1
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Park Y, Matsumoto S, Ogata K, Ma B, Kanada R, Isaka Y, Arichi N, Liang X, Maki R, Kozasa T, Okuno Y, Ohno H, Ishihama Y, Toyoshima F. Receptor-independent regulation of Gα13 by alpha-1-antitrypsin C-terminal peptides. J Biol Chem 2024:108136. [PMID: 39730062 DOI: 10.1016/j.jbc.2024.108136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2024] [Revised: 12/17/2024] [Accepted: 12/19/2024] [Indexed: 12/29/2024] Open
Abstract
Alpha-1-antitrypsin (AAT), a circulating serine protease inhibitor, is an acute inflammatory response protein with anti-inflammatory functions. The C-terminal peptides of AAT are found in various tissues and have been proposed as putative bioactive peptides with multiple functions, but its mechanism of action remains unclear. We previously reported that a mouse AAT C-terminal peptide of 35 amino acids (mAAT-C1-35) penetrates plasma membrane and associates guanine nucleotide-binding protein subunit alpha 13 (Gα13). Here, we show that mAAT-C1-35 binds directly to the guanosine diphosphate (GDP)-bound form of Gα13 through the N-terminal region (mAAT-C1-17), thereby facilitating the interaction of Gα13・GDP with its effector proteins. The minimal sequence (mAAT-C3-16) and essential amino acid residue (Phe11) of mAAT-C1-17 were identified as being necessary for this effect. A molecular dynamics simulation for the Gα13・GDP-mAAT-C1-17 complex model showed that binding of mAAT-C1-17 to the region surrounded by switch regions of Gα13 stabilizes the flexible switch II and III regions, thereby maintaining their active conformation. In addition, mAAT-C1-35 activates the Gα13 signalling pathway in cells where Phe11 is required. Our study reveals the structure-based mechanism of action of AAT-C peptides in the regulation of Gα13, and demonstrates that AAT-C peptides represent a biological peptide capable of activating G protein signals in a manner that is independent of G-protein-coupled receptors.
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Affiliation(s)
- Yonghak Park
- Department of Biosystems Science, Institute for Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan; Department of Mammalian and Regulatory Networks, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Shigeyuki Matsumoto
- Department of Biomedical Data Intelligence, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan.
| | - Kosuke Ogata
- Department of Molecular Systems BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Biao Ma
- RIKEN Center for Computational Science, Kobe, 650-0047 Hyogo, Japan
| | - Ryo Kanada
- RIKEN Center for Computational Science, Kobe, 650-0047 Hyogo, Japan
| | - Yuta Isaka
- RIKEN Center for Computational Science, Kobe, 650-0047 Hyogo, Japan
| | - Norihito Arichi
- Department of Bioorganic Medicinal Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Xiaowen Liang
- Department of Biosystems Science, Institute for Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan; Department of Mammalian and Regulatory Networks, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan
| | - Ritsuko Maki
- Department of Biosystems Science, Institute for Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan
| | - Tohru Kozasa
- Department of Biochemistry, Yokohama University of Pharmacy, Yokohama 245-0066, Japan
| | - Yasushi Okuno
- Department of Biomedical Data Intelligence, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan; RIKEN Center for Computational Science, Kobe, 650-0047 Hyogo, Japan
| | - Hiroaki Ohno
- Department of Bioorganic Medicinal Chemistry, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Yasushi Ishihama
- Department of Molecular Systems BioAnalysis, Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Fumiko Toyoshima
- Department of Biosystems Science, Institute for Life and Medical Sciences, Kyoto University, Kyoto 606-8507, Japan; Department of Mammalian and Regulatory Networks, Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan; Department of Homeostatic Medicine, Medical Research Laboratory, Institute of Integrated Research, Institute of Science Tokyo, Yushima Bunkyo-ku, Tokyo 113-8510, Japan.
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2
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Ferreras-Gutiérrez M, Mínguez-Toral M, Ibáñez de Opakua A, Martín-Santamaría S, García-Marcos M, Medrano FJ, Blanco FJ. Integrated NMR-crystallography-computational approach for molecular recognition studies of human Gαi3 protein by a small molecule inhibitor. Int J Biol Macromol 2024; 290:138977. [PMID: 39706421 DOI: 10.1016/j.ijbiomac.2024.138977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2024] [Revised: 12/16/2024] [Accepted: 12/17/2024] [Indexed: 12/23/2024]
Abstract
The small molecule IGGi-11 targets Gαi subunits of heterotrimeric guanine nucleotide-binding proteins. Gα subunits are activated by G-protein-coupled receptors in response to extracellular stimuli by accelerating the exchange of GDP for GTP, but they are also activated by intracellular proteins like GIV, of which elevated levels correlate with increased cell migration and cancer metastasis. IGGi-11 disrupts the interaction of Gαi proteins with GIV and inhibits pro-invasive traits of metastatic breast cancer cells without interfering with GPCR signaling. IGGi-11 is a competitive inhibitor but binds Gαi3 with a 10-fold lower affinity than GIV. To guide the design of higher affinity inhibitors, we aimed at obtaining high-resolution structural data on the complex. To facilitate its crystallization, we have removed the most flexible residues at the chain ends of Gαi3, identified by NMR. While Gαi3 crystals grown with excess IGGi-11 did not show the bound compound, computational docking and molecular dynamics simulations identified the interactions driving the molecular recognition. This approach revealed heterogeneous binding due to the symmetry of IGGi-11 chemical structure and to the elongated shape and flexibility of the binding site. Our results suggest that chemical modifications breaking IGGi-11 symmetry might yield inhibitors with higher affinity and potential as antimetastatic drugs.
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Affiliation(s)
| | - Marina Mínguez-Toral
- Centro de Investigaciones Biológicas Margarita Salas (CIB), CSIC, Madrid 28040, Spain
| | | | | | - Mikel García-Marcos
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, MA 02118, USA; Department of Biology, College of Arts & Sciences, Boston University, Boston, MA 02115, USA
| | - Francisco J Medrano
- Centro de Investigaciones Biológicas Margarita Salas (CIB), CSIC, Madrid 28040, Spain
| | - Francisco J Blanco
- Instituto de Biomedicina de Valencia (IBV), CSIC, Valencia 46010, Spain; Centro de Investigación Príncipe Felipe, Unidad Asociada a IBV, Valencia 46012, Spain.
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3
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Dwyer MB, Aumiller JL, Wedegaertner PB. Going Rogue: Mechanisms, Regulation, and Roles of Mutationally Activated G α in Human Cancer. Mol Pharmacol 2024; 106:198-215. [PMID: 39187387 PMCID: PMC11493338 DOI: 10.1124/molpharm.124.000743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2024] [Revised: 08/19/2024] [Accepted: 08/21/2024] [Indexed: 08/28/2024] Open
Abstract
G protein-coupled receptors (GPCRs) couple to heterotrimeric G proteins, comprised of α and βγ subunits, to convert extracellular signals into activation of intracellular signaling pathways. Canonically, GPCR-mediated activation results in the exchange of GDP for GTP on G protein α subunits (Gα) and the dissociation of Gα-GTP and G protein βγ subunits (Gβγ), both of which can regulate a variety of signaling pathways. Hydrolysis of bound GTP by Gα returns the protein to Gα-GDP and allows reassociation with Gβγ to reform the inactive heterotrimer. Naturally occurring mutations in Gα have been found at conserved glutamine and arginine amino acids that disrupt the canonical G protein cycle by inhibiting GTP hydrolysis, rendering these mutants constitutively active. Interestingly, these dysregulated Gα mutants are found in many different cancers due to their ability to sustain aberrant signaling without a need for activation by GPCRs. This review will highlight an increased recognition of the prevalence of such constitutively activating Gα mutations in cancers and the signaling pathways activated. In addition, we will discuss new knowledge regarding how these constitutively active Gα are regulated, how different mutations are biochemically distinct, and how mutationally activated Gα are unique compared with GPCR-activated Gα Lastly, we will discuss recent progress in developing inhibitors directly targeting constitutively active Gα mutants. SIGNIFICANCE STATEMENT: Constitutively activating mutations in G protein α subunits (Gα) widely occur in and contribute to the development of many human cancers. To develop ways to inhibit dysregulated, oncogenic signaling by these mutant Gα, it is crucial to better understand mechanisms that lead to constitutive Gα activation and unique mechanisms that regulate mutationally activated Gα in cells. The prevalence of activating mutations in Gα in various cancers makes Gα proteins compelling targets for the development of therapeutics.
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Affiliation(s)
- Morgan B Dwyer
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Jenna L Aumiller
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Philip B Wedegaertner
- Department of Biochemistry and Molecular Biology, Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, Pennsylvania
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4
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Pepanian A, Binbay FA, Pei D, Imhof D. Design, synthesis, and analysis of macrobicyclic peptides for targeting the Gαi protein. J Pept Sci 2024; 30:e3565. [PMID: 38232955 PMCID: PMC11065574 DOI: 10.1002/psc.3565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2023] [Revised: 12/13/2023] [Accepted: 12/14/2023] [Indexed: 01/19/2024]
Abstract
Bicyclic peptides are important chemical tools that can function, for example, as bioactive ligands switching on/off signaling pathways mediated by guanine nucleotide-binding proteins as bicycles are more broadly applicable. Despite their relevance in medicinal chemistry, the synthesis of such peptides is challenging, and the final yield is highly dependent on the chemical composition and physicochemical properties of the scaffold. We recently discovered novel, state-specific peptide modulators targeting the Gαi protein, namely, GPM-2/GPM-3, by screening a one-bead-two-compound combinatorial library. A more detailed analysis, including sequence alignments and computer-assisted conformational studies based on the hit compounds, revealed the new peptide 10 as a potential macrobicyclic Gαi ligand sharing high sequence similarity to the known Gαi modulators. The Gαs protein was included in this study for comparison and to unravel the criteria for the specificity of modulator binding to Gαi versus Gαs. This work provides in-depth computer-assisted experimental studies for the analysis of novel macrobicyclic, library-derived Gαi protein ligands. The sequence and structural comparison of 10 with the lead compounds GPM-2 and GPM-3 reveals the importance of the size and amino acid composition of one ring of the bicyclic system and suggests features enhancing the binding affinity of the peptides to the Gαi protein.
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Affiliation(s)
- Anna Pepanian
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany
| | - F. Ayberk Binbay
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany
| | - Dehua Pei
- Department of Chemistry and Biochemistry, The Ohio State University, 578 Biological Sciences Building, 484 W 12th Avenue, Columbus, OH 43210, USA
| | - Diana Imhof
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, 53121 Bonn, Germany
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5
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Shewani K, Madhu MK, Murarka RK. Mechanistic insights into G-protein activation via phosphorylation mediated non-canonical pathway. Biophys Chem 2024; 309:107234. [PMID: 38603989 DOI: 10.1016/j.bpc.2024.107234] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 03/21/2024] [Accepted: 04/02/2024] [Indexed: 04/13/2024]
Abstract
Activation of heterotrimeric G-proteins (Gαβγ) downstream to receptor tyrosine kinases (RTKs) is a well-established crosstalk between the signaling pathways mediated by G-protein coupled receptors (GPCRs) and RTKs. While GPCR serves as a guanine exchange factor (GEF) in the canonical activation of Gα that facilitates the exchange of GDP for GTP, the mechanism through which RTK phosphorylations induce Gα activation remains unclear. Recent experimental studies revealed that the epidermal growth factor receptor (EGFR), a well-known RTK, phosphorylates the helical domain tyrosine residues Y154 and Y155 and accelerates the GDP release from the Gαi3, a subtype of Gα-protein. Using well-tempered metadynamics and extensive unbiased molecular dynamics simulations, we captured the GDP release event and identified the intermediates between bound and unbound states through Markov state models. In addition to weakened salt bridges at the domain interface, phosphorylations induced the unfolding of helix αF, which contributed to increased flexibility near the hinge region, facilitating a greater distance between domains in the phosphorylated Gαi3. Although the larger domain separation in the phosphorylated system provided an unobstructed path for the nucleotide, the accelerated release of GDP was attributed to increased fluctuations in several conserved regions like P-loop, switch 1, and switch 2. Overall, this study provides atomistic insights into the activation of G-proteins induced by RTK phosphorylations and identifies the specific structural motifs involved in the process. The knowledge gained from the study could establish a foundation for targeting non-canonical signaling pathways and developing therapeutic strategies against the ailments associated with dysregulated G-protein signaling.
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Affiliation(s)
- Kunal Shewani
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhopal 462066, MP, India
| | - Midhun K Madhu
- Department of Biological Sciences, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhopal 462066, MP, India
| | - Rajesh K Murarka
- Department of Chemistry, Indian Institute of Science Education and Research Bhopal, Bhopal Bypass Road, Bhopal 462066, MP, India.
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6
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Nürnberg B, Beer-Hammer S, Reisinger E, Leiss V. Non-canonical G protein signaling. Pharmacol Ther 2024; 255:108589. [PMID: 38295906 DOI: 10.1016/j.pharmthera.2024.108589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Revised: 12/18/2023] [Accepted: 01/08/2024] [Indexed: 02/17/2024]
Abstract
The original paradigm of classical - also referred to as canonical - cellular signal transduction of heterotrimeric G proteins (G protein) is defined by a hierarchical, orthograde interaction of three players: the agonist-activated G protein-coupled receptor (GPCR), which activates the transducing G protein, that in turn regulates its intracellular effectors. This receptor-transducer-effector concept was extended by the identification of regulators and adapters such as the regulators of G protein signaling (RGS), receptor kinases like βARK, or GPCR-interacting arrestin adapters that are integrated into this canonical signaling process at different levels to enable fine-tuning. Finally, the identification of atypical signaling mechanisms of classical regulators, together with the discovery of novel modulators, added a new and fascinating dimension to the cellular G protein signal transduction. This heterogeneous group of accessory G protein modulators was coined "activators of G protein signaling" (AGS) proteins and plays distinct roles in canonical and non-canonical G protein signaling pathways. AGS proteins contribute to the control of essential cellular functions such as cell development and division, intracellular transport processes, secretion, autophagy or cell movements. As such, they are involved in numerous biological processes that are crucial for diseases, like diabetes mellitus, cancer, and stroke, which represent major health burdens. Although the identification of a large number of non-canonical G protein signaling pathways has broadened the spectrum of this cellular communication system, their underlying mechanisms, functions, and biological effects are poorly understood. In this review, we highlight and discuss atypical G protein-dependent signaling mechanisms with a focus on inhibitory G proteins (Gi) involved in canonical and non-canonical signal transduction, review recent developments and open questions, address the potential of new approaches for targeted pharmacological interventions.
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Affiliation(s)
- Bernd Nürnberg
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, and ICePhA Mouse Clinic, University of Tübingen, Wilhelmstraße 56, D-72074 Tübingen, Germany.
| | - Sandra Beer-Hammer
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, and ICePhA Mouse Clinic, University of Tübingen, Wilhelmstraße 56, D-72074 Tübingen, Germany
| | - Ellen Reisinger
- Gene Therapy for Hearing Impairment Group, Department of Otolaryngology - Head & Neck Surgery, University of Tübingen Medical Center, Elfriede-Aulhorn-Straße 5, D-72076 Tübingen, Germany
| | - Veronika Leiss
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, and ICePhA Mouse Clinic, University of Tübingen, Wilhelmstraße 56, D-72074 Tübingen, Germany
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7
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Garcia-Marcos M. Heterotrimeric G protein signaling without GPCRs: The Gα-binding-and-activating (GBA) motif. J Biol Chem 2024; 300:105756. [PMID: 38364891 PMCID: PMC10943482 DOI: 10.1016/j.jbc.2024.105756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 01/30/2024] [Accepted: 02/02/2024] [Indexed: 02/18/2024] Open
Abstract
Heterotrimeric G proteins (Gαβγ) are molecular switches that relay signals from 7-transmembrane receptors located at the cell surface to the cytoplasm. The function of these receptors is so intimately linked to heterotrimeric G proteins that they are named G protein-coupled receptors (GPCRs), showcasing the interdependent nature of this archetypical receptor-transducer axis of transmembrane signaling in eukaryotes. It is generally assumed that activation of heterotrimeric G protein signaling occurs exclusively by the action of GPCRs, but this idea has been challenged by the discovery of alternative mechanisms by which G proteins can propagate signals in the cell. This review will focus on a general principle of G protein signaling that operates without the direct involvement of GPCRs. The mechanism of G protein signaling reviewed here is mediated by a class of G protein regulators defined by containing an evolutionarily conserved sequence named the Gα-binding-and-activating (GBA) motif. Using the best characterized proteins with a GBA motif as examples, Gα-interacting vesicle-associated protein (GIV)/Girdin and dishevelled-associating protein with a high frequency of leucine residues (DAPLE), this review will cover (i) the mechanisms by which extracellular cues not relayed by GPCRs promote the coupling of GBA motif-containing regulators with G proteins, (ii) the structural and molecular basis for how GBA motifs interact with Gα subunits to facilitate signaling, (iii) the relevance of this mechanism in different cellular and pathological processes, including cancer and birth defects, and (iv) strategies to manipulate GBA-G protein coupling for experimental therapeutics purposes, including the development of rationally engineered proteins and chemical probes.
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Affiliation(s)
- Mikel Garcia-Marcos
- Department of Biochemistry & Cell Biology, Chobanian & Avedisian School of Medicine, Boston University, Boston, Massachusetts, USA; Department of Biology, College of Arts & Sciences, Boston University, Boston, Massachusetts, USA.
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8
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Mohanasundaram B, Pandey S. Moving beyond the arabidopsis-centric view of G-protein signaling in plants. TRENDS IN PLANT SCIENCE 2023; 28:1406-1421. [PMID: 37625950 DOI: 10.1016/j.tplants.2023.07.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Revised: 07/24/2023] [Accepted: 07/28/2023] [Indexed: 08/27/2023]
Abstract
Heterotrimeric G-protein-mediated signaling is a key mechanism to transduce a multitude of endogenous and environmental signals in diverse organisms. The scope and expectations of plant G-protein research were set by pioneering work in metazoans. Given the similarity of the core constituents, G-protein-signaling mechanisms were presumed to be universally conserved. However, because of the enormous diversity of survival strategies and endless forms among eukaryotes, the signal, its interpretation, and responses vary even among different plant groups. Earlier G-protein research in arabidopsis (Arabidopsis thaliana) has emphasized its divergence from Metazoa. Here, we compare recent evidence from diverse plant lineages with the available arabidopsis G-protein model and discuss the conserved and novel protein components, signaling mechanisms, and response regulation.
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Affiliation(s)
| | - Sona Pandey
- Donald Danforth Plant Science Center, 975 N. Warson Road, St Louis, MO 63132, USA.
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9
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Pepanian A, Binbay FA, Roy S, Nubbemeyer B, Koley A, Rhodes CA, Ammer H, Pei D, Ghosh P, Imhof D. Bicyclic Peptide Library Screening for the Identification of Gαi Protein Modulators. J Med Chem 2023; 66:12396-12406. [PMID: 37587416 PMCID: PMC11000586 DOI: 10.1021/acs.jmedchem.3c00873] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2023]
Abstract
Noncanonical G protein activation and inactivation, particularly for the Gαi/s protein subfamilies, have long been a focus of chemical research. Combinatorial libraries were already effectively applied to identify modulators of the guanine-nucleotide exchange, as can be exemplified with peptides such as KB-752 and GPM-1c/d, the so-called guanine-nucleotide exchange modulators. In this study, we identified novel bicyclic peptides from a combinatorial library screening that show prominent properties as molecular switch-on/off modulators of Gαi signaling. Among the series of hits, the exceptional paradigm of GPM-3, a protein and state-specific bicyclic peptide, is the first chemically identified GAP (GTPase-activating protein) modulator with a high binding affinity for Gαi protein. Computational analyses identified and assessed the structure of the bicyclic peptides, novel ligand-protein interaction sites, and their subsequent impact on the nucleotide binding site. This approach can therefore lead the way for the development of efficient chemical biological probes targeting Gαi protein modulation within a cellular context.
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Affiliation(s)
- Anna Pepanian
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenbeurg 4, Bonn 53121, Germany
| | - Furkan Ayberk Binbay
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenbeurg 4, Bonn 53121, Germany
| | - Suchismita Roy
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093, United States
| | - Britta Nubbemeyer
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenbeurg 4, Bonn 53121, Germany
| | - Amritendu Koley
- Department of Chemistry and Biochemistry, The Ohio State University, 578 Biological Sciences Building, 484 W 12th Avenue, Columbus, Ohio 43210, United States
| | - Curran A Rhodes
- Department of Chemistry and Biochemistry, The Ohio State University, 578 Biological Sciences Building, 484 W 12th Avenue, Columbus, Ohio 43210, United States
| | - Hermann Ammer
- Institute of Pharmacology Toxicology and Pharmacy, Veterinary Faculty, Ludwig Maximilian University of Munich, Königinstr. 16, Munich 80539, Germany
| | - Dehua Pei
- Department of Chemistry and Biochemistry, The Ohio State University, 578 Biological Sciences Building, 484 W 12th Avenue, Columbus, Ohio 43210, United States
| | - Pradipta Ghosh
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92093, United States
- Department of Medicine, University of California San Diego, La Jolla, California 92093, United States
| | - Diana Imhof
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenbeurg 4, Bonn 53121, Germany
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10
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Ahn D, Provasi D, Duc NM, Xu J, Salas-Estrada L, Spasic A, Yun MW, Kang J, Gim D, Lee J, Du Y, Filizola M, Chung KY. Gαs slow conformational transition upon GTP binding and a novel Gαs regulator. iScience 2023; 26:106603. [PMID: 37128611 PMCID: PMC10148139 DOI: 10.1016/j.isci.2023.106603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 03/16/2023] [Accepted: 03/29/2023] [Indexed: 05/03/2023] Open
Abstract
G proteins are major signaling partners for G protein-coupled receptors (GPCRs). Although stepwise structural changes during GPCR-G protein complex formation and guanosine diphosphate (GDP) release have been reported, no information is available with regard to guanosine triphosphate (GTP) binding. Here, we used a novel Bayesian integrative modeling framework that combines data from hydrogen-deuterium exchange mass spectrometry, tryptophan-induced fluorescence quenching, and metadynamics simulations to derive a kinetic model and atomic-level characterization of stepwise conformational changes incurred by the β2-adrenergic receptor (β2AR)-Gs complex after GDP release and GTP binding. Our data suggest rapid GTP binding and GTP-induced dissociation of Gαs from β2AR and Gβγ, as opposed to a slow closing of the Gαs α-helical domain (AHD). Yeast-two-hybrid screening using Gαs AHD as bait identified melanoma-associated antigen D2 (MAGE D2) as a novel AHD-binding protein, which was also shown to accelerate the GTP-induced closing of the Gαs AHD.
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Affiliation(s)
- Donghoon Ahn
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Davide Provasi
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Nguyen Minh Duc
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jun Xu
- Molecular and Cellular Physiology, School of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Leslie Salas-Estrada
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Aleksandar Spasic
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Min Woo Yun
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Juyeong Kang
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Biopharmaceutical Convergence, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Dongmin Gim
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Biopharmaceutical Convergence, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Jaecheol Lee
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Biopharmaceutical Convergence, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Biomedical Institute for Convergence at SKKU (BICS), Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Yang Du
- School of Life and Health Sciences, Kobilka Institute of Innovative Drug Discovery, Chinese University of Hong Kong, Shenzhen, Guangdong 518172, China
| | - Marta Filizola
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY 10029, USA
| | - Ka Young Chung
- School of Pharmacy, Sungkyunkwan University, Suwon 16419, Republic of Korea
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11
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Zhao J, DiGiacomo V, Ferreras-Gutierrez M, Dastjerdi S, Ibáñez de Opakua A, Park JC, Luebbers A, Chen Q, Beeler A, Blanco FJ, Garcia-Marcos M. Small-molecule targeting of GPCR-independent noncanonical G-protein signaling in cancer. Proc Natl Acad Sci U S A 2023; 120:e2213140120. [PMID: 37098067 PMCID: PMC10160980 DOI: 10.1073/pnas.2213140120] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 03/06/2023] [Indexed: 04/26/2023] Open
Abstract
Activation of heterotrimeric G-proteins (Gαβγ) by G-protein-coupled receptors (GPCRs) is a quintessential mechanism of cell signaling widely targeted by clinically approved drugs. However, it has become evident that heterotrimeric G-proteins can also be activated via GPCR-independent mechanisms that remain untapped as pharmacological targets. GIV/Girdin has emerged as a prototypical non-GPCR activator of G proteins that promotes cancer metastasis. Here, we introduce IGGi-11, a first-in-class small-molecule inhibitor of noncanonical activation of heterotrimeric G-protein signaling. IGGi-11 binding to G-protein α-subunits (Gαi) specifically disrupted their engagement with GIV/Girdin, thereby blocking noncanonical G-protein signaling in tumor cells and inhibiting proinvasive traits of metastatic cancer cells. In contrast, IGGi-11 did not interfere with canonical G-protein signaling mechanisms triggered by GPCRs. By revealing that small molecules can selectively disable noncanonical mechanisms of G-protein activation dysregulated in disease, these findings warrant the exploration of therapeutic modalities in G-protein signaling that go beyond targeting GPCRs.
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Affiliation(s)
- Jingyi Zhao
- Department of Biochemistry & Cell Biology, Boston University, Chobanian & Avedisian School of Medicine, Boston, MA02118
| | - Vincent DiGiacomo
- Department of Biochemistry & Cell Biology, Boston University, Chobanian & Avedisian School of Medicine, Boston, MA02118
| | | | - Shiva Dastjerdi
- Department of Chemistry, Boston University, College of Arts & Sciences, Boston, MA02115
| | | | - Jong-Chan Park
- Department of Biochemistry & Cell Biology, Boston University, Chobanian & Avedisian School of Medicine, Boston, MA02118
| | - Alex Luebbers
- Department of Biochemistry & Cell Biology, Boston University, Chobanian & Avedisian School of Medicine, Boston, MA02118
| | - Qingyan Chen
- Department of Biochemistry & Cell Biology, Boston University, Chobanian & Avedisian School of Medicine, Boston, MA02118
| | - Aaron Beeler
- Department of Chemistry, Boston University, College of Arts & Sciences, Boston, MA02115
| | - Francisco J. Blanco
- Centro de Investigaciones Biológicas-Centro Superior de Investigaciones Cientificas, Madrid, Spain
| | - Mikel Garcia-Marcos
- Department of Biochemistry & Cell Biology, Boston University, Chobanian & Avedisian School of Medicine, Boston, MA02118
- Department of Biology, College of Arts & Sciences, Boston University, Boston, MA02115
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12
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Qiao L, Sinha S, Abd El‐Hafeez AA, Lo I, Midde KK, Ngo T, Aznar N, Lopez‐Sanchez I, Gupta V, Farquhar MG, Rangamani P, Ghosh P. A circuit for secretion-coupled cellular autonomy in multicellular eukaryotic cells. Mol Syst Biol 2023; 19:e11127. [PMID: 36856068 PMCID: PMC10090951 DOI: 10.15252/msb.202211127] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Revised: 02/06/2023] [Accepted: 02/07/2023] [Indexed: 03/02/2023] Open
Abstract
Cancers represent complex autonomous systems, displaying self-sufficiency in growth signaling. Autonomous growth is fueled by a cancer cell's ability to "secrete-and-sense" growth factors (GFs): a poorly understood phenomenon. Using an integrated computational and experimental approach, here we dissect the impact of a feedback-coupled GTPase circuit within the secretory pathway that imparts secretion-coupled autonomy. The circuit is assembled when the Ras-superfamily monomeric GTPase Arf1, and the heterotrimeric GTPase Giαβγ and their corresponding GAPs and GEFs are coupled by GIV/Girdin, a protein that is known to fuel aggressive traits in diverse cancers. One forward and two key negative feedback loops within the circuit create closed-loop control, allow the two GTPases to coregulate each other, and convert the expected switch-like behavior of Arf1-dependent secretion into an unexpected dose-response alignment behavior of sensing and secretion. Such behavior translates into cell survival that is self-sustained by stimulus-proportionate secretion. Proteomic studies and protein-protein interaction network analyses pinpoint GFs (e.g., the epidermal GF) as key stimuli for such self-sustenance. Findings highlight how the enhanced coupling of two biological switches in cancer cells is critical for multiscale feedback control to achieve secretion-coupled autonomy of growth factors.
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Affiliation(s)
- Lingxia Qiao
- Department of Mechanical and Aerospace Engineering, Jacob's School of EngineeringUniversity of California San DiegoLa JollaCAUSA
| | - Saptarshi Sinha
- Department of Cellular and Molecular Medicine, School of MedicineUniversity of California San DiegoLa JollaCAUSA
| | - Amer Ali Abd El‐Hafeez
- Department of Cellular and Molecular Medicine, School of MedicineUniversity of California San DiegoLa JollaCAUSA
- Present address:
Pharmacology and Experimental Oncology Unit, Cancer Biology Department, National Cancer InstituteCairo UniversityCairoEgypt
| | - I‐Chung Lo
- Department of Cellular and Molecular Medicine, School of MedicineUniversity of California San DiegoLa JollaCAUSA
| | - Krishna K Midde
- Department of Cellular and Molecular Medicine, School of MedicineUniversity of California San DiegoLa JollaCAUSA
| | - Tony Ngo
- Skaggs School of Pharmacy and Pharmaceutical ScienceUniversity of California San DiegoLa JollaCAUSA
| | - Nicolas Aznar
- Department of Cellular and Molecular Medicine, School of MedicineUniversity of California San DiegoLa JollaCAUSA
| | - Inmaculada Lopez‐Sanchez
- Department of Cellular and Molecular Medicine, School of MedicineUniversity of California San DiegoLa JollaCAUSA
| | - Vijay Gupta
- Department of Cellular and Molecular Medicine, School of MedicineUniversity of California San DiegoLa JollaCAUSA
| | - Marilyn G Farquhar
- Department of Cellular and Molecular Medicine, School of MedicineUniversity of California San DiegoLa JollaCAUSA
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, Jacob's School of EngineeringUniversity of California San DiegoLa JollaCAUSA
| | - Pradipta Ghosh
- Department of Cellular and Molecular Medicine, School of MedicineUniversity of California San DiegoLa JollaCAUSA
- Moores Comprehensive Cancer CenterUniversity of California San DiegoLa JollaCAUSA
- Department of Medicine, School of MedicineUniversity of California San DiegoLa JollaCAUSA
- Veterans Affairs Medical CenterLa JollaCAUSA
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13
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Cao S, Zhang Y, Jiang H, Hou X, Wang W. Structural insight into TIPE1 functioning as a lipid transfer protein. J Biomol Struct Dyn 2023; 41:14049-14062. [PMID: 36898854 DOI: 10.1080/07391102.2023.2187641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2022] [Accepted: 01/30/2023] [Indexed: 03/12/2023]
Abstract
As a member of the tumor necrosis factor-α-induced protein 8 (TNFAIP8/TIPE) family, TIPE1 has been found to be associated with many cellular signaling pathways in regulating apoptosis, autophagy, and tumorigenesis. However, the position of TIPE1 in the signaling network remains elusive. Here we present the crystal structure of zebrafish TIPE1 in complex with phosphatidylethanolamine (PE) at a resolution of 1.38 Å. By comparison with structures of other three TIPE family proteins, a universal phospholipid-binding mode was proposed. Namely, the hydrophobic cavity binds to fatty acid tails, while 'X-R-R' triad nearby the entrance of cavity recognizes the phosphate group head. Using molecular dynamics (MD) simulations, we further elaborated the mechanism of how the lysine-rich N-terminal domain assisting TIPE1 to favorably bind to phosphatidylinositol (PI). Beside small molecule substrate, we identified Gαi3 as a direct-binding partner of TIPE1 using GST pull-down assay and size-exclusion chromatography. Analyses of key-residue mutations and predicted complex structure revealed that the binding mode of TIPE1 to Gαi3 could be non-canonical. In summary, our findings narrowed down TIPE1's position in Gαi3-related and PI-inducing signaling pathways.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Sujian Cao
- Advanced Medical Research Institute, Interventional Medicine Department, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
- The GBA National Institute for Nanotechnology Innovation, Guangzhou, China
| | - Ye Zhang
- Advanced Medical Research Institute, Interventional Medicine Department, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
| | | | - Xuben Hou
- School of Pharmaceutical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Wei Wang
- Advanced Medical Research Institute, Interventional Medicine Department, The Second Hospital, Cheeloo College of Medicine, Shandong University, Jinan, China
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14
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Zhao J, DiGiacomo V, Ferreras-Gutierrez M, Dastjerdi S, de Opakua AI, Park JC, Luebbers A, Chen Q, Beeler A, Blanco FJ, Garcia-Marcos M. Small-molecule targeting of GPCR-independent non-canonical G protein signaling inhibits cancer progression. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.02.18.529092. [PMID: 36824907 PMCID: PMC9949157 DOI: 10.1101/2023.02.18.529092] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
Activation of heterotrimeric G-proteins (Gαβγ) by G-protein-coupled receptors (GPCRs) is a quintessential mechanism of cell signaling widely targeted by clinically-approved drugs. However, it has become evident that heterotrimeric G-proteins can also be activated via GPCR-independent mechanisms that remain untapped as pharmacological targets. GIV/Girdin has emerged as a prototypical non-GPCR activator of G proteins that promotes cancer metastasis. Here, we introduce IGGi-11, a first-in-class smallmolecule inhibitor of non-canonical activation of heterotrimeric G-protein signaling. IGGi-11 binding to G-protein α-subunits (Gαi) specifically disrupted their engagement with GIV/Girdin, thereby blocking non-canonical G-protein signaling in tumor cells, and inhibiting pro-invasive traits of metastatic cancer cells in vitro and in mice. In contrast, IGGi-11 did not interfere with canonical G-protein signaling mechanisms triggered by GPCRs. By revealing that small molecules can selectively disable non-canonical mechanisms of G-protein activation dysregulated in disease, these findings warrant the exploration of therapeutic modalities in G-protein signaling that go beyond targeting GPCRs.
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15
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Abd El-Hafeez AA, Sun N, Chakraborty A, Ear J, Roy S, Chamarthi P, Rajapakse N, Das S, Luker KE, Hazra TK, Luker GD, Ghosh P. Regulation of DNA damage response by trimeric G-proteins. iScience 2023; 26:105973. [PMID: 36756378 PMCID: PMC9900518 DOI: 10.1016/j.isci.2023.105973] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2020] [Revised: 08/14/2022] [Accepted: 01/10/2023] [Indexed: 01/14/2023] Open
Abstract
Upon sensing DNA double-strand breaks (DSBs), eukaryotic cells either die or repair DSBs via one of the two competing pathways, i.e., non-homologous end-joining (NHEJ) or homologous recombination (HR). We show that cell fate after DSBs hinges on GIV/Girdin, a guanine nucleotide-exchange modulator of heterotrimeric Giα•βγ protein. GIV suppresses HR by binding and sequestering BRCA1, a key coordinator of multiple steps within the HR pathway, away from DSBs; it does so using a C-terminal motif that binds BRCA1's BRCT-modules via both phospho-dependent and -independent mechanisms. Using another non-overlapping C-terminal motif GIV binds and activates Gi and enhances the "free" Gβγ→PI-3-kinase→Akt pathway, which promotes survival and is known to suppress HR, favor NHEJ. Absence of GIV, or loss of either of its C-terminal motifs enhanced cell death upon genotoxic stress. Because GIV selectively binds other BRCT-containing proteins suggests that G-proteins may fine-tune sensing, repair, and survival after diverse types of DNA damage.
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Affiliation(s)
- Amer Ali Abd El-Hafeez
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Pharmacology and Experimental Oncology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt
| | - Nina Sun
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Anirban Chakraborty
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Jason Ear
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Biological Sciences Department, California State Polytechnic University, Pomona, CA 91768, USA
| | - Suchismita Roy
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Pranavi Chamarthi
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Navin Rajapakse
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
| | - Soumita Das
- Department of Pathology, University of California San Diego, La Jolla, CA 92093, USA
| | - Kathryn E. Luker
- Center for Molecular Imaging, Department of Radiology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA
| | - Tapas K. Hazra
- Department of Internal Medicine, University of Texas Medical Branch, Galveston, TX 77555, USA
| | - Gary D. Luker
- Center for Molecular Imaging, Department of Radiology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA
- Department of Biomedical Engineering, University of Michigan, 2200 Bonisteel, Blvd., Ann Arbor, MI 48109-2099, USA
- Department of Microbiology and Immunology, University of Michigan, 109 Zina Pitcher Place, Ann Arbor, MI 48109-2200, USA
| | - Pradipta Ghosh
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Department of Medicine, University of California San Diego, La Jolla, CA 92093, USA
- Moores Comprehensive Cancer Center, University of California San Diego, La Jolla, CA 92093, USA
- Veterans Affairs Medical Center, La Jolla, CA, USA
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16
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Qiao L, Ghosh P, Rangamani P. Design principles of improving the dose-response alignment in coupled GTPase switches. NPJ Syst Biol Appl 2023; 9:3. [PMID: 36720885 PMCID: PMC9889403 DOI: 10.1038/s41540-023-00266-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2022] [Accepted: 01/17/2023] [Indexed: 02/02/2023] Open
Abstract
"Dose-response alignment" (DoRA), where the downstream response of cellular signaling pathways closely matches the fraction of activated receptor, can improve the fidelity of dose information transmission. The negative feedback has been experimentally identified as a key component for DoRA, but numerical simulations indicate that negative feedback is not sufficient to achieve perfect DoRA, i.e., perfect match of downstream response and receptor activation level. Thus a natural question is whether there exist design principles for signaling motifs within only negative feedback loops to improve DoRA to near-perfect DoRA. Here, we investigated several model formulations of an experimentally validated circuit that couples two molecular switches-mGTPase (monomeric GTPase) and tGTPase (heterotrimeric GTPases) - with negative feedback loops. In the absence of feedback, the low and intermediate mGTPase activation levels benefit DoRA in mass action and Hill-function models, respectively. Adding negative feedback has versatile roles on DoRA: it may impair DoRA in the mass action model with low mGTPase activation level and Hill-function model with intermediate mGTPase activation level; in other cases, i.e., the mass action model with a high mGTPase activation level or the Hill-function model with a non-intermediate mGTPase activation level, it improves DoRA. Furthermore, we found that DoRA in a longer cascade (i.e., tGTPase) can be obtained using Hill-function kinetics under certain conditions. In summary, we show how ranges of activity of mGTPase, reaction kinetics, the negative feedback, and the cascade length affect DoRA. This work provides a framework for improving the DoRA performance in signaling motifs with negative feedback.
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Affiliation(s)
- Lingxia Qiao
- Department of Mechanical and Aerospace Engineering, Jacob's School of Engineering, University of California San Diego, La Jolla, CA, USA
| | - Pradipta Ghosh
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA.
- Moores Comprehensive Cancer Center, University of California San Diego, La Jolla, CA, USA.
- Department of Medicine, School of Medicine, University of California San Diego, La Jolla, CA, USA.
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, Jacob's School of Engineering, University of California San Diego, La Jolla, CA, USA.
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17
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Effect of α-helical domain of Gi/o α subunit on GDP/GTP turnover. Biochem J 2022; 479:1843-1855. [PMID: 36000572 DOI: 10.1042/bcj20220163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 08/11/2022] [Accepted: 08/24/2022] [Indexed: 11/17/2022]
Abstract
Heterotrimeric guanine nucleotide-binding proteins (G proteins) are composed of α, β, and γ subunits, and Gα has a GDP/GTP-binding pocket. When a guanine nucleotide exchange factor (GEF) interacts with Gα, GDP is released, and GTP interacts to Gα. The GTP-bound activated Gα dissociates from GEF and Gβγ, mediating the induction of various intracellular signaling pathways. Depending on the sequence similarity and cellular function, Gα subunits are subcategorized into four subfamilies: Gαi/o, Gαs, Gαq/11, and Gα12/13. Although the Gαi/o subtype family proteins, Gαi3 and GαoA, share similar sequences and functions, they differ in their GDP/GTP turnover profiles, with GαoA possessing faster rates than Gαi3. The structural factors responsible for these differences remain unknown. In this study, we employed hydrogen/deuterium exchange mass spectrometry and mutational studies to investigate the factors responsible for these functional differences. The Gα subunit consists of a Ras-like domain (RD) and an α-helical domain (AHD). The RD has GTPase activity and receptor-binding and effector-binding regions; however, the function of the AHD has not yet been extensively studied. In this study, the chimeric construct containing the RD of Gαi3 and the AHD of GαoA showed a GDP/GTP turnover profile similar to that of GαoA, suggesting that the AHD is the major regulator of the GDP/GTP turnover profile. Additionally, site-directed mutagenesis revealed the importance of the N-terminal part of αA and αA/αB loops in the AHD for the GDP/GTP exchange. These results suggest that the AHD regulates the nucleotide exchange rate within the Gα subfamily.
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18
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Molina JA, Galaz-Davison P, Komives EA, Artsimovitch I, Ramírez-Sarmiento CA. Allosteric couplings upon binding of RfaH to transcription elongation complexes. Nucleic Acids Res 2022; 50:6384-6397. [PMID: 35670666 PMCID: PMC9226497 DOI: 10.1093/nar/gkac453] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 05/07/2022] [Accepted: 05/18/2022] [Indexed: 12/03/2022] Open
Abstract
In every domain of life, NusG-like proteins bind to the elongating RNA polymerase (RNAP) to support processive RNA synthesis and to couple transcription to ongoing cellular processes. Structures of factor-bound transcription elongation complexes (TECs) reveal similar contacts to RNAP, consistent with a shared mechanism of action. However, NusG homologs differ in their regulatory roles, modes of recruitment, and effects on RNA synthesis. Some of these differences could be due to conformational changes in RNAP and NusG-like proteins, which cannot be captured in static structures. Here, we employed hydrogen-deuterium exchange mass spectrometry to investigate changes in local and non-local structural dynamics of Escherichia coli NusG and its paralog RfaH, which have opposite effects on expression of xenogenes, upon binding to TEC. We found that NusG and RfaH regions that bind RNAP became solvent-protected in factor-bound TECs, whereas RNAP regions that interact with both factors showed opposite deuterium uptake changes when bound to NusG or RfaH. Additional changes far from the factor-binding site were observed only with RfaH. Our results provide insights into differences in structural dynamics exerted by NusG and RfaH during binding to TEC, which may explain their different functional outcomes and allosteric regulation of transcriptional pausing by RfaH.
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Affiliation(s)
- José Alejandro Molina
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Pablo Galaz-Davison
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
| | - Elizabeth A Komives
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Irina Artsimovitch
- Department of Microbiology and The Center for RNA Biology, The Ohio State University, Columbus, OH 43210, USA
| | - César A Ramírez-Sarmiento
- Institute for Biological and Medical Engineering, Schools of Engineering, Medicine and Biological Sciences, Pontificia Universidad Católica de Chile, Santiago, Chile.,ANID - Millennium Science Initiative Program - Millennium Institute for Integrative Biology (iBio), Santiago, Chile
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19
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Nubbemeyer B, George AAP, Kühl T, Pepanian A, Beck MS, Maghraby R, Boushehri MS, Muehlhaupt M, Pfeil EM, Annala SK, Ammer H, Imhof D, Pei D. Targeting Gαi/s Proteins with Peptidyl Nucleotide Exchange Modulators. ACS Chem Biol 2022; 17:463-473. [PMID: 35042325 PMCID: PMC11002716 DOI: 10.1021/acschembio.1c00929] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Chemical probes that specifically modulate the activity of heterotrimeric G proteins provide excellent tools for investigating G protein-mediated cell signaling. Herein, we report a family of selective peptidyl Gαi/s modulators derived from peptide library screening and optimization. Conjugation to a cell-penetrating peptide rendered the peptides cell-permeable and biologically active in cell-based assays. The peptides exhibit potent guanine-nucleotide exchange modulator-like activity toward Gαi and Gαs. Molecular docking and dynamic simulations revealed the molecular basis of the protein-ligand interactions and their effects on GDP binding. This study demonstrates the feasibility of developing direct Gαi/s modulators and provides a novel chemical probe for investigating cell signaling through GPCRs/G proteins.
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Affiliation(s)
- Britta Nubbemeyer
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Ajay Abisheck Paul George
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
- BioSolveIT GmbH, An der Ziegelei 79, 53757, Sankt Augustin, Germany
| | - Toni Kühl
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Anna Pepanian
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Maximilian Steve Beck
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Rahma Maghraby
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Maryam Shetab Boushehri
- Pharmaceutical Technology and Biopharmacy, University of Bonn, Gerhard-Domagk-Str. 3, 53121, Bonn, Germany
| | - Maximilian Muehlhaupt
- Institute of Pharmacology, Toxicology and Pharmacy, Veterinary Faculty, Ludwig Maximilian University of Munich, Königinstr. 16, 80539, Munich, Germany
| | - Eva Marie Pfeil
- Molecular, Cellular and Pharmacobiology Section, Institute of Pharmaceutical Biology, University of Bonn, Nussallee 6, 53115, Bonn, Germany
| | - Suvi Katariina Annala
- Molecular, Cellular and Pharmacobiology Section, Institute of Pharmaceutical Biology, University of Bonn, Nussallee 6, 53115, Bonn, Germany
| | - Hermann Ammer
- Institute of Pharmacology, Toxicology and Pharmacy, Veterinary Faculty, Ludwig Maximilian University of Munich, Königinstr. 16, 80539, Munich, Germany
| | - Diana Imhof
- Pharmaceutical Biochemistry and Bioanalytics, Pharmaceutical Institute, University of Bonn, An der Immenburg 4, 53121, Bonn, Germany
| | - Dehua Pei
- Department of Chemistry and Biochemistry, The Ohio State University, 578 Biosciences Building, 484 W 12 Avenue, Columbus, OH 43210, USA
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20
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Wang Y, Li M, Liang W, Shi X, Fan J, Kong R, Liu Y, Zhang J, Chen T, Lu S. Delineating the activation mechanism and conformational landscape of a class B G protein-coupled receptor glucagon receptor. Comput Struct Biotechnol J 2022; 20:628-639. [PMID: 35140883 PMCID: PMC8801358 DOI: 10.1016/j.csbj.2022.01.015] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 01/17/2022] [Accepted: 01/17/2022] [Indexed: 02/09/2023] Open
Abstract
Class B G protein-coupled receptors (GPCRs) are important targets in the treatment of metabolic syndrome and diabetes. Although multiple structures of class B GPCRs-G protein complexes have been elucidated, the detailed activation mechanism of the receptors remains unclear. Here, we combine Gaussian accelerated molecular dynamics simulations and Markov state models (MSM) to investigate the activation mechanism of a canonical class B GPCR, human glucagon receptor-GCGR, including the negative allosteric modulator-bound inactive state, the agonist glucagon-bound active state, and both glucagon- and Gs-bound fully active state. The free-energy landscapes of GCGR show the conformational ensemble consisting of three activation-associated states: inactive, active, and fully active. The structural analysis indicates the high dynamics of GCGR upon glucagon binding with both active and inactive conformations in the ensemble. Significantly, the H8 and TM6 exhibits distinct features from the inactive to the active states. The additional simulations demonstrate the role of H8 in the recruitment of Gs. Gs binding presents a crucial function of stabilizing the glucagon binding site and MSM highlights the absolute requirement of Gs to help the GCGR reach the fully active state. Together, our results reveal the detailed activation mechanism of GCGR from the view of conformational dynamics.
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Affiliation(s)
- Ying Wang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
- Medicinal Chemistry and Bioinformatics Center, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Mingyu Li
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Wenqi Liang
- Department of Emergency, Changhai Hospital, Naval Medical University, Shanghai 200433, China
| | - Xinchao Shi
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Jigang Fan
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Ren Kong
- Institute of Bioinformatics and Medical Engineering, School of Electrical and Information Engineering, Jiangsu University of Technology, Changzhou 213001, China
| | - Yaqin Liu
- Medicinal Chemistry and Bioinformatics Center, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Jian Zhang
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
- Medicinal Chemistry and Bioinformatics Center, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
| | - Ting Chen
- Department of Cardiology, Changzheng Hospital, Naval Medical University, Shanghai 200023, China
| | - Shaoyong Lu
- Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
- Medicinal Chemistry and Bioinformatics Center, Shanghai Jiao Tong University, School of Medicine, Shanghai 200025, China
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21
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Reynoso S, Castillo V, Katkar GD, Lopez-Sanchez I, Taheri S, Espinoza C, Rohena C, Sahoo D, Gagneux P, Ghosh P. GIV/Girdin, a non-receptor modulator for Gαi/s, regulates spatiotemporal signaling during sperm capacitation and is required for male fertility. eLife 2021; 10:69160. [PMID: 34409938 PMCID: PMC8376251 DOI: 10.7554/elife.69160] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Accepted: 08/05/2021] [Indexed: 12/25/2022] Open
Abstract
For a sperm to successfully fertilize an egg, it must first undergo capacitation in the female reproductive tract and later undergo acrosomal reaction (AR) upon encountering an egg surrounded by its vestment. How premature AR is avoided despite rapid surges in signaling cascades during capacitation remains unknown. Using a combination of conditional knockout (cKO) mice and cell-penetrating peptides, we show that GIV (CCDC88A), a guanine nucleotide-exchange modulator (GEM) for trimeric GTPases, is highly expressed in spermatocytes and is required for male fertility. GIV is rapidly phosphoregulated on key tyrosine and serine residues in human and murine spermatozoa. These phosphomodifications enable GIV-GEM to orchestrate two distinct compartmentalized signaling programs in the sperm tail and head; in the tail, GIV enhances PI3K→Akt signals, sperm motility and survival, whereas in the head it inhibits cAMP surge and premature AR. Furthermore, GIV transcripts are downregulated in the testis and semen of infertile men. These findings exemplify the spatiotemporally segregated signaling programs that support sperm capacitation and shed light on a hitherto unforeseen cause of infertility in men.
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Affiliation(s)
- Sequoyah Reynoso
- Department of Pathology, School of Medicine, University of California San Diego, San Diego, United States
| | - Vanessa Castillo
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, San Diego, United States
| | - Gajanan Dattatray Katkar
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, San Diego, United States
| | - Inmaculada Lopez-Sanchez
- Department of Medicine, School of Medicine, University of California San Diego, San Diego, United States
| | - Sahar Taheri
- Department of Computer Science and Engineering, Jacob's School of Engineering, University of California San Diego, San Diego, United States
| | - Celia Espinoza
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, San Diego, United States
| | - Cristina Rohena
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, San Diego, United States
| | - Debashis Sahoo
- Department of Computer Science and Engineering, Jacob's School of Engineering, University of California San Diego, San Diego, United States.,Moore's Comprehensive Cancer Center, University of California San Diego, San Diego, United States.,Department of Pediatrics, School of Medicine, University of California San Diego, San Diego, United States
| | - Pascal Gagneux
- Department of Pathology, School of Medicine, University of California San Diego, San Diego, United States
| | - Pradipta Ghosh
- Department of Cellular and Molecular Medicine, School of Medicine, University of California San Diego, San Diego, United States.,Department of Medicine, School of Medicine, University of California San Diego, San Diego, United States.,Moore's Comprehensive Cancer Center, University of California San Diego, San Diego, United States.,Veterans Affairs Medical Center, Washington DC, United States
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22
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Abd El-hafeez AA, Sun N, Chakraborty A, Ear J, Roy S, Chamarthi P, Rajapakse N, Das S, Luker KE, Hazra TK, Luker GD, Ghosh P. Regulation of DNA damage response by trimeric G-protein Signaling.. [DOI: 10.1101/2021.07.21.452842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
AbstractUpon sensing DNA double-strand breaks (DSBs), eukaryotic cells either die or repair DSBs via one of two competing pathways, i.e., non-homologous end-joining (NHEJ) or homologous recombination (HR). We show that cell fate after DNA damage hinges on the guanine nucleotide-exchange modulator of heterotrimeric G-protein, Giα•βγ, GIV/Girdin. GIV suppresses HR by binding and sequestering BRCA1, a key coordinator of multiple steps within the HR pathway, away from DSBs; it does so using a C-terminal motif that binds BRCA1’s BRCT-modules via both phospho-dependent and -independent mechanisms. GIV promotes NHEJ, and binds and activates Gi and enhances the ‘free’ Gβγ→PI-3-kinase→Akt pathway, thus revealing the enigmatic origin of prosurvival Akt signals during dsDNA repair. Absence of GIV, or the loss of either of its two functions impaired DNA repair, and induced cell death when challenged with numerous cytotoxic agents. That GIV selectively binds few other BRCT-containing proteins suggests convergent signaling such that heterotrimeric G-proteins may finetune sensing, repair, and outcome after DNA damage.GRAPHIC ABSTRACTHIGHLIGHTSNon-receptor G protein modulator, GIV/Girdin binds BRCA1Binding occurs in both canonical and non-canonical modesGIV sequesters BRCA1 away from dsDNA breaks, suppresses HRActivation of Gi by GIV enhances Akt signals, favors NHEJIN BRIEFIn this work, the authors show that heterotrimeric G protein signaling that is triggered by non-receptor GEF, GIV/Girdin, in response to double-stranded DNA breaks is critical for decisive signaling events which favor non-homologous end-joining (NHEJ) and inhibit homologous recombination (HR).
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23
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Nubbemeyer B, Pepanian A, Paul George AA, Imhof D. Strategies towards Targeting Gαi/s Proteins: Scanning of Protein-Protein Interaction Sites To Overcome Inaccessibility. ChemMedChem 2021; 16:1696-1715. [PMID: 33615736 PMCID: PMC8252600 DOI: 10.1002/cmdc.202100039] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Indexed: 12/16/2022]
Abstract
Heterotrimeric G proteins are classified into four subfamilies and play a key role in signal transduction. They transmit extracellular signals to intracellular effectors subsequent to the activation of G protein-coupled receptors (GPCRs), which are targeted by over 30 % of FDA-approved drugs. However, addressing G proteins as drug targets represents a compelling alternative, for example, when G proteins act independently of the corresponding GPCRs, or in cases of complex multifunctional diseases, when a large number of different GPCRs are involved. In contrast to Gαq, efforts to target Gαi/s by suitable chemical compounds has not been successful so far. Here, a comprehensive analysis was conducted examining the most important interface regions of Gαi/s with its upstream and downstream interaction partners. By assigning the existing compounds and the performed approaches to the respective interfaces, the druggability of the individual interfaces was ranked to provide perspectives for selective targeting of Gαi/s in the future.
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Affiliation(s)
- Britta Nubbemeyer
- Pharmaceutical Biochemistry and BioanalyticsPharmaceutical InstituteUniversity of BonnAn der Immenburg 453121BonnGermany
| | - Anna Pepanian
- Pharmaceutical Biochemistry and BioanalyticsPharmaceutical InstituteUniversity of BonnAn der Immenburg 453121BonnGermany
| | | | - Diana Imhof
- Pharmaceutical Biochemistry and BioanalyticsPharmaceutical InstituteUniversity of BonnAn der Immenburg 453121BonnGermany
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24
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Ghosh P, Mullick M. Building unconventional G protein-coupled receptors, one block at a time. Trends Pharmacol Sci 2021; 42:514-517. [PMID: 33985816 DOI: 10.1016/j.tips.2021.04.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2021] [Revised: 04/05/2021] [Accepted: 04/19/2021] [Indexed: 10/21/2022]
Abstract
The structure, function, and dynamics of canonical activation of heterotrimeric G proteins by the seven-transmembrane G protein-coupled receptors (GPCRs) have been illustrated in detail. However, emerging studies during the past decade have started to shed light on how the same G proteins may also be accessed and modulated by a diverse family of receptors that are not conventional GPCRs. Can we learn about common themes and variations in how cells assemble these atypical GPCRs?
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Affiliation(s)
- Pradipta Ghosh
- Department of Medicine, University of California, San Diego, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California, San Diego, CA 92093, USA.
| | - Madhubanti Mullick
- Department of Cellular and Molecular Medicine, University of California, San Diego, CA 92093, USA
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25
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Qiao L, Sinha S, El-hafeez AAA, Lo I, Midde KK, Ngo T, Aznar N, Lopez-sanchez I, Gupta V, Farquhar MG, Rangamani P, Ghosh P. A Circuit for Secretion-coupled Cellular Autonomy in Multicellular Eukaryotes.. [DOI: 10.1101/2021.03.18.436048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
ABSTRACTCancers represent complex autonomous systems, displaying self-sufficiency in growth signaling. Autonomous growth is fueled by a cancer cell’s ability to ‘secrete-and-sense’ growth factors: a poorly understood phenomenon. Using an integrated systems and experimental approach, here we dissect the impact of a feedback-coupled GTPase circuit within the secretory pathway that imparts secretion-coupled autonomy. The circuit is assembled when the Ras-superfamily monomeric GTPase Arf1, and the heterotrimeric GTPase Giαβγ and their corresponding GAPs and GEFs are coupled by GIV/Girdin, a protein that is known to fuel aggressive traits in diverse cancers. One forward and two key negative feedback loops within the circuit create closed-loop control (CLC), allow the two GTPases to coregulate each other, and convert the expected switch-like behavior of Arf1-dependent secretion into an unexpected dose response alignment behavior of sensing and secretion. Such behavior translates into cell survival that is self-sustained by stimulus-proportionate secretion. Proteomic studies and protein-protein interaction network analyses pinpoint growth factors (e.g., the epidermal growth factor; EGF) as a key stimuli for such self-sustenance. Findings highlight how enhanced coupling of two biological switches in cancer cells is critical for multiscale feedback control to achieve secretion-coupled autonomy of growth factors.SYNOPSIS IMAGESTANDFIRST TEXTThis work defines the inner workings of a Golgi-localized molecular circuitry comprised of coupled GTPases, which empowers cells to achieve self-sufficiency in growth factor signaling by creating a secrete-and-sense autocrine loop.HIGHLIGHTS/MAIN FINDINGSModeling and experimental approaches were used to dissect a coupled GTPase circuit.Coupling enables closed loop feedback and mutual control of GTPases.Coupling generates dose response alignment behavior of sensing and secretion of growth factors.Coupling is critical for multiscale feedback control to achieve secretion-coupled autonomy.
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26
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Ham D, Ahn D, Ashim J, Cho Y, Kim HR, Yu W, Chung KY. Conformational switch that induces GDP release from Gi. J Struct Biol 2021; 213:107694. [PMID: 33418033 DOI: 10.1016/j.jsb.2020.107694] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 12/14/2020] [Accepted: 12/24/2020] [Indexed: 12/26/2022]
Abstract
Heterotrimeric guanine nucleotide-binding proteins (G proteins) are composed of α, β, and γ subunits. Gα switches between guanosine diphosphate (GDP)-bound inactive and guanosine triphosphate (GTP)-bound active states, and Gβγ interacts with the GDP-bound state. The GDP-binding regions are composed of two sites: the phosphate-binding and guanine-binding regions. The turnover of GDP and GTP is induced by guanine nucleotide-exchange factors (GEFs), including G protein-coupled receptors (GPCRs), Ric8A, and GIV/Girdin. However, the key structural factors for stabilizing the GDP-bound state of G proteins and the direct structural event for GDP release remain unclear. In this study, we investigated structural factors affecting GDP release by introducing point mutations in selected, conserved residues in Gαi3. We examined the effects of these mutations on the GDP/GTP turnover rate and the overall conformation of Gαi3 as well as the binding free energy between Gαi3 and GDP. We found that dynamic changes in the phosphate-binding regions are an immediate factor for the release of GDP.
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Affiliation(s)
- Donghee Ham
- School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Donghoon Ahn
- School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Janbolat Ashim
- Department of Brain and Cognitive Sciences, DGIST, 333 Techno jungang-daero, Daegu 42988, Republic of Korea
| | - Yejin Cho
- School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Hee Ryung Kim
- School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea
| | - Wookyung Yu
- Department of Brain and Cognitive Sciences, DGIST, 333 Techno jungang-daero, Daegu 42988, Republic of Korea; Core Protein Resources Center, DGIST, 333 Techno jungang-daero, Daegu 42988, Republic of Korea.
| | - Ka Young Chung
- School of Pharmacy, Sungkyunkwan University, 2066 Seobu-ro, Jangan-gu, Suwon 16419, Republic of Korea.
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27
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Ear J, Abd El-Hafeez AA, Roy S, Ngo T, Rajapakse N, Choi J, Khandelwal S, Ghassemian M, McCaffrey L, Kufareva I, Sahoo D, Ghosh P. A long isoform of GIV/Girdin contains a PDZ-binding module that regulates localization and G-protein binding. J Biol Chem 2021; 296:100493. [PMID: 33675748 PMCID: PMC8042451 DOI: 10.1016/j.jbc.2021.100493] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 02/19/2021] [Accepted: 02/26/2021] [Indexed: 11/28/2022] Open
Abstract
PDZ domains are one of the most abundant protein domains in eukaryotes and are frequently found on junction-localized scaffold proteins. Various signaling molecules bind to PDZ proteins via PDZ-binding motifs (PBM) and fine-tune cellular signaling. However, how such interaction affects protein function is difficult to predict and must be solved empirically. Here we describe a long isoform of the guanine nucleotide exchange factor GIV/Girdin (CCDC88A) that we named GIV-L, which is conserved throughout evolution, from invertebrates to vertebrates, and contains a PBM. Unlike GIV, which lacks PBM and is cytosolic, GIV-L localizes onto cell junctions and has a PDZ interactome (as shown through annotating Human Cell Map and BioID-proximity labeling studies), which impacts GIV-L's ability to bind and activate trimeric G-protein, Gαi, through its guanine-nucleotide exchange modulator (GEM) module. This GEM module is found exclusively in vertebrates. We propose that the two functional modules in GIV may have evolved sequentially: the ability to bind PDZ proteins via the PBM evolved earlier in invertebrates, whereas G-protein binding and activation may have evolved later only among vertebrates. Phenotypic studies in Caco-2 cells revealed that GIV and GIV-L may have antagonistic effects on cell growth, proliferation (cell cycle), and survival. Immunohistochemical analysis in human colon tissues showed that GIV expression increases with a concomitant decrease in GIV-L during cancer initiation. Taken together, these findings reveal how regulation in GIV/CCDC88A transcript helps to achieve protein modularity, which allows the protein to play opposing roles either as a tumor suppressor (GIV-L) or as an oncogene (GIV).
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Affiliation(s)
- Jason Ear
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA; Biological Sciences Department, California State Polytechnic University, Pomona, California, USA.
| | - Amer Ali Abd El-Hafeez
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA; Pharmacology and Experimental Oncology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt
| | - Suchismita Roy
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Tony Ngo
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Navin Rajapakse
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Julie Choi
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
| | - Soni Khandelwal
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Majid Ghassemian
- Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, California, USA
| | - Luke McCaffrey
- Rosalind and Morris Goodman Cancer Research Centre, McGill University, Montreal, Canada; Gerald Bronfman Department of Oncology, McGill University, Montreal, Canada
| | - Irina Kufareva
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California, USA
| | - Debashis Sahoo
- Department of Pediatrics, University of California San Diego, La Jolla, California, USA
| | - Pradipta Ghosh
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA; Department of Medicine, University of California San Diego, La Jolla, California, USA; Rebecca and John Moore Comprehensive Cancer Center, University of California San Diego, La Jolla, California, USA; Veterans Affairs Medical Center, La Jolla, California, USA.
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28
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Receptor tyrosine kinases activate heterotrimeric G proteins via phosphorylation within the interdomain cleft of Gαi. Proc Natl Acad Sci U S A 2020; 117:28763-28774. [PMID: 33139573 DOI: 10.1073/pnas.2004699117] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The molecular mechanisms by which receptor tyrosine kinases (RTKs) and heterotrimeric G proteins, two major signaling hubs in eukaryotes, independently relay signals across the plasma membrane have been extensively characterized. How these hubs cross-talk has been a long-standing question, but answers remain elusive. Using linear ion-trap mass spectrometry in combination with biochemical, cellular, and computational approaches, we unravel a mechanism of activation of heterotrimeric G proteins by RTKs and chart the key steps that mediate such activation. Upon growth factor stimulation, the guanine-nucleotide exchange modulator dissociates Gαi•βγ trimers, scaffolds monomeric Gαi with RTKs, and facilitates the phosphorylation on two tyrosines located within the interdomain cleft of Gαi. Phosphorylation triggers the activation of Gαi and inhibits second messengers (cAMP). Tumor-associated mutants reveal how constitutive activation of this pathway impacts cell's decision to "go" vs. "grow." These insights define a tyrosine-based G protein signaling paradigm and reveal its importance in eukaryotes.
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29
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Ear J, Ali Abd El-hafeez A, Roy S, Ngo T, Rajapakse N, Choi J, Khandelwal S, Ghassemian M, Mccaffrey L, Kufareva I, Sahoo D, Ghosh P. Evolution of Modularity, Interactome and Functions of GIV/Girdin (CCDC88A) from Invertebrates to Vertebrates.. [DOI: 10.1101/2020.09.28.317172] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/02/2023]
Abstract
AbstractPDZ domains are one of the most abundant protein domains in eukaryotes and frequently found on junction-localized scaffold proteins. Various signaling molecules bind to PDZ proteins via PDZ-binding motifs (PBM) and finetune cellular signaling. Here we describe the presence of a PBM on GIV/Girdin (CCDC88A) that is conserved throughout evolution, from invertebrates to vertebrates, and is generated as a long isoform-variant in humans, which we named GIV-L. Unlike GIV, which lacks PBM and is cytosolic, GIV-L localizes to the cell junctions, and has a unique PDZ-interactome, which impacts GIV-L’s ability to bind and activate trimeric G-protein, Gi through its guanine-nucleotide exchange modulator (GEM) module; the GEM module is found exclusively in vertebrates. Thus, the two functional modules in GIV evolved sequentially: the ability to bind PDZ proteins via the PBM evolved earlier in invertebrates, whereas G-protein binding and activation may have evolved later only among vertebrates. Phenotypic studies in Caco-2 cells revealed that GIV and GIV-L may have antagonistic effects on cell growth, proliferation (cell cycle), and survival. Immunohistochemical analyses in human colon tissues showed that GIV expression increases with a concomitant decrease in GIV-L during cancer initiation. Taken together, these findings reveal how GIV/CCDC88A in humans displays evolutionary flexibility in modularity, which allows the resultant isoforms to play opposing roles either as a tumor suppressor (GIV-L) or as an oncogene (GIV).
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30
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Garcia-Marcos M, Parag-Sharma K, Marivin A, Maziarz M, Luebbers A, Nguyen LT. Optogenetic activation of heterotrimeric G-proteins by LOV2GIVe, a rationally engineered modular protein. eLife 2020; 9:60155. [PMID: 32936073 PMCID: PMC7515630 DOI: 10.7554/elife.60155] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 09/15/2020] [Indexed: 12/24/2022] Open
Abstract
Heterotrimeric G-proteins are signal transducers involved in mediating the action of many natural extracellular stimuli and many therapeutic agents. Non-invasive approaches to manipulate the activity of G-proteins with high precision are crucial to understand their regulation in space and time. Here, we developed LOV2GIVe, an engineered modular protein that allows the activation of heterotrimeric G-proteins with blue light. This optogenetic construct relies on a versatile design that differs from tools previously developed for similar purposes, that is metazoan opsins, which are light-activated G-protein-coupled receptors (GPCRs). Instead, LOV2GIVe consists of the fusion of a G-protein activating peptide derived from a non-GPCR regulator of G-proteins to a small plant protein domain, such that light uncages the G-protein activating module. Targeting LOV2GIVe to cell membranes allowed for light-dependent activation of Gi proteins in different experimental systems. In summary, LOV2GIVe expands the armamentarium and versatility of tools available to manipulate heterotrimeric G-protein activity.
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Affiliation(s)
- Mikel Garcia-Marcos
- Department of Biochemistry, Boston University School of Medicine, Boston, United States
| | - Kshitij Parag-Sharma
- Department of Biochemistry, Boston University School of Medicine, Boston, United States
| | - Arthur Marivin
- Department of Biochemistry, Boston University School of Medicine, Boston, United States
| | - Marcin Maziarz
- Department of Biochemistry, Boston University School of Medicine, Boston, United States
| | - Alex Luebbers
- Department of Biochemistry, Boston University School of Medicine, Boston, United States
| | - Lien T Nguyen
- Department of Biochemistry, Boston University School of Medicine, Boston, United States
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31
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Rohena C, Rajapakse N, Lo IC, Novick P, Sahoo D, Ghosh P. GIV/Girdin and Exo70 Collaboratively Regulate the Mammalian Polarized Exocytic Machinery. iScience 2020; 23:101246. [PMID: 32590327 PMCID: PMC7322189 DOI: 10.1016/j.isci.2020.101246] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 04/20/2020] [Accepted: 06/03/2020] [Indexed: 11/17/2022] Open
Abstract
Polarized exocytosis is a fundamental process by which membranes and cargo proteins are delivered to the cell surface with precise spatial control. Although the need for the octameric exocyst complex is conserved from yeast to humans, what imparts spatial control is known only in yeast, i.e., a polarity scaffold called Bem1p. We demonstrate here that the mammalian scaffold protein, GIV/Girdin, fulfills the key criteria and functions of its yeast counterpart Bem1p; both bind Exo70 proteins via similar short-linear interaction motifs, and each prefers its evolutionary counterpart. Selective disruption of the GIV⋅Exo-70 interaction derails the delivery of the metalloprotease MT1-MMP to invadosomes and impairs collagen degradation and haptotaxis through basement membrane matrix. GIV's interacting partners reveal other components of polarized exocytosis in mammals. Findings expose how the exocytic functions aid GIV's pro-metastatic functions and how signal integration via GIV may represent an evolutionary advancement of the exocytic process in mammals.
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Affiliation(s)
- Cristina Rohena
- Department of Medicine, University of California San Diego, 9500 Gilman Drive (MC 0651), George E. Palade Bldg, Rm 232, 239, La Jolla, CA 92093, USA
| | - Navin Rajapakse
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA
| | - I-Chung Lo
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA
| | - Peter Novick
- Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA
| | - Debashis Sahoo
- Department of Pediatrics, University of California San Diego, San Diego, CA 92093, USA; Department of Computer Science and Engineering, Jacob's School of Engineering, University of California San Diego, San Diego, CA 92093, USA; Rebecca and John Moore Comprehensive Cancer Center, University of California San Diego, San Diego, CA 92093, USA
| | - Pradipta Ghosh
- Department of Medicine, University of California San Diego, 9500 Gilman Drive (MC 0651), George E. Palade Bldg, Rm 232, 239, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California San Diego, San Diego, CA 92093, USA; Rebecca and John Moore Comprehensive Cancer Center, University of California San Diego, San Diego, CA 92093, USA; Veterans Affairs Medical Center, 3350 La Jolla Village Dr, San Diego, CA 92161, USA.
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32
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Rohena C, Kalogriopoulos N, Rajapakse N, Roy S, Lopez-Sanchez I, Ablack J, Sahoo D, Ghosh P. GIV•Kindlin Interaction Is Required for Kindlin-Mediated Integrin Recognition and Activation. iScience 2020; 23:101209. [PMID: 32535026 PMCID: PMC7300163 DOI: 10.1016/j.isci.2020.101209] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2020] [Revised: 04/15/2020] [Accepted: 05/24/2020] [Indexed: 11/16/2022] Open
Abstract
Cells perceive and respond to the extracellular matrix via integrin receptors; their dysregulation has been implicated in inflammation and cancer metastasis. Here we show that a guanine nucleotide-exchange modulator of trimeric-GTPase Gαi, GIV (a.k.a Girdin), directly binds the integrin adaptor Kindlin-2. A non-canonical short linear motif within the C terminus of GIV binds Kindlin-2-FERM3 domain at a site that is distinct from the binding site for the canonical NPxY motif on the -integrin tail. Binding of GIV to Kindlin-2 allosterically enhances Kindlin-2's affinity for β1-integrin. Consequently, integrin activation and clustering are maximized, which augments cell adhesion, spreading, and invasion. Findings elucidate how the GIV•Kindlin-2 complex has a 2-fold impact: it allosterically synergizes integrin activation and enables β1-integrins to indirectly access and modulate trimeric GTPases via the complex. Furthermore, Cox proportional-hazard models on tumor transcriptomics provide trans-scale evidence of synergistic interactions between GIV•Kindlin-2•β1-integrin on time to progression to metastasis. GIV and Kindlin (K2), two integrin adaptors that promote metastasis, bind each other Binding of GIV or integrin to K2 allosterically enhances GIV•K2•integrin complexes Binding is required for the maximal recruitment of GIV and K2 to active integrins Binding facilitates integrin clustering, activation, tumor cell adhesion, invasion
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Affiliation(s)
- Cristina Rohena
- Department of Medicine, University of California San Diego, 9500 Gilman Drive (MC 0651), George E. Palade Bldg, Rm 239, La Jolla, CA 92093, USA
| | - Nicholas Kalogriopoulos
- Department of Medicine, University of California San Diego, 9500 Gilman Drive (MC 0651), George E. Palade Bldg, Rm 239, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California San Diego, CA 92093, USA
| | - Navin Rajapakse
- Department of Cellular and Molecular Medicine, University of California San Diego, CA 92093, USA
| | - Suchismita Roy
- Department of Cellular and Molecular Medicine, University of California San Diego, CA 92093, USA
| | - Inmaculada Lopez-Sanchez
- Department of Medicine, University of California San Diego, 9500 Gilman Drive (MC 0651), George E. Palade Bldg, Rm 239, La Jolla, CA 92093, USA
| | - Jailal Ablack
- Department of Medicine, University of California San Diego, 9500 Gilman Drive (MC 0651), George E. Palade Bldg, Rm 239, La Jolla, CA 92093, USA
| | - Debashis Sahoo
- Department of Pediatrics, University of California San Diego, CA 92093, USA; Department of Computer Science and Engineering, Jacob's School of Engineering, University of California San Diego, CA 92093, USA; Rebecca and John Moore Comprehensive Cancer Center, University of California San Diego, CA 92093, USA
| | - Pradipta Ghosh
- Department of Medicine, University of California San Diego, 9500 Gilman Drive (MC 0651), George E. Palade Bldg, Rm 239, La Jolla, CA 92093, USA; Department of Cellular and Molecular Medicine, University of California San Diego, CA 92093, USA; Rebecca and John Moore Comprehensive Cancer Center, University of California San Diego, CA 92093, USA; Veterans Affairs Medical Center, 3350 La Jolla Village Drive, San Diego, CA 92161, USA.
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Getz M, Rangamani P, Ghosh P. Regulating cellular cyclic adenosine monophosphate: "Sources," "sinks," and now, "tunable valves". WILEY INTERDISCIPLINARY REVIEWS-SYSTEMS BIOLOGY AND MEDICINE 2020; 12:e1490. [PMID: 32323924 DOI: 10.1002/wsbm.1490] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 01/31/2020] [Accepted: 03/31/2020] [Indexed: 12/16/2022]
Abstract
A number of hormones and growth factors stimulate target cells via the second messenger pathways, which in turn regulate cellular phenotypes. Cyclic adenosine monophosphate (cAMP) is a ubiquitous second messenger that facilitates numerous signal transduction pathways; its production in cells is tightly balanced by ligand-stimulated receptors that activate adenylate cyclases (ACs), that is, "source" and by phosphodiesterases (PDEs) that hydrolyze it, that is, "sinks." Because it regulates various cellular functions, including cell growth and differentiation, gene transcription and protein expression, the cAMP signaling pathway has been exploited for the treatment of numerous human diseases. Reduction in cAMP is achieved by blocking "sources"; however, elevation in cAMP is achieved by either stimulating "source" or blocking "sinks." Here we discuss an alternative paradigm for the regulation of cellular cAMP via GIV/Girdin, the prototypical member of a family of modulators of trimeric GTPases, Guanine nucleotide Exchange Modulators (GEMs). Cells upregulate or downregulate cellular levels of GIV-GEM, which modulates cellular cAMP via spatiotemporal mechanisms distinct from the two most often targeted classes of cAMP modulators, "sources" and "sinks." A network-based compartmental model for the paradigm of GEM-facilitated cAMP signaling has recently revealed that GEMs such as GIV serve much like a "tunable valve" that cells may employ to finetune cellular levels of cAMP. Because dysregulated signaling via GIV and other GEMs has been implicated in multiple disease states, GEMs constitute a hitherto untapped class of targets that could be exploited for modulating aberrant cAMP signaling in disease states. This article is categorized under: Models of Systems Properties and Processes > Mechanistic Models Biological Mechanisms > Cell Signaling.
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Affiliation(s)
- Michael Getz
- Chemical Engineering Graduate Program, University of California San Diego, La Jolla, California, USA
| | - Padmini Rangamani
- Department of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, California, USA
| | - Pradipta Ghosh
- Department of Medicine, University of California San Diego, La Jolla, California, USA
- Department of Cellular and Molecular Medicine, University of California San Diego, La Jolla, California, USA
- Moores Comprehensive Cancer Center, University of California San Diego, La Jolla, California, USA
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34
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Srivastava D, Artemyev NO. Ric-8A, a GEF, and a Chaperone for G Protein α-Subunits: Evidence for the Two-Faced Interface. Bioessays 2020; 42:e1900208. [PMID: 31967346 PMCID: PMC7034654 DOI: 10.1002/bies.201900208] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 12/30/2019] [Indexed: 12/21/2022]
Abstract
Resistance to inhibitors of cholinesterase 8A (Ric-8A) is a prominent non-receptor GEF and a chaperone of G protein α-subunits (Gα). Recent studies shed light on the structure of Ric-8A, providing insights into the mechanisms underlying its interaction with Gα. Ric-8A is composed of a core armadillo-like domain and a flexible C-terminal tail. Interaction of a conserved concave surface of its core domain with the Gα C-terminus appears to mediate formation of the initial Ric-8A/GαGDP intermediate, followed by the formation of a stable nucleotide-free complex. The latter event involves a large-scale dislocation of the Gα α5-helix that produces an extensive primary interface and disrupts the nucleotide-binding site of Gα. The distal portion of the C-terminal tail of Ric-8A forms a smaller secondary interface, which ostensibly binds the switch II region of Gα, facilitating binding of GTP. The two-site Gα interface of Ric-8A is distinct from that of GPCRs, and might have evolved to support the chaperone function of Ric-8A.
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Affiliation(s)
- Dhiraj Srivastava
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA 52242
| | - Nikolai O. Artemyev
- Department of Molecular Physiology and Biophysics, The University of Iowa Carver College of Medicine, Iowa City, IA 52242
- Department of Ophthalmology and Visual Sciences, The University of Iowa Carver College of Medicine, Iowa City, IA 52242
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Marivin A, Maziarz M, Zhao J, DiGiacomo V, Olmos Calvo I, Mann EA, Ear J, Blanco-Canosa JB, Ross EM, Ghosh P, Garcia-Marcos M. DAPLE protein inhibits nucleotide exchange on Gα s and Gα q via the same motif that activates Gαi. J Biol Chem 2020; 295:2270-2284. [PMID: 31949046 DOI: 10.1074/jbc.ra119.011648] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 01/08/2020] [Indexed: 01/03/2023] Open
Abstract
Besides being regulated by G-protein-coupled receptors, the activity of heterotrimeric G proteins is modulated by many cytoplasmic proteins. GIV/Girdin and DAPLE (Dvl-associating protein with a high frequency of leucine) are the best-characterized members of a group of cytoplasmic regulators that contain a Gα-binding and -activating (GBA) motif and whose dysregulation underlies human diseases, including cancer and birth defects. GBA motif-containing proteins were originally reported to modulate G proteins by binding Gα subunits of the Gi/o family (Gαi) over other families (such as Gs, Gq/11, or G12/13), and promoting nucleotide exchange in vitro However, some evidence suggests that this is not always the case, as phosphorylation of the GBA motif of GIV promotes its binding to Gαs and inhibits nucleotide exchange. The G-protein specificity of DAPLE and how it might affect nucleotide exchange on G proteins besides Gαi remain to be investigated. Here, we show that DAPLE's GBA motif, in addition to Gαi, binds efficiently to members of the Gs and Gq/11 families (Gαs and Gαq, respectively), but not of the G12/13 family (Gα12) in the absence of post-translational phosphorylation. We pinpointed Met-1669 as the residue in the GBA motif of DAPLE that diverges from that in GIV and enables better binding to Gαs and Gαq Unlike the nucleotide-exchange acceleration observed for Gαi, DAPLE inhibited nucleotide exchange on Gαs and Gαq These findings indicate that GBA motifs have versatility in their G-protein-modulating effect, i.e. they can bind to Gα subunits of different classes and either stimulate or inhibit nucleotide exchange depending on the G-protein subtype.
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Affiliation(s)
- Arthur Marivin
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Marcin Maziarz
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Jingyi Zhao
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Vincent DiGiacomo
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Isabel Olmos Calvo
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Emily A Mann
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118
| | - Jason Ear
- Department of Medicine and Cellular and Molecular Medicine, University of California, San Diego, California 92093
| | - Juan B Blanco-Canosa
- Department of Biological Chemistry, Institute for Advanced Chemistry of Catalonia (IQAC-CSIC), Barcelona, Spain 08034
| | - Elliott M Ross
- Department of Pharmacology, Green Center for Systems Biology, University of Texas Southwestern Medical Center, Dallas, Texas 75390
| | - Pradipta Ghosh
- Department of Medicine and Cellular and Molecular Medicine, University of California, San Diego, California 92093
| | - Mikel Garcia-Marcos
- Department of Biochemistry, Boston University School of Medicine, Boston, Massachusetts 02118.
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36
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Ghosh P, Garcia-Marcos M. Do All Roads Lead to Rome in G-Protein Activation? Trends Biochem Sci 2019; 45:182-184. [PMID: 31753703 DOI: 10.1016/j.tibs.2019.10.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 10/17/2019] [Accepted: 10/24/2019] [Indexed: 11/15/2022]
Abstract
High-resolution structural studies on G-protein-coupled receptors (GPCRs) have flourished recently, providing long-sought insights into the dynamic process of guanine nucleotide-binding protein (G-protein) activation. In parallel, analogous studies are starting to shed light on how the same G-proteins are activated by non-GPCR proteins. Can we learn about common themes and variations in G-protein activation from them?
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Affiliation(s)
- Pradipta Ghosh
- Department of Medicine and Cellular and Molecular Medicine, University of California, San Diego, CA 92093, USA.
| | - Mikel Garcia-Marcos
- Department of Biochemistry, Boston University School of Medicine, Boston, MA 02118, USA.
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Srivastava D, Artemyev NO. Large-scale conformational rearrangement of the α5-helix of Gα subunits in complex with the guanine nucleotide exchange factor Ric8A. J Biol Chem 2019; 294:17875-17882. [PMID: 31624147 DOI: 10.1074/jbc.ac119.011135] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 10/02/2019] [Indexed: 11/06/2022] Open
Abstract
Resistance to inhibitors of cholinesterase 8A (Ric8A) protein is an important G protein-coupled receptor (GPCR)-independent regulator of G protein α-subunits (Gα), acting as a guanine nucleotide exchange factor (GEF) and a chaperone. Insights into the complex between Ric8A and Gα hold the key to understanding the mechanisms underlying noncanonical activation of G-protein signaling as well as the folding of nascent Gα proteins. Here, we examined the structure of the complex of Ric8A with minimized Gαi (miniGαi) in solution by small-angle X-ray scattering (SAXS) and exploited the scattering profile in modeling of the Ric8A/miniGαi complex by steered molecular dynamics (SMD) simulations. A small set of models of the complex featured minimal clash scores, excellent agreement with the experimental SAXS data, and a large-scale rearrangement of the signal-transducing α5-helix of Gα away from its β-sheet core. The resulting interface involved the Gα α5-helix bound to the concave surface of Ric8A and the Gα β-sheet that wraps around the C-terminal part of the Ric8A armadillo domain, leading to a severe disruption of the GDP-binding site. Further modeling of the flexible C-terminal tail of Ric8A indicated that it interacts with the effector surface of Gα. This smaller interface may enable the Ric8A-bound Gα to interact with GTP. The two-interface interaction with Gα described here distinguishes Ric8A from GPCRs and non-GPCR regulators of G-protein signaling.
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Affiliation(s)
- Dhiraj Srivastava
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
| | - Nikolai O Artemyev
- Department of Molecular Physiology and Biophysics, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242 .,Department of Ophthalmology and Visual Sciences, University of Iowa Carver College of Medicine, Iowa City, Iowa 52242
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