1
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Pimm ML, Haarer BK, Nobles AD, Haney LM, Marcin AG, Alcaide Eligio M, Henty-Ridilla JL. Coordination of actin plus-end dynamics by IQGAP1, formin, and capping protein. J Cell Biol 2024; 223:e202305065. [PMID: 38787349 PMCID: PMC11117073 DOI: 10.1083/jcb.202305065] [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: 05/16/2023] [Revised: 04/01/2024] [Accepted: 05/13/2024] [Indexed: 05/25/2024] Open
Abstract
Cell processes require precise regulation of actin polymerization that is mediated by plus-end regulatory proteins. Detailed mechanisms that explain plus-end dynamics involve regulators with opposing roles, including factors that enhance assembly, e.g., the formin mDia1, and others that stop growth (capping protein, CP). We explore IQGAP1's roles in regulating actin filament plus-ends and the consequences of perturbing its activity in cells. We confirm that IQGAP1 pauses elongation and interacts with plus ends through two residues (C756 and C781). We directly visualize the dynamic interplay between IQGAP1 and mDia1, revealing that IQGAP1 displaces the formin to influence actin assembly. Using four-color TIRF, we show that IQGAP1's displacement activity extends to formin-CP "decision complexes," promoting end-binding protein turnover at plus-ends. Loss of IQGAP1 or its plus-end activities disrupts morphology and migration, emphasizing its essential role. These results reveal a new role for IQGAP1 in promoting protein turnover on filament ends and provide new insights into how plus-end actin assembly is regulated in cells.
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Affiliation(s)
- Morgan L. Pimm
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Brian K. Haarer
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Alexander D. Nobles
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Laura M. Haney
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Alexandra G. Marcin
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Marcela Alcaide Eligio
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
| | - Jessica L. Henty-Ridilla
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical University, Syracuse, NY, USA
- Department of Neuroscience and Physiology, SUNY Upstate Medical University, Syracuse, NY, USA
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2
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Martin-Vega A, Cobb MH. Navigating the ERK1/2 MAPK Cascade. Biomolecules 2023; 13:1555. [PMID: 37892237 PMCID: PMC10605237 DOI: 10.3390/biom13101555] [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: 09/30/2023] [Revised: 10/16/2023] [Accepted: 10/18/2023] [Indexed: 10/29/2023] Open
Abstract
The RAS-ERK pathway is a fundamental signaling cascade crucial for many biological processes including proliferation, cell cycle control, growth, and survival; common across all cell types. Notably, ERK1/2 are implicated in specific processes in a context-dependent manner as in stem cells and pancreatic β-cells. Alterations in the different components of this cascade result in dysregulation of the effector kinases ERK1/2 which communicate with hundreds of substrates. Aberrant activation of the pathway contributes to a range of disorders, including cancer. This review provides an overview of the structure, activation, regulation, and mutational frequency of the different tiers of the cascade; with a particular focus on ERK1/2. We highlight the importance of scaffold proteins that contribute to kinase localization and coordinate interaction dynamics of the kinases with substrates, activators, and inhibitors. Additionally, we explore innovative therapeutic approaches emphasizing promising avenues in this field.
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Affiliation(s)
- Ana Martin-Vega
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Rd., Dallas, TX 75390, USA;
| | - Melanie H. Cobb
- Department of Pharmacology, UT Southwestern Medical Center, 6001 Forest Park Rd., Dallas, TX 75390, USA;
- Simmons Comprehensive Cancer Center, UT Southwestern Medical Center, 6001 Forest Park Rd., Dallas, TX 75390, USA
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3
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Papadaki V, Erpapazoglou Z, Kokkori M, Rogalska M, Potiri M, Birladeanu A, Tsakiri E, Ashktorab H, Smoot D, Papanikolopoulou K, Samiotaki M, Kafasla P. IQGAP1 mediates the communication between the nucleus and the mitochondria via NDUFS4 alternative splicing. NAR Cancer 2023; 5:zcad046. [PMID: 37636315 PMCID: PMC10448856 DOI: 10.1093/narcan/zcad046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2022] [Revised: 08/04/2023] [Accepted: 08/10/2023] [Indexed: 08/29/2023] Open
Abstract
Constant communication between mitochondria and nucleus ensures cellular homeostasis and adaptation to mitochondrial stress. Anterograde regulatory pathways involving a large number of nuclear-encoded proteins control mitochondrial biogenesis and functions. Such functions are deregulated in cancer cells, resulting in proliferative advantages, aggressive disease and therapeutic resistance. Transcriptional networks controlling the nuclear-encoded mitochondrial genes are known, however alternative splicing (AS) regulation has not been implicated in this communication. Here, we show that IQGAP1, a scaffold protein regulating AS of distinct gene subsets in gastric cancer cells, participates in AS regulation that strongly affects mitochondrial respiration. Combined proteomic and RNA-seq analyses of IQGAP1KO and parental cells show that IQGAP1KO alters an AS event of the mitochondrial respiratory chain complex I (CI) subunit NDUFS4 and downregulates a subset of CI subunits. In IQGAP1KO cells, CI intermediates accumulate, resembling assembly deficiencies observed in patients with Leigh syndrome bearing NDUFS4 mutations. Mitochondrial CI activity is significantly lower in KO compared to parental cells, while exogenous expression of IQGAP1 reverses mitochondrial defects of IQGAP1KO cells. Our work sheds light to a novel facet of IQGAP1 in mitochondrial quality control that involves fine-tuning of CI activity through AS regulation in gastric cancer cells relying highly on mitochondrial respiration.
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Affiliation(s)
- Vasiliki Papadaki
- Institute for Fundamental Biomedical Research, BSRC “Al. Fleming”, Vari 16672, Greece
| | - Zoi Erpapazoglou
- Institute for Fundamental Biomedical Research, BSRC “Al. Fleming”, Vari 16672, Greece
| | - Maria Kokkori
- Institute for Fundamental Biomedical Research, BSRC “Al. Fleming”, Vari 16672, Greece
| | - Malgorzata Ewa Rogalska
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Myrto Potiri
- Institute for Fundamental Biomedical Research, BSRC “Al. Fleming”, Vari 16672, Greece
| | - Andrada Birladeanu
- Institute for Fundamental Biomedical Research, BSRC “Al. Fleming”, Vari 16672, Greece
| | - Eleni N Tsakiri
- Institute for Fundamental Biomedical Research, BSRC “Al. Fleming”, Vari 16672, Greece
| | - Hassan Ashktorab
- Department of Medicine and Cancer Center, Howard University, Washington, DC, USA
| | - Duane T Smoot
- Department of Medicine, Meharry Medical Center, Nashville, TN, USA
| | | | | | - Panagiota Kafasla
- Institute for Fundamental Biomedical Research, BSRC “Al. Fleming”, Vari 16672, Greece
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4
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Ren X, Guo X, Liang Z, Guo R, Liang S, Liu H. Hax1 regulate focal adhesion dynamics through IQGAP1. Cell Commun Signal 2023; 21:182. [PMID: 37488602 PMCID: PMC10364419 DOI: 10.1186/s12964-023-01189-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2023] [Accepted: 06/07/2023] [Indexed: 07/26/2023] Open
Abstract
Cell migration is a highly orchestrated process requiring the coordination between the cytoskeleton, cell membrane and extracellular matrix adhesions. Our previous study demonstrated that Hax1 interacts with EB2, a microtubule end-binding protein, and this interaction regulate cell migration in keratinocytes. However, little is known about the underlying regulatory mechanism. Here, we show that Hax1 links dynamic focal adhesions to regulate cell migration via interacting with IQGAP1, a multidomain scaffolding protein, which was identified by affinity purification coupled with LC-MS/MS. Biochemical characterizations revealed that C-terminal region of Hax1 and RGCT domain of IQGAP1 are the most critical binding determinants for its interaction. IQGAP1/Hax1 interaction is essential for cell migration in MCF7 cells. Knockdown of HAX1 not only stabilizes focal adhesions, but also impairs the accumulation of IQGAP in focal adhesions. Further study indicates that this interaction is critical for maintaining efficient focal adhesion turnover. Perturbation of the IQGAP1/Hax1 interaction in vivo using a membrane-permeable TAT-RGCT peptide results in impaired focal adhesion turnover, thus leading to inhibition of directional cell migration. Together, our findings unravel a novel interaction between IQGAP1 and Hax1, suggesting that IQGAP1 association with Hax1 plays a significant role in focal adhesion turnover and directional cell migration. Video Abstract.
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Affiliation(s)
- Xinyi Ren
- School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Xiaopu Guo
- School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Zihan Liang
- School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Renxian Guo
- School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China
| | - Shaohui Liang
- School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China.
| | - Han Liu
- School of Basic Medical Sciences, Wenzhou Medical University, Wenzhou, 325035, Zhejiang, China.
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5
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Martinez-Lopez N, Mattar P, Toledo M, Bains H, Kalyani M, Aoun ML, Sharma M, McIntire LBJ, Gunther-Cummins L, Macaluso FP, Aguilan JT, Sidoli S, Bourdenx M, Singh R. mTORC2-NDRG1-CDC42 axis couples fasting to mitochondrial fission. Nat Cell Biol 2023:10.1038/s41556-023-01163-3. [PMID: 37386153 PMCID: PMC10344787 DOI: 10.1038/s41556-023-01163-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Accepted: 05/04/2023] [Indexed: 07/01/2023]
Abstract
Fasting triggers diverse physiological adaptations including increases in circulating fatty acids and mitochondrial respiration to facilitate organismal survival. The mechanisms driving mitochondrial adaptations and respiratory sufficiency during fasting remain incompletely understood. Here we show that fasting or lipid availability stimulates mTORC2 activity. Activation of mTORC2 and phosphorylation of its downstream target NDRG1 at serine 336 sustains mitochondrial fission and respiratory sufficiency. Time-lapse imaging shows that NDRG1, but not the phosphorylation-deficient NDRG1Ser336Ala mutant, engages with mitochondria to facilitate fission in control cells, as well as in those lacking DRP1. Using proteomics, a small interfering RNA screen, and epistasis experiments, we show that mTORC2-phosphorylated NDRG1 cooperates with small GTPase CDC42 and effectors and regulators of CDC42 to orchestrate fission. Accordingly, RictorKO, NDRG1Ser336Ala mutants and Cdc42-deficient cells each display mitochondrial phenotypes reminiscent of fission failure. During nutrient surplus, mTOR complexes perform anabolic functions; however, paradoxical reactivation of mTORC2 during fasting unexpectedly drives mitochondrial fission and respiration.
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Affiliation(s)
- Nuria Martinez-Lopez
- Department of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- Vatche and Tamar Manoukian Division of Digestive Diseases, University of California Los Angeles, Los Angeles, CA, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
- Liver Basic Research Center at University of California Los Angeles, Los Angeles, CA, USA
| | - Pamela Mattar
- Department of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Miriam Toledo
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
- Neuronal Control of Metabolism Laboratory, Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Henrietta Bains
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Manu Kalyani
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Marie Louise Aoun
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Mridul Sharma
- Department of Medicine, University of California Los Angeles, Los Angeles, CA, USA
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
| | | | - Leslie Gunther-Cummins
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Frank P Macaluso
- Department of Anatomy and Structural Biology, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Jennifer T Aguilan
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Simone Sidoli
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Mathieu Bourdenx
- UK Dementia Research Institute, London, UK
- UCL Queen Square Institute of Neurology, London, UK
| | - Rajat Singh
- Department of Medicine, University of California Los Angeles, Los Angeles, CA, USA.
- Vatche and Tamar Manoukian Division of Digestive Diseases, University of California Los Angeles, Los Angeles, CA, USA.
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA.
- Liver Basic Research Center at University of California Los Angeles, Los Angeles, CA, USA.
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, Bronx, NY, USA.
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6
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Ahmad SMS, Nazar H, Rahman MM, Rusyniak RS, Ouhtit A. ITGB1BP1, a Novel Transcriptional Target of CD44-Downstream Signaling Promoting Cancer Cell Invasion. BREAST CANCER (DOVE MEDICAL PRESS) 2023; 15:373-380. [PMID: 37252376 PMCID: PMC10225144 DOI: 10.2147/bctt.s404565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Accepted: 04/25/2023] [Indexed: 05/31/2023]
Abstract
Breast cancer (BC) is the most common malignancy worldwide and has a poor prognosis, because it begins in the breast and disseminates to lymph nodes and distant organs. While invading, BC cells acquire aggressive characteristics from the tumor microenvironment through several mechanisms. Thus, understanding the mechanisms underlying the process of BC cell invasion can pave the way towards the development of targeted therapeutics focused on metastasis. We have previously reported that the activation of CD44 receptor with its major ligand hyaluronan (HA) promotes BC metastasis to the liver in vivo. Next, a gene expression profiling microarray analysis was conducted to identify and validate CD44-downstream transcriptional targets mediating its pro-metastatic function from RNA samples collected from Tet CD44-induced versus control MCF7-B5 cells. We have already validated a number of novel CD44-target genes and published their underlying signaling pathways in promoting BC cell invasion. From the same microarray analysis, Integrin subunit beta 1 binding protein 1 (ITGB1BP1) was also identified as a potential CD44-target gene that was upregulated (2-fold) upon HA activation of CD44. This report will review the lines of evidence collected from the literature to support our hypothesis, and further discuss the possible mechanisms linking HA activation of CD44 to its novel potential transcriptional target ITGB1BP1.
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Affiliation(s)
- Salma M S Ahmad
- Biological Sciences Program, Department of Biological and Environmental Sciences, College of Arts and Science, Qatar University, Doha, Qatar
| | - Hanan Nazar
- Biological Sciences Program, Department of Biological and Environmental Sciences, College of Arts and Science, Qatar University, Doha, Qatar
| | - Md Mizanur Rahman
- Biological Sciences Program, Department of Biological and Environmental Sciences, College of Arts and Science, Qatar University, Doha, Qatar
| | - Radoslaw Stefan Rusyniak
- Biological Sciences Program, Department of Biological and Environmental Sciences, College of Arts and Science, Qatar University, Doha, Qatar
| | - Allal Ouhtit
- Biological Sciences Program, Department of Biological and Environmental Sciences, College of Arts and Science, Qatar University, Doha, Qatar
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7
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IQGAP1 Is a Phosphotyrosine-Regulated Scaffold for SH2-Containing Proteins. Cells 2023; 12:cells12030483. [PMID: 36766826 PMCID: PMC9913818 DOI: 10.3390/cells12030483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Revised: 01/07/2023] [Accepted: 01/30/2023] [Indexed: 02/05/2023] Open
Abstract
The scaffold protein IQGAP1 associates with over 150 interactors to influence multiple biological processes. The molecular mechanisms that underly spatial and temporal regulation of these interactions, which are crucial for proper cell functions, remain poorly understood. The receptor tyrosine kinase MET phosphorylates IQGAP1 on Tyr1510. Separately, Src homology 2 (SH2) domains mediate protein-protein interactions by binding specific phosphotyrosine residues. Here, we investigate whether MET-catalyzed phosphorylation of Tyr1510 of IQGAP1 regulates the docking of SH2-containing proteins. Using a peptide array, we identified SH2 domains from several proteins, including the non-receptor tyrosine kinases Abl1 and Abl2, that bind to the Tyr1510 of IQGAP1 in a phosphorylation-dependent manner. Using pure proteins, we validated that full-length Abl1 and Abl2 bind directly to phosphorylated Tyr1510 of IQGAP1. In cells, MET inhibition decreases endogenous IQGAP1 phosphorylation and interaction with endogenous Abl1 and Abl2, indicating that binding is regulated by MET-catalyzed phosphorylation of IQGAP1. Functionally, IQGAP1 modulates basal and HGF-stimulated Abl signaling. Moreover, IQGAP1 binds directly to MET, inhibiting its activation and signaling. Collectively, our study demonstrates that IQGAP1 is a phosphotyrosine-regulated scaffold for SH2-containing proteins, thereby uncovering a previously unidentified mechanism by which IQGAP1 coordinates intracellular signaling.
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8
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Khan S, Patra PH, Somerfield H, Benya-Aphikul H, Upadhya M, Zhang X. IQGAP1 promotes chronic pain by regulating the trafficking and sensitization of TRPA1 channels. Brain 2022:6881565. [PMID: 36477832 DOI: 10.1093/brain/awac462] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Revised: 11/14/2022] [Accepted: 11/24/2022] [Indexed: 12/12/2022] Open
Abstract
TRPA1 channels have been implicated in mechanical and cold hypersensitivity in chronic pain. But how TRPA1 mediates this process is unclear. Here we show that IQ-motif containing GTPase activating protein 1 (IQGAP1) is responsible using a combination of biochemical, molecular, Ca2+ imaging and behavioural approaches. TRPA1 and IQGAP1 bind to each other and are highly colocalised in sensory DRG neurons in mice. The expression of IQGAP1 but not TRPA1 is increased in chronic inflammatory and neuropathic pain. However, TRPA1 undergoes increased trafficking to the membrane of DRG neurons catalysed by the small GTPase Cdc42 associated with IQGAP1, leading to functional sensitization of the channel. Activation of PKA is also sufficient to evoke TRPA1 trafficking and sensitization. All these responses are, however, completely prevented in the absence of IQGAP1. Concordantly, deletion of IQGAP1 markedly reduces mechanical and cold hypersensitivity in chronic inflammatory and neuropathic pain in mice. IQGAP1 thus promotes chronic pain by coupling the trafficking and signalling machineries to TRPA1 channels.
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Affiliation(s)
- Shakil Khan
- School of Health & Life Sciences, Aston University, Birmingham B4 7ET, UK
| | - Pabitra H Patra
- School of Health & Life Sciences, Aston University, Birmingham B4 7ET, UK
| | - Hannah Somerfield
- School of Health & Life Sciences, Aston University, Birmingham B4 7ET, UK
| | | | - Manoj Upadhya
- School of Health & Life Sciences, Aston University, Birmingham B4 7ET, UK
| | - Xuming Zhang
- School of Health & Life Sciences, Aston University, Birmingham B4 7ET, UK
- School of Life Sciences, University of Warwick, Coventry CV4 7AL, UK
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9
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Liao Y, Chen X, Miller‐Little W, Wang H, Willard B, Bulek K, Zhao J, Li X. The Ras GTPase-activating-like protein IQGAP1 bridges Gasdermin D to the ESCRT system to promote IL-1β release via exosomes. EMBO J 2022; 42:e110780. [PMID: 36373462 PMCID: PMC9811620 DOI: 10.15252/embj.2022110780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 09/23/2022] [Accepted: 10/18/2022] [Indexed: 11/16/2022] Open
Abstract
IL-1β can exit the cytosol as an exosomal cargo following inflammasome activation in intestinal epithelial cells (IECs) in a Gasdermin D (GSDMD)-dependent manner. The mechanistic connection linking inflammasome activation and the biogenesis of exosomes has so far remained largely elusive. Here, we report the Ras GTPase-activating-like protein IQGAP1 functions as an adaptor, bridging GSDMD to the endosomal sorting complexes required for transport (ESCRT) machinery to promote the biogenesis of pro-IL-1β-containing exosomes in response to NLPR3 inflammasome activation. We identified IQGAP1 as a GSDMD-interacting protein through a non-biased proteomic analysis. Functional investigation indicated the IQGAP1-GSDMD interaction is required for LPS and ATP-induced exosome release. Further analysis revealed that IQGAP1 serves as an adaptor which bridges GSDMD and associated IL-1β complex to Tsg101, a component of the ESCRT complex, and enables the packaging of GSDMD and IL-1β into exosomes. Importantly, this process is dependent on an LPS-induced increase in GTP-bound CDC42, a small GTPase known to activate IQGAP1. Taken together, this study reveals IQGAP1 as a link between inflammasome activation and GSDMD-dependent, ESCRT-mediated exosomal release of IL-1β.
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Affiliation(s)
- Yun Liao
- Department of Inflammation and ImmunityCleveland Clinic Lerner Research InstituteClevelandOHUSA
| | - Xing Chen
- Department of Inflammation and ImmunityCleveland Clinic Lerner Research InstituteClevelandOHUSA
| | - William Miller‐Little
- Department of Inflammation and ImmunityCleveland Clinic Lerner Research InstituteClevelandOHUSA
| | - Han Wang
- Department of Inflammation and ImmunityCleveland Clinic Lerner Research InstituteClevelandOHUSA
| | - Belinda Willard
- Proteomics and Metabolomics CoreCleveland Clinic Lerner Research InstituteClevelandOHUSA
| | - Katarzyna Bulek
- Department of Inflammation and ImmunityCleveland Clinic Lerner Research InstituteClevelandOHUSA
| | - Junjie Zhao
- Department of Inflammation and ImmunityCleveland Clinic Lerner Research InstituteClevelandOHUSA
| | - Xiaoxia Li
- Department of Inflammation and ImmunityCleveland Clinic Lerner Research InstituteClevelandOHUSA
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10
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Sayedyahossein S, Smith J, Barnaeva E, Li Z, Choe J, Ronzetti M, Dextras C, Hu X, Marugan J, Southall N, Baljinnyam B, Thines L, Tran AD, Ferrer M, Sacks DB. Discovery of small molecule inhibitors that effectively disrupt IQGAP1-Cdc42 interaction in breast cancer cells. Sci Rep 2022; 12:17372. [PMID: 36253497 PMCID: PMC9576799 DOI: 10.1038/s41598-022-21342-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Accepted: 09/26/2022] [Indexed: 01/10/2023] Open
Abstract
The small GTPase Cdc42 is an integral component of the cytoskeleton, and its dysregulation leads to pathophysiological conditions, such as cancer. Binding of Cdc42 to the scaffold protein IQGAP1 stabilizes Cdc42 in its active form. The interaction between Cdc42 and IQGAP1 enhances migration and invasion of cancer cells. Disrupting this association could impair neoplastic progression and metastasis; however, no effective means to achieve this has been described. Here, we screened 78,500 compounds using a homogeneous time resolved fluorescence-based assay to identify small molecules that disrupt the binding of Cdc42 to IQGAP1. From the combined results of the validation assay and counter-screens, we selected 44 potent compounds for cell-based experiments. Immunoprecipitation and cell viability analysis rendered four lead compounds, namely NCGC00131308, NCGC00098561, MLS000332963 and NCGC00138812, three of which inhibited proliferation and migration of breast carcinoma cells. Microscale thermophoresis revealed that two compounds bind directly to Cdc42. One compound reduced the amount of active Cdc42 in cells and effectively impaired filopodia formation. Docking analysis provided plausible models of the compounds binding to the hydrophobic pocket adjacent to the GTP binding site of Cdc42. In conclusion, we identified small molecules that inhibit binding between Cdc42 and IQGAP1, which could potentially yield chemotherapeutic agents.
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Affiliation(s)
- Samar Sayedyahossein
- grid.94365.3d0000 0001 2297 5165Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD 20892 USA ,grid.39381.300000 0004 1936 8884Present Address: Department of Physiology and Pharmacology, University of Western Ontario, London, ON Canada
| | - Jessica Smith
- grid.94365.3d0000 0001 2297 5165Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD 20892 USA ,grid.94365.3d0000 0001 2297 5165Present Address: Center for Scientific Review, National Institutes of Health, Bethesda, MD USA
| | - Elena Barnaeva
- grid.94365.3d0000 0001 2297 5165National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD USA
| | - Zhigang Li
- grid.94365.3d0000 0001 2297 5165Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD 20892 USA
| | - Jun Choe
- grid.94365.3d0000 0001 2297 5165National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD USA
| | - Michael Ronzetti
- grid.94365.3d0000 0001 2297 5165National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD USA
| | - Christopher Dextras
- grid.94365.3d0000 0001 2297 5165National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD USA
| | - Xin Hu
- grid.94365.3d0000 0001 2297 5165National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD USA
| | - Juan Marugan
- grid.94365.3d0000 0001 2297 5165National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD USA
| | - Noel Southall
- grid.94365.3d0000 0001 2297 5165National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD USA
| | - Bolormaa Baljinnyam
- grid.94365.3d0000 0001 2297 5165National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD USA
| | - Louise Thines
- grid.94365.3d0000 0001 2297 5165Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD 20892 USA
| | - Andy D. Tran
- grid.48336.3a0000 0004 1936 8075Confocal Microscopy Core Facility, Laboratory of Cancer Biology and Genetics, NCI, National Institutes of Health, Rockville, MD USA
| | - Marc Ferrer
- grid.94365.3d0000 0001 2297 5165National Center for Advancing Translational Sciences, National Institutes of Health, Rockville, MD USA
| | - David B. Sacks
- grid.94365.3d0000 0001 2297 5165Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD 20892 USA
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11
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Hoeprich GJ, Sinclair AN, Shekhar S, Goode BL. Single-molecule imaging of IQGAP1 regulating actin filament dynamics. Mol Biol Cell 2021; 33:ar2. [PMID: 34731043 PMCID: PMC8886817 DOI: 10.1091/mbc.e21-04-0211] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
IQGAP is a conserved family of actin-binding proteins with essential roles in cell motility, cytokinesis, and cell adhesion, yet there remains a limited understanding of how IQGAP proteins directly influence actin filament dynamics. To close this gap, we used single-molecule and single-filament total internal reflection fluorescence microscopy to observe IQGAP regulating actin dynamics in real time. To our knowledge, this is the first study to do so. Our results demonstrate that full-length human IQGAP1 forms dimers that stably bind to actin filament sides and transiently cap barbed ends. These interactions organize filaments into thin bundles, suppress barbed end growth, and inhibit filament disassembly. Surprisingly, each activity depends on distinct combinations of IQGAP1 domains and/or dimerization, suggesting that different mechanisms underlie each functional effect on actin. These observations have important implications for how IQGAP functions as an actin regulator in vivo and how it may be regulated in different biological settings.
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Affiliation(s)
- Gregory J Hoeprich
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02453, USA
| | - Amy N Sinclair
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02453, USA
| | - Shashank Shekhar
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02453, USA.,Present address: Departments of Physics and Cell Biology, Emory University, Atlanta, GA 30322
| | - Bruce L Goode
- Department of Biology, Brandeis University, 415 South Street, Waltham, MA 02453, USA
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12
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Regulation of Rac1 Activation in Choroidal Endothelial Cells: Insights into Mechanisms in Age-Related Macular Degeneration. Cells 2021; 10:cells10092414. [PMID: 34572063 PMCID: PMC8469925 DOI: 10.3390/cells10092414] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Revised: 09/07/2021] [Accepted: 09/08/2021] [Indexed: 12/11/2022] Open
Abstract
Age-related macular degeneration (AMD) is one of the leading causes of blindness worldwide. Vision loss from the neovascular form is associated with the invasion of choroidal endothelial cells into the neural retina to form vision-threatening macular neovascularization (MNV). Anti-angiogenic agents are the current standard of care but are effective in only ~50% of AMD cases. The molecular mechanisms involved in invasive MNV point to the importance of regulating signaling pathways that lead to pathologic biologic outcomes. In studies testing the effects of AMD-related stresses, activation of the Rho GTPase, Rac1, was found to be important for the choroidal endothelial cell invasion into the neural retina. However, current approaches to prevent Rac1 activation are inefficient and less effective. We summarize active Rac1-mediated mechanisms that regulate choroidal endothelial cell migration. Specifically, we discuss our work regarding the role of a multidomain protein, IQ motif containing GTPase activating protein 1 (IQGAP1), in sustaining pathologic Rac1 activation and a mechanism by which active Rap1, a Ras-like GTPase, may prevent active Rac1-mediated choroidal endothelial cell migration.
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13
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Birladeanu AM, Rogalska M, Potiri M, Papadaki V, Andreadou M, Kontoyiannis DL, Lewis JD, Erpapazoglou Z, Kafasla P. The scaffold protein IQGAP1 links heat-induced stress signals to alternative splicing regulation in gastric cancer cells. Oncogene 2021; 40:5518-5532. [PMID: 34294847 DOI: 10.1038/s41388-021-01963-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 07/06/2021] [Accepted: 07/13/2021] [Indexed: 02/07/2023]
Abstract
In response to oncogenic signals, Alternative Splicing (AS) regulators such as SR and hnRNP proteins show altered expression levels, subnuclear distribution and/or post-translational modification status, but the link between signals and these changes remains unknown. Here, we report that a cytosolic scaffold protein, IQGAP1, performs this task in response to heat-induced signals. We show that in gastric cancer cells, a nuclear pool of IQGAP1 acts as a tethering module for a group of spliceosome components, including hnRNPM, a splicing factor critical for the response of the spliceosome to heat-shock. IQGAP1 controls hnRNPM's sumoylation, subnuclear localisation and the relevant response of the AS machinery to heat-induced stress. Genome-wide analyses reveal that IQGAP1 and hnRNPM co-regulate the AS of a cell cycle-related RNA regulon in gastric cancer cells, thus favouring the accelerated proliferation phenotype of gastric cancer cells. Overall, we reveal a missing link between stress signals and AS regulation.
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Affiliation(s)
- Andrada-Maria Birladeanu
- Institute for Fundamental Biomedical Research, B.S.R.C. "Alexander Fleming", 34 Fleming st. 16672 Vari, Athens, Greece
| | - Malgorzata Rogalska
- Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Dr Aiguader 88, Barcelona, 08003, Spain.,Universitat Pompeu Fabra (UPF), Barcelona, 08003, Spain
| | - Myrto Potiri
- Institute for Fundamental Biomedical Research, B.S.R.C. "Alexander Fleming", 34 Fleming st. 16672 Vari, Athens, Greece
| | - Vasiliki Papadaki
- Institute for Fundamental Biomedical Research, B.S.R.C. "Alexander Fleming", 34 Fleming st. 16672 Vari, Athens, Greece
| | - Margarita Andreadou
- Institute for Fundamental Biomedical Research, B.S.R.C. "Alexander Fleming", 34 Fleming st. 16672 Vari, Athens, Greece
| | - Dimitris L Kontoyiannis
- Institute for Fundamental Biomedical Research, B.S.R.C. "Alexander Fleming", 34 Fleming st. 16672 Vari, Athens, Greece.,Department of Biology, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Joe D Lewis
- European Molecular Biology Laboratory, 69117, Heidelberg, Germany
| | - Zoi Erpapazoglou
- Institute for Fundamental Biomedical Research, B.S.R.C. "Alexander Fleming", 34 Fleming st. 16672 Vari, Athens, Greece
| | - Panagiota Kafasla
- Institute for Fundamental Biomedical Research, B.S.R.C. "Alexander Fleming", 34 Fleming st. 16672 Vari, Athens, Greece.
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14
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Dalal PJ, Sullivan DP, Weber EW, Sacks DB, Gunzer M, Grumbach IM, Heller Brown J, Muller WA. Spatiotemporal restriction of endothelial cell calcium signaling is required during leukocyte transmigration. J Exp Med 2021; 218:152118. [PMID: 32970800 PMCID: PMC7953625 DOI: 10.1084/jem.20192378] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2019] [Revised: 05/04/2020] [Accepted: 07/07/2020] [Indexed: 12/30/2022] Open
Abstract
Endothelial cell calcium flux is critical for leukocyte transendothelial migration (TEM), which in turn is essential for the inflammatory response. Intravital microscopy of endothelial cell calcium dynamics reveals that calcium increases locally and transiently around the transmigration pore during TEM. Endothelial calmodulin (CaM), a key calcium signaling protein, interacts with the IQ domain of IQGAP1, which is localized to endothelial junctions and is required for TEM. In the presence of calcium, CaM binds endothelial calcium/calmodulin kinase IIδ (CaMKIIδ). Disrupting the function of CaM or CaMKII with small-molecule inhibitors, expression of a CaMKII inhibitory peptide, or expression of dominant negative CaMKIIδ significantly reduces TEM by interfering with the delivery of the lateral border recycling compartment (LBRC) to the site of TEM. Endothelial CaMKII is also required for TEM in vivo as shown in two independent mouse models. These findings highlight novel roles for endothelial CaM and CaMKIIδ in transducing the spatiotemporally restricted calcium signaling required for TEM.
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Affiliation(s)
- Prarthana J Dalal
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - David P Sullivan
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - Evan W Weber
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL
| | - David B Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD
| | - Matthias Gunzer
- Institute for Experimental Immunology and Imaging, University Hospital, University Duisburg-Essen, Essen, Germany
| | - Isabella M Grumbach
- Department of Internal Medicine, University of Iowa, Carver College of Medicine, Iowa City, IA
| | - Joan Heller Brown
- Department of Pharmacology, University of California, San Diego, La Jolla, CA
| | - William A Muller
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, IL
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15
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Fréchette L, Degrandmaison J, Binda C, Boisvert M, Côté L, Michaud T, Lalumière MP, Gendron L, Parent JL. Identification of the interactome of the DP1 receptor for Prostaglandin D 2: Regulation of DP1 receptor signaling and trafficking by IQGAP1. Biochim Biophys Acta Gen Subj 2021; 1865:129969. [PMID: 34352343 DOI: 10.1016/j.bbagen.2021.129969] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 07/19/2021] [Accepted: 07/25/2021] [Indexed: 01/16/2023]
Abstract
BACKGROUND Mechanisms governing localization, trafficking and signaling of G protein-coupled receptors (GPCRs) are critical in cell function. Protein-protein interactions are determinant in these processes. However, there are very little interacting proteins known to date for the DP1 receptor for prostaglandin D2. METHODS We performed LC-MS/MS analyses of the DP1 receptor interactome in HEK293 cells. To functionally validate our LC-MS/MS data, we studied the implications of the interaction with the IQGAP1 scaffold protein in the trafficking and signaling of DP1. RESULTS In addition to expected interacting proteins such as heterotrimeric G protein subunits, we identified proteins involved in signaling, trafficking, and folding localized in various cell compartments. Endogenous DP1-IQGAP1 co-immunoprecipitation was observed in colon cancer HT-29 cells. The interaction was augmented by DP1 agonist activation in HEK293 cells and GST-pulldown assays showed that IQGAP1 binds to intracellular loops 2 and 3 of DP1. Co-localization of the two proteins was observed by confocal microscopy at the cell periphery and in intracellular vesicles in the basal state. PGD2 treatment resulted in the redistribution of the DP1-IQGAP1 co-localization in the perinuclear vicinity. DP1 receptor internalization was promoted by overexpression of IQGAP1, while it was diminished by IQGAP1 knockdown with DsiRNAs. DP1-mediated ERK1/2 activation was augmented and sustained overtime by overexpression of IQGAP1 when compared to DP1 expressed alone. IQGAP1 knockdown decreased ERK1/2 activation by DP1 stimulation. Interestingly, ERK1/2 signaling by DP1 was increased when IQGAP2 was silenced, while it was impaired by IQGAP3 knockdown. CONCLUSIONS Our findings define the putative DP1 interactome, a patho-physiologically important receptor, and validated the interaction with IQGAP1 in DP1 function. Our data also reveal that IQGAP proteins may differentially regulate GPCR signaling. GENERAL SIGNIFICANCE The identified putative DP1-interacting proteins open multiple lines of research in DP1 and GPCR biology in various cell compartments.
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Affiliation(s)
- Louis Fréchette
- Département de Médecine, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Institut de Pharmacologie de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Centre de recherche du Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Jade Degrandmaison
- Département de Médecine, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Institut de Pharmacologie de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Centre de recherche du Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Chantal Binda
- Département de Médecine, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Institut de Pharmacologie de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Centre de recherche du Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Marilou Boisvert
- Département de Médecine, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Institut de Pharmacologie de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Centre de recherche du Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Laurie Côté
- Département de Médecine, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Institut de Pharmacologie de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Centre de recherche du Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Thomas Michaud
- Département de Médecine, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Institut de Pharmacologie de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Centre de recherche du Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Marie-Pier Lalumière
- Département de Médecine, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Institut de Pharmacologie de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Centre de recherche du Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Louis Gendron
- Département de Pharmacologie-Physiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Département d'Anesthésiologie, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Institut de Pharmacologie de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Centre de recherche du Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Québec, Canada
| | - Jean-Luc Parent
- Département de Médecine, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Institut de Pharmacologie de Sherbrooke, Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Canada; Centre de recherche du Centre Hospitalier de l'Université de Sherbrooke, Sherbrooke, Québec, Canada.
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16
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Claude-Taupin A, Jia J, Bhujabal Z, Garfa-Traoré M, Kumar S, da Silva GPD, Javed R, Gu Y, Allers L, Peters R, Wang F, da Costa LJ, Pallikkuth S, Lidke KA, Mauthe M, Verlhac P, Uchiyama Y, Salemi M, Phinney B, Tooze SA, Mari MC, Johansen T, Reggiori F, Deretic V. ATG9A protects the plasma membrane from programmed and incidental permeabilization. Nat Cell Biol 2021; 23:846-858. [PMID: 34257406 PMCID: PMC8276549 DOI: 10.1038/s41556-021-00706-w] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Accepted: 06/03/2021] [Indexed: 12/11/2022]
Abstract
The integral membrane protein ATG9A plays a key role in autophagy. It displays a broad intracellular distribution and is present in numerous compartments, including the plasma membrane (PM). The reasons for the distribution of ATG9A to the PM and its role at the PM are not understood. Here, we show that ATG9A organizes, in concert with IQGAP1, components of the ESCRT system and uncover cooperation between ATG9A, IQGAP1 and ESCRTs in protection from PM damage. ESCRTs and ATG9A phenocopied each other in protection against PM injury. ATG9A knockouts sensitized the PM to permeabilization by a broad spectrum of microbial and endogenous agents, including gasdermin, MLKL and the MLKL-like action of coronavirus ORF3a. Thus, ATG9A engages IQGAP1 and the ESCRT system to maintain PM integrity.
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Affiliation(s)
- Aurore Claude-Taupin
- Autophagy, Inflammation and Metabolic (AIM) Center of Biochemical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Jingyue Jia
- Autophagy, Inflammation and Metabolic (AIM) Center of Biochemical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Zambarlal Bhujabal
- Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
| | - Meriem Garfa-Traoré
- Cell Imaging Platform, INSERM US24 Structure Fédérative de Recherche Necker, Université de Paris, Paris, France
| | - Suresh Kumar
- Autophagy, Inflammation and Metabolic (AIM) Center of Biochemical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Gustavo Peixoto Duarte da Silva
- Autophagy, Inflammation and Metabolic (AIM) Center of Biochemical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
- Departamento de Virologia, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Ruheena Javed
- Autophagy, Inflammation and Metabolic (AIM) Center of Biochemical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Yuexi Gu
- Autophagy, Inflammation and Metabolic (AIM) Center of Biochemical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Lee Allers
- Autophagy, Inflammation and Metabolic (AIM) Center of Biochemical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Ryan Peters
- Autophagy, Inflammation and Metabolic (AIM) Center of Biochemical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Fulong Wang
- Autophagy, Inflammation and Metabolic (AIM) Center of Biochemical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA
| | - Luciana Jesus da Costa
- Departamento de Virologia, Instituto de Microbiologia Paulo de Góes, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Sandeep Pallikkuth
- Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA
| | - Keith A Lidke
- Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM, USA
| | - Mario Mauthe
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Pauline Verlhac
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Yasuo Uchiyama
- Department of Cellular and Molecular Neuropathology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Michelle Salemi
- Proteomics Core Facility, UC Davis Genome Center, University of California, Davis, Davis, CA, USA
| | - Brett Phinney
- Proteomics Core Facility, UC Davis Genome Center, University of California, Davis, Davis, CA, USA
| | - Sharon A Tooze
- The Francis Crick Institute, Molecular Cell Biology of Autophagy Laboratory, London, UK
| | - Muriel C Mari
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Terje Johansen
- Molecular Cancer Research Group, Institute of Medical Biology, University of Tromsø-The Arctic University of Norway, Tromsø, Norway
| | - Fulvio Reggiori
- Department of Biomedical Sciences of Cells and Systems, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - Vojo Deretic
- Autophagy, Inflammation and Metabolic (AIM) Center of Biochemical Research Excellence, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
- Department of Molecular Genetics and Microbiology, University of New Mexico Health Sciences Center, Albuquerque, NM, USA.
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17
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Filić V, Mijanović L, Putar D, Talajić A, Ćetković H, Weber I. Regulation of the Actin Cytoskeleton via Rho GTPase Signalling in Dictyostelium and Mammalian Cells: A Parallel Slalom. Cells 2021; 10:1592. [PMID: 34202767 PMCID: PMC8305917 DOI: 10.3390/cells10071592] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/16/2021] [Accepted: 06/16/2021] [Indexed: 01/15/2023] Open
Abstract
Both Dictyostelium amoebae and mammalian cells are endowed with an elaborate actin cytoskeleton that enables them to perform a multitude of tasks essential for survival. Although these organisms diverged more than a billion years ago, their cells share the capability of chemotactic migration, large-scale endocytosis, binary division effected by actomyosin contraction, and various types of adhesions to other cells and to the extracellular environment. The composition and dynamics of the transient actin-based structures that are engaged in these processes are also astonishingly similar in these evolutionary distant organisms. The question arises whether this remarkable resemblance in the cellular motility hardware is accompanied by a similar correspondence in matching software, the signalling networks that govern the assembly of the actin cytoskeleton. Small GTPases from the Rho family play pivotal roles in the control of the actin cytoskeleton dynamics. Indicatively, Dictyostelium matches mammals in the number of these proteins. We give an overview of the Rho signalling pathways that regulate the actin dynamics in Dictyostelium and compare them with similar signalling networks in mammals. We also provide a phylogeny of Rho GTPases in Amoebozoa, which shows a variability of the Rho inventories across different clades found also in Metazoa.
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Affiliation(s)
- Vedrana Filić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia; (L.M.); (D.P.); (A.T.); (H.Ć.)
| | | | | | | | | | - Igor Weber
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia; (L.M.); (D.P.); (A.T.); (H.Ć.)
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18
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Özsoy Ş, Vujovic F, Simonian M, Valova V, Hunter N, Farahani RM. Cannibalized erythroblasts accelerate developmental neurogenesis by regulating mitochondrial dynamics. Cell Rep 2021; 35:108942. [PMID: 33826895 DOI: 10.1016/j.celrep.2021.108942] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Revised: 11/18/2020] [Accepted: 03/12/2021] [Indexed: 11/29/2022] Open
Abstract
Metabolic support was long considered to be the only developmental function of hematopoiesis, a view that is gradually changing. Here, we disclose a mechanism triggered during neurulation that programs brain development by donation of sacrificial yolk sac erythroblasts to neuroepithelial cells. At embryonic day (E) 8.5, neuroepithelial cells transiently integrate with the endothelium of yolk sac blood vessels and cannibalize intravascular erythroblasts as transient heme-rich endosymbionts. This cannibalistic behavior instructs precocious neuronal differentiation of neuroepithelial cells in the proximity of blood vessels. By experiments in vitro, we show that access to erythroblastic heme accelerates the pace of neurogenesis by induction of a truncated neurogenic differentiation program from a poised state. Mechanistically, the poised state is invoked by activation of the mitochondrial electron transport chain that leads to amplified production of reactive oxygen species in addition to omnipresent guanosine triphosphate (GTP) with consequential upregulation of pro-differentiation β-catenin.
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Affiliation(s)
- Şükran Özsoy
- IDR/Westmead Institute for Medical Research, Westmead, NSW, Australia; Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Filip Vujovic
- Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia
| | - Mary Simonian
- IDR/Westmead Institute for Medical Research, Westmead, NSW, Australia
| | - Valentina Valova
- Children's Medical Research Institute, University of Sydney, Westmead, NSW, Australia
| | - Neil Hunter
- IDR/Westmead Institute for Medical Research, Westmead, NSW, Australia
| | - Ramin M Farahani
- IDR/Westmead Institute for Medical Research, Westmead, NSW, Australia; Faculty of Medicine and Health, University of Sydney, Sydney, NSW, Australia.
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19
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Calmodulin influences MAPK signaling by binding KSR1. J Biol Chem 2021; 296:100577. [PMID: 33766558 PMCID: PMC8079274 DOI: 10.1016/j.jbc.2021.100577] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2021] [Revised: 02/12/2021] [Accepted: 03/21/2021] [Indexed: 11/24/2022] Open
Abstract
The mitogen-activated protein kinase (MAPK) cascade is a fundamental signaling pathway that regulates cell fate decisions in response to external stimuli. Several scaffold proteins bind directly to kinase components of this pathway and regulate their activation by growth factors. One of the best studied MAPK scaffolds is kinase suppressor of Ras1 (KSR1), which is induced by epidermal growth factor (EGF) to translocate to the plasma membrane where it activates extracellular signal-regulated kinase (ERK). While Ca2+ has been shown to modulate MAPK signaling, the molecular mechanisms by which this occurs are incompletely understood. Here we tested the hypothesis that Ca2+ alters MAPK activity at least in part via KSR1. Using several approaches, including fusion proteins, immunoprecipitation, confocal microscopy, and a cell-permeable chemical inhibitor, we investigated the functional interaction between KSR1 and calmodulin. In vitro analysis with pure proteins reveals that calmodulin binds directly to KSR1. Moreover, endogenous calmodulin and KSR1 co-immunoprecipitate from mammalian cell lysates. Importantly, Ca2+ is required for the association between calmodulin and KSR1, both in vitro and in cells. The cell-permeable calmodulin antagonist CGS9343B significantly reduced activation of ERK by EGF in mouse embryo fibroblasts that overexpress KSR1, but not in control cells. Moreover, CGS9343B impaired the ability of EGF to induce KSR1 translocation to the plasma membrane and to stimulate formation of KSR1-ERK and KSR1-pERK (phosphorylated ERK) complexes in cells. Collectively, our data identify a previously unrecognized mechanism by which the scaffold protein KSR1 couples Ca2+ and calmodulin signaling to the MAPK cascade.
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20
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Peng X, Wang T, Gao H, Yue X, Bian W, Mei J, Zhang Y. The interplay between IQGAP1 and small GTPases in cancer metastasis. Biomed Pharmacother 2021; 135:111243. [PMID: 33434854 DOI: 10.1016/j.biopha.2021.111243] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Revised: 12/27/2020] [Accepted: 12/31/2020] [Indexed: 01/07/2023] Open
Abstract
The metastatic spread of tumor cells to distant anatomical locations is a critical cause for disease progression and leads to more than 90 % of cancer-related deaths. IQ motif-containing GTPase-activating protein 1 (IQGAP1), a prominent regulator in the cancer metastasis process, is a scaffold protein that interacts with components of the cytoskeleton. As a critical node within the small GTPase network, IQGAP1 acts as a binding partner of several small GTPases, which in turn function as molecular switches to control most cellular processes, including cell migration and invasion. Given the significant interaction between IQGAP1 and small GTPases in cancer metastasis, we briefly elucidate the role of IQGAP1 in regulating cancer metastasis and the varied interactions existing between IQGAP1 and small GTPases. In addition, the potential regulators for IQGAP1 activity and its interaction with small GTPases are also incorporated in this review. Overall, we comprehensively summarize the role of IQGAP1 in cancer tumorigenicity and metastasis, which may be a potential anti-tumor target to restrain cancer progression.
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Affiliation(s)
- Xiafeng Peng
- Department of Gynecology and Obstetrics, Wuxi Maternal and Child Health Hospital, the Affiliated Hospital to Nanjing Medical University, Wuxi, 214023, China; First Clinical Medicine College, Nanjing Medical University, Nanjing, 211166, China.
| | - Tiejun Wang
- Department of Gynecology and Obstetrics, Wuxi Maternal and Child Health Hospital, the Affiliated Hospital to Nanjing Medical University, Wuxi, 214023, China.
| | - Han Gao
- School of Medicine, Jiangnan University, Wuxi, 214122, China.
| | - Xin Yue
- First Clinical Medicine College, Nanjing Medical University, Nanjing, 211166, China.
| | - Weiqi Bian
- First Clinical Medicine College, Nanjing Medical University, Nanjing, 211166, China.
| | - Jie Mei
- Department of Gynecology and Obstetrics, Wuxi Maternal and Child Health Hospital, the Affiliated Hospital to Nanjing Medical University, Wuxi, 214023, China; Wuxi Clinical Medical College, Nanjing Medical University, Wuxi, 214023, China.
| | - Yan Zhang
- Department of Gynecology and Obstetrics, Wuxi Maternal and Child Health Hospital, the Affiliated Hospital to Nanjing Medical University, Wuxi, 214023, China.
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21
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Hedman AC, McNulty DE, Li Z, Gorisse L, Annan RS, Sacks DB. Tyrosine phosphorylation of the scaffold protein IQGAP1 in the MET pathway alters function. J Biol Chem 2020; 295:18105-18121. [PMID: 33087447 DOI: 10.1074/jbc.ra120.015891] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Revised: 10/14/2020] [Indexed: 12/20/2022] Open
Abstract
IQGAP1 is a key scaffold protein that regulates numerous cellular processes and signaling pathways. Analogous to many other cellular proteins, IQGAP1 undergoes post-translational modifications, including phosphorylation. Nevertheless, very little is known about the specific sites of phosphorylation or the effects on IQGAP1 function. Here, using several approaches, including MS, site-directed mutagenesis, siRNA-mediated gene silencing, and chemical inhibitors, we identified the specific tyrosine residues that are phosphorylated on IQGAP1 and evaluated the effect on function. Tyr-172, Tyr-654, Tyr-855, and Tyr-1510 were phosphorylated on IQGAP1 when phosphotyrosine phosphatase activity was inhibited in cells. IQGAP1 was phosphorylated exclusively on Tyr-1510 under conditions with enhanced MET or c-Src signaling, including in human lung cancer cell lines. This phosphorylation was significantly reduced by chemical inhibitors of MET or c-Src or by siRNA-mediated knockdown of MET. To investigate the biological sequelae of phosphorylation, we generated a nonphosphorylatable IQGAP1 construct by replacing Tyr-1510 with alanine. The ability of hepatocyte growth factor, the ligand for MET, to promote AKT activation and cell migration was significantly greater when IQGAP1-null cells were reconstituted with IQGAP1 Y1510A than when cells were reconstituted with WT IQGAP1. Collectively, our data suggest that phosphorylation of Tyr-1510 of IQGAP1 alters cell function. Because increased MET signaling is implicated in the development and progression of several types of carcinoma, IQGAP1 may be a potential therapeutic target in selected malignancies.
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Affiliation(s)
- Andrew C Hedman
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - Dean E McNulty
- Discovery Analytical, GlaxoSmithKline, Collegeville, Pennsylvania, USA
| | - Zhigang Li
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - Laëtitia Gorisse
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - Roland S Annan
- Discovery Analytical, GlaxoSmithKline, Collegeville, Pennsylvania, USA
| | - David B Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, USA.
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22
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Hedman AC, Li Z, Gorisse L, Parvathaneni S, Morgan CJ, Sacks DB. IQGAP1 binds AMPK and is required for maximum AMPK activation. J Biol Chem 2020; 296:100075. [PMID: 33191271 PMCID: PMC7948462 DOI: 10.1074/jbc.ra120.016193] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 11/15/2020] [Indexed: 12/25/2022] Open
Abstract
AMP-activated protein kinase (AMPK) is a fundamental component of a protein kinase cascade that is an energy sensor. AMPK maintains energy homeostasis in the cell by promoting catabolic and inhibiting anabolic pathways. Activation of AMPK requires phosphorylation by the liver kinase B1 or by the Ca2+/calmodulin-dependent protein kinase 2 (CaMKK2). The scaffold protein IQGAP1 regulates intracellular signaling pathways, such as the mitogen-activated protein kinase and AKT signaling cascades. Recent work implicates the participation of IQGAP1 in metabolic function, but the molecular mechanisms underlying these effects are poorly understood. Here, using several approaches including binding analysis with fusion proteins, siRNA-mediated gene silencing, RT-PCR, and knockout mice, we investigated whether IQGAP1 modulates AMPK signaling. In vitro analysis reveals that IQGAP1 binds directly to the α1 subunit of AMPK. In addition, we observed a direct interaction between IQGAP1 and CaMKK2, which is mediated by the IQ domain of IQGAP1. Both CaMKK2 and AMPK associate with IQGAP1 in cells. The ability of metformin and increased intracellular free Ca2+ concentrations to activate AMPK is reduced in cells lacking IQGAP1. Importantly, Ca2+-stimulated AMPK phosphorylation was rescued by re-expression of IQGAP1 in IQGAP1-null cell lines. Comparison of the fasting response in wild-type and IQGAP1-null mice revealed that transcriptional regulation of the gluconeogenesis genes PCK1 and G6PC and the fatty acid synthesis genes FASN and ACC1 is impaired in IQGAP1-null mice. Our data disclose a previously unidentified functional interaction between IQGAP1 and AMPK and suggest that IQGAP1 modulates AMPK signaling.
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Affiliation(s)
- Andrew C Hedman
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - Zhigang Li
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - Laëtitia Gorisse
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - Swetha Parvathaneni
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - Chase J Morgan
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, USA
| | - David B Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, USA.
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23
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Dawes ML, Soeller C, Scholpp S. Studying molecular interactions in the intact organism: fluorescence correlation spectroscopy in the living zebrafish embryo. Histochem Cell Biol 2020; 154:507-519. [PMID: 33067656 PMCID: PMC7609432 DOI: 10.1007/s00418-020-01930-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2020] [Indexed: 02/07/2023]
Abstract
Cell behaviour and function is determined through the interactions of a multitude of molecules working in concert. To observe these molecular dynamics, biophysical studies have been developed that track single interactions. Fluorescence correlation spectroscopy (FCS) is an optical biophysical technique that non-invasively resolves single molecules through recording the signal intensity at the femtolitre scale. However, recording the behaviour of these biomolecules using in vitro-based assays often fails to recapitulate the full range of variables in vivo that directly confer dynamics. Therefore, there has been an increasing interest in observing the state of these biomolecules within living organisms such as the zebrafish Danio rerio. In this review, we explore the advancements of FCS within the zebrafish and compare and contrast these findings to those found in vitro.
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Affiliation(s)
- Michael L Dawes
- Living Systems Institute, School of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Christian Soeller
- Living Systems Institute, College of Engineering, Mathematics, and Physical Sciences, University of Exeter, Exeter, EX4 4QD, UK
| | - Steffen Scholpp
- Living Systems Institute, School of Biosciences, College of Life and Environmental Sciences, University of Exeter, Exeter, EX4 4QD, UK.
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24
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Pleiotropic Roles of Calmodulin in the Regulation of KRas and Rac1 GTPases: Functional Diversity in Health and Disease. Int J Mol Sci 2020; 21:ijms21103680. [PMID: 32456244 PMCID: PMC7279331 DOI: 10.3390/ijms21103680] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/18/2020] [Accepted: 05/21/2020] [Indexed: 12/21/2022] Open
Abstract
Calmodulin is a ubiquitous signalling protein that controls many biological processes due to its capacity to interact and/or regulate a large number of cellular proteins and pathways, mostly in a Ca2+-dependent manner. This complex interactome of calmodulin can have pleiotropic molecular consequences, which over the years has made it often difficult to clearly define the contribution of calmodulin in the signal output of specific pathways and overall biological response. Most relevant for this review, the ability of calmodulin to influence the spatiotemporal signalling of several small GTPases, in particular KRas and Rac1, can modulate fundamental biological outcomes such as proliferation and migration. First, direct interaction of calmodulin with these GTPases can alter their subcellular localization and activation state, induce post-translational modifications as well as their ability to interact with effectors. Second, through interaction with a set of calmodulin binding proteins (CaMBPs), calmodulin can control the capacity of several guanine nucleotide exchange factors (GEFs) to promote the switch of inactive KRas and Rac1 to an active conformation. Moreover, Rac1 is also an effector of KRas and both proteins are interconnected as highlighted by the requirement for Rac1 activation in KRas-driven tumourigenesis. In this review, we attempt to summarize the multiple layers how calmodulin can regulate KRas and Rac1 GTPases in a variety of cellular events, with biological consequences and potential for therapeutic opportunities in disease settings, such as cancer.
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25
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Gorisse L, Li Z, Wagner CD, Worthylake DK, Zappacosta F, Hedman AC, Annan RS, Sacks DB. Ubiquitination of the scaffold protein IQGAP1 diminishes its interaction with and activation of the Rho GTPase CDC42. J Biol Chem 2020; 295:4822-4835. [PMID: 32094223 DOI: 10.1074/jbc.ra119.011491] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2019] [Revised: 02/19/2020] [Indexed: 12/12/2022] Open
Abstract
IQ motif-containing GTPase-activating protein 1 (IQGAP1) is a scaffold protein that interacts with numerous binding partners and thereby regulates fundamental biological processes. The functions of IQGAP1 are modulated by several mechanisms, including protein binding, self-association, subcellular localization, and phosphorylation. Proteome-wide screens have indicated that IQGAP1 is ubiquitinated, but the possible effects of this post-translational modification on its function are unknown. Here we characterized and evaluated the function of IQGAP1 ubiquitination. Using MS-based analysis in HEK293 cells, we identified six lysine residues (Lys-556, -1155, -1230, -1465, -1475, and -1528) as ubiquitination sites in IQGAP1. To elucidate the biological consequences of IQGAP1 ubiquitination, we converted each of these lysines to arginine and found that replacing two of these residues, Lys-1155 and Lys-1230, in the GAP-related domain of IQGAP1 (termed IQGAP1 GRD-2K) reduces its ubiquitination. Moreover, IQGAP1 GRD-2K bound a significantly greater proportion of the two Rho GTPases cell division cycle 42 (CDC42) and Rac family small GTPase 1 (RAC1) than did WT IQGAP1. Consistent with this observation, reconstitution of IQGAP1-null cells with IQGAP1 GRD-2K significantly increased the amount of active CDC42 and enhanced cell migration significantly more than WT IQGAP1. Our results reveal that ubiquitination of the CDC42 regulator IQGAP1 alters its ability to bind to and activate this GTPase, leading to physiological effects. Collectively, these findings expand our view of the role of ubiquitination in cell signaling and provide additional insight into CDC42 regulation.
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Affiliation(s)
- Laëtitia Gorisse
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - Zhigang Li
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - Craig D Wagner
- Discovery Analytical, GlaxoSmithKline, Collegeville, Pennsylvania 19426
| | - David K Worthylake
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences, New Orleans, Louisiana 70112
| | | | - Andrew C Hedman
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - Roland S Annan
- Discovery Analytical, GlaxoSmithKline, Collegeville, Pennsylvania 19426
| | - David B Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
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26
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The scaffold protein IQGAP1 is crucial for extravasation and metastasis. Sci Rep 2020; 10:2439. [PMID: 32051509 PMCID: PMC7015931 DOI: 10.1038/s41598-020-59438-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 01/29/2020] [Indexed: 12/21/2022] Open
Abstract
IQGAP1 is a scaffold protein involved in a range of cellular activities, including migration, invasion, adhesion and proliferation. It is also oncogenic in a variety of cancers, promoting primary tumor growth and invasiveness. However, the role of IQGAP1 in tumor progression and metastasis remains unclear. In this study, we use both knockdown and knockout of IQGAP1 to investigate its role in the metastatic cascade of both melanoma and breast cancer cells in vivo. We find that reduction of IQGAP1 expression decreases the formation of both spontaneous and experimental metastases, without limiting primary or metastatic tumor growth. Furthermore, IQGAP1 knockout significantly inhibits extravasation of tumor cells from circulation, possibly involving invadopodial function. By expressing mutant forms of IQGAP1 in a knockout context, we also determine that IQGAP1’s pro-metastatic functions are dependent on multiple domains and functions. These data demonstrate that IQGAP1 is crucial for metastasis in vivo through regulation of extravasation and suggest that it may represent a valid therapeutic target for inhibiting metastasis.
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27
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Miningou N, Blackwell KT. The road to ERK activation: Do neurons take alternate routes? Cell Signal 2020; 68:109541. [PMID: 31945453 DOI: 10.1016/j.cellsig.2020.109541] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 01/11/2020] [Accepted: 01/12/2020] [Indexed: 01/29/2023]
Abstract
The ERK cascade is a central signaling pathway that regulates a wide variety of cellular processes including proliferation, differentiation, learning and memory, development, and synaptic plasticity. A wide range of inputs travel from the membrane through different signaling pathway routes to reach activation of one set of output kinases, ERK1&2. The classical ERK activation pathway beings with growth factor activation of receptor tyrosine kinases. Numerous G-protein coupled receptors and ionotropic receptors also lead to ERK through increases in the second messengers calcium and cAMP. Though both types of pathways are present in diverse cell types, a key difference is that most stimuli to neurons, e.g. synaptic inputs, are transient, on the order of milliseconds to seconds, whereas many stimuli acting on non-neural tissue, e.g. growth factors, are longer duration. The ability to consolidate these inputs to regulate the activation of ERK in response to diverse signals raises the question of which factors influence the difference in ERK activation pathways. This review presents both experimental studies and computational models aimed at understanding the control of ERK activation and whether there are fundamental differences between neurons and other cells. Our main conclusion is that differences between cell types are quite subtle, often related to differences in expression pattern and quantity of some molecules such as Raf isoforms. In addition, the spatial location of ERK is critical, with regulation by scaffolding proteins producing differences due to colocalization of upstream molecules that may differ between neurons and other cells.
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Affiliation(s)
- Nadiatou Miningou
- Department of Chemistry and Biochemistry, George Mason University, Fairfax, VA 22030, United States of America
| | - Kim T Blackwell
- Interdisciplinary Program in Neuroscience and Bioengineering Department, George Mason University, Fairfax, VA 22030, United States of America.
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28
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Zhang M, Li Z, Jang H, Hedman AC, Sacks DB, Nussinov R. Ca 2+-Dependent Switch of Calmodulin Interaction Mode with Tandem IQ Motifs in the Scaffolding Protein IQGAP1. Biochemistry 2019; 58:4903-4911. [PMID: 31724397 PMCID: PMC8195445 DOI: 10.1021/acs.biochem.9b00854] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
IQ domain GTPase-activating scaffolding protein 1 (IQGAP1) mediates cytoskeleton, cell migration, proliferation, and apoptosis events. Calmodulin (CaM) modulates IQGAP1 functions by binding to its four tandem IQ motifs. Exactly how CaM binds the IQ motifs and which functions of IQGAP1 CaM regulates and how are fundamental mechanistic questions. We combine experimental pull-down assays, mutational data, and molecular dynamics simulations to understand the IQ-CaM complexes with and without Ca2+ at the atomic level. Apo-CaM favors the IQ3 and IQ4 motifs but not the IQ1 and IQ2 motifs that lack two hydrophobic residues for interactions with apo-CaM's hydrophobic pocket. Ca2+-CaM binds all four IQ motifs, with both N- and C-lobes tightly wrapped around each motif. Ca2+ promotes IQ-CaM interactions and increases the amount of IQGAP1-loaded CaM for IQGAP1-mediated signaling. Collectively, we describe IQ-CaM binding in atomistic detail and feature the emergence of Ca2+ as a key modulator of the CaM-IQGAP1 interactions.
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Affiliation(s)
- Mingzhen Zhang
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 20892, United States
| | - Zhigang Li
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Hyunbum Jang
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Andrew C. Hedman
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - David B. Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892, United States
| | - Ruth Nussinov
- Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, Maryland 20892, United States
- Sackler Institute of Molecular Medicine, Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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29
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Morgan CJ, Hedman AC, Li Z, Sacks DB. Endogenous IQGAP1 and IQGAP3 do not functionally interact with Ras. Sci Rep 2019; 9:11057. [PMID: 31363101 PMCID: PMC6667474 DOI: 10.1038/s41598-019-46677-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 06/28/2019] [Indexed: 02/07/2023] Open
Abstract
The Ras family of small GTPases modulates numerous essential processes. Activating Ras mutations result in hyper-activation of selected signaling cascades, which leads to human diseases. The high frequency of Ras mutations in human malignant neoplasms has led to Ras being a desirable chemotherapeutic target. The IQGAP family of scaffold proteins binds to and regulates multiple signaling molecules, including the Rho family GTPases Rac1 and Cdc42. There are conflicting data in the published literature regarding interactions between IQGAP and Ras proteins. Initial reports showed no binding, but subsequent studies claim associations of IQGAP1 and IQGAP3 with K-Ras and H-Ras, respectively. Therefore, we set out to resolve this controversy. Here we demonstrate that neither endogenous IQGAP1 nor endogenous IQGAP3 binds to the major Ras isoforms, namely H-, K-, and N-Ras. Importantly, Ras activation by epidermal growth factor is not altered when IQGAP1 or IQGAP3 proteins are depleted from cells. These data strongly suggest that IQGAP proteins are not functional interactors of H-, K-, or N-Ras and challenge the rationale for targeting the interaction of Ras with IQGAP for the development of therapeutic agents.
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Affiliation(s)
- Chase J Morgan
- From the Department of Laboratory Medicine, National Institutes of Health, 10 Center Drive, Bethesda, Maryland, 20892, USA
| | - Andrew C Hedman
- From the Department of Laboratory Medicine, National Institutes of Health, 10 Center Drive, Bethesda, Maryland, 20892, USA
| | - Zhigang Li
- From the Department of Laboratory Medicine, National Institutes of Health, 10 Center Drive, Bethesda, Maryland, 20892, USA
| | - David B Sacks
- From the Department of Laboratory Medicine, National Institutes of Health, 10 Center Drive, Bethesda, Maryland, 20892, USA.
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30
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IQGAP1 binds the Axl receptor kinase and inhibits its signaling. Biochem J 2018; 475:3073-3086. [PMID: 30185434 DOI: 10.1042/bcj20180594] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Revised: 08/31/2018] [Accepted: 09/05/2018] [Indexed: 02/06/2023]
Abstract
Axl is a tyrosine kinase receptor that is important for hematopoiesis, the innate immune response, platelet aggregation, engulfment of apoptotic cells and cell survival. Binding of growth arrest-specific protein 6 (Gas6) activates Axl signaling, but the mechanism of inactivation of the Axl receptor is poorly understood. In the present study, we show that IQGAP1 modulates Axl signaling. IQGAP1 is a scaffold protein that integrates cell signaling pathways by binding several growth factor receptors and intracellular signaling molecules. Our in vitro analysis revealed a direct interaction between the IQ domain of IQGAP1 and Axl. Analysis by both immunoprecipitation and proximity ligation assays demonstrated an association between Axl and IQGAP1 in cells and this interaction was decreased by Gas6. Unexpectedly, reducing IQGAP1 levels in cells significantly enhanced the ability of Gas6 to stimulate both Axl phosphorylation and activation of Akt. Moreover, IQGAP1 regulates the interaction of Axl with the epidermal growth factor receptor. Our data identify IQGAP1 as a previously undescribed suppressor of Axl and provide insight into regulation of Axl function.
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31
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Ozdemir ES, Jang H, Gursoy A, Keskin O, Li Z, Sacks DB, Nussinov R. Unraveling the molecular mechanism of interactions of the Rho GTPases Cdc42 and Rac1 with the scaffolding protein IQGAP2. J Biol Chem 2018; 293:3685-3699. [PMID: 29358323 PMCID: PMC5846150 DOI: 10.1074/jbc.ra117.001596] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2017] [Revised: 01/12/2018] [Indexed: 12/22/2022] Open
Abstract
IQ motif-containing GTPase-activating proteins (IQGAPs) are scaffolding proteins playing central roles in cell-cell adhesion, polarity, and motility. The Rho GTPases Cdc42 and Rac1, in their GTP-bound active forms, interact with all three human IQGAPs. The IQGAP-Cdc42 interaction promotes metastasis by enhancing actin polymerization. However, despite their high sequence identity, Cdc42 and Rac1 differ in their interactions with IQGAP. Two Cdc42 molecules can bind to the Ex-domain and the RasGAP site of the GTPase-activating protein (GAP)-related domain (GRD) of IQGAP and promote IQGAP dimerization. Only one Rac1 molecule might bind to the RasGAP site of GRD and may not facilitate the dimerization, and the exact mechanism of Cdc42 and Rac1 binding to IQGAP is unclear. Using all-atom molecular dynamics simulations, site-directed mutagenesis, and Western blotting, we unraveled the detailed mechanisms of Cdc42 and Rac1 interactions with IQGAP2. We observed that Cdc42 binding to the Ex-domain of GRD of IQGAP2 (GRD2) releases the Ex-domain at the C-terminal region of GRD2, facilitating IQGAP2 dimerization. Cdc42 binding to the Ex-domain promoted allosteric changes in the RasGAP site, providing a binding site for the second Cdc42 in the RasGAP site. Of note, the Cdc42 "insert loop" was important for the interaction of the first Cdc42 with the Ex-domain. By contrast, differences in Rac1 insert-loop sequence and structure precluded its interaction with the Ex-domain. Rac1 could bind only to the RasGAP site of apo-GRD2 and could not facilitate IQGAP2 dimerization. Our detailed mechanistic insights help decipher how Cdc42 can stimulate actin polymerization in metastasis.
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Affiliation(s)
- E Sila Ozdemir
- From the Departments of Chemical and Biological Engineering and
| | - Hyunbum Jang
- the Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, NCI-Frederick, Frederick, Maryland 21702
| | - Attila Gursoy
- Computer Engineering, Koc University, Istanbul 34450, Turkey,
| | - Ozlem Keskin
- From the Departments of Chemical and Biological Engineering and
| | - Zhigang Li
- the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892, and
| | - David B Sacks
- the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892, and
| | - Ruth Nussinov
- the Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, NCI-Frederick, Frederick, Maryland 21702,
- the Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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32
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Reimer M, Denby E, Zustiak SP, Schober JM. Ras GAP-related and C-terminal domain-dependent localization and tumorigenic activities of IQGAP1 in melanoma cells. PLoS One 2017; 12:e0189589. [PMID: 29240845 PMCID: PMC5730206 DOI: 10.1371/journal.pone.0189589] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Accepted: 11/29/2017] [Indexed: 12/19/2022] Open
Abstract
IQGAP1 interacts with a number of binding partners through a calponin homology domain (CHD), a WW motif, IQ repeats, a Ras GAP-related domain (GRD), and a conserved C-terminal (CT) domain. Among various biological and cellular functions, IQGAP1 is known to play a role in actin cytoskeleton dynamics during membrane ruffling and lamellipodium protrusion. In addition, phosphorylation near the CT domain is thought to control IQGAP1 activity through regulation of intramolecular interaction. In a previous study, we discovered that IQGAP1 preferentially localizes to retracting areas in B16F10 mouse melanoma cells, not areas of membrane ruffling and lamellipodium protrusion. Nothing is known of the domains needed for retraction localization and very little is known of IQGAP1 function in the actin cytoskeleton of melanoma cells. Thus, we examined localization of IQGAP1 mutants to retracting areas, and characterized knock down phenotypes on tissue culture plastic and physiologic-stiffness hydrogels. Localization of IQGAP1 mutants (S1441E/S1443D, S1441A/S1443A, ΔCHD, ΔGRD or ΔCT) to retracting and protruding cell edges were measured. In retracting areas there was a decrease in S1441A/S1443A, ΔGRD and ΔCT localization, a minor decrease in ΔCHD localization, and normal localization of the S1441E/S1443D mutant. In areas of cell protrusion just behind the lamellipodium leading edge, we surprisingly observed both ΔGRD and ΔCT localization, and increased number of microtubules. IQGAP1 knock down caused loss of cell polarity on laminin-coated glass, decreased proliferation on tissue culture polystyrene, and abnormal spheroid growth on laminin-coated hydrogels. We propose that the GRD and CT domains regulate IQGAP1 localization to retracting actin networks to promote a tumorigenic role in melanoma cells.
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Affiliation(s)
- Michael Reimer
- Department of Pharmaceutical Sciences, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
| | - Elisabeth Denby
- Department of Pharmaceutical Sciences, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
| | - Silviya P. Zustiak
- Department of Biomedical Engineering, Saint Louis University, Saint Louis, Missouri, United States of America
| | - Joseph M. Schober
- Department of Pharmaceutical Sciences, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
- * E-mail:
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33
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Abstract
The specific and rapid formation of protein complexes, involving IQGAP family proteins, is essential for diverse cellular processes, such as adhesion, polarization, and directional migration. Although CDC42 and RAC1, prominent members of the RHO GTPase family, have been implicated in binding to and activating IQGAP1, the exact nature of this protein-protein recognition process has remained obscure. Here, we propose a mechanistic framework model that is based on a multiple-step binding process, which is a prerequisite for the dynamic functions of IQGAP1 as a scaffolding protein and a critical mechanism in temporal regulation and integration of cellular pathways.
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Affiliation(s)
- Kazem Nouri
- Institute of Biochemistry and Molecular Biology II, Medical faculty of the Heinrich-Heine University, Düsseldorf, Germany
| | - David J Timson
- School of Pharmacy and Biomolecular Sciences, University of Brighton, Huxley Building, Lewes Road, Brighton, BN2 4GJ, United Kingdom
| | - Mohammad R Ahmadian
- Institute of Biochemistry and Molecular Biology II, Medical faculty of the Heinrich-Heine University, Düsseldorf, Germany
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34
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Bardwell AJ, Lagunes L, Zebarjedi R, Bardwell L. The WW domain of the scaffolding protein IQGAP1 is neither necessary nor sufficient for binding to the MAPKs ERK1 and ERK2. J Biol Chem 2017; 292:8750-8761. [PMID: 28396345 DOI: 10.1074/jbc.m116.767087] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 04/07/2017] [Indexed: 01/09/2023] Open
Abstract
Mitogen-activated protein kinase (MAPK) scaffold proteins, such as IQ motif containing GTPase activating protein 1 (IQGAP1), are promising targets for novel therapies against cancer and other diseases. Such approaches require accurate information about which domains on the scaffold protein bind to the kinases in the MAPK cascade. Results from previous studies have suggested that the WW domain of IQGAP1 binds to the cancer-associated MAPKs ERK1 and ERK2, and that this domain might thus offer a new tool to selectively inhibit MAPK activation in cancer cells. The goal of this work was therefore to critically evaluate which IQGAP1 domains bind to ERK1/2. Here, using quantitative in vitro binding assays, we show that the IQ domain of IQGAP1 is both necessary and sufficient for binding to ERK1 and ERK2, as well as to the MAPK kinases MEK1 and MEK2. Furthermore, we show that the WW domain is not required for ERK-IQGAP1 binding, and contributes little or no binding energy to this interaction, challenging previous models of how WW-based peptides might inhibit tumorigenesis. Finally, we show that the ERK2-IQGAP1 interaction does not require ERK2 phosphorylation or catalytic activity and does not involve known docking recruitment sites on ERK2, and we obtain an estimate of the dissociation constant (Kd ) for this interaction of 8 μm These results prompt a re-evaluation of published findings and a refined model of IQGAP scaffolding.
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Affiliation(s)
- A Jane Bardwell
- From the Department of Developmental and Cell Biology, Center for Complex Biological Systems, University of California, Irvine, California 92697
| | - Leonila Lagunes
- From the Department of Developmental and Cell Biology, Center for Complex Biological Systems, University of California, Irvine, California 92697
| | - Ronak Zebarjedi
- From the Department of Developmental and Cell Biology, Center for Complex Biological Systems, University of California, Irvine, California 92697
| | - Lee Bardwell
- From the Department of Developmental and Cell Biology, Center for Complex Biological Systems, University of California, Irvine, California 92697
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35
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Li Z, Zhang Y, Hedman AC, Ames JB, Sacks DB. Calmodulin Lobes Facilitate Dimerization and Activation of Estrogen Receptor-α. J Biol Chem 2017; 292:4614-4622. [PMID: 28174300 DOI: 10.1074/jbc.m116.754804] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2016] [Revised: 01/30/2017] [Indexed: 02/03/2023] Open
Abstract
Estrogen receptor α (ER-α) is a nuclear hormone receptor that controls selected genes, thereby regulating proliferation and differentiation of target tissues, such as breast. Gene expression controlled by ER-α is modulated by Ca2+ via calmodulin (CaM). Here we present the NMR structure of Ca2+-CaM bound to two molecules of ER-α (residues 287-305). The two lobes of CaM bind to the same site on two separate ER-α molecules (residues 292, 296, 299, 302, and 303), which explains why CaM binds two molecules of ER-α in a 1:2 complex and stabilizes ER-α dimerization. Exposed glutamate residues in CaM (Glu-11, Glu-14, Glu-84, and Glu-87) form salt bridges with key lysine residues in ER-α (Lys-299, Lys-302, and Lys-303), which is likely to prevent ubiquitination at these sites and inhibit degradation of ER-α. Transfection of cells with full-length CaM slightly increased the ability of estrogen to enhance transcriptional activation by ER-α of endogenous estrogen-responsive genes. By contrast, expression of either the N- or C-lobe of CaM abrogated estrogen-stimulated transcription of the estrogen responsive genes pS2 and progesterone receptor. These data suggest that CaM-induced dimerization of ER-α is required for estrogen-stimulated transcriptional activation by the receptor. In light of the critical role of ER-α in breast carcinoma, our data suggest that small molecules that selectively disrupt the interaction of ER-α with CaM may be useful in the therapy of breast carcinoma.
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Affiliation(s)
- Zhigang Li
- From the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - Yonghong Zhang
- the Department of Chemistry, University of Texas Rio Grande Valley, Edinburgh, Texas 78539, and
| | - Andrew C Hedman
- From the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - James B Ames
- the Department of Chemistry, University of California, Davis, California 95616
| | - David B Sacks
- From the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892,
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36
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Chawla B, Hedman AC, Sayedyahossein S, Erdemir HH, Li Z, Sacks DB. Absence of IQGAP1 Protein Leads to Insulin Resistance. J Biol Chem 2017; 292:3273-3289. [PMID: 28082684 DOI: 10.1074/jbc.m116.752642] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2016] [Revised: 01/10/2017] [Indexed: 11/06/2022] Open
Abstract
Insulin binds to the insulin receptor (IR) and induces tyrosine phosphorylation of the receptor and insulin receptor substrate-1 (IRS-1), leading to activation of the PKB/Akt and MAPK/ERK pathways. IQGAP1 is a scaffold protein that interacts with multiple binding partners and integrates diverse signaling cascades. Here we show that IQGAP1 associates with both IR and IRS-1 and influences insulin action. In vitro analysis with pure proteins revealed that the IQ region of IQGAP1 binds directly to the intracellular domain of IR. Similarly, the phosphotyrosine-binding domain of IRS-1 mediates a direct interaction with the C-terminal tail of IQGAP1. Consistent with these observations, both IR and IRS-1 co-immunoprecipitated with IQGAP1 from cells. Investigation of the functional effects of the interactions revealed that in the absence of IQGAP1, insulin-stimulated phosphorylation of Akt and ERK, as well as the association of phosphatidylinositol 3-kinase with IRS-1, were significantly decreased. Importantly, loss of IQGAP1 results in impaired insulin signaling and glucose homeostasis in vivo Collectively, these data reveal that IQGAP1 is a scaffold for IR and IRS-1 and implicate IQGAP1 as a participant in insulin signaling.
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Affiliation(s)
- Bhavna Chawla
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - Andrew C Hedman
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - Samar Sayedyahossein
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - Huseyin H Erdemir
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - Zhigang Li
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - David B Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892.
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37
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Wang T, Gross C, Desai AA, Zemskov E, Wu X, Garcia AN, Jacobson JR, Yuan JXJ, Garcia JGN, Black SM. Endothelial cell signaling and ventilator-induced lung injury: molecular mechanisms, genomic analyses, and therapeutic targets. Am J Physiol Lung Cell Mol Physiol 2016; 312:L452-L476. [PMID: 27979857 DOI: 10.1152/ajplung.00231.2016] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Revised: 12/08/2016] [Accepted: 12/11/2016] [Indexed: 12/13/2022] Open
Abstract
Mechanical ventilation is a life-saving intervention in critically ill patients with respiratory failure due to acute respiratory distress syndrome (ARDS). Paradoxically, mechanical ventilation also creates excessive mechanical stress that directly augments lung injury, a syndrome known as ventilator-induced lung injury (VILI). The pathobiology of VILI and ARDS shares many inflammatory features including increases in lung vascular permeability due to loss of endothelial cell barrier integrity resulting in alveolar flooding. While there have been advances in the understanding of certain elements of VILI and ARDS pathobiology, such as defining the importance of lung inflammatory leukocyte infiltration and highly induced cytokine expression, a deep understanding of the initiating and regulatory pathways involved in these inflammatory responses remains poorly understood. Prevailing evidence indicates that loss of endothelial barrier function plays a primary role in the development of VILI and ARDS. Thus this review will focus on the latest knowledge related to 1) the key role of the endothelium in the pathogenesis of VILI; 2) the transcription factors that relay the effects of excessive mechanical stress in the endothelium; 3) the mechanical stress-induced posttranslational modifications that influence key signaling pathways involved in VILI responses in the endothelium; 4) the genetic and epigenetic regulation of key target genes in the endothelium that are involved in VILI responses; and 5) the need for novel therapeutic strategies for VILI that can preserve endothelial barrier function.
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Affiliation(s)
- Ting Wang
- Department of Medicine, The University of Arizona Health Sciences, Tucson, Arizona
| | - Christine Gross
- Vascular Biology Center, Augusta University, Augusta, Georgia
| | - Ankit A Desai
- Department of Medicine, The University of Arizona Health Sciences, Tucson, Arizona
| | - Evgeny Zemskov
- Department of Medicine, The University of Arizona Health Sciences, Tucson, Arizona
| | - Xiaomin Wu
- Department of Medicine, The University of Arizona Health Sciences, Tucson, Arizona
| | - Alexander N Garcia
- Department of Pharmacology University of Illinois at Chicago, Chicago, Illinois; and
| | - Jeffrey R Jacobson
- Department of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Jason X-J Yuan
- Department of Medicine, The University of Arizona Health Sciences, Tucson, Arizona
| | - Joe G N Garcia
- Department of Medicine, The University of Arizona Health Sciences, Tucson, Arizona
| | - Stephen M Black
- Department of Medicine, The University of Arizona Health Sciences, Tucson, Arizona;
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Liu J, Kurella VB, LeCour L, Vanagunas T, Worthylake DK. The IQGAP1 N-Terminus Forms Dimers, and the Dimer Interface Is Required for Binding F-Actin and Calcium-Bound Calmodulin. Biochemistry 2016; 55:6433-6444. [PMID: 27798963 DOI: 10.1021/acs.biochem.6b00745] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
IQGAP1 is a multidomain scaffold protein involved in many cellular processes. We have determined the crystal structure of an N-terminal fragment spanning residues 1-191 (CHDF hereafter) that contains the entire calponin homology domain. The structure of the CHDF is very similar to those of other type 3 calponin homology domains like those from calponin, Vav, and the yeast IQGAP1 ortholog Rng2. However, in the crystal, two CHDF molecules form a "head-to-head" or parallel dimer through mostly hydrophobic interactions. Binding experiments indicate that the CHDF binds to both F-actin and Ca2+/calmodulin, but binding is mutually exclusive. On the basis of the structure, two dimer interface substitutions were introduced. While CHDFL157D disrupts the dimer in gel filtration experiments, oxidized CHDFK161C stabilizes the dimer. These results imply that the CHDF forms the same dimer in solution that is seen in the crystal structure. The disulfide-stabilized dimer displays a reduced level of F-actin binding in sedimentation assays and shows no binding to Ca2+/calmodulin in isothermal titration calorimetry (ITC) experiments, indicating that interface residues are utilized for both binding events. The Calmodulin Target Database predicts that residues 93KK94 are important for CaM binding, and indeed, the 93EE94 double mutation displays a reduced level of binding to Ca2+/calmodulin in ITC experiments. Our results indicate that the CHDF dimer interface is used for both F-actin and Ca2+/calmodulin binding, and the 93KK94 pair, near the interface, is also used for Ca2+/calmodulin binding. These results are also consistent with full-length IQGAP1 forming a parallel homodimer.
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Affiliation(s)
- Jing Liu
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center-New Orleans , 1901 Perdido Street, New Orleans, Louisiana 70112, United States
| | - Vinodh B Kurella
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center-New Orleans , 1901 Perdido Street, New Orleans, Louisiana 70112, United States
| | - Louis LeCour
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center-New Orleans , 1901 Perdido Street, New Orleans, Louisiana 70112, United States
| | - Tomas Vanagunas
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center-New Orleans , 1901 Perdido Street, New Orleans, Louisiana 70112, United States
| | - David K Worthylake
- Department of Biochemistry and Molecular Biology, Louisiana State University Health Sciences Center-New Orleans , 1901 Perdido Street, New Orleans, Louisiana 70112, United States
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39
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Nouri K, Fansa EK, Amin E, Dvorsky R, Gremer L, Willbold D, Schmitt L, Timson DJ, Ahmadian MR. IQGAP1 Interaction with RHO Family Proteins Revisited: KINETIC AND EQUILIBRIUM EVIDENCE FOR MULTIPLE DISTINCT BINDING SITES. J Biol Chem 2016; 291:26364-26376. [PMID: 27815503 PMCID: PMC5159498 DOI: 10.1074/jbc.m116.752121] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2016] [Revised: 10/27/2016] [Indexed: 11/16/2022] Open
Abstract
IQ motif-containing GTPase activating protein 1 (IQGAP1) plays a central role in the physical assembly of relevant signaling networks that are responsible for various cellular processes, including cell adhesion, polarity, and transmigration. The RHO family proteins CDC42 and RAC1 have been shown to mainly interact with the GAP-related domain (GRD) of IQGAP1. However, the role of its RASGAP C-terminal (RGCT) and C-terminal domains in the interactions with RHO proteins has remained obscure. Here, we demonstrate that IQGAP1 interactions with RHO proteins underlie a multiple-step binding mechanism: (i) a high affinity, GTP-dependent binding of RGCT to the switch regions of CDC42 or RAC1 and (ii) a very low affinity binding of GRD and a C terminus adjacent to the switch regions. These data were confirmed by phosphomimetic mutation of serine 1443 to glutamate within RGCT, which led to a significant reduction of IQGAP1 affinity for CDC42 and RAC1, clearly disclosing the critical role of RGCT for these interactions. Unlike CDC42, an extremely low affinity was determined for the RAC1-GRD interaction, suggesting that the molecular nature of IQGAP1 interaction with CDC42 partially differs from that of RAC1. Our study provides new insights into the interaction characteristics of IQGAP1 with RHO family proteins and highlights the complementary importance of kinetic and equilibrium analyses. We propose that the ability of IQGAP1 to interact with RHO proteins is based on a multiple-step binding process, which is a prerequisite for the dynamic functions of IQGAP1 as a scaffolding protein and a critical mechanism in temporal regulation and integration of IQGAP1-mediated cellular responses.
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Affiliation(s)
- Kazem Nouri
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Eyad K Fansa
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Ehsan Amin
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Radovan Dvorsky
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine University, 40225 Düsseldorf, Germany
| | - Lothar Gremer
- the Institute of Physical Biology, Heinrich-Heine University, 40225 Düsseldorf, Germany.,Forschungszentrum Jülich, ICS-6, 52428 Jülich, Germany
| | - Dieter Willbold
- the Institute of Physical Biology, Heinrich-Heine University, 40225 Düsseldorf, Germany.,Forschungszentrum Jülich, ICS-6, 52428 Jülich, Germany
| | - Lutz Schmitt
- the Institute of Biochemistry, Heinrich-Heine University, 40225 Düsseldorf, Germany, and
| | - David J Timson
- the School of Pharmacy and Biomolecular Sciences, University of Brighton, Huxley Building, Lewes Road, Brighton BN2 4GJ, United Kingdom
| | - Mohammad R Ahmadian
- From the Institute of Biochemistry and Molecular Biology II, Medical Faculty of the Heinrich-Heine University, 40225 Düsseldorf, Germany,
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40
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Huang JK, Ma L, Song WH, Lu BY, Huang YB, Dong HM, Ma XK, Zhu ZZ, Zhou R. MALAT1 promotes the proliferation and invasion of thyroid cancer cells via regulating the expression of IQGAP1. Biomed Pharmacother 2016; 83:1-7. [DOI: 10.1016/j.biopha.2016.05.039] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Revised: 05/20/2016] [Accepted: 05/23/2016] [Indexed: 01/17/2023] Open
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41
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The Structural Basis for Cdc42-Induced Dimerization of IQGAPs. Structure 2016; 24:1499-508. [PMID: 27524202 DOI: 10.1016/j.str.2016.06.016] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2016] [Revised: 06/18/2016] [Accepted: 06/20/2016] [Indexed: 01/18/2023]
Abstract
In signaling, Rho-family GTPases bind effector proteins and alter their behavior. Here we present the crystal structure of Cdc42·GTP bound to the GTPase-activating protein (GAP)-related domain (GRD) of IQGAP2. Four molecules of Cdc42 are bound to two GRD molecules, which bind each other in a parallel dimer. Two Cdc42s bind very similarly to the Ras/RasGAP interaction, while the other two bind primarily to "extra domain" sequences from both GRDs, tying the GRDs together. Calorimetry confirms two-site binding of Cdc42·GTP for the GRDs of both IQGAP2 and IQGAP1. Mutation of important extra domain residues reduces binding to single-site and abrogates Cdc42 binding to a much larger IQGAP1 fragment. Importantly, Rac1·GTP displays only single-site binding to the GRDs, indicating that only Cdc42 promotes IQGAP dimerization. The structure identifies an unexpected role for Cdc42 in protein dimerization, thus expanding the repertoire of interactions of Ras family proteins with their targets.
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42
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Sayedyahossein S, Li Z, Hedman AC, Morgan CJ, Sacks DB. IQGAP1 Binds to Yes-associated Protein (YAP) and Modulates Its Transcriptional Activity. J Biol Chem 2016; 291:19261-73. [PMID: 27440047 DOI: 10.1074/jbc.m116.732529] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Indexed: 01/09/2023] Open
Abstract
During development, the Hippo signaling pathway regulates key physiological processes, such as control of organ size, regeneration, and stem cell biology. Yes-associated protein (YAP) is a major transcriptional co-activator of the Hippo pathway. The scaffold protein IQGAP1 interacts with more than 100 binding partners to integrate diverse signaling pathways. In this study, we report that IQGAP1 binds to YAP and modulates its activity. IQGAP1 and YAP co-immunoprecipitated from cells. In vitro analysis with pure proteins demonstrated a direct interaction between IQGAP1 and YAP. Analysis with multiple fragments of each protein showed that the interaction occurs via the IQ domain of IQGAP1 and the TEAD-binding domain of YAP. The interaction between IQGAP1 and YAP has functional effects. Knock-out of endogenous IQGAP1 significantly increased the formation of nuclear YAP-TEAD complexes. Transcription assays were performed with IQGAP1-null mouse embryonic fibroblasts and HEK293 cells with IQGAP1 knockdown by CRISPR/Cas9. Quantification demonstrated that YAP-TEAD-mediated transcription in cells lacking IQGAP1 was significantly greater than in control cells. These data reveal that IQGAP1 binds to YAP and modulates its co-transcriptional function, suggesting that IQGAP1 participates in Hippo signaling.
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Affiliation(s)
- Samar Sayedyahossein
- From the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - Zhigang Li
- From the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - Andrew C Hedman
- From the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - Chase J Morgan
- From the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
| | - David B Sacks
- From the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
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43
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Cammarata GM, Bearce EA, Lowery LA. Cytoskeletal social networking in the growth cone: How +TIPs mediate microtubule-actin cross-linking to drive axon outgrowth and guidance. Cytoskeleton (Hoboken) 2016; 73:461-76. [PMID: 26783725 DOI: 10.1002/cm.21272] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Revised: 01/08/2016] [Accepted: 01/08/2016] [Indexed: 11/08/2022]
Abstract
The growth cone is a unique structure capable of guiding axons to their proper destinations. Within the growth cone, extracellular guidance cues are interpreted and then transduced into physical changes in the actin filament (F-actin) and microtubule cytoskeletons, providing direction and movement. While both cytoskeletal networks individually possess important growth cone-specific functions, recent data over the past several years point towards a more cooperative role between the two systems. Facilitating this interaction between F-actin and microtubules, microtubule plus-end tracking proteins (+TIPs) have been shown to link the two cytoskeletons together. Evidence suggests that many +TIPs can couple microtubules to F-actin dynamics, supporting both microtubule advance and retraction in the growth cone periphery. In addition, growing in vitro and in vivo data support a secondary role for +TIPs in which they may participate as F-actin nucleators, thus directly influencing F-actin dynamics and organization. This review focuses on how +TIPs may link F-actin and microtubules together in the growth cone, and how these interactions may influence axon guidance. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
| | | | - Laura Anne Lowery
- Department of Biology, Boston College, Chestnut Hill, Massachusetts.
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44
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Lu R, Herrera BB, Eshleman HD, Fu Y, Bloom A, Li Z, Sacks DB, Goldberg MB. Shigella Effector OspB Activates mTORC1 in a Manner That Depends on IQGAP1 and Promotes Cell Proliferation. PLoS Pathog 2015; 11:e1005200. [PMID: 26473364 PMCID: PMC4608727 DOI: 10.1371/journal.ppat.1005200] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Accepted: 09/10/2015] [Indexed: 12/12/2022] Open
Abstract
The intracellular bacterial pathogen Shigella infects and spreads through the human intestinal epithelium. Effector proteins delivered by Shigella into cells promote infection by modulating diverse host functions. We demonstrate that the effector protein OspB interacts directly with the scaffolding protein IQGAP1, and that the absence of either OspB or IQGAP1 during infection leads to larger areas of S. flexneri spread through cell monolayers. We show that the effect on the area of bacterial spread is due to OspB triggering increased cell proliferation at the periphery of infected foci, thereby replacing some of the cells that die within infected foci and restricting the area of bacterial spread. We demonstrate that OspB enhancement of cell proliferation results from activation of mTORC1, a master regulator of cell growth, and is blocked by the mTORC1-specific inhibitor rapamycin. OspB activation of mTORC1, and its effects on cell proliferation and bacterial spread, depends on IQGAP1. Our results identify OspB as a regulator of mTORC1 and mTORC1-dependent cell proliferation early during S. flexneri infection and establish a role for IQGAP1 in mTORC1 signaling. They also raise the possibility that IQGAP1 serves as a scaffold for the assembly of an OspB-mTORC1 signaling complex. During infection, Shigella spp. deliver into the cytoplasm of cells effector proteins that manipulate host cell processes in ways that promote infection and bacterial spread. We have discovered that the Shigella effector protein OspB interacts with the cellular scaffolding protein IQGAP1. OspB induces increased cell proliferation by activating mTORC1 kinase, a master regulator of cellular growth, in a manner that depends on IQGAP1. As IQGAP1 has been shown to interact with mTOR and with the mTORC1 activators ERK1/2, we propose that IQGAP1 serves as a scaffold for OspB activation of mTORC1. The presence of OspB and IQGAP1 lead to restricting the area of spread of S. flexneri in cell monolayers; our data support a model in which the effect of OspB and IQGAP1 on the area of S. flexneri spread is due to effects on cell proliferation locally within infected foci. As infection of cells and tissue by Shigella spp. leads to cell death, increased local cellular proliferation may serve to provide additional protective intracellular niches for the organism within infected tissue.
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Affiliation(s)
- Richard Lu
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Bobby Brooke Herrera
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
| | - Heather D. Eshleman
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Yang Fu
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
| | - Alexander Bloom
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
| | - Zhigang Li
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - David B. Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland, United States of America
| | - Marcia B. Goldberg
- Department of Medicine, Division of Infectious Diseases, Massachusetts General Hospital, Cambridge, Massachusetts, United States of America
- Department of Microbiology and Immunobiology, Harvard Medical School, Boston, Massachusetts, United States of America
- * E-mail:
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45
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Fang X, Zhang B, Thisse B, Bloom GS, Thisse C. IQGAP3 is essential for cell proliferation and motility during zebrafish embryonic development. Cytoskeleton (Hoboken) 2015; 72:422-33. [PMID: 26286209 DOI: 10.1002/cm.21237] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Revised: 08/07/2015] [Accepted: 08/11/2015] [Indexed: 12/22/2022]
Abstract
IQGAPs are scaffolding proteins that regulate actin assembly, exocyst function, cell motility, morphogenesis, adhesion and division. Vertebrates express 3 family members: IQGAP1, IQGAP2, and IQGAP3. IQGAP1 is known to stimulate nucleation of branched actin filaments through N-WASP and the Arp2/3 complex following direct binding to cytoplasmic tails of ligand-activated growth factor receptors, including EGFR, VEGFR2 and FGFR1. By contrast, little is known about functions of IQGAP2 or IQGAP3. Using in situ hybridization on whole mount zebrafish (Danio rerio) embryos, we show that IQGAP1 and IQGAP2 are associated with discrete tissues and organs, while IQGAP3 is mainly expressed in proliferative cells throughout embryonic and larval development. Morpholino knockdowns of IQGAP1 and IQGAP2 have little effect on embryo morphology while loss of function of IQGAP3 affects both cell proliferation and cell motility. IQGAP3 morphant phenotypes are similar to those resulting from overexpression of dominant negative forms of Ras or of Fibroblast Growth Factor Receptor 1 (FGFR1), suggesting that IQGAP3 plays a role in FGFR1-Ras-ERK signaling. In support of this hypothesis, dominant negative forms of FGFR1 or Ras could be rescued by co-injection of zebrafish IQGAP3 mRNA, strongly suggesting that IQGAP3 acts as a downstream regulator of the FGFR1-Ras signaling pathway.
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Affiliation(s)
- Xiaolan Fang
- Department of Biology, University of Virginia, Charlottesville, Virginia
| | - Bianhong Zhang
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia.,Institute of Biomedical Science, School of Science, East China Normal University, Shanghai, China
| | - Bernard Thisse
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia
| | - George S Bloom
- Department of Biology, University of Virginia, Charlottesville, Virginia.,Department of Cell Biology, University of Virginia, Charlottesville, Virginia
| | - Christine Thisse
- Department of Cell Biology, University of Virginia, Charlottesville, Virginia
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46
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Watanabe T, Wang S, Kaibuchi K. IQGAPs as Key Regulators of Actin-cytoskeleton Dynamics. Cell Struct Funct 2015; 40:69-77. [PMID: 26051604 DOI: 10.1247/csf.15003] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
The actin-cytoskeleton plays a critical role in various biological processes, including cell migration, development, tissue remodeling, and memory formation. Both extracellular and intracellular signals regulate reorganization of the actin-cytoskeleton to modulate tissue architecture and cellular morphology in a spatiotemporal manner. Since the discovery that activation of Rho family GTPases induces actin-cytoskeleton reorganization, the mode of action of Rho family GTPases has been extensively studied and individual effectors have been characterized. The actin-binding protein IQGAP1 was identified as an effector of Rac and Cdc42 and is the founding member of the IQGAP family with two additional isoforms. The IQGAP family shows conserved domain organization, and each member displays a specific expression pattern in mammalian tissues. IQGAPs regulate the actin-cytoskeleton alone and with their binding partners, thereby controlling diverse cellular processes, such as cell migration and adhesion. Here, we introduce IQGAPs as an actin-cytoskeleton regulator.
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Affiliation(s)
- Takashi Watanabe
- Department of Cell Pharmacology, Nagoya University, Graduate School of Medicine
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Lian ATY, Hains PG, Sarcevic B, Robinson PJ, Chircop M. IQGAP1 is associated with nuclear envelope reformation and completion of abscission. Cell Cycle 2015; 14:2058-74. [PMID: 25928398 DOI: 10.1080/15384101.2015.1044168] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
The final stage of mitosis is cytokinesis, which results in 2 independent daughter cells. Cytokinesis has 2 phases: membrane ingression followed by membrane abscission. IQGAP1 is a scaffold protein that interacts with proteins implicated in mitosis, including F-actin, myosin and CaM. IQGAP1 in yeast recruits actin and myosin II filaments to the contractile ring for membrane ingression. In contrast, we show that mammalian IQGAP1 is not required for ingression, but coordinates nuclear pore complex (NPC) reassembly and completion of abscission. Depletion of IQGAP1 disrupts Nup98 and mAb414 nuclear envelope localization and delays abscission timing. IQGAP1 phosphorylation increases 15-fold upon mitotic entry at S86, S330 and T1434, with the latter site being targeted by CDK2/Cyclin A and CDK1/Cyclin A/B in vitro. Expressing the phospho-deficient mutant IQGAP1-S330A impairs NPC reassembly in cells undergoing abscission. Thus, mammalian IQGAP1 functions later in mitosis than its yeast counterpart to regulate nuclear pore assembly in a S330 phosphorylation-dependent manner during the abscission phase of cytokinesis.
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Affiliation(s)
- Audrey T Y Lian
- a Children's Medical Research Institute; The University of Sydney ; Westmead , New South Wales , Australia
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Abel AM, Schuldt KM, Rajasekaran K, Hwang D, Riese MJ, Rao S, Thakar MS, Malarkannan S. IQGAP1: insights into the function of a molecular puppeteer. Mol Immunol 2015; 65:336-49. [PMID: 25733387 DOI: 10.1016/j.molimm.2015.02.012] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 02/09/2015] [Accepted: 02/09/2015] [Indexed: 02/06/2023]
Abstract
The intracellular spatiotemporal organization of signaling events is critical for normal cellular function. In response to environmental stimuli, cells utilize highly organized signaling pathways that are subject to multiple layers of regulation. However, the molecular mechanisms that coordinate these complex processes remain an enigma. Scaffolding proteins (scaffolins) have emerged as critical regulators of signaling pathways, many of which have well-described functions in immune cells. IQGAP1, a highly conserved cytoplasmic scaffold protein, is able to curb, compartmentalize, and coordinate multiple signaling pathways in a variety of cell types. IQGAP1 plays a central role in cell-cell interaction, cell adherence, and movement via actin/tubulin-based cytoskeletal reorganization. Evidence also implicates IQGAP1 as an essential regulator of the MAPK and Wnt/β-catenin signaling pathways. Here, we summarize the recent advances on the cellular and molecular biology of IQGAP1. We also describe how this pleiotropic scaffolin acts as a true molecular puppeteer, and highlight the significance of future research regarding the role of IQGAP1 in immune cells.
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Affiliation(s)
- Alex M Abel
- Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Microbiology & Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Kristina M Schuldt
- Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Kamalakannan Rajasekaran
- Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - David Hwang
- Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Matthew J Riese
- Department of Microbiology & Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Sridhar Rao
- Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Monica S Thakar
- Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA
| | - Subramaniam Malarkannan
- Laboratory of Molecular Immunology and Immunotherapy, Blood Research Institute, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Microbiology & Molecular Genetics, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Medicine, Medical College of Wisconsin, Milwaukee, WI 53226, USA; Department of Pediatrics, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
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Hedman AC, Smith JM, Sacks DB. The biology of IQGAP proteins: beyond the cytoskeleton. EMBO Rep 2015; 16:427-46. [PMID: 25722290 DOI: 10.15252/embr.201439834] [Citation(s) in RCA: 145] [Impact Index Per Article: 16.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Accepted: 01/07/2015] [Indexed: 01/02/2023] Open
Abstract
IQGAP scaffold proteins are evolutionarily conserved in eukaryotes and facilitate the formation of complexes that regulate cytoskeletal dynamics, intracellular signaling, and intercellular interactions. Fungal and mammalian IQGAPs are implicated in cytokinesis. IQGAP1, IQGAP2, and IQGAP3 have diverse roles in vertebrate physiology, operating in the kidney, nervous system, cardio-vascular system, pancreas, and lung. The functions of IQGAPs can be corrupted during oncogenesis and are usurped by microbial pathogens. Therefore, IQGAPs represent intriguing candidates for novel therapeutic agents. While modulation of the cytoskeletal architecture was initially thought to be the primary function of IQGAPs, it is now clear that they have roles beyond the cytoskeleton. This review describes contributions of IQGAPs to physiology at the organism level.
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Affiliation(s)
- Andrew C Hedman
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD, USA
| | - Jessica M Smith
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD, USA
| | - David B Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD, USA
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IQGAPs choreograph cellular signaling from the membrane to the nucleus. Trends Cell Biol 2015; 25:171-84. [PMID: 25618329 DOI: 10.1016/j.tcb.2014.12.005] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2014] [Revised: 12/02/2014] [Accepted: 12/03/2014] [Indexed: 12/18/2022]
Abstract
Since its discovery in 1994, recognized cellular functions for the scaffold protein IQGAP1 have expanded immensely. Over 100 unique IQGAP1-interacting proteins have been identified, implicating IQGAP1 as a critical integrator of cellular signaling pathways. Initial research established functions for IQGAP1 in cell-cell adhesion, cell migration, and cell signaling. Recent studies have revealed additional IQGAP1 binding partners, expanding the biological roles of IQGAP1. These include crosstalk between signaling cascades, regulation of nuclear function, and Wnt pathway potentiation. Investigation of the IQGAP2 and IQGAP3 homologs demonstrates unique functions, some of which differ from those of IQGAP1. Summarized here are recent observations that enhance our understanding of IQGAP proteins in the integration of diverse signaling pathways.
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