TG, UK
| | - Anil K Sood
- Gynecologic Oncology, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA; Center for RNAi and Non-Coding RNA, The University of Texas MD Anderson Cancer Center, 1515 Holcombe Boulevard, Houston, TX 77030, USA
| | - Takeshi Motohara
- Department of Obstetrics and Gynecology, Faculty of Life Sciences, Kumamoto University, Kumamoto 860-8556, Japan
| | - Stefan Knapp
- Structural Genomics Consortium, Nuffield Department of Medicine, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ, UK; Nuffield Department of Medicine, Target Discovery Institute, University of Oxford, Oxford OX3 7FZ, UK; Goethe-University Frankfurt, Institute for Pharmaceutical Chemistry and Buchmann Institute for Life Sciences, Riedberg Campus, 60438 Frankfurt am Main, Germany
| | - Ahmed Ashour Ahmed
- Ovarian Cancer Cell Laboratory, Weatherall Institute of Molecular Medicine, University of Oxford, Headington, Oxford OX3 9DS, UK; Nuffield Department of Obstetrics and Gynaecology, University of Oxford, Women's Centre, John Radcliffe Hospital, Oxford OX3 9DU, UK.
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24
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Carnagarin R, Dharmarajan AM, Dass CR. Molecular aspects of glucose homeostasis in skeletal muscle--A focus on the molecular mechanisms of insulin resistance. Mol Cell Endocrinol 2015; 417:52-62. [PMID: 26362689 DOI: 10.1016/j.mce.2015.09.004] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/18/2015] [Accepted: 09/02/2015] [Indexed: 01/14/2023]
Abstract
Among all the varied actions of insulin, regulation of glucose homeostasis is the most critical and intensively studied. With the availability of glucose from nutrient metabolism, insulin action in muscle results in increased glucose disposal via uptake from the circulation and storage of excess, thereby maintaining euglycemia. This major action of insulin is executed by redistribution of the glucose transporter protein, GLUT4 from intracellular storage sites to the plasma membrane and storage of glucose in the form of glycogen which also involves modulation of actin dynamics that govern trafficking of all the signal proteins of insulin signal transduction. The cellular mechanisms responsible for these trafficking events and the defects associated with insulin resistance are largely enigmatic, and this review provides a consolidated overview of the various molecular mechanisms involved in insulin-dependent glucose homeostasis in skeletal muscle, as insulin resistance at this major peripheral site impacts whole body glucose homeostasis.
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Affiliation(s)
- Revathy Carnagarin
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Pharmacy, Curtin University, Bentley 6102, Australia
| | - Arun M Dharmarajan
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Biomedical Science, Curtin University, Bentley 6102, Australia
| | - Crispin R Dass
- Curtin Biosciences Research Precinct, Bentley 6102, Australia; School of Pharmacy, Curtin University, Bentley 6102, Australia.
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25
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LoPiccolo J, Kim SJ, Shi Y, Wu B, Wu H, Chait BT, Singer RH, Sali A, Brenowitz M, Bresnick AR, Backer JM. Assembly and Molecular Architecture of the Phosphoinositide 3-Kinase p85α Homodimer. J Biol Chem 2015; 290:30390-405. [PMID: 26475863 DOI: 10.1074/jbc.m115.689604] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Indexed: 11/06/2022] Open
Abstract
Phosphoinositide 3-kinases (PI3Ks) are a family of lipid kinases that are activated by growth factor and G-protein-coupled receptors and propagate intracellular signals for growth, survival, proliferation, and metabolism. p85α, a modular protein consisting of five domains, binds and inhibits the enzymatic activity of class IA PI3K catalytic subunits. Here, we describe the structural states of the p85α dimer, based on data from in vivo and in vitro solution characterization. Our in vitro assembly and structural analyses have been enabled by the creation of cysteine-free p85α that is functionally equivalent to native p85α. Analytical ultracentrifugation studies showed that p85α undergoes rapidly reversible monomer-dimer assembly that is highly exothermic in nature. In addition to the documented SH3-PR1 dimerization interaction, we identified a second intermolecular interaction mediated by cSH2 domains at the C-terminal end of the polypeptide. We have demonstrated in vivo concentration-dependent dimerization of p85α using fluorescence fluctuation spectroscopy. Finally, we have defined solution conditions under which the protein is predominantly monomeric or dimeric, providing the basis for small angle x-ray scattering and chemical cross-linking structural analysis of the discrete dimer. These experimental data have been used for the integrative structure determination of the p85α dimer. Our study provides new insight into the structure and assembly of the p85α homodimer and suggests that this protein is a highly dynamic molecule whose conformational flexibility allows it to transiently associate with multiple binding proteins.
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Affiliation(s)
| | - Seung Joong Kim
- the Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, and California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California 94158, and
| | - Yi Shi
- the Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York 10065
| | - Bin Wu
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Haiyan Wu
- From the Department of Molecular Pharmacology
| | - Brian T Chait
- the Laboratory of Mass Spectrometry and Gaseous Ion Chemistry, The Rockefeller University, New York, New York 10065
| | - Robert H Singer
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, New York 10461
| | - Andrej Sali
- the Department of Bioengineering and Therapeutic Sciences, Department of Pharmaceutical Chemistry, and California Institute for Quantitative Biosciences, University of California, San Francisco, San Francisco, California 94158, and
| | | | | | - Jonathan M Backer
- From the Department of Molecular Pharmacology, Department of Biochemistry,
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26
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Cheung LWT, Walkiewicz KW, Besong TMD, Guo H, Hawke DH, Arold ST, Mills GB. Regulation of the PI3K pathway through a p85α monomer-homodimer equilibrium. eLife 2015; 4:e06866. [PMID: 26222500 PMCID: PMC4518712 DOI: 10.7554/elife.06866] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2015] [Accepted: 07/04/2015] [Indexed: 12/20/2022] Open
Abstract
The canonical action of the p85α regulatory subunit of phosphatidylinositol 3-kinase (PI3K) is to associate with the p110α catalytic subunit to allow stimuli-dependent activation of the PI3K pathway. We elucidate a p110α-independent role of homodimerized p85α in the positive regulation of PTEN stability and activity. p110α-free p85α homodimerizes via two intermolecular interactions (SH3:proline-rich region and BH:BH) to selectively bind unphosphorylated activated PTEN. As a consequence, homodimeric but not monomeric p85α suppresses the PI3K pathway by protecting PTEN from E3 ligase WWP2-mediated proteasomal degradation. Further, the p85α homodimer enhances the lipid phosphatase activity and membrane association of PTEN. Strikingly, we identified cancer patient-derived oncogenic p85α mutations that target the homodimerization or PTEN interaction surface. Collectively, our data suggest the equilibrium of p85α monomer-dimers regulates the PI3K pathway and disrupting this equilibrium could lead to disease development.
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Affiliation(s)
- Lydia WT Cheung
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, United States
| | - Katarzyna W Walkiewicz
- Computational Bioscience Research Center, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Tabot MD Besong
- Division of Physical Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Huifang Guo
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, United States
| | - David H Hawke
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, United States
| | - Stefan T Arold
- Computational Bioscience Research Center, Division of Biological and Environmental Sciences and Engineering, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Gordon B Mills
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, United States
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27
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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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28
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Abstract
Rho GTPases are critical for platelet function. Although the roles of RhoA, Rac and Cdc42 are characterized, platelets express other Rho GTPases, whose activities are less well understood. This review summarizes our understanding of the roles of platelet Rho GTPases and focuses particularly on the functions of Rif and RhoG. In human platelets, Rif interacts with cytoskeleton regulators including formins mDia1 and mDia3, whereas RhoG binds SNARE-complex proteins and cytoskeletal regulators ELMO and DOCK1. Knockout mouse studies suggest that Rif plays no critical functions in platelets, likely due to functional overlap with other Rho GTPases. In contrast, RhoG is essential for normal granule secretion downstream of the collagen receptor GPVI. The central defect in RhoG-/- platelets is reduced dense granule secretion, which impedes integrin activation and aggregation and limits platelet recruitment to growing thrombi under shear, translating into reduced thrombus formation in vivo. Potential avenues for future work on Rho GTPases in platelets are also highlighted, including identification of the key regulator for platelet filopodia formation and investigation of the role of the many Rho GTPase regulators in platelet function in both health and disease.
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29
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Cheung LWT, Yu S, Zhang D, Li J, Ng PKS, Panupinthu N, Mitra S, Ju Z, Yu Q, Liang H, Hawke DH, Lu Y, Broaddus RR, Mills GB. Naturally occurring neomorphic PIK3R1 mutations activate the MAPK pathway, dictating therapeutic response to MAPK pathway inhibitors. Cancer Cell 2014; 26:479-94. [PMID: 25284480 PMCID: PMC4198486 DOI: 10.1016/j.ccell.2014.08.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2013] [Revised: 06/05/2014] [Accepted: 08/26/2014] [Indexed: 12/17/2022]
Abstract
PIK3R1 (p85α regulatory subunit of PI3K) is frequently mutated across cancer lineages. Herein, we demonstrate that the most common recurrent PIK3R1 mutation PIK3R1(R348∗) and a nearby mutation PIK3R1(L370fs), in contrast to wild-type and mutations in other regions of PIK3R1, confers an unexpected sensitivity to MEK and JNK inhibitors in vitro and in vivo. Consistent with the response to inhibitors, PIK3R1(R348∗) and PIK3R1(L370fs) unexpectedly increase JNK and ERK phosphorylation. Surprisingly, p85α R348(∗) and L370fs localize to the nucleus where the mutants provide a scaffold for multiple JNK pathway components facilitating nuclear JNK pathway activation. Our findings uncover an unexpected neomorphic role for PIK3R1(R348∗) and neighboring truncation mutations in cellular signaling, providing a rationale for therapeutic targeting of these mutant tumors.
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Affiliation(s)
- Lydia W T Cheung
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
| | - Shuangxing Yu
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Dong Zhang
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Jie Li
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Patrick K S Ng
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Nattapon Panupinthu
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of Physiology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
| | - Shreya Mitra
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Zhenlin Ju
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Qinghua Yu
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Han Liang
- Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - David H Hawke
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA; Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Yiling Lu
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Russell R Broaddus
- Department of Pathology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Gordon B Mills
- Department of Systems Biology, University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
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30
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Cariaga-Martínez AE, Cortés I, García E, Pérez-García V, Pajares MJ, Idoate MA, Redondo-Muñóz J, Antón IM, Carrera AC. Phosphoinositide 3-kinase p85beta regulates invadopodium formation. Biol Open 2014; 3:924-36. [PMID: 25217619 PMCID: PMC4197441 DOI: 10.1242/bio.20148185] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The acquisition of invasiveness is characteristic of tumor progression. Numerous genetic changes are associated with metastasis, but the mechanism by which a cell becomes invasive remains unclear. Expression of p85β, a regulatory subunit of phosphoinositide-3-kinase, markedly increases in advanced carcinoma, but its mode of action is unknown. We postulated that p85β might facilitate cell invasion. We show that p85β localized at cell adhesions in complex with focal adhesion kinase and enhanced stability and maturation of cell adhesions. In addition, p85β induced development at cell adhesions of an F-actin core that extended several microns into the cell z-axis resembling the skeleton of invadopodia. p85β lead to F-actin polymerization at cell adhesions by recruiting active Cdc42/Rac at these structures. In accordance with p85β function in invadopodium-like formation, p85β levels increased in metastatic melanoma and p85β depletion reduced invadopodium formation and invasion. These results show that p85β enhances invasion by inducing cell adhesion development into invadopodia-like structures explaining the metastatic potential of tumors with increased p85β levels.
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Affiliation(s)
- Ariel E Cariaga-Martínez
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
| | - Isabel Cortés
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
| | - Esther García
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
| | - Vicente Pérez-García
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
| | - María J Pajares
- Biomarkers Laboratory, Division of Oncology, Center for Applied Biomedical Research (CIMA), University of Navarra, Pamplona E-31008, Spain
| | - Miguel A Idoate
- Pathology Department, Hospital Clinic of Navarra, University of Navarra, Pamplona, E-31008, Spain
| | - Javier Redondo-Muñóz
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
| | - Inés M Antón
- Department of Molecular and Cell Biology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
| | - Ana C Carrera
- Department of Immunology and Oncology, Centro Nacional de Biotecnología (CNB-CSIC), Campus de Cantoblanco, Madrid E-28049, Spain
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31
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Kolluru GK, Majumder S, Chatterjee S. Rho-kinase as a therapeutic target in vascular diseases: striking nitric oxide signaling. Nitric Oxide 2014; 43:45-54. [PMID: 25196952 DOI: 10.1016/j.niox.2014.09.002] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2014] [Revised: 09/03/2014] [Accepted: 09/03/2014] [Indexed: 11/27/2022]
Abstract
Rho GTPases are a globular, monomeric group of small signaling G-protein molecules. Rho-associated protein kinase/Rho-kinase (ROCK) is a downstream effector protein of the Rho GTPase. Rho-kinases are the potential therapeutic targets in the treatment of cardiovascular diseases. Here, we have primarily discussed the intriguing roles of ROCK in cardiovascular health in relation to nitric oxide signaling. Further, we highlighted the biphasic effects of Y-27632, a ROCK inhibitor under shear stress, which acts as an agonist of nitric oxide production in endothelial cells. The biphasic effects of this inhibitor raised the question of safety of the drug usage in treating cardiovascular diseases.
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Affiliation(s)
| | - Syamantak Majumder
- Aab Cardiovascular Research Institute, School of Medicine and Dentistry, University of Rochester, Rochester, NY, USA
| | - Suvro Chatterjee
- Department of Biotechnology, Anna University, Chennai, India; Vascular Biology Lab, AU-KBC Research Centre, Anna University, Chennai, India.
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32
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Swanson JA. Phosphoinositides and engulfment. Cell Microbiol 2014; 16:1473-83. [PMID: 25073505 DOI: 10.1111/cmi.12334] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2014] [Revised: 07/17/2014] [Accepted: 07/28/2014] [Indexed: 12/24/2022]
Abstract
Cellular engulfment of particles, cells or solutes displaces large domains of plasma membrane into intracellular membranous vacuoles. This transfer of membrane is accompanied by major transitions of the phosphoinositide (PI) species that comprise the cytoplasmic face of membrane bilayers. Mapping of membrane PIs during engulfment reveals distinct patterns of protein and PI distributions associated with each stage of engulfment, which correspond with activities that regulate the actin cytoskeleton, membrane movements and vesicle secretion. Experimental manipulation of PI chemistry during engulfment indicates that PIs integrate organelle identity and orient signal transduction cascades within confined subdomains of membrane. These pathways are exploited by microbial pathogens to direct or redirect the engulfment process.
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Affiliation(s)
- Joel A Swanson
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, MI, 48109-5620, USA
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33
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Abstract
Hedgehog (Hh) pathway activation and Gli-dependent transcription play critical roles in embryonic patterning, tissue homeostasis, and tumorigenesis. By conducting a genome-scale cDNA overexpression screen, we have identified the Rho GAP family member Arhgap36 as a positive regulator of the Hh pathway in vitro and in vivo. Arhgap36 acts in a Smoothened (Smo)-independent manner to inhibit Gli repressor formation and to promote the activation of full-length Gli proteins. Arhgap36 concurrently induces the accumulation of Gli proteins in the primary cilium, and its ability to induce Gli-dependent transcription requires kinesin family member 3a and intraflagellar transport protein 88, proteins that are essential for ciliogenesis. Arhgap36 also functionally and biochemically interacts with Suppressor of Fused. Transcriptional profiling further reveals that Arhgap36 is overexpressed in murine medulloblastomas that acquire resistance to chemical Smo inhibitors and that ARHGAP36 isoforms capable of Gli activation are up-regulated in a subset of human medulloblastomas. Our findings reveal a new mechanism of Gli transcription factor activation and implicate ARHGAP36 dysregulation in the onset and/or progression of GLI-dependent cancers.
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34
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Nayak RC, Chang KH, Vaitinadin NS, Cancelas JA. Rho GTPases control specific cytoskeleton-dependent functions of hematopoietic stem cells. Immunol Rev 2014; 256:255-68. [PMID: 24117826 DOI: 10.1111/imr.12119] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The Rho family of guanosine triphosphatases (GTPases) is composed of members of the Ras superfamily of proteins. They are GTP-bound molecules with a modest intrinsic GTPase activity that can be accelerated upon activation/localization of specialized guanine nucleotide exchange factors. Members of this family act as molecular switches and are required for coordinated cytoskeletal rearrangements that are crucial in a set of specialized functions of mammalian stem cells. These functions include self-renewal, adhesion, and migration. Mouse gene-targeting studies have provided convincing evidence of the indispensable and dispensable roles of individual members of the Rho GTPase family and the putative upstream and downstream mediators in stem cell-specific functions. The role of Rho GTPases and related signaling pathways previously seen in other cell types and organisms have been confirmed in mammalian hematopoietic stem cells (HSCs), and new signaling pathways and unexpected functions unique to HSCs have been identified and dissected. This review summarizes our current understanding of the role of Rho family of GTPases on HSC and progenitor activity through cytoskeleton-mediated signaling pathways, providing insight about relevant signaling pathways that regulate mammalian stem cell self-renewal, adhesion, and migration.
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Affiliation(s)
- Ramesh C Nayak
- Stem Cell Program, Cancer and Blood Diseases Institute, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, USA
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35
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Salamon RS, Backer JM. Phosphatidylinositol-3,4,5-trisphosphate: tool of choice for class I PI 3-kinases. Bioessays 2014; 35:602-11. [PMID: 23765576 DOI: 10.1002/bies.201200176] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Class I PI 3-kinases signal by producing the signaling lipid phosphatidylinositol(3,4,5) trisphosphate, which in turn acts by recruiting downstream effectors that contain specific lipid-binding domains. The class I PI 3-kinases comprise four distinct catalytic subunits linked to one of seven different regulatory subunits. All the class I PI 3-kinases produce the same signaling lipid, PIP3, and the different isoforms have overlapping expression patterns and are coupled to overlapping sets of upstream activators. Nonetheless, studies in cultured cells and in animals have demonstrated that the different isoforms are coupled to distinct ranges of downstream responses. This review focuses on the mechanisms by which the production of a common product, PIP3, can produce isoform-specific signaling by PI 3-kinases.
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Affiliation(s)
- Rachel Schnur Salamon
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, USA
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36
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Assessing the subcellular distribution of oncogenic phosphoinositide 3-kinase using microinjection into live cells. Biosci Rep 2014; 34:BSR20130133. [PMID: 27919038 PMCID: PMC3985441 DOI: 10.1042/bsr20130133] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2013] [Revised: 02/18/2014] [Accepted: 03/04/2014] [Indexed: 02/07/2023] Open
Abstract
Oncogenic mutations in PIK3CA lead to an increase in intrinsic phosphoinositide kinase activity, but it is thought that increased access of PI3Kα (phosphoinositide 3-kinase α) to its PM (plasma membrane) localized substrate is also required for increased levels of downstream PIP3/Akt [phosphoinositide-3,4,5-trisphosphate/also called PKB (protein kinase B)] signalling. We have studied the subcellular localization of wild-type and the two most common oncogenic mutants of PI3Kα in cells maintained in growth media, and starved or stimulated cells using a novel method in which PI3Kα is pre-formed as a 1:1 p110α:p85α complex in vitro then introduced into live cells by microinjection. Oncogenic E545K and H1047R mutants did not constitutively interact with membrane lipids in vitro or in cells maintained in 10% (v/v) FBS. Following stimulation of RTKs (receptor tyrosine kinases), microinjected PI3Kα was recruited to the PM, but oncogenic forms of PI3Kα were not recruited to the PM to a greater extent and did not reside at the PM longer than the wild-type PI3Kα. Instead, the E545K mutant specifically bound activated Cdc42 in vitro and microinjection of E545K was associated with the formation of cellular protrusions, providing some preliminary evidence that changes in protein–protein interactions may play a role in the oncogenicity of the E545K mutant in addition to the well-known changes in lipid kinase activity. Oncogenic forms of PI3Kα (phosphoinositide 3-kinase α) microinjected into live cells are not recruited to the PM (plasma membrane) to a greater extent, and do not reside at the PM longer, than wild-type PI3Kα.
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37
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Fritsch R, de Krijger I, Fritsch K, George R, Reason B, Kumar M, Diefenbacher M, Stamp G, Downward J. RAS and RHO families of GTPases directly regulate distinct phosphoinositide 3-kinase isoforms. Cell 2013; 153:1050-63. [PMID: 23706742 PMCID: PMC3690480 DOI: 10.1016/j.cell.2013.04.031] [Citation(s) in RCA: 220] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 03/25/2013] [Accepted: 04/08/2013] [Indexed: 12/31/2022]
Abstract
RAS proteins are important direct activators of p110α, p110γ, and p110δ type I phosphoinositide 3-kinases (PI3Ks), interacting via an amino-terminal RAS-binding domain (RBD). Here, we investigate the regulation of the ubiquitous p110β isoform of PI3K, implicated in G-protein-coupled receptor (GPCR) signaling, PTEN-loss-driven cancers, and thrombocyte function. Unexpectedly, RAS is unable to interact with p110β, but instead RAC1 and CDC42 from the RHO subfamily of small GTPases bind and activate p110β via its RBD. In fibroblasts, GPCRs couple to PI3K through Dock180/Elmo1-mediated RAC activation and subsequent interaction with p110β. Cells from mice carrying mutations in the p110β RBD show reduced PI3K activity and defective chemotaxis, and these mice are resistant to experimental lung fibrosis. These findings revise our understanding of the regulation of type I PI3K by showing that both RAS and RHO family GTPases directly regulate distinct ubiquitous PI3K isoforms and that RAC activates p110β downstream of GPCRs.
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Affiliation(s)
- Ralph Fritsch
- Signal Transduction Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
| | - Inge de Krijger
- Signal Transduction Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
| | - Kornelia Fritsch
- Experimental Histopathology Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
| | - Roger George
- Protein Purification Facility, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
| | - Beth Reason
- Signal Transduction Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
| | - Madhu S. Kumar
- Signal Transduction Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
| | - Markus Diefenbacher
- Mammalian Genetics Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
| | - Gordon Stamp
- Experimental Histopathology Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
| | - Julian Downward
- Signal Transduction Laboratory, Cancer Research UK London Research Institute, 44 Lincoln’s Inn Fields, London WC2A 3LY, UK
- Lung Cancer Group, Division of Cancer Biology, The Institute of Cancer Research, 237 Fulham Road, London SW3 6JB, UK
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38
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Redelman-Sidi G, Iyer G, Solit DB, Glickman MS. Oncogenic activation of Pak1-dependent pathway of macropinocytosis determines BCG entry into bladder cancer cells. Cancer Res 2013; 73:1156-67. [PMID: 23378476 DOI: 10.1158/0008-5472.can-12-1882] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Bacille Calmette-Guerin (BCG) is an attenuated strain of Mycobacterium bovis that is used widely as a vaccine for tuberculosis and is used as an effective treatment for superficial bladder carcinoma. Despite being the most successful cancer biotherapy, its mechanism of action and response determinants remain obscure. Here, we establish a model system to analyze BCG interaction with bladder cancer cells, using it to show that these cells vary dramatically in their susceptibility to BCG infection. Unexpectedly, the uptake of BCG by bladder cancer cells occurs by macropinocytosis rather than phagocytosis. BCG entry into bladder cancer cells relied upon Rac1, Cdc42, and their effector kinase Pak1. The difference in susceptibility between BCG-permissive and -resistant bladder cancer cells was due to oncogenic activation of signaling pathways that activate macropinocytosis, with phosphoinositide 3-kinase inhibitor activation stimulating BCG uptake independently of Akt. Similarly, activated Ras strongly activated Pak1-dependent uptake of BCG. These results reveal that oncogenic activation of macropinocytosis determines BCG uptake by bladder cancer cells, implying that tumor responsiveness to BCG may be governed by the specific mutations present in the treated cancer cell.
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Affiliation(s)
- Gil Redelman-Sidi
- Infectious Diseases Service, Memorial Sloan Kettering Cancer Center, New York, NY 10065, USA
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39
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Basquin C, Malardé V, Mellor P, Anderson DH, Meas-Yedid V, Olivo-Marin JC, Dautry-Varsat A, Sauvonnet N. The signalling factor PI 3-kinase is a specific regulator of the clathrin-independent dynamin-dependent endocytosis of IL-2 receptors. J Cell Sci 2013; 126:1099-108. [DOI: 10.1242/jcs.110932] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Receptor-mediated endocytosis is an essential process used by eukaryotic cells to internalise many molecules. Several clathrin-independent endocytic routes exist but the molecular mechanism of each pathway remains to be uncovered. This study focuses on a clathrin-independent, dynamin-dependent pathway used by interleukin 2 receptors (IL-2R), essential players of the immune response. Rac1 and its targets the p21-activated kinases (Pak) are specific regulators of this pathway, acting on cortactin and actin polymerization. Here, our study reveals a dual and specific role of phosphatidylinositol 3-kinase (PI 3-kinase) in IL-2R endocytosis. Firstly, the inhibition of the catalytic activity of PI 3-kinase strongly affects IL-2R endocytosis, in contrast to transferrin (Tf) uptake, a marker of the clathrin-mediated pathway. Moreover, Vav2, a GTPase exchange factor (GEF) induced upon PI 3-kinase activation, is specifically involved in IL-2R entry. The second action of PI 3-kinase is via its regulatory subunit, p85α, which binds to and recruits Rac1 during IL-2R internalisation. Indeed, the overexpression of a p85α mutant missing the Rac1 binding motif, leads to the specific inhibition of IL-2R endocytosis. The inhibitory effect of this p85α mutant could be rescued by the overexpression of either Rac1 or the active form of Pak, indicating that p85α acts upstream of the Rac1-Pak cascade. Finally, biochemical and fluorescent microscopy techniques reveal an interaction between p85α, Rac1 and IL-2R that is enhanced by IL-2. In summary our results point out a key role of class I PI 3-kinase in IL-2R endocytosis that creates a link with IL-2 signalling.
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40
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Nakhaei-Nejad M, Haddad G, Zhang QX, Murray AG. Facio-Genital Dysplasia-5 Regulates Matrix Adhesion and Survival of Human Endothelial Cells. Arterioscler Thromb Vasc Biol 2012; 32:2694-701. [DOI: 10.1161/atvbaha.112.300074] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
| | - George Haddad
- From the Department of Medicine, University of Alberta, Edmonton, Canada
| | - Qiu-Xia Zhang
- From the Department of Medicine, University of Alberta, Edmonton, Canada
| | - Allan G. Murray
- From the Department of Medicine, University of Alberta, Edmonton, Canada
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41
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Stengel KR, Zheng Y. Essential role of Cdc42 in Ras-induced transformation revealed by gene targeting. PLoS One 2012; 7:e37317. [PMID: 22719838 PMCID: PMC3377703 DOI: 10.1371/journal.pone.0037317] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2012] [Accepted: 04/18/2012] [Indexed: 01/12/2023] Open
Abstract
The ras proto-oncogene is one of the most frequently mutated genes in human cancer. However, given the prevalence of activating mutations in Ras and its association with aggressive forms of cancer, attempts to therapeutically target aberrant Ras signaling have been largely disappointing. This lack of progress highlights the deficiency in our understanding of cellular pathways required for Ras-mediated tumorigenesis and suggests the importance of identifying new molecular pathways associated with Ras-driven malignancies. Cdc42 is a Ras-related small GTPase that is known to play roles in oncogenic processes such as cell growth, survival, invasion, and migration. A pan-dominant negative mutant overexpression approach to suppress Cdc42 and related pathways has previously shown a requirement for Cdc42 in Ras-induced anchorage-independent cell growth, however the lack of specificity of such approaches make it difficult to determine if effects are directly related to changes in Cdc42 activity or other Rho family members. Therefore, in order to directly and unambiguously address the role of Cdc42 in Ras-mediated transformation, tumor formation and maintenance, we have developed a model of conditional cdc42 gene in Ras-transformed cells. Loss of Cdc42 drastically alters the cell morphology and inhibits proliferation, cell cycle progression and tumorigenicity of Ras-transformed cells, while non-transformed cells or c-Myc transformed cells are largely unaffected. The loss of Cdc42 in Ras-transformed cells results in reduced Akt signaling, restoration of which could partially rescues the proliferation defects associated with Cdc42 loss. Moreover, disruption of Cdc42 function in established tumors inhibited continued tumor growth. These studies implicate Cdc42 in Ras-driven tumor growth and suggest that targeting Cdc42 is beneficial in Ras-mediated malignancies.
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Affiliation(s)
- Kristy R. Stengel
- Division of Experimental Hematology and Cancer Biology, Children’s Research Foundation; Department of Cancer and Cell Biology, College of Medicine, University of Cincinnati, Ohio, United States of America
| | - Yi Zheng
- Division of Experimental Hematology and Cancer Biology, Children’s Research Foundation; Department of Cancer and Cell Biology, College of Medicine, University of Cincinnati, Ohio, United States of America
- * E-mail:
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42
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Marée AFM, Grieneisen VA, Edelstein-Keshet L. How cells integrate complex stimuli: the effect of feedback from phosphoinositides and cell shape on cell polarization and motility. PLoS Comput Biol 2012; 8:e1002402. [PMID: 22396633 PMCID: PMC3291540 DOI: 10.1371/journal.pcbi.1002402] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2011] [Accepted: 01/07/2012] [Indexed: 12/03/2022] Open
Abstract
To regulate shape changes, motility and chemotaxis in eukaryotic cells, signal transduction pathways channel extracellular stimuli to the reorganization of the actin cytoskeleton. The complexity of such networks makes it difficult to understand the roles of individual components, let alone their interactions and multiple feedbacks within a given layer and between layers of signalling. Even more challenging is the question of if and how the shape of the cell affects and is affected by this internal spatiotemporal reorganization. Here we build on our previous 2D cell motility model where signalling from the Rho family GTPases (Cdc42, Rac, and Rho) was shown to organize the cell polarization, actin reorganization, shape change, and motility in simple gradients. We extend this work in two ways: First, we investigate the effects of the feedback between the phosphoinositides (PIs) , and Rho family GTPases. We show how that feedback increases heights and breadths of zones of Cdc42 activity, facilitating global communication between competing cell “fronts”. This hastens the commitment to a single lamellipodium initiated in response to multiple, complex, or rapidly changing stimuli. Second, we show how cell shape feeds back on internal distribution of GTPases. Constraints on chemical isocline curvature imposed by boundary conditions results in the fact that dynamic cell shape leads to faster biochemical redistribution when the cell is repolarized. Cells with frozen cytoskeleton, and static shapes, consequently respond more slowly to reorienting stimuli than cells with dynamic shape changes, the degree of the shape-induced effects being proportional to the extent of cell deformation. We explain these concepts in the context of several in silico experiments using our 2D computational cell model. Single cells, such as amoeba and white blood cells, change shape and move in response to environmental stimuli. Their behaviour is a consequence of the intracellular properties balanced by external forces. The internal regulation is modulated by several proteins that interact with one another and with membrane lipids. We examine, through in silico experiments using a computational model of a moving cell, the interactions of an important class of such proteins (Rho GTPases) and lipids (phosphoinositides, PIs), their spatial redistribution, and how they affect and are affected by cell shape. Certain GTPases promote the assembly of the actin cytoskeleton. This then leads to the formation of a cell protrusion, the leading edge. The feedback between PIs and GTPases facilitates global communication across the cell, ensuring that multiple, complex, or rapidly changing stimuli can be resolved into a single decision for positioning the leading edge. Interestingly, the cell shape itself affects the intracellular biochemistry, resulting from interactions between the curvature of the chemical fronts and the cell edge. Cells with static shapes consequently respond more slowly to reorienting stimuli than cells with dynamic shape changes. This potential to respond more rapidly to external stimuli depends on the degree of cellular shape deformation.
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Affiliation(s)
- Athanasius F M Marée
- Computational & Systems Biology, John Innes Centre, Norwich Research Park, Norwich, United Kingdom.
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Kim I, Han SJ, Kim Y, Ahn Y, Chay KO, Lee SR. Tyr740 and Tyr751 residues of platelet-derived growth factor beta receptor are responsible for the redox regulation of phosphatase and tensin homolog in the cells stimulated with platelet-derived growth factor. Redox Rep 2011; 16:181-6. [PMID: 21888769 DOI: 10.1179/1351000211y.0000000005] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
Exposure of cells to hydrogen peroxide or platelet-derived growth factor (PDGF) induced Akt phosphorylation and oxidation of phosphatase and tensin homolog (PTEN). The Cys124 and Cys71 residues of PTEN were critical for the formation of a disulfide bond and the intermediate glutathionylation in the process of reduction of the disulfide bond. To determine which specific tyrosine residues of the PDGF beta receptor (PDGFβR) is involved in PDGF-induced PTEN oxidation and Akt phosphorylation, we investigated a kinase activity-deficient mutant and PDGFβR mutants where the tyrosine residues in the binding site for phosphoinositide 3-kinase (PI3K), GTPase-activating protein of Ras, Src homology 2 domain containing protein-tyrosine phosphatase-2, and phospholipase C-1 were replaced by Phe. Both PTEN oxidation and Akt phosphorylation did not occur in response to PDGF in the kinase-deficient mutant and in the PDGFβR mutant with a mutation in the PI3K binding site (Tyr740 and Tyr751). Thus, the kinase activity and the constituent Tyr740 and Tyr751 residues of PDGFβR in the cells stimulated with PDGF are responsible for the oxidation of PTEN and the Akt phosphorylation.
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Affiliation(s)
- Inyoung Kim
- Department of Biochemistry, Research Center for Aging and Geriatrics, Research Institute of Medical Sciences, Chonnam National University Medical School, Gwangju, Republic of Korea
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Multiple roles for the p85α isoform in the regulation and function of PI3K signalling and receptor trafficking. Biochem J 2011; 441:23-37. [DOI: 10.1042/bj20111164] [Citation(s) in RCA: 72] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The p85α protein is best known as the regulatory subunit of class 1A PI3Ks (phosphoinositide 3-kinases) through its interaction, stabilization and repression of p110-PI3K catalytic subunits. PI3Ks play multiple roles in the regulation of cell survival, signalling, proliferation, migration and vesicle trafficking. The present review will focus on p85α, with special emphasis on its important roles in the regulation of PTEN (phosphatase and tensin homologue deleted on chromosome 10) and Rab5 functions. The phosphatidylinositol-3-phosphatase PTEN directly counteracts PI3K signalling through dephosphorylation of PI3K lipid products. Thus the balance of p85α–p110 and p85α–PTEN complexes determines the signalling output of the PI3K/PTEN pathway, and under conditions of reduced p85α levels, the p85α–PTEN complex is selectively reduced, promoting PI3K signalling. Rab5 GTPases are important during the endocytosis, intracellular trafficking and degradation of activated receptor complexes. The p85α protein helps switch off Rab5, and if defective in this p85α function, results in sustained activated receptor tyrosine kinase signalling and cell transformation through disrupted receptor trafficking. The central role for p85α in the regulation of PTEN and Rab5 has widened the scope of p85α functions to include integration of PI3K activation (p110-mediated), deactivation (PTEN-mediated) and receptor trafficking/signalling (Rab5-mediated) functions, all with key roles in maintaining cellular homoeostasis.
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45
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Stengel K, Zheng Y. Cdc42 in oncogenic transformation, invasion, and tumorigenesis. Cell Signal 2011; 23:1415-23. [PMID: 21515363 DOI: 10.1016/j.cellsig.2011.04.001] [Citation(s) in RCA: 176] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2011] [Accepted: 04/04/2011] [Indexed: 12/23/2022]
Abstract
The Rho family of GTPases represents a class of Ras-related signaling molecules often deregulated in cancer. Rho GTPases switch from a GDP-bound, inactive state to a GTP-bound, active state in response to extracellular stimuli such as mitogens and extracellular matrix. In addition, Rho GTPase signaling can be altered in response to cell intrinsic factors such as changes in oncogenic or tumor suppressor signaling. In their active form, these proteins bind to a number of effector molecules, activating signaling cascades which regulate a variety of cellular processes including cytoskeletal reorganization, cell cycle progression, cell polarity and transcription. Here, we focus on one Rho family member, Cdc42, which is overexpressed in a number of human cancers. Consistent with a role in the promotion of tumorigenesis, activating mutations in Cdc42 and guanine nucleotide exchange factors are transforming, while inhibition of Cdc42 activity can impinge on cellular transformation following the activation of oncoproteins or loss of tumor suppressor function. Furthermore, Cdc42 activity has been implicated in the invasive phenotype which characterizes tumor metastasis, further suggesting that Cdc42 may be a useful target for therapeutic intervention. However, several recent studies in mice have unveiled a putative tumor suppressor function of Cdc42 in several tissue types which may involve cell polarity maintenance, suggesting that the role of Cdc42 in cancer development is complex and may be cell type specific.
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Affiliation(s)
- Kristy Stengel
- Division of Experimental Hematology and Cancer Biology, Children's Research Foundation, 3333 Burnet Avenue, Cincinnati, OH 45229, USA
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Backer JM. The regulation of class IA PI 3-kinases by inter-subunit interactions. Curr Top Microbiol Immunol 2011; 346:87-114. [PMID: 20544340 DOI: 10.1007/82_2010_52] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Phosphoinositide 3-kinases (PI 3-kinases) are activated by growth factor and hormone receptors, and regulate cell growth, survival, motility, and responses to changes in nutritional conditions (Engelman et al. 2006). PI 3-kinases have been classified according to their subunit composition and their substrate specificity for phosphoinositides (Vanhaesebroeck et al. 2001). The class IA PI 3-kinase is a heterodimer consisting of one regulatory subunit (p85α, p85β, p55α, p50α, or p55γ) and one 110-kDa catalytic subunit (p110α, β or δ). The Class IB PI 3-kinase is also a dimer, composed of one regulatory subunit (p101 or p87) and one catalytic subunit (p110γ) (Wymann et al. 2003). Class I enzymes will utilize PI, PI[4]P, or PI[4,5]P2 as substrates in vitro, but are thought to primarily produce PI[3,4,5]P3 in cells.The crystal structure of the Class IB PI 3-kinase catalytic subunit p110γ was solved in 1999 (Walker et al. 1999), and crystal or NMR structures of the Class IA p110α catalytic subunit and all of the individual domains of the Class IA p85α regulatory subunit have been solved (Booker et al. 1992; Günther et al. 1996; Hoedemaeker et al. 1999; Huang et al. 2007; Koyama et al. 1993; Miled et al. 2007; Musacchio et al. 1996; Nolte et al. 1996; Siegal et al. 1998). However, a structure of an intact PI 3-kinase enzyme has remained elusive. In spite of this, studies over the past 10 years have lead to important insights into how the enzyme is regulated under physiological conditions. This chapter will specifically discuss the regulation of Class IA PI 3-kinase enzymatic activity, focusing on regulatory interactions between the p85 and p110 subunits and the modulation of these interactions by physiological activators and oncogenic mutations. The complex web of signaling downstream from Class IA PI 3-kinases will be discussed in other chapters in this volume.
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Affiliation(s)
- Jonathan M Backer
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, 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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Abstract
During murine peri-implantation development, the egg cylinder forms from a solid cell mass by the apoptotic removal of inner cells that do not contact the basement membrane (BM) and the selective survival of the epiblast epithelium, which does. The signaling pathways that mediate this fundamental biological process are largely unknown. Here we demonstrate that Rac1 ablation in embryonic stem cell-derived embryoid bodies (EBs) leads to massive apoptosis of epiblast cells in contact with the BM. Expression of wild-type Rac1 in the mutant EBs rescues the BM-contacting epiblast, while expression of a constitutively active Rac1 additionally blocks the apoptosis of inner cells and cavitation, indicating that the spatially regulated activation of Rac1 is required for epithelial cyst formation. We further show that Rac1 is activated through integrin-mediated recruitment of the Crk-DOCK180 complex and mediates BM-dependent epiblast survival through activating the phosphatidylinositol 3-kinase (PI3K)-Akt signaling pathway. Our results reveal a signaling cascade triggered by cell-BM interactions essential for epithelial morphogenesis.
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49
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Sinnamon RH, McDevitt P, Pietrak BL, Leydon VR, Xue Y, Lehr R, Qi H, Burns M, Elkins P, Ward P, Vincentini G, Fisher D, Grimes M, Brandt M, Auger KR, Ho T, Johanson K, Jones CS, Schwartz B, Sweitzer TD, Kirkpatrick RB. Baculovirus production of fully-active phosphoinositide 3-kinase alpha as a p85alpha-p110alpha fusion for X-ray crystallographic analysis with ATP competitive enzyme inhibitors. Protein Expr Purif 2010; 73:167-76. [PMID: 20457255 DOI: 10.1016/j.pep.2010.05.002] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2010] [Revised: 04/30/2010] [Accepted: 05/03/2010] [Indexed: 01/05/2023]
Abstract
Phosphoinositide 3-kinases have been targeted for therapeutic research because they are key components of a cell signaling cascade controlling proliferation, growth, and survival. Direct activation of the PI3Kalpha pathway contributes to the development and progression of solid tumors in breast, endometrial, colon, ovarian, and gastric cancers. In the context of a drug discovery effort, the availability of a robust crystallographic system is a means to understand the subtle differences between ATP competitive inhibitor interactions with the active site and their selectivity against other PI3Kinase enzymes. To generate a suitable recombinant design for this purpose, a p85alpha-p110alpha fusion system was developed which enabled the expression and purification of a stoichiometrically homogeneous, constitutively active enzyme for structure determination with potent ATP competitive inhibitors (Raha et al., in preparation) [56]. This approach has yielded preparations with activity and inhibition characteristics comparable to those of the full-length PI3Kalpha from which X-ray diffracting crystals were grown with inhibitors bound in the active site.
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Affiliation(s)
- Robert H Sinnamon
- Biological Reagents and Assay Development Department, Molecular Discovery Research, GlaxoSmithKline, Upper Providence, 1250 South Collegeville Rd., Collegeville, PA 19426, USA.
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50
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Park SW, Zhou Y, Lee J, Lu A, Sun C, Chung J, Ueki K, Ozcan U. The regulatory subunits of PI3K, p85alpha and p85beta, interact with XBP-1 and increase its nuclear translocation. Nat Med 2010; 16:429-37. [PMID: 20348926 DOI: 10.1038/nm.2099] [Citation(s) in RCA: 231] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Accepted: 01/04/2010] [Indexed: 12/12/2022]
Abstract
Despite the fact that X-box binding protein-1 (XBP-1) is one of the main regulators of the unfolded protein response (UPR), the modulators of XBP-1 are poorly understood. Here, we show that the regulatory subunits of phosphotidyl inositol 3-kinase (PI3K), p85alpha (encoded by Pik3r1) and p85beta (encoded by Pik3r2) form heterodimers that are disrupted by insulin treatment. This disruption of heterodimerization allows the resulting monomers of p85 to interact with, and increase the nuclear translocation of, the spliced form of XBP-1 (XBP-1s). The interaction between p85 and XBP-1s is lost in ob/ob mice, resulting in a severe defect in XBP-1s translocation to the nucleus and thus in the resolution of endoplasmic reticulum (ER) stress. These defects are ameliorated when p85alpha and p85beta are overexpressed in the liver of ob/ob mice. Our results define a previously unknown insulin receptor signaling pathway and provide new mechanistic insight into the development of ER stress during obesity.
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Affiliation(s)
- Sang Won Park
- Division of Endocrinology, Children's Hospital Boston, Harvard Medical School, Boston, Massachusetts, USA
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