1
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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2
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Song F, Dai Q, Grimm MO, Steinbach D. The Antithetic Roles of IQGAP2 and IQGAP3 in Cancers. Cancers (Basel) 2023; 15:cancers15041115. [PMID: 36831467 PMCID: PMC9953781 DOI: 10.3390/cancers15041115] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 02/02/2023] [Accepted: 02/08/2023] [Indexed: 02/12/2023] Open
Abstract
The scaffold protein family of IQ motif-containing GTPase-activating proteins (IQGAP1, 2, and 3) share a high degree of homology and comprise six functional domains. IQGAPs bind and regulate the cytoskeleton, interact with MAP kinases and calmodulin, and have GTPase-related activity, as well as a RasGAP domain. Thus, IQGAPs regulate multiple cellular processes and pathways, affecting cell division, growth, cell-cell interactions, migration, and invasion. In the past decade, significant evidence on the function of IQGAPs in signal transduction during carcinogenesis has emerged. Compared with IQGAP1, IQGAP2 and IQGAP3 were less analyzed. In this review, we summarize the different signaling pathways affected by IQGAP2 and IQGAP3, and the antithetic roles of IQGAP2 and IQGAP3 in different types of cancer. IQGAP2 expression is reduced and plays a tumor suppressor role in most solid cancer types, while IQGAP3 is overexpressed and acts as an oncogene. In lymphoma, for example, IQGAPs have partially opposite functions. There is considerable evidence that IQGAPs regulate a multitude of pathways to modulate cancer processes and chemoresistance, but some questions, such as how they trigger this signaling, through which domains, and why they play opposite roles on the same pathways, are still unanswered.
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Affiliation(s)
- Fei Song
- Department of Urology, Jena University Hospital, 07740 Jena, Germany
| | - Qingqing Dai
- Department of Internal Medicine IV (Gastroenterology, Hepatology, and Infectious Diseases), Jena University Hospital, 07740 Jena, Germany
| | - Marc-Oliver Grimm
- Department of Urology, Jena University Hospital, 07740 Jena, Germany
| | - Daniel Steinbach
- Department of Urology, Jena University Hospital, 07740 Jena, Germany
- Correspondence:
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3
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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4
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Lee M, Nagashima K, Yoon J, Sun J, Wang Z, Carpenter C, Lee HK, Hwang YS, Westlake CJ, Daar IO. CEP97 phosphorylation by Dyrk1a is critical for centriole separation during multiciliogenesis. J Cell Biol 2022; 221:e202102110. [PMID: 34787650 PMCID: PMC8719716 DOI: 10.1083/jcb.202102110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 08/18/2021] [Accepted: 10/04/2021] [Indexed: 11/22/2022] Open
Abstract
Proper cilia formation in multiciliated cells (MCCs) is necessary for appropriate embryonic development and homeostasis. Multicilia share many structural characteristics with monocilia and primary cilia, but there are still significant gaps in our understanding of the regulation of multiciliogenesis. Using the Xenopus embryo, we show that CEP97, which is known as a negative regulator of primary cilia formation, interacts with dual specificity tyrosine phosphorylation regulated kinase 1A (Dyrk1a) to modulate multiciliogenesis. We show that Dyrk1a phosphorylates CEP97, which in turn promotes the recruitment of Polo-like kinase 1 (Plk1), which is a critical regulator of MCC maturation that functions to enhance centriole disengagement in cooperation with the enzyme Separase. Knockdown of either CEP97 or Dyrk1a disrupts cilia formation and centriole disengagement in MCCs, but this defect is rescued by overexpression of Separase. Thus, our study reveals that Dyrk1a and CEP97 coordinate with Plk1 to promote Separase function to properly form multicilia in vertebrate MCCs.
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Affiliation(s)
| | - Kunio Nagashima
- Electron Microscopy Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Jaeho Yoon
- National Cancer Institute, Frederick, MD
| | - Jian Sun
- National Cancer Institute, Frederick, MD
| | - Ziqiu Wang
- Electron Microscopy Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD
| | - Christina Carpenter
- Electron Microscopy Laboratory, Frederick National Laboratory for Cancer Research, Frederick, MD
| | | | | | - Christopher J. Westlake
- Laboratory of Cellular and Developmental Signaling, Center for Cancer Research, National Cancer Institute, National Institutes of Health, Frederick, MD
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5
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Ramshekar A, Wang H, Hartnett ME. Regulation of Rac1 Activation in Choroidal Endothelial Cells: Insights into Mechanisms in Age-Related Macular Degeneration. Cells 2021; 10:2414. [PMID: 34572063 DOI: 10.3390/cells10092414] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [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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6
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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7
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Ramshekar A, Wang H, Kunz E, Pappas C, Hageman GS, Chaqour B, Sacks DB, Hartnett ME. Active Rap1-mediated inhibition of choroidal neovascularization requires interactions with IQGAP1 in choroidal endothelial cells. FASEB J 2021; 35:e21642. [PMID: 34166557 PMCID: PMC8238370 DOI: 10.1096/fj.202100112r] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Revised: 04/08/2021] [Accepted: 04/19/2021] [Indexed: 01/13/2023]
Abstract
Neovascular age-related macular degeneration (nAMD) is a leading cause of blindness. The pathophysiology involves activation of choroidal endothelial cells (CECs) to transmigrate the retinal pigment epithelial (RPE) monolayer and form choroidal neovascularization (CNV) in the neural retina. The multidomain GTPase binding protein, IQGAP1, binds active Rac1 and sustains activation of CECs, thereby enabling migration associated with vision-threatening CNV. IQGAP1 also binds the GTPase, Rap1, which when activated reduces Rac1 activation in CECs and CNV. In this study, we tested the hypothesis that active Rap1 binding to IQGAP1 is necessary and sufficient to reduce Rac1 activation in CECs, and CNV. We found that pharmacologic activation of Rap1 or adenoviral transduction of constitutively active Rap1a reduced VEGF-mediated Rac1 activation, migration, and tube formation in CECs. Following pharmacologic activation of Rap1, VEGF-mediated Rac1 activation was reduced in CECs transfected with an IQGAP1 construct that increased active Rap1-IQGAP1 binding but not in CECs transfected with an IQGAP1 construct lacking the Rap1 binding domain. Specific knockout of IQGAP1 in endothelial cells reduced laser-induced CNV and Rac1 activation in CNV lesions, but pharmacologic activation of Rap1 did not further reduce CNV compared to littermate controls. Taken together, our findings provide evidence that active Rap1 binding to the IQ domain of IQGAP1 is sufficient to interfere with active Rac1-mediated CEC activation and CNV formation.
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Affiliation(s)
- Aniket Ramshekar
- The John A Moran Eye Center, University of Utah, Salt Lake
City, UT, USA
| | - Haibo Wang
- The John A Moran Eye Center, University of Utah, Salt Lake
City, UT, USA
| | - Eric Kunz
- The John A Moran Eye Center, University of Utah, Salt Lake
City, UT, USA
| | - Christian Pappas
- The John A Moran Eye Center, University of Utah, Salt Lake
City, UT, USA,Steele Center for Translational Medicine, John A. Moran Eye
Center, University of Utah, Salt Lake City, UT, USA
| | - Gregory S. Hageman
- The John A Moran Eye Center, University of Utah, Salt Lake
City, UT, USA,Steele Center for Translational Medicine, John A. Moran Eye
Center, University of Utah, Salt Lake City, UT, USA
| | - Brahim Chaqour
- Department of Ophthalmology, Downstate Medical Center,
Brooklyn, NY, USA
| | - David B. Sacks
- Department of Laboratory Medicine, National Institutes of
Health, Bethesda, MD, USA
| | - M. Elizabeth Hartnett
- The John A Moran Eye Center, University of Utah, Salt Lake
City, UT, USA,Correspondence to: M. Elizabeth Hartnett,
MD, Address: 65 Mario Capecchi Drive, Salt Lake City, UT 84132. Tel:
801-213-4110; Fax: 801-581-3357,
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8
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Parvathaneni S, Li Z, Sacks DB. Calmodulin influences MAPK signaling by binding KSR1. J Biol Chem 2021; 296:100577. [PMID: 33766558 DOI: 10.1016/j.jbc.2021.100577] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [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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9
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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10
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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11
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Tebar F, Chavero A, Agell N, Lu A, Rentero C, Enrich C, Grewal T. Pleiotropic Roles of Calmodulin in the Regulation of KRas and Rac1 GTPases: Functional Diversity in Health and Disease. Int J Mol Sci 2020; 21:E3680. [PMID: 32456244 DOI: 10.3390/ijms21103680] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [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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12
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Arora PD, Nakajima K, Nanda A, Plaha A, Wilde A, Sacks DB, McCulloch CA. Flightless anchors IQGAP1 and R-ras to mediate cell extension formation and matrix remodeling. Mol Biol Cell 2020; 31:1595-1610. [PMID: 32432944 PMCID: PMC7521798 DOI: 10.1091/mbc.e19-10-0554] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Tractional remodeling of collagen fibrils by fibroblasts requires long cell extensions that mediate fibril alignment. The formation of these cell extensions involves flightless I (FliI), an actin-binding protein that contains a leucine-rich-repeat (LRR), which binds R-ras and may regulate cdc42. We considered that FliI interacts with small GTPases and their regulators to mediate assembly of cell extensions. Mass spectrometry analyses of FliI immunoprecipitates showed abundant Ras GTPase-activating-like protein (IQGAP1), which in immunostained samples colocalized with FliI at cell adhesions. Knockdown of IQGAP1 reduced the numbers of cell extensions and the alignment of collagen fibrils. In experiments using dominant negative mutants, cdc42 activity was required for the formation of short extensions while R-ras was required for the formation of long extensions. Immunoprecipitation of wild-type and mutant constructs showed that IQGAP1 associated with cdc42 and R-ras; this association required the GAP-related domain (1004–1237 aa) of IQGAP1. In cells transfected with FliI mutants, the LRR of FliI, but not its gelsolin-like domains, mediated association with cdc42, R-ras, and IQGAP1. We conclude that FliI interacts with IQGAP1 and co-ordinates with cdc42 and R-ras to control the formation of cell extensions that enable collagen tractional remodeling.
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Affiliation(s)
- P D Arora
- Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1G6, Canada
| | - K Nakajima
- Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1G6, Canada
| | - A Nanda
- Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1G6, Canada
| | - A Plaha
- Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1G6, Canada
| | - A Wilde
- Departments of Medical Genetics and Biochemistry, Faculty of Medicine, University of Toronto, Toronto, ON M5G 1L7, Canada
| | - D B Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD 20892
| | - C A McCulloch
- Faculty of Dentistry, University of Toronto, Toronto, ON M5G 1G6, Canada
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13
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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14
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Villalobo A, Berchtold MW. The Role of Calmodulin in Tumor Cell Migration, Invasiveness, and Metastasis. Int J Mol Sci 2020; 21:ijms21030765. [PMID: 31991573 PMCID: PMC7037201 DOI: 10.3390/ijms21030765] [Citation(s) in RCA: 40] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2019] [Revised: 01/18/2020] [Accepted: 01/21/2020] [Indexed: 12/12/2022] Open
Abstract
Calmodulin (CaM) is the principal Ca2+ sensor protein in all eukaryotic cells, that upon binding to target proteins transduces signals encoded by global or subcellular-specific changes of Ca2+ concentration within the cell. The Ca2+/CaM complex as well as Ca2+-free CaM modulate the activity of a vast number of enzymes, channels, signaling, adaptor and structural proteins, and hence the functionality of implicated signaling pathways, which control multiple cellular functions. A basic and important cellular function controlled by CaM in various ways is cell motility. Here we discuss the role of CaM-dependent systems involved in cell migration, tumor cell invasiveness, and metastasis development. Emphasis is given to phosphorylation/dephosphorylation events catalyzed by myosin light-chain kinase, CaM-dependent kinase-II, as well as other CaM-dependent kinases, and the CaM-dependent phosphatase calcineurin. In addition, the role of the CaM-regulated small GTPases Rac1 and Cdc42 (cell division cycle protein 42) as well as CaM-binding adaptor/scaffold proteins such as Grb7 (growth factor receptor bound protein 7), IQGAP (IQ motif containing GTPase activating protein) and AKAP12 (A kinase anchoring protein 12) will be reviewed. CaM-regulated mechanisms in cancer cells responsible for their greater migratory capacity compared to non-malignant cells, invasion of adjacent normal tissues and their systemic dissemination will be discussed, including closely linked processes such as the epithelial–mesenchymal transition and the activation of metalloproteases. This review covers as well the role of CaM in establishing metastatic foci in distant organs. Finally, the use of CaM antagonists and other blocking techniques to downregulate CaM-dependent systems aimed at preventing cancer cell invasiveness and metastasis development will be outlined.
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Affiliation(s)
- Antonio Villalobo
- Cancer and Human Molecular Genetics Area—Oto-Neurosurgery Research Group, University Hospital La Paz Research Institute (IdiPAZ), Paseo de la Castellana 261, E-28046 Madrid, Spain
- Correspondence: (A.V.); (M.W.B.)
| | - Martin W. Berchtold
- Department of Biology, University of Copenhagen, 13 Universitetsparken, DK-2100 Copenhagen, Denmark
- Correspondence: (A.V.); (M.W.B.)
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15
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Dalal PJ, Muller WA, Sullivan DP. Endothelial Cell Calcium Signaling during Barrier Function and Inflammation. Am J Pathol 2019; 190:535-542. [PMID: 31866349 DOI: 10.1016/j.ajpath.2019.11.004] [Citation(s) in RCA: 106] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2019] [Revised: 11/11/2019] [Accepted: 11/25/2019] [Indexed: 12/13/2022]
Abstract
Calcium is an essential second messenger in endothelial cells and plays a pivotal role in regulating a number of physiologic processes, including cell migration, angiogenesis, barrier function, and inflammation. An increase in intracellular Ca2+ concentration can trigger a number of diverse signaling pathways under both physiologic and pathologic conditions. In this review, we discuss how calcium signaling pathways in endothelial cells play an essential role in affecting barrier function and facilitating inflammation. Inflammatory mediators, such as thrombin and histamine, increase intracellular calcium levels. This calcium influx causes adherens junction disassembly and cytoskeletal rearrangements to facilitate endothelial cell retraction and increased permeability. During inflammation endothelial cell calcium entry and the calcium-related signaling events also help facilitate several leukocyte-endothelial cell interactions, such as leukocyte rolling, adhesion, and ultimately transendothelial migration.
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Affiliation(s)
- Prarthana J Dalal
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - William A Muller
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
| | - David P Sullivan
- Department of Pathology, Northwestern University Feinberg School of Medicine, Chicago, Illinois.
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16
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Stucchi R, Plucińska G, Hummel JJA, Zahavi EE, Guerra San Juan I, Klykov O, Scheltema RA, Altelaar AFM, Hoogenraad CC. Regulation of KIF1A-Driven Dense Core Vesicle Transport: Ca 2+/CaM Controls DCV Binding and Liprin-α/TANC2 Recruits DCVs to Postsynaptic Sites. Cell Rep 2019; 24:685-700. [PMID: 30021165 PMCID: PMC6077247 DOI: 10.1016/j.celrep.2018.06.071] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Revised: 05/13/2018] [Accepted: 06/15/2018] [Indexed: 01/21/2023] Open
Abstract
Tight regulation of neuronal transport allows for cargo binding and release at specific cellular locations. The mechanisms by which motor proteins are loaded on vesicles and how cargoes are captured at appropriate sites remain unclear. To better understand how KIF1A-driven dense core vesicle (DCV) transport is regulated, we identified the KIF1A interactome and focused on three binding partners, the calcium binding protein calmodulin (CaM) and two synaptic scaffolding proteins: liprin-α and TANC2. We showed that calcium, acting via CaM, enhances KIF1A binding to DCVs and increases vesicle motility. In contrast, liprin-α and TANC2 are not part of the KIF1A-cargo complex but capture DCVs at dendritic spines. Furthermore, we found that specific TANC2 mutations—reported in patients with different neuropsychiatric disorders—abolish the interaction with KIF1A. We propose a model in which Ca2+/CaM regulates cargo binding and liprin-α and TANC2 recruit KIF1A-transported vesicles. KIF1A directly interacts with CaM and with the scaffolds liprin-α and TANC2 KIF1A is regulated by a Ca2+/CaM-dependent mechanism, which allows for DCV loading Liprin-α and TANC2 are static PSD proteins that are not part of the KIF1A-DCV complex KIF1A-driven DCVs are recruited to dendritic spines by liprin-α and TANC2
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Affiliation(s)
- Riccardo Stucchi
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands; Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Gabriela Plucińska
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Jessica J A Hummel
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Eitan E Zahavi
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Irune Guerra San Juan
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Oleg Klykov
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Richard A Scheltema
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 Utrecht, the Netherlands
| | - A F Maarten Altelaar
- Biomolecular Mass Spectrometry and Proteomics, Bijvoet Center for Biomolecular Research and Utrecht Institute for Pharmaceutical Sciences, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands; Netherlands Proteomics Centre, Padualaan 8, 3584 Utrecht, the Netherlands
| | - Casper C Hoogenraad
- Cell Biology, Department of Biology, Faculty of Science, Utrecht University, Padualaan 8, 3584 Utrecht, the Netherlands.
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17
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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 DOI: 10.1021/acs.biochem.9b00854] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [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
- Center for Cancer Research, National Cancer Institute , National Institutes of Health , Frederick , 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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18
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Sullivan DP, Dalal PJ, Jaulin F, Sacks DB, Kreitzer G, Muller WA. Endothelial IQGAP1 regulates leukocyte transmigration by directing the LBRC to the site of diapedesis. J Exp Med 2019; 216:2582-2601. [PMID: 31395618 PMCID: PMC6829592 DOI: 10.1084/jem.20190008] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2019] [Revised: 06/10/2019] [Accepted: 07/03/2019] [Indexed: 01/09/2023] Open
Abstract
The function of endothelial cell IQGAP1 during diapedesis requires its actin-binding domain and IQ motifs to recruit the lateral border recycling compartment. Genetic ablation of endothelial cell IQGAP1 expression in vivo causes significant disruption of diapedesis in two models of inflammation. Transendothelial migration (TEM) of leukocytes across the endothelium is critical for inflammation. In the endothelium, TEM requires the coordination of membrane movements and cytoskeletal interactions, including, prominently, recruitment of the lateral border recycling compartment (LBRC). The scaffold protein IQGAP1 was recently identified in a screen for LBRC-interacting proteins. Knockdown of endothelial IQGAP1 disrupted the directed movement of the LBRC and substantially reduced leukocyte TEM. Expression of truncated IQGAP1 constructs demonstrated that the calponin homology domain is required for IQGAP1 localization to endothelial borders and that the IQ domain, on the same IQGAP1 polypeptide, is required for its function in TEM. This is the first reported function of IQGAP1 requiring two domains to be present on the same polypeptide. Additionally, we show for the first time that IQGAP1 in the endothelium is required for efficient TEM in vivo. These findings reveal a novel function for IQGAP1 and demonstrate that IQGAP1 in endothelial cells facilitates TEM by directing the LBRC to the site of TEM.
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Affiliation(s)
- David P Sullivan
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | - Prarthana J Dalal
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL
| | | | - David B Sacks
- Department of Laboratory Medicine, National Institutes of Health, Bethesda, MD
| | - Geri Kreitzer
- Department of Molecular, Cellular and Biomedical Sciences, City University of New York School of Medicine, The City College of New York, New York, NY
| | - William A Muller
- Department of Pathology, Feinberg School of Medicine, Northwestern University, Chicago, IL
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19
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Liu Y, Su H, Ma C, Ji D, Zheng X, Wang P, Zheng S, Wang L, Wang Z, Xu D. IQGAP1 mediates podocyte injury in diabetic kidney disease by regulating nephrin endocytosis. Cell Signal 2019; 59:13-23. [DOI: 10.1016/j.cellsig.2019.03.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 01/02/2023]
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20
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Gorisse L, Li Z, Hedman AC, Sacks DB. IQGAP1 binds the Axl receptor kinase and inhibits its signaling. Biochem J 2018; 475:3073-86. [PMID: 30185434 DOI: 10.1042/BCJ20180594] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [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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21
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Nussinov R, Zhang M, Tsai CJ, Liao TJ, Fushman D, Jang H. Autoinhibition in Ras effectors Raf, PI3Kα, and RASSF5: a comprehensive review underscoring the challenges in pharmacological intervention. Biophys Rev 2018; 10:1263-82. [PMID: 30269291 DOI: 10.1007/s12551-018-0461-0] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Accepted: 09/17/2018] [Indexed: 02/06/2023] Open
Abstract
Autoinhibition is an effective mechanism that guards proteins against spurious activation. Despite its ubiquity, the distinct organizations of the autoinhibited states and their release mechanisms differ. Signaling is most responsive to the cell environment only if a small shift in the equilibrium is required to switch the system from an inactive (occluded) to an active (exposed) state. Ras signaling follows this paradigm. This underscores the challenge in pharmacological intervention to exploit and enhance autoinhibited states. Here, we review autoinhibition and release mechanisms at the membrane focusing on three representative Ras effectors, Raf protein kinase, PI3Kα lipid kinase, and NORE1A (RASSF5) tumor suppressor, and point to the ramifications to drug discovery. We further touch on Ras upstream and downstream signaling, Ras activation, and the Ras superfamily in this light, altogether providing a broad outlook of the principles and complexities of autoinhibition.
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22
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Thomas CM, Timson DJ. Calmodulins from Schistosoma mansoni: Biochemical analysis and interaction with IQ-motifs from voltage-gated calcium channels. Cell Calcium 2018; 74:1-13. [DOI: 10.1016/j.ceca.2018.05.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 05/08/2018] [Accepted: 05/16/2018] [Indexed: 01/27/2023]
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23
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Nussinov R, Zhang M, Tsai CJ, Jang H. Calmodulin and IQGAP1 activation of PI3Kα and Akt in KRAS, HRAS and NRAS-driven cancers. Biochim Biophys Acta Mol Basis Dis 2018; 1864:2304-2314. [DOI: 10.1016/j.bbadis.2017.10.032] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Revised: 10/24/2017] [Accepted: 10/27/2017] [Indexed: 02/06/2023]
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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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25
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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26
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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27
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Choi S, Hedman AC, Sayedyahossein S, Thapa N, Sacks DB, Anderson RA. Agonist-stimulated phosphatidylinositol-3,4,5-trisphosphate generation by scaffolded phosphoinositide kinases. Nat Cell Biol 2016; 18:1324-35. [PMID: 27870828 DOI: 10.1038/ncb3441] [Citation(s) in RCA: 89] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2016] [Accepted: 10/20/2016] [Indexed: 12/11/2022]
Abstract
Generation of the lipid messenger phosphatidylinositol-3,4,5-trisphosphate (PtdIns(3,4,5)P3) is crucial for development, cell growth and survival, and motility, and it becomes dysfunctional in many diseases including cancers. Here we reveal a mechanism for PtdIns(3,4,5)P3 generation by scaffolded phosphoinositide kinases. In this pathway, class I phosphatidylinositol-3-OH kinase (PI(3)K) is assembled by IQGAP1 with PI(4)KIIIα and PIPKIα, which sequentially generate PtdIns(3,4,5)P3 from phosphatidylinositol. By scaffolding these kinases into functional proximity, the PtdIns(4,5)P2 generated is selectively used by PI(3)K for PtdIns(3,4,5)P3 generation, which then signals to PDK1 and Akt that are also in the complex. Moreover, multiple receptor types stimulate the assembly of this IQGAP1-PI(3)K signalling complex. Blockade of IQGAP1 interaction with PIPKIα or PI(3)K inhibited PtdIns(3,4,5)P3 generation and signalling, and selectively diminished cancer cell survival, revealing a target for cancer chemotherapy.
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28
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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29
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Marschall R, Tudzynski P. BcIqg1, a fungal IQGAP homolog, interacts with NADPH oxidase, MAP kinase and calcium signaling proteins and regulates virulence and development inBotrytis cinerea. Mol Microbiol 2016; 101:281-98. [DOI: 10.1111/mmi.13391] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/29/2016] [Indexed: 12/18/2022]
Affiliation(s)
- Robert Marschall
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms Universität; Schlossplatz 8 D-48143 Münster Germany
| | - Paul Tudzynski
- Institut für Biologie und Biotechnologie der Pflanzen, Westfälische Wilhelms Universität; Schlossplatz 8 D-48143 Münster Germany
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30
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Schroyen M, Eisley C, Koltes JE, Fritz-Waters E, Choi I, Plastow GS, Guan L, Stothard P, Bao H, Kommadath A, Reecy JM, Lunney JK, Rowland RRR, Dekkers JCM, Tuggle CK. Bioinformatic analyses in early host response to Porcine Reproductive and Respiratory Syndrome virus (PRRSV) reveals pathway differences between pigs with alternate genotypes for a major host response QTL. BMC Genomics 2016; 17:196. [PMID: 26951612 PMCID: PMC4782518 DOI: 10.1186/s12864-016-2547-z] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2015] [Accepted: 02/26/2016] [Indexed: 01/01/2023] Open
Abstract
Background A region on Sus scrofa chromosome 4 (SSC4) surrounding single nucleotide polymorphism (SNP) marker WUR10000125 (WUR) has been reported to be strongly associated with both weight gain and serum viremia in pigs after infection with PRRS virus (PRRSV). A proposed causal mutation in the guanylate binding protein 5 gene (GBP5) is predicted to truncate the encoded protein. To investigate transcriptional differences between WUR genotypes in early host response to PRRSV infection, an RNA-seq experiment was performed on globin depleted whole blood RNA collected on 0, 4, 7, 10 and 14 days post-infection (dpi) from eight littermate pairs with one AB (favorable) and one AA (unfavorable) WUR genotype animal per litter. Results Gene Ontology (GO) enrichment analysis of transcripts that were differentially expressed (DE) between dpi across both genotypes revealed an inflammatory response for all dpi when compared to day 0. However, at the early time points of 4 and 7dpi, several GO terms had higher enrichment scores compared to later dpi, including inflammatory response (p < 10-7), specifically regulation of NFkappaB (p < 0.01), cytokine, and chemokine activity (p < 0.01). At 10 and 14dpi, GO term enrichment indicated a switch to DNA damage response, cell cycle checkpoints, and DNA replication. Few transcripts were DE between WUR genotypes on individual dpi or averaged over all dpi, and little enrichment of any GO term was found. However, there were differences in expression patterns over time between AA and AB animals, which was confirmed by genotype-specific expression patterns of several modules that were identified in weighted gene co-expression network analyses (WGCNA). Minor differences between AA and AB animals were observed in immune response and DNA damage response (p = 0.64 and p = 0.11, respectively), but a significant effect between genotypes pointed to a difference in ion transport/homeostasis and the participation of G-coupled protein receptors (p = 8e-4), which was reinforced by results from regulatory and phenotypic impact factor analyses between genotypes. Conclusion We propose these pathway differences between WUR genotypes are the result of the inability of the truncated GBP5 of the AA genotyped pigs to inhibit viral entry and replication as quickly as the intact GBP5 protein of the AB genotyped pigs. Electronic supplementary material The online version of this article (doi:10.1186/s12864-016-2547-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Martine Schroyen
- Department of Animal Science, Iowa State University, 2255 Kildee Hall, Ames, IA, 50011, USA.
| | - Christopher Eisley
- Department of Statistics, Iowa State University, 1121 Snedecor Hall, Ames, IA, 50011, USA.
| | - James E Koltes
- Department of Animal Science, University of Arkansas, AFLS B106D, Fayetteville, AR, 72701, USA.
| | - Eric Fritz-Waters
- Department of Animal Science, Iowa State University, 2255 Kildee Hall, Ames, IA, 50011, USA.
| | - Igseo Choi
- USDA-ARS, BARC, APDL, Bldg.1040, Beltsville, MD, 20705, USA.
| | - Graham S Plastow
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada.
| | - Leluo Guan
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada.
| | - Paul Stothard
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada.
| | - Hua Bao
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada.
| | - Arun Kommadath
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada.
| | - James M Reecy
- Department of Animal Science, Iowa State University, 2255 Kildee Hall, Ames, IA, 50011, USA.
| | - Joan K Lunney
- USDA-ARS, BARC, APDL, Bldg.1040, Beltsville, MD, 20705, USA.
| | - Robert R R Rowland
- College of Veterinary Medicine, Kansas State University, K-231 Mosier Hall, Manhattan, KS, 66506, USA.
| | - Jack C M Dekkers
- Department of Animal Science, Iowa State University, 2255 Kildee Hall, Ames, IA, 50011, USA.
| | - Christopher K Tuggle
- Department of Animal Science, Iowa State University, 2255 Kildee Hall, Ames, IA, 50011, USA.
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31
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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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32
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Ambrozkiewicz MC, Kawabe H. HECT-type E3 ubiquitin ligases in nerve cell development and synapse physiology. FEBS Lett 2015; 589:1635-43. [PMID: 25979171 DOI: 10.1016/j.febslet.2015.05.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2015] [Revised: 05/03/2015] [Accepted: 05/05/2015] [Indexed: 12/21/2022]
Abstract
The development of neurons is precisely controlled. Nerve cells are born from progenitor cells, migrate to their future target sites, extend dendrites and an axon to form synapses, and thus establish neural networks. All these processes are governed by multiple intracellular signaling cascades, among which ubiquitylation has emerged as a potent regulatory principle that determines protein function and turnover. Dysfunctions of E3 ubiquitin ligases or aberrant ubiquitin signaling contribute to a variety of brain disorders like X-linked mental retardation, schizophrenia, autism or Parkinson's disease. In this review, we summarize recent findings about molecular pathways that involve E3 ligases of the Homologous to E6-AP C-terminus (HECT) family and that control neuritogenesis, neuronal polarity formation, and synaptic transmission.
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Affiliation(s)
- Mateusz Cyryl Ambrozkiewicz
- Max Planck Institute of Experimental Medicine, Department of Molecular Neurobiology, Hermann-Rein-Straße 3, D-37075 Göttingen, Germany.
| | - Hiroshi Kawabe
- Max Planck Institute of Experimental Medicine, Department of Molecular Neurobiology, Hermann-Rein-Straße 3, D-37075 Göttingen, Germany.
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33
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Smith JM, Hedman AC, Sacks DB. 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] [What about the content of this article? (0)] [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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34
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Atcheson E, Hamilton E, Pathmanathan S, Greer B, Harriott P, Timson DJ. IQ-motif selectivity in human IQGAP2 and IQGAP3: binding of calmodulin and myosin essential light chain. Biosci Rep. 2011;Epub ahead of print. [PMID: 21299499 PMCID: PMC3263943 DOI: 10.1042/bsr20100123] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The IQGAP [IQ-motif-containing GAP (GTPase-activating protein)] family members are eukaryotic proteins that act at the interface between cellular signalling and the cytoskeleton. As such they collect numerous inputs from a variety of signalling pathways. A key binding partner is the calcium-sensing protein CaM (calmodulin). This protein binds mainly through a series of IQ-motifs which are located towards the middle of the primary sequence of the IQGAPs. In some IQGAPs, these motifs also provide binding sites for CaM-like proteins such as myosin essential light chain and S100B. Using synthetic peptides and native gel electrophoresis, the binding properties of the IQ-motifs from human IQGAP2 and IQGAP3 have been mapped. The second and third IQ-motifs in IQGAP2 and all four of the IQ-motifs of IQGAP3 interacted with CaM in the presence of calcium ions. However, there were differences in the type of interaction: while some IQ-motifs were able to form complexes with CaM which were stable under the conditions of the experiment, others formed more transient interactions. The first IQ-motifs from IQGAP2 and IQGAP3 formed transient interactions with CaM in the absence of calcium and the first motif from IQGAP3 formed a transient interaction with the myosin essential light chain Mlc1sa. None of these IQ-motifs interacted with S100B. Molecular modelling suggested that all of the IQ-motifs, except the first one from IQGAP2 formed α-helices in solution. These results extend our knowledge of the selectivity of IQ-motifs for CaM and related proteins.
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35
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Li RK, Tan JL, Chen LT, Feng JS, Liang WX, Guo XJ, Liu P, Chen Z, Sha JH, Wang YF, Chen SJ. Iqcg is essential for sperm flagellum formation in mice. PLoS One 2014; 9:e98053. [PMID: 24849454 PMCID: PMC4029791 DOI: 10.1371/journal.pone.0098053] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2014] [Accepted: 04/28/2014] [Indexed: 11/30/2022] Open
Abstract
Mammalian spermatogenesis comprises three successive phases: mitosis phase, meiosis phase, and spermiogenesis. During spermiogenesis, round spermatid undergoes dramatic morphogenesis to give rise to mature spermatozoon, including the condensation and elongation of nucleus, development of acrosome, formation of flagellum, and removal of excessive cytoplasm. Although these transformations are well defined at the morphological level, the mechanisms underlying these intricate processes are largely unknown. Here, we report that Iqcg, which was previously characterized to be involved in a chromosome translocation of human leukemia, is highly expressed in the spermatogenesis of mice and localized to the manchette in developing spermatids. Iqcg knockout causes male infertility, due to severe defects of spermiogenesis and resultant total immobility of spermatozoa. The axoneme in the Iqcg knockout sperm flagellum is disorganized and hardly any typical (“9+2”) pattern of microtubule arrangement could be found in Iqcg knockout spermatids. Iqcg interacts with calmodulin in a calcium dependent manner in the testis, suggesting that Iqcg may play a role through calcium signaling. Furthermore, cilia structures in the trachea and oviduct, as well as histological appearances of other major tissues, remain unchanged in the Iqcg knockout mice, suggesting that Iqcg is specifically required for spermiogenesis in mammals. These results might also provide new insights into the genetic causes of human infertility.
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Affiliation(s)
- Ren-Ke Li
- State Key Laboratory of Medical Genomics, Institute of Health Sciences, Shanghai Institutes for Biological Sciences and Graduate School, Chinese Academy of Sciences and Shanghai Institute of Hematology, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jue-Ling Tan
- State Key Laboratory of Medical Genomics, Institute of Health Sciences, Shanghai Institutes for Biological Sciences and Graduate School, Chinese Academy of Sciences and Shanghai Institute of Hematology, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Li-Ting Chen
- State Key Laboratory of Medical Genomics, Institute of Health Sciences, Shanghai Institutes for Biological Sciences and Graduate School, Chinese Academy of Sciences and Shanghai Institute of Hematology, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jing-Sheng Feng
- Department of Histology and Embryology, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Wen-Xue Liang
- Central Laboratory, Lianyungang First People's Hospital, Lianyungang, China
| | - Xue-Jiang Guo
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Ping Liu
- State Key Laboratory of Medical Genomics, Institute of Health Sciences, Shanghai Institutes for Biological Sciences and Graduate School, Chinese Academy of Sciences and Shanghai Institute of Hematology, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Zhu Chen
- State Key Laboratory of Medical Genomics, Institute of Health Sciences, Shanghai Institutes for Biological Sciences and Graduate School, Chinese Academy of Sciences and Shanghai Institute of Hematology, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Jia-Hao Sha
- State Key Laboratory of Reproductive Medicine, Department of Histology and Embryology, Nanjing Medical University, Nanjing, Jiangsu Province, China
| | - Yi-Fei Wang
- Department of Histology and Embryology, School of Medicine, Shanghai Jiao Tong University, Shanghai, China
| | - Sai-Juan Chen
- State Key Laboratory of Medical Genomics, Institute of Health Sciences, Shanghai Institutes for Biological Sciences and Graduate School, Chinese Academy of Sciences and Shanghai Institute of Hematology, Rui Jin Hospital affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
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36
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Schiefermeier N, Scheffler JM, de Araujo MEG, Stasyk T, Yordanov T, Ebner HL, Offterdinger M, Munck S, Hess MW, Wickström SA, Lange A, Wunderlich W, Fässler R, Teis D, Huber LA. The late endosomal p14-MP1 (LAMTOR2/3) complex regulates focal adhesion dynamics during cell migration. ACTA ACUST UNITED AC 2014; 205:525-40. [PMID: 24841562 PMCID: PMC4033770 DOI: 10.1083/jcb.201310043] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Late endosomes locally regulate cell migration by transporting the p14–MP1 scaffold complex to the vicinity of focal adhesions. Cell migration is mediated by the dynamic remodeling of focal adhesions (FAs). Recently, an important role of endosomal signaling in regulation of cell migration was recognized. Here, we show an essential function for late endosomes carrying the p14–MP1 (LAMTOR2/3) complex in FA dynamics. p14–MP1-positive endosomes move to the cell periphery along microtubules (MTs) in a kinesin1- and Arl8b-dependent manner. There they specifically target FAs to regulate FA turnover, which is required for cell migration. Using genetically modified fibroblasts from p14-deficient mice and Arl8b-depleted cells, we demonstrate that MT plus end–directed traffic of p14–MP1-positive endosomes triggered IQGAP1 disassociation from FAs. The release of IQGAP was required for FA dynamics. Taken together, our results suggest that late endosomes contribute to the regulation of cell migration by transporting the p14–MP1 scaffold complex to the vicinity of FAs.
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Affiliation(s)
- Natalia Schiefermeier
- Division of Cell Biology and Division of Neurobiochemistry/Biooptics, Biocenter, Department of Physiology and Medical Physics, Division of Physiology, Department of Traumatology, Center of Operative Medicine, and Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, AustriaDivision of Cell Biology and Division of Neurobiochemistry/Biooptics, Biocenter, Department of Physiology and Medical Physics, Division of Physiology, Department of Traumatology, Center of Operative Medicine, and Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Julia M Scheffler
- Division of Cell Biology and Division of Neurobiochemistry/Biooptics, Biocenter, Department of Physiology and Medical Physics, Division of Physiology, Department of Traumatology, Center of Operative Medicine, and Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Mariana E G de Araujo
- Division of Cell Biology and Division of Neurobiochemistry/Biooptics, Biocenter, Department of Physiology and Medical Physics, Division of Physiology, Department of Traumatology, Center of Operative Medicine, and Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Taras Stasyk
- Division of Cell Biology and Division of Neurobiochemistry/Biooptics, Biocenter, Department of Physiology and Medical Physics, Division of Physiology, Department of Traumatology, Center of Operative Medicine, and Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Teodor Yordanov
- Division of Cell Biology and Division of Neurobiochemistry/Biooptics, Biocenter, Department of Physiology and Medical Physics, Division of Physiology, Department of Traumatology, Center of Operative Medicine, and Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Hannes L Ebner
- Division of Cell Biology and Division of Neurobiochemistry/Biooptics, Biocenter, Department of Physiology and Medical Physics, Division of Physiology, Department of Traumatology, Center of Operative Medicine, and Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, AustriaDivision of Cell Biology and Division of Neurobiochemistry/Biooptics, Biocenter, Department of Physiology and Medical Physics, Division of Physiology, Department of Traumatology, Center of Operative Medicine, and Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Martin Offterdinger
- Division of Cell Biology and Division of Neurobiochemistry/Biooptics, Biocenter, Department of Physiology and Medical Physics, Division of Physiology, Department of Traumatology, Center of Operative Medicine, and Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Sebastian Munck
- VIB Center for the Biology of Disease, KU Leuven, 3000 Leuven, Belgium
| | - Michael W Hess
- Division of Cell Biology and Division of Neurobiochemistry/Biooptics, Biocenter, Department of Physiology and Medical Physics, Division of Physiology, Department of Traumatology, Center of Operative Medicine, and Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Sara A Wickström
- Paul Gerson Unna group "Skin Homeostasis and Ageing", Max Planck Institute for Biology of Ageing, 50931 Cologne, Germany Department of Molecular Medicine, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Anika Lange
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Winfried Wunderlich
- Division of Cell Biology and Division of Neurobiochemistry/Biooptics, Biocenter, Department of Physiology and Medical Physics, Division of Physiology, Department of Traumatology, Center of Operative Medicine, and Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, Austria Oncotyrol, 6020 Innsbruck, Austria
| | - Reinhard Fässler
- Department of Molecular Medicine, Max Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - David Teis
- Division of Cell Biology and Division of Neurobiochemistry/Biooptics, Biocenter, Department of Physiology and Medical Physics, Division of Physiology, Department of Traumatology, Center of Operative Medicine, and Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, Austria
| | - Lukas A Huber
- Division of Cell Biology and Division of Neurobiochemistry/Biooptics, Biocenter, Department of Physiology and Medical Physics, Division of Physiology, Department of Traumatology, Center of Operative Medicine, and Division of Histology and Embryology, Innsbruck Medical University, 6020 Innsbruck, Austria
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37
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Abstract
The estrogen receptor (ER) is a steroid hormone receptor that acts as a transcription factor, modulating genes that regulate a vast range of cellular functions. IQGAP1 interacts with several signaling proteins, cytoskeletal components, and transmembrane receptors, thereby serving as a scaffold to integrate signaling pathways. Both ERα and IQGAP1 contribute to breast cancer. In this study, we report that IQGAP1 binds ERα and ERβ. In vitro analysis with pure proteins revealed a direct interaction between IQGAP1 and ERα. Investigation with multiple short fragments of each protein showed that ERα binds to the IQ domain of IQGAP1, whereas the hinge region of ERα is responsible for binding IQGAP1. In addition, IQGAP1 and ERα co-immunoprecipitated from cells, and the association was modulated by estradiol. The interaction has functional effects. Knockdown of endogenous IQGAP1 attenuated the ability of estradiol to induce transcription of the estrogen-responsive genes pS2, progesterone receptor, and cyclin D1. These data reveal that IQGAP1 binds to ERα and modulates its transcriptional function, suggesting that IQGAP1 might be a target for therapy in patients with breast carcinoma.
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Affiliation(s)
- Huseyin H Erdemir
- From the Department of Laboratory Medicine, National Institutes of Health, Bethesda, Maryland 20892
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38
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Goto T, Sato A, Adachi S, Iemura SI, Natsume T, Shibuya H. IQGAP1 protein regulates nuclear localization of β-catenin via importin-β5 protein in Wnt signaling. J Biol Chem 2013; 288:36351-60. [PMID: 24196961 DOI: 10.1074/jbc.m113.520528] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In the canonical Wnt signaling pathway, the translocation of β-catenin is important for the activation of target genes in the nucleus. However, the molecular mechanisms underlying its nuclear localization remain unclear. In the present study, we found IQGAP1 to be a regulator of β-catenin function via importin-β5. In Xenopus embryos, depletion of IQGAP1 reduced Wnt-induced nuclear accumulation of β-catenin and expression of Wnt target genes during early embryogenesis. Depletion of endogenous importin-β5 associated with IQGAP1 also reduced expression of Wnt target genes and the nuclear localization of IQGAP1 and β-catenin. Moreover, a small GTPase, Ran1, contributes to the nuclear translocation of β-catenin and the activation of Wnt target genes. These results suggest that IQGAP1 functions as a regulator of translocation of β-catenin in the canonical Wnt signaling pathway.
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Affiliation(s)
- Toshiyasu Goto
- From the Department of Molecular Cell Biology, Medical Research Institute, Tokyo Medical and Dental University, Bunkyo-ku, Tokyo 113-8510 and
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39
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Berchtold MW, Villalobo A. The many faces of calmodulin in cell proliferation, programmed cell death, autophagy, and cancer. Biochim Biophys Acta 2013; 1843:398-435. [PMID: 24188867 DOI: 10.1016/j.bbamcr.2013.10.021] [Citation(s) in RCA: 221] [Impact Index Per Article: 20.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Revised: 10/24/2013] [Accepted: 10/26/2013] [Indexed: 12/21/2022]
Abstract
Calmodulin (CaM) is a ubiquitous Ca(2+) receptor protein mediating a large number of signaling processes in all eukaryotic cells. CaM plays a central role in regulating a myriad of cellular functions via interaction with multiple target proteins. This review focuses on the action of CaM and CaM-dependent signaling systems in the control of vertebrate cell proliferation, programmed cell death and autophagy. The significance of CaM and interconnected CaM-regulated systems for the physiology of cancer cells including tumor stem cells, and processes required for tumor progression such as growth, tumor-associated angiogenesis and metastasis are highlighted. Furthermore, the potential targeting of CaM-dependent signaling processes for therapeutic use is discussed.
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Key Words
- (4-[3,5-bis-[2-(4-hydroxy-3-methoxy-phenyl)-ethyl]-4,5-dihydro-pyrazol-1-yl]-benzoic acid
- (4-[3,5-bis-[2-(4-hydroxy-3-methoxy-phenyl)-vinyl]-4,5-dihydro-pyrazol-1-yl]-phenyl)-(4-methyl-piperazin-1-yl)-methanone
- (−) enantiomer of dihydropyrine 3-methyl-5-3-(4,4-diphenyl-1-piperidinyl)-propyl-1,4-dihydro-2,6-dimethyl-4-(3-nitrophenyl)-piridine-3,5-dicarboxylate-hydrochloride (niguldipine)
- 1-[N,O-bis(5-isoquinolinesulfonyl)-N-methyl-l-tyrosyl]-4-phenylpiperazine
- 12-O-tetradecanoyl-phorbol-13-acetate
- 2-chloro-(ε-amino-Lys(75))-[6-(4-(N,N′-diethylaminophenyl)-1,3,5-triazin-4-yl]-CaM adduct
- 3′-(β-chloroethyl)-2′,4′-dioxo-3,5′-spiro-oxazolidino-4-deacetoxy-vinblastine
- 7,12-dimethylbenz[a]anthracene
- Apoptosis
- Autophagy
- B859-35
- CAPP(1)-CaM
- Ca(2+) binding protein
- Calmodulin
- Cancer biology
- Cell proliferation
- DMBA
- EBB
- FL-CaM
- FPCE
- HBC
- HBCP
- J-8
- KAR-2
- KN-62
- KN-93
- N-(4-aminobutyl)-2-naphthalenesulfonamide
- N-(4-aminobutyl)-5-chloro-2-naphthalenesulfonamide
- N-(6-aminohexyl)-1-naphthalenesulfonamide
- N-(6-aminohexyl)-5-chloro-1-naphthalenesulfonamide
- N-8-aminooctyl-5-iodo-naphthalenesulfonamide
- N-[2-[N-(4-chlorocinnamyl)-N-methylaminomethyl]phenyl]-N-(2-hydroxyethyl)-4-methoxybenzenesulfonamide
- O-(4-ethoxyl-butyl)-berbamine
- RITC-CaM
- TA-CaM
- TFP
- TPA
- W-12
- W-13
- W-5
- W-7
- fluorescein-CaM adduct
- fluphenazine-N-2-chloroethane
- norchlorpromazine-CaM adduct
- rhodamine isothiocyanate-CaM adduct
- trifluoperazine
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Affiliation(s)
- Martin W Berchtold
- Department of Biology, University of Copenhagen, Copenhagen Biocenter 4-2-09 Ole Maaløes Vej 5, DK-2200 Copenhagen N, Denmark.
| | - Antonio Villalobo
- Instituto de Investigaciones Biomédicas, Department of Cancer Biology, Consejo Superior de Investigaciones Científicas and Universidad Autónoma de Madrid, c/Arturo Duperier 4, E-28029 Madrid, Spain.
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40
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Vetterkind S, Poythress RH, Lin QQ, Morgan KG. Hierarchical scaffolding of an ERK1/2 activation pathway. Cell Commun Signal 2013; 11:65. [PMID: 23987506 PMCID: PMC3846746 DOI: 10.1186/1478-811x-11-65] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 08/27/2013] [Indexed: 12/30/2022] Open
Abstract
Background Scaffold proteins modulate cellular signaling by facilitating assembly of specific signaling pathways. However, there is at present little information if and how scaffold proteins functionally interact with each other. Results Here, we show that two scaffold proteins, caveolin-1 and IQGAP1, are required for phosphorylation of the actin associated pool of extracellular signal regulated kinase 1 and 2 (ERK1/2) in response to protein kinase C activation. We show by immunofluorescence and proximity ligation assays, that IQGAP1 tethers ERK1/2 to actin filaments. Moreover, siRNA experiments demonstrate that IQGAP1 is required for activation of actin-bound ERK1/2. Caveolin-1 is also necessary for phosphorylation of actin-bound ERK1/2 in response to protein kinase C, but is dispensible for ERK1/2 association with actin. Simultaneous knock down of caveolin-1 and IQGAP1 decreases total phorbol ester-induced ERK1/2 phosphorylation to the same degree as single knock down of either caveolin-1 or IQGAP1, indicating that caveolin-1 and IQGAP1 operate in the same ERK activation pathway. We further show that caveolin-1 knock down, but not IQGAP1 knock down, reduces C-Raf phosphorylation in response to phorbol ester stimulation. Conclusions Based on our data, we suggest that caveolin-1 and IQGAP1 assemble distinct signaling modules, which are then linked in a hierarchical arrangement to generate a functional ERK1/2 activation pathway.
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Affiliation(s)
- Susanne Vetterkind
- Department of Health Sciences, Boston University, Boston, MA 02215, USA.
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41
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Choi S, Thapa N, Hedman AC, Li Z, Sacks DB, Anderson RA. IQGAP1 is a novel phosphatidylinositol 4,5 bisphosphate effector in regulation of directional cell migration. EMBO J 2013; 32:2617-30. [PMID: 23982733 DOI: 10.1038/emboj.2013.191] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Accepted: 07/29/2013] [Indexed: 12/15/2022] Open
Abstract
Phosphatidylinositol 4,5 bisphosphate (PIP₂) is a key lipid messenger for regulation of cell migration. PIP₂ modulates many effectors, but the specificity of PIP₂ signalling can be defined by interactions of PIP₂-generating enzymes with PIP₂ effectors. Here, we show that type Iγ phosphatidylinositol 4-phosphate 5-kinase (PIPKIγ) interacts with the cytoskeleton regulator, IQGAP1, and modulates IQGAP1 function in migration. We reveal that PIPKIγ is required for IQGAP1 recruitment to the leading edge membrane in response to integrin or growth factor receptor activation. Moreover, IQGAP1 is a PIP₂ effector that directly binds PIP₂ through a polybasic motif and PIP₂ binding activates IQGAP1, facilitating actin polymerization. IQGAP1 mutants that lack PIPKIγ or PIP₂ binding lose the ability to control directional cell migration. Collectively, these data reveal a synergy between PIPKIγ and IQGAP1 in the control of cell migration.
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Affiliation(s)
- Suyong Choi
- Cellular and Molecular Biology Graduate Program, University of Wisconsin-Madison, School of Medicine and Public Health, Madison, WI, USA
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42
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Cheung KL, Lee JH, Shu L, Kim JH, Sacks DB, Kong ANT. The Ras GTPase-activating-like protein IQGAP1 mediates Nrf2 protein activation via the mitogen-activated protein kinase/extracellular signal-regulated kinase (ERK) kinase (MEK)-ERK pathway. J Biol Chem 2013; 288:22378-86. [PMID: 23788642 DOI: 10.1074/jbc.m112.444182] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Nrf2 plays a critical role in the regulation of cellular oxidative stress. MEK-ERK activation has been shown to be one of the major pathways resulting in the activation of Nrf2 and induction of Nrf2 downstream targets, including phase II detoxifying/antioxidant genes in response to oxidative stress and xenobiotics. In this study, IQGAP1 (IQ motif-containing GTPase-activating protein 1), a new Nrf2 interaction partner that we have published previously, was found to modulate MEK-ERK-mediated Nrf2 activation and induction of phase II detoxifying/antioxidant genes. Nrf2 binds directly to the IQ domain (amino acids 699-905) of IQGAP1. Knockdown of IQGAP1 significantly attenuated phenethyl isothiocyanate- or MEK-mediated activation of the MEK-ERK-Nrf2 pathway. Knockdown of IQGAP1 also attenuated MEK-mediated increased stability of Nrf2, which in turn was associated with a decrease in the nuclear translocation of Nrf2 and a decrease in the expression of phase II detoxifying/antioxidant genes. In the aggregate, these results suggest that IQGAP1 may play an important role in the MEK-ERK-Nrf2 signaling pathway.
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Affiliation(s)
- Ka Lung Cheung
- Graduate Program in Pharmaceutical Science, Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, New Jersey 08854, USA
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43
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Goto T, Sato A, Shimizu M, Adachi S, Satoh K, Iemura S, Natsume T, Shibuya H. IQGAP1 functions as a modulator of dishevelled nuclear localization in Wnt signaling. PLoS One 2013; 8:e60865. [PMID: 23577172 DOI: 10.1371/journal.pone.0060865] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2013] [Accepted: 03/04/2013] [Indexed: 11/19/2022] Open
Abstract
Dishevelled (DVL) is a central factor in the Wnt signaling pathway, which is highly conserved among various organisms. DVL plays important roles in transcriptional activation in the nucleus, but the molecular mechanisms underlying their nuclear localization remain unclear. In the present study, we identified IQGAP1 as a regulator of DVL function. In Xenopus embryos, depletion of IQGAP1 reduced Wnt-induced nuclear accumulation of DVL, and expression of Wnt target genes during early embryogenesis. The domains in DVL and IQGAP1 that mediated their interaction are also required for their nuclear localization. Endogenous expression of Wnt target genes was reduced by depletion of IQGAP1 during early embryogenesis, but notably not by depletion of other IQGAP family genes. Moreover, expression of Wnt target genes caused by depletion of endogenous IQGAP1 could be rescued by expression of wild-type IQGAP1, but not IQGAP1 deleting DVL binding region. These results provide the first evidence that IQGAP1 functions as a modulator in the canonical Wnt signaling pathway.
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44
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Andrews WJ, Bradley CA, Hamilton E, Daly C, Mallon T, Timson DJ. A calcium-dependent interaction between calmodulin and the calponin homology domain of human IQGAP1. Mol Cell Biochem 2012; 371:217-23. [PMID: 22944912 DOI: 10.1007/s11010-012-1438-0] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2012] [Accepted: 08/25/2012] [Indexed: 01/01/2023]
Abstract
IQGAPs are cytoskeletal scaffolding proteins which collect information from a variety of signalling pathways and pass it on to the microfilaments and microtubules. There is a well-characterised interaction between IQGAP and calmodulin through a series of IQ-motifs towards the middle of the primary sequence. However, it has been shown previously that the calponin homology domain (CHD), located at the N-terminus of the protein, can also interact weakly with calmodulin. Using a recombinant fragment of human IQGAP1 which encompasses the CHD, we have demonstrated that the CHD undergoes a calcium ion-dependent interaction with calmodulin. The CHD can also displace the hydrophobic fluorescent probe 1-anilinonaphthalene-8-sulphonate from calcium-calmodulin, suggesting that the interaction involves non-polar residues on the surface of calmodulin. Molecular modelling identified a possible site on the CHD for calmodulin interaction. The physiological significance of this interaction remains to be discovered.
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Affiliation(s)
- William J Andrews
- School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK
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45
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Jang DJ. Characterization for calmodulin binding activity of IQ motifs on the IQGAP3. Analytical Science and Technology 2012. [DOI: 10.5806/ast.2012.25.5.333] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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46
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Abstract
Purkinje cell protein 4-like 1 (Pcp4l1) is a small neuronal IQ motif protein closely related to the calmodulin-binding protein Pcp4/PEP-19. PEP-19 interacts with calmodulin via its IQ motif to inhibit calmodulin-dependent enzymes and we hypothesized Pcp4l1 would have similar properties. Surprisingly, full-length Pcp4l1 does not interact with calmodulin in yeast two-hybrid or pulldown experiments yet a synthetic peptide constituting only the IQ motif of Pcp4l1 binds calmodulin and inhibits calmodulin-dependent kinase II. A nine-residue glutamic acid-rich sequence in Pcp4l1 confers these unexpected properties. This element lies outside the IQ motif and its deletion or exchange with the homologous region of PEP-19 restores calmodulin binding. Conversion of a single isoleucine (Ile36) within this motif to phenylalanine, the residue present in PEP-19, imparts calmodulin binding onto Pcp4l1. Moreover, only aromatic amino acid substitutions at position 36 in Pcp4l1 allow binding. Thus, despite their sequence similarities PEP-19 and Pcp4l1 have distinct properties with the latter harboring an element that can functionally suppress an IQ motif. We speculate Pcp4l1 may be a latent calmodulin inhibitor regulated by post-translational modification and/or co-factor interactions.
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Affiliation(s)
- Marc A J Morgan
- Sir William Dunn School of Pathology, University of Oxford, Oxford, UK.
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47
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Elliott SF, Allen G, Timson DJ. Biochemical analysis of the interactions of IQGAP1 C-terminal domain with CDC42. World J Biol Chem 2012; 3:53-60. [PMID: 22451851 PMCID: PMC3312201 DOI: 10.4331/wjbc.v3.i3.53] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2011] [Revised: 01/31/2012] [Accepted: 02/07/2012] [Indexed: 02/05/2023] Open
Abstract
AIM: To understand the interaction of human IQGAP1 and CDC42, especially the effects of phosphorylation and a cancer-associated mutation.
METHODS: Recombinant CDC42 and a novel C-terminal fragment of IQGAP1 were expressed in, and purified from, Escherichia coli. Site directed mutagenesis was used to create coding sequences for three phosphomimicking variants (S1441E, S1443D and S1441E/S1443D) and to recapitulate a cancer-associated mutation (M1231I). These variant proteins were also expressed and purified. Protein-protein crosslinking using 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide was used to investigate interactions between the C-terminal fragment and CDC42. These interactions were quantified using surface plasmon resonance measurements. Molecular modelling was employed to make predictions about changes to the structure and flexibility of the protein which occur in the cancer-associated variant.
RESULTS: The novel, C-terminal region of human IQGAP1 (residues 877-1558) is soluble following expression and purification. It is also capable of binding to CDC42, as judged by crosslinking experiments. Interaction appears to be strongest in the presence of added GTP. The three phosphomimicking mutants had different affinities for CDC42. S1441E had an approximately 200-fold reduction in affinity compared to wild type. This was caused largely by a dramatic reduction in the association rate constant. In contrast, both S1443D and the double variant S1441E/S1443D had similar affinities to the wild type. The cancer-associated variant, M1231I, also had a similar affinity to wild type. However, in the case of this variant, both the association and dissociation rate constants were reduced approximately 10-fold. Molecular modelling of the M1231I variant, based on the published crystal structure of part of the C-terminal region, revealed no gross structural changes compared to wild type (root mean square deviation of 0.564 Å over 5556 equivalent atoms). However, predictions of the flexibility of the polypeptide backbone suggested that some regions of the variant protein had greatly increased rigidity compared to wild type. One such region is a loop linking the proposed CDC42 binding site with the helix containing the altered residue. It is suggested that this increase in rigidity is responsible for the observed changes in association and dissociation rate constants.
CONCLUSION: The consequences of introducing negative charge at Ser-1441 or Ser-1443 in IQGAP1 are different. The cancer-associated variant M1231I exerts its effects partly by rigidifying the protein.
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Affiliation(s)
- Sarah F Elliott
- Sarah F Elliott, George Allen, David J Timson, School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, Belfast, BT9 7BL, United Kingdom
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48
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Jang DJ. Analysis of calmodulin binding property of IQ motifs of IQGAP1. Analytical Science and Technology 2011. [DOI: 10.5806/ast.2011.24.6.527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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49
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White CD, Erdemir HH, Sacks DB. IQGAP1 and its binding proteins control diverse biological functions. Cell Signal 2011; 24:826-34. [PMID: 22182509 DOI: 10.1016/j.cellsig.2011.12.005] [Citation(s) in RCA: 171] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2011] [Accepted: 12/04/2011] [Indexed: 12/26/2022]
Abstract
IQGAP proteins have been identified in a wide spectrum of organisms, ranging from yeast to humans. The most extensively studied family member is the ubiquitously expressed scaffold protein IQGAP1, which participates in multiple essential aspects of mammalian biology. IQGAP1 mediates these effects by binding to and regulating the function of numerous interacting proteins. Over ninety proteins have been reported to associate with IQGAP1, either directly or as part of a larger complex. In this review, we summarise those IQGAP1 binding partners that have been identified in the last five years. The molecular mechanisms by which these interactions contribute to the functions of receptors and their signalling cascades, small GTPase function, cytoskeletal dynamics, neuronal regulation and intracellular trafficking are evaluated. The evidence that has accumulated recently validates the role of IQGAP1 as a scaffold protein and expands the repertoire of cellular activities in which it participates.
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Affiliation(s)
- Colin D White
- Department of Pathology, Beth Israel Deaconess Medical Centre and Harvard Medical School, 3 Blackfan Circle, Boston, MA 02115, USA
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50
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Jang DJ, Ban B, Lee JA. Characterization of novel calmodulin binding domains within IQ motifs of IQGAP1. Mol Cells 2011; 32:511-8. [PMID: 22080369 PMCID: PMC3887683 DOI: 10.1007/s10059-011-0109-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2011] [Revised: 09/22/2011] [Accepted: 09/22/2011] [Indexed: 12/11/2022] Open
Abstract
IQ motif-containing GTPase-activating protein 1 (IQGAP1), which is a well-known calmodulin (CaM) binding protein, is involved in a wide range of cellular processes including cell proliferation, tumorigenesis, adhesion, and migration. Interaction of IQGAP1 with CaM is important for its cellular functions. Although each IQ domain of IQGAP1 for CaM binding has been characterized in a Ca(2+)-dependent or -independent manner, it was not clear which IQ motifs are physiologically relevant for CaM binding in the cells. In this study, we performed immunoprecipitation using 3xFLAGhCaM in mammalian cell lines to characterize the domains of IQGAP1 that are key for CaM binding under physiological conditions. Interestingly, using this method, we identified two novel domains, IQ(2.7-3) and IQ(3.5-4.4), within IQGAP1 that were involved in Ca(2+)-independent or -dependent CaM binding, respectively. Mutant analysis clearly showed that the hydrophobic regions within IQ(2.7-3) were mainly involved in apoCaM binding, while the basic amino acids and hydrophobic region of IQ(3.5-4.4) were required for Ca(2+)/CaM binding. Finally, we showed that IQ(2.7-3) was the main apoCaM binding domain and both IQ(2.7-3) and IQ(3.5-4.4) were required for Ca(2+)/CaM binding within IQ(1-2-3-4). Thus, we identified and characterized novel direct CaM binding motifs essential for IQGAP1. This finding indicates that IQGAP1 plays a dynamic role via direct interactions with CaM in a Ca(2+)-dependent or -independent manner.
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Affiliation(s)
- Deok-Jin Jang
- Department of Applied Biology, College of Ecology and Environment, Kyungpook National University, Daegu 742-711, Korea
- These authors contributed equally to this work
| | - Byungkwan Ban
- Department of Biotechnology, College of Life Science and Nano Technology, Hannam University, Daejeon 305-811, Korea
- These authors contributed equally to this work
| | - Jin-A Lee
- Department of Biotechnology, College of Life Science and Nano Technology, Hannam University, Daejeon 305-811, Korea
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