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Fam BSDO, Vargas-Pinilla P, Paré P, Landau L, Viscardi LH, Pissinatti A, Falótico T, Maestri R, Bortolini MC. Exploring the diversity of AVPR2 in Primates and its evolutionary implications. Genet Mol Biol 2023; 46:e20230045. [PMID: 37930141 PMCID: PMC10626583 DOI: 10.1590/1678-4685-gmb-2023-0045] [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: 03/21/2023] [Accepted: 09/09/2023] [Indexed: 11/07/2023] Open
Abstract
The current study focuses on the investigation of AVPR2 (VTR2C) protein-coupled receptor variants specific to different primate taxa. AVPR2 is activated by the neurohormone AVP, which modulates physiological processes, including water homeostasis. Our findings reveal positive selection at three AVPR2 sites at positions 190, 250, and 346. Variation at position 250 is associated with human Congenital Nephrogenic Diabetes Insipidus (cNDI), a condition characterized by excessive water loss. Other 13 functional sites with potential adaptive relevance include positions 185, 202, 204, and 252 associated with cNDI. We identified SH3-binding motifs in AVPR2's ICL3 and N-terminus domains, with some losses observed in clades of Cercopithecidae, Callitrichinae, and Atelidae. SH3-binding motifs are crucial in regulating cellular physiology, indicating that the differences may be adaptive. Co-evolution was found between AVPR2 residues and those in the AVP signal peptide/Neurophysin-2 and AQP2, other molecules in the same signaling cascade. No significant correlation was found between these Primates' taxon-specific variants and the bioclimatic variables of the areas where they live. Distinct co-evolving amino acid sequences in functional sites were found in Platyrrhini and Catarrhini, which may have adaptive implications involving glucocorticoid hormones, suggesting varied selective pressures. Further studies are required to confirm these results.
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Affiliation(s)
- Bibiana Sampaio de Oliveira Fam
- Universidade Federal do Rio Grande do Sul, Departamento de Genética,
Laboratório de Evolução Humana e Molecular, Porto Alegre, RS, Brazil
| | - Pedro Vargas-Pinilla
- Universidade Federal do Rio Grande do Sul, Departamento de Genética,
Laboratório de Evolução Humana e Molecular, Porto Alegre, RS, Brazil
- Universidade de São Paulo, Faculdade de Medicina, Departamento de
Bioquímica e Imunologia, Ribeirão Preto, SP, Brazil
| | - Pâmela Paré
- Universidade Federal do Rio Grande do Sul, Departamento de Genética,
Laboratório de Evolução Humana e Molecular, Porto Alegre, RS, Brazil
| | - Luane Landau
- Universidade Federal do Rio Grande do Sul, Departamento de Genética,
Laboratório de Evolução Humana e Molecular, Porto Alegre, RS, Brazil
| | - Lucas H. Viscardi
- Universidade Federal do Rio Grande do Sul, Departamento de Genética,
Laboratório de Evolução Humana e Molecular, Porto Alegre, RS, Brazil
| | | | - Tiago Falótico
- Universidade de São Paulo, Escola de Artes, Ciências e Humanidades,
São Paulo, SP, Brazil
| | - Renan Maestri
- Universidade Federal do Rio Grande do Sul, Departamento de Ecologia,
Laboratório de Ecomorfologia e Macroevolução, Porto Alegre, RS, Brazil
| | - Maria Cátira Bortolini
- Universidade Federal do Rio Grande do Sul, Departamento de Genética,
Laboratório de Evolução Humana e Molecular, Porto Alegre, RS, Brazil
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2
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Yeast-based directed-evolution for high-throughput structural stabilization of G protein-coupled receptors (GPCRs). Sci Rep 2022; 12:8657. [PMID: 35606532 PMCID: PMC9126886 DOI: 10.1038/s41598-022-12731-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 05/10/2022] [Indexed: 11/08/2022] Open
Abstract
The immense potential of G protein-coupled receptors (GPCRs) as targets for drug discovery is not fully realized due to the enormous difficulties associated with structure elucidation of these profoundly unstable membrane proteins. The existing methods of GPCR stability-engineering are cumbersome and low-throughput; in addition, the scope of GPCRs that could benefit from these techniques is limited. Here, we present a yeast-based screening platform for a single-step isolation of GRCR variants stable in the presence of short-chain detergents, a feature essential for their successful crystallization using vapor diffusion method. The yeast detergent-resistant cell wall presents a unique opportunity for compartmentalization, to physically link the receptor's phenotype to its encoding DNA, and thus enable discovery of stable GPCR variants with unprecedent efficiency. The scope of mutations identified by the method reveals a surprising amenability of the GPCR scaffold to stabilization, and suggests an intriguing possibility of amending the stability properties of GPCR by varying the structural status of the C-terminus.
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3
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Structural Insights into the Intrinsically Disordered GPCR C-Terminal Region, Major Actor in Arrestin-GPCR Interaction. Biomolecules 2022; 12:biom12050617. [PMID: 35625550 PMCID: PMC9138321 DOI: 10.3390/biom12050617] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2022] [Revised: 04/12/2022] [Accepted: 04/19/2022] [Indexed: 02/04/2023] Open
Abstract
Arrestin-dependent pathways are a central component of G protein-coupled receptor (GPCRs) signaling. However, the molecular processes regulating arrestin binding are to be further illuminated, in particular with regard to the structural impact of GPCR C-terminal disordered regions. Here, we used an integrated biophysical strategy to describe the basal conformations of the C-terminal domains of three class A GPCRs, the vasopressin V2 receptor (V2R), the growth hormone secretagogue or ghrelin receptor type 1a (GHSR) and the β2-adernergic receptor (β2AR). By doing so, we revealed the presence of transient secondary structures in these regions that are potentially involved in the interaction with arrestin. These secondary structure elements differ from those described in the literature in interaction with arrestin. This suggests a mechanism where the secondary structure conformational preferences in the C-terminal regions of GPCRs could be a central feature for optimizing arrestins recognition.
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4
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Song W, Duncan AL, Sansom MSP. Modulation of adenosine A2a receptor oligomerization by receptor activation and PIP 2 interactions. Structure 2021; 29:1312-1325.e3. [PMID: 34270937 PMCID: PMC8581623 DOI: 10.1016/j.str.2021.06.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/28/2021] [Accepted: 06/25/2021] [Indexed: 11/23/2022]
Abstract
GPCRs have been shown to form oligomers, which generate distinctive signaling outcomes. However, the structural nature of the oligomerization process remains uncertain. We have characterized oligomeric configurations of the adenosine A2a receptor (A2aR) by combining large-scale molecular dynamics simulations with Markov state models. These oligomeric structures may also serve as templates for studying oligomerization of other class A GPCRs. Our simulation data revealed that receptor activation results in enhanced oligomerization, more diverse oligomer populations, and a more connected oligomerization network. The active state conformation of the A2aR shifts protein-protein association interfaces to those involving intracellular loop ICL3 and transmembrane helix TM6. Binding of PIP2 to A2aR stabilizes protein-protein interactions via PIP2-mediated association interfaces. These results indicate that A2aR oligomerization is responsive to the local membrane lipid environment. This, in turn, suggests a modulatory effect on A2aR whereby a given oligomerization profile favors the dynamic formation of specific supramolecular signaling complexes.
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Affiliation(s)
- Wanling Song
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Anna L Duncan
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, UK.
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5
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Guidolin D, Tortorella C, Marcoli M, Cervetto C, Maura G, Agnati LF. Receptor-Receptor Interactions and Glial Cell Functions with a Special Focus on G Protein-Coupled Receptors. Int J Mol Sci 2021; 22:8656. [PMID: 34445362 PMCID: PMC8395429 DOI: 10.3390/ijms22168656] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Revised: 07/30/2021] [Accepted: 08/11/2021] [Indexed: 12/18/2022] Open
Abstract
The discovery that receptors from all families can establish allosteric receptor-receptor interactions and variably associate to form receptor complexes operating as integrative input units endowed with a high functional and structural plasticity has expanded our understanding of intercellular communication. Regarding the nervous system, most research in the field has focused on neuronal populations and has led to the identification of many receptor complexes representing an important mechanism to fine-tune synaptic efficiency. Receptor-receptor interactions, however, also modulate glia-neuron and glia-glia intercellular communication, with significant consequences on synaptic activity and brain network plasticity. The research on this topic is probably still at the beginning and, here, available evidence will be reviewed and discussed. It may also be of potential interest from a pharmacological standpoint, opening the possibility to explore, inter alia, glia-based neuroprotective therapeutic strategies.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience, Section of Anatomy, University of Padova, 35121 Padova, Italy;
| | - Cinzia Tortorella
- Department of Neuroscience, Section of Anatomy, University of Padova, 35121 Padova, Italy;
| | - Manuela Marcoli
- Department of Pharmacy, Center of Excellence for Biomedical Research, University of Genova, 16126 Genova, Italy; (M.M.); (C.C.); (G.M.)
| | - Chiara Cervetto
- Department of Pharmacy, Center of Excellence for Biomedical Research, University of Genova, 16126 Genova, Italy; (M.M.); (C.C.); (G.M.)
| | - Guido Maura
- Department of Pharmacy, Center of Excellence for Biomedical Research, University of Genova, 16126 Genova, Italy; (M.M.); (C.C.); (G.M.)
| | - Luigi F. Agnati
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, 41125 Modena, Italy;
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6
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Nguyen KDQ, Vigers M, Sefah E, Seppälä S, Hoover JP, Schonenbach NS, Mertz B, O'Malley MA, Han S. Homo-oligomerization of the human adenosine A 2A receptor is driven by the intrinsically disordered C-terminus. eLife 2021; 10:e66662. [PMID: 34269678 PMCID: PMC8328514 DOI: 10.7554/elife.66662] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2021] [Accepted: 07/15/2021] [Indexed: 11/27/2022] Open
Abstract
G protein-coupled receptors (GPCRs) have long been shown to exist as oligomers with functional properties distinct from those of the monomeric counterparts, but the driving factors of oligomerization remain relatively unexplored. Herein, we focus on the human adenosine A2A receptor (A2AR), a model GPCR that forms oligomers both in vitro and in vivo. Combining experimental and computational approaches, we discover that the intrinsically disordered C-terminus of A2AR drives receptor homo-oligomerization. The formation of A2AR oligomers declines progressively with the shortening of the C-terminus. Multiple interaction types are responsible for A2AR oligomerization, including disulfide linkages, hydrogen bonds, electrostatic interactions, and hydrophobic interactions. These interactions are enhanced by depletion interactions, giving rise to a tunable network of bonds that allow A2AR oligomers to adopt multiple interfaces. This study uncovers the disordered C-terminus as a prominent driving factor for the oligomerization of a GPCR, offering important insight into the effect of C-terminus modification on receptor oligomerization of A2AR and other GPCRs reconstituted in vitro for biophysical studies.
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Affiliation(s)
- Khanh Dinh Quoc Nguyen
- Department of Chemistry and Biochemistry, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Michael Vigers
- Department of Chemical Engineering, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Eric Sefah
- C. Eugene Bennett Department of Chemistry, West Virginia UniversityMorgantownUnited States
| | - Susanna Seppälä
- Department of Chemical Engineering, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Jennifer Paige Hoover
- Department of Chemistry and Biochemistry, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Nicole Star Schonenbach
- Department of Chemical Engineering, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Blake Mertz
- C. Eugene Bennett Department of Chemistry, West Virginia UniversityMorgantownUnited States
| | - Michelle Ann O'Malley
- Department of Chemical Engineering, University of California, Santa BarbaraSanta BarbaraUnited States
| | - Songi Han
- Department of Chemistry and Biochemistry, University of California, Santa BarbaraSanta BarbaraUnited States
- Department of Chemical Engineering, University of California, Santa BarbaraSanta BarbaraUnited States
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7
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Aneskievich BJ, Shamilov R, Vinogradova O. Intrinsic disorder in integral membrane proteins. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2021; 183:101-134. [PMID: 34656327 DOI: 10.1016/bs.pmbts.2021.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The well-defined roles and specific protein-protein interactions of many integral membrane proteins (IMPs), such as those functioning as receptors for extracellular matrix proteins and soluble growth factors, easily align with considering IMP structure as a classical "lock-and-key" concept. Nevertheless, continued advances in understanding protein conformation, such as those which established the widespread existence of intrinsically disordered proteins (IDPs) and especially intrinsically disordered regions (IDRs) in otherwise three-dimensionally organized proteins, call for ongoing reevaluation of transmembrane proteins. Here, we present basic traits of IDPs and IDRs, and, for some select single-span IMPs, consider the potential functional advantages intrinsic disorder might provide and the possible conformational impact of disease-associated mutations. For transmembrane proteins in general, we highlight several investigational approaches, such as biophysical and computational methods, stressing the importance of integrating them to produce a more-complete mechanistic model of disorder-containing IMPs. These procedures, when synergized with in-cell assessments, will likely be key in translating in silico and in vitro results to improved understanding of IMP conformational flexibility in normal cell physiology as well as disease, and will help to extend their potential as therapeutic targets.
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Affiliation(s)
- Brian J Aneskievich
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT, United States
| | - Rambon Shamilov
- Graduate Program in Pharmacology and Toxicology, Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT, United States
| | - Olga Vinogradova
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, CT, United States.
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8
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Kassem N, Kassem MM, Pedersen SF, Pedersen PA, Kragelund BB. Yeast recombinant production of intact human membrane proteins with long intrinsically disordered intracellular regions for structural studies. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2020; 1862:183272. [PMID: 32169592 DOI: 10.1016/j.bbamem.2020.183272] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2019] [Revised: 03/08/2020] [Accepted: 03/09/2020] [Indexed: 01/07/2023]
Abstract
Membrane proteins exist in lipid bilayers and mediate solute transport, signal transduction, cell-cell communication and energy conversion. Their activities are fundamental for life, which make them prominent subjects of study, but access to only a limited number of high-resolution structures complicates their mechanistic understanding. The absence of such structures relates mainly to difficulties in expressing and purifying high quality membrane protein samples in large quantities. An additional layer of complexity stems from the presence of intra- and/or extra-cellular domains constituted by unstructured intrinsically disordered regions (IDR), which can be hundreds of residues long. Although IDRs form key interaction hubs that facilitate biological processes, these are regularly removed to enable structural studies. To advance mechanistic insight into intact intrinsically disordered membrane proteins, we have developed a protocol for their purification. Using engineered yeast cells for optimized expression and purification, we have purified to homogeneity two very different human membrane proteins each with >300 residues long IDRs; the sodium proton exchanger 1 and the growth hormone receptor. Subsequent to their purification we have further explored their incorporation into membrane scaffolding protein nanodiscs, which will enable future structural studies.
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Affiliation(s)
- Noah Kassem
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark
| | - Maher M Kassem
- Machine Learning, Department of Computer Science, University of Copenhagen, Universitetsparken 5, DK-2100, Copenhagen Ø, Denmark
| | - Stine F Pedersen
- Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark
| | - Per Amstrup Pedersen
- Cell Biology and Physiology, Department of Biology, University of Copenhagen, Universitetsparken 13, DK-2100 Copenhagen Ø, Denmark.
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory, Department of Biology, University of Copenhagen, Ole Maaloes Vej 5, DK-2200 Copenhagen N, Denmark.
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9
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Guidolin D, Marcoli M, Tortorella C, Maura G, Agnati LF. Adenosine A 2A-dopamine D 2 receptor-receptor interaction in neurons and astrocytes: Evidence and perspectives. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 169:247-277. [PMID: 31952688 DOI: 10.1016/bs.pmbts.2019.11.004] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The discovery of receptor-receptor interactions in the early 1980s, together with a more accurate focusing of allosteric mechanisms in proteins, expanded the knowledge on the G protein-coupled receptor (GPCR)-mediated signaling processes. GPCRs were seen to operate not only as monomers, but also as quaternary structures shaped by allosteric interactions. These integrative mechanisms can change the function of the GPCRs involved, leading to a sophisticated dynamic of the receptor assembly in terms of modulation of recognition and signaling. In this context, the heterodimeric complex formed by the adenosine A2A and the dopamine D2 receptors likely represents a prototypical example. The pharmacological evidence obtained, together with the tissue distribution of the A2A-D2 heteromeric complexes, suggested they could represent a target for new therapeutic strategies addressing significant disorders of the central nervous system. The research findings and the perspectives they offer from the therapeutic standpoint are the focus of the here presented discussion.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience, Section of Anatomy, University of Padova, Padova, Italy.
| | - Manuela Marcoli
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova, Genova, Italy
| | - Cinzia Tortorella
- Department of Neuroscience, Section of Anatomy, University of Padova, Padova, Italy
| | - Guido Maura
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova, Genova, Italy
| | - Luigi F Agnati
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy; Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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10
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Chen C, Nguyen BN, Mitchell G, Margolis SR, Ma D, Portnoy DA. The Listeriolysin O PEST-like Sequence Co-opts AP-2-Mediated Endocytosis to Prevent Plasma Membrane Damage during Listeria Infection. Cell Host Microbe 2019; 23:786-795.e5. [PMID: 29902442 DOI: 10.1016/j.chom.2018.05.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 04/23/2018] [Accepted: 05/11/2018] [Indexed: 10/14/2022]
Abstract
Listeriolysin O (LLO) is a cholesterol-dependent cytolysin that mediates escape of Listeria monocytogenes from a phagosome, enabling growth of the bacteria in the host cell cytosol. LLO contains a PEST-like sequence that prevents it from killing infected cells, but the mechanism involved is unknown. We found that the LLO PEST-like sequence was necessary to mediate removal of LLO from the interior face of the plasma membrane, where it coalesces into discrete puncta. LLO interacts with Ap2a2, an adaptor protein involved in endocytosis, via its PEST-like sequence, and Ap2a2-dependent endocytosis is required to prevent LLO-induced cytotoxicity. An unrelated PEST-like sequence from a human G protein-coupled receptor (GPCR), which also interacts with Ap2a2, could functionally complement the PEST-like sequence in L. monocytogenes LLO. These data revealed that LLO co-opts the host endocytosis machinery to protect the integrity of the host plasma membrane during L. monocytogenes infection.
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Affiliation(s)
- Chen Chen
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Brittney N Nguyen
- Graduate Group in Microbiology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Gabriel Mitchell
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Shally R Margolis
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Darren Ma
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA
| | - Daniel A Portnoy
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA; School of Public Health, University of California, Berkeley, Berkeley, CA 94720, USA.
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11
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Guidolin D, Marcoli M, Tortorella C, Maura G, Agnati LF. Receptor-Receptor Interactions as a Widespread Phenomenon: Novel Targets for Drug Development? Front Endocrinol (Lausanne) 2019; 10:53. [PMID: 30833931 PMCID: PMC6387912 DOI: 10.3389/fendo.2019.00053] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/24/2018] [Accepted: 01/21/2019] [Indexed: 12/19/2022] Open
Abstract
The discovery of receptor-receptor interactions (RRI) has expanded our understanding of the role that G protein-coupled receptors (GPCRs) play in intercellular communication. The finding that GPCRs can operate as receptor complexes, and not only as monomers, suggests that several different incoming signals could already be integrated at the plasma membrane level via direct allosteric interactions between the protomers that form the complex. Most research in this field has focused on neuronal populations and has led to the identification of a large number of RRI. However, RRI have been seen to occur not only in neurons but also in astrocytes and, outside the central nervous system, in cells of the cardiovascular and endocrine systems and in cancer cells. Furthermore, RRI involving the formation of macromolecular complexes are not limited to GPCRs, being also observed in other families of receptors. Thus, RRI appear as a widespread phenomenon and oligomerization as a common mechanism for receptor function and regulation. The discovery of these macromolecular assemblies may well have a major impact on pharmacology. Indeed, the formation of receptor complexes significantly broadens the spectrum of mechanisms available to receptors for recognition and signaling, which may be implemented through modulation of the binding sites of the adjacent protomers and of their signal transduction features. In this context, the possible appearance of novel allosteric sites in the receptor complex structure may be of particular relevance. Thus, the existence of RRI offers the possibility of new therapeutic approaches, and novel pharmacological strategies for disease treatment have already been proposed. Several challenges, however, remain. These include the accurate characterization of the role that the receptor complexes identified so far play in pathological conditions and the development of ligands specific to given receptor complexes, in order to efficiently exploit the pharmacological properties of these complexes.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience, University of Padova, Padova, Italy
- *Correspondence: Diego Guidolin
| | - Manuela Marcoli
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova, Genoa, Italy
| | | | - Guido Maura
- Department of Pharmacy and Center of Excellence for Biomedical Research, University of Genova, Genoa, Italy
| | - Luigi F. Agnati
- Department of Biomedical Sciences, University of Modena and Reggio Emilia, Modena, Italy
- Department of Neuroscience, Karolinska Institutet, Stockholm, Sweden
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12
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Ireton K. A Helpful PEST for Listeriolysin O? Cell Host Microbe 2018; 23:693-694. [PMID: 29902431 DOI: 10.1016/j.chom.2018.05.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Listeriolysin O (LLO) perforates host vacuoles, allowing Listeria monocytogenes to escape to the cytosol. How cytosolic LLO prevents cell lysis was not understood. In this issue of Cell Host & Microbe, Chen et al. (2018) show that a PEST sequence prevents cytotoxicity by mediating LLO endocytosis from the plasma membrane.
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Affiliation(s)
- Keith Ireton
- Department of Microbiology and Immunology, University of Otago, Dunedin 9054, New Zealand.
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13
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Zhou J, Zhao S, Dunker AK. Intrinsically Disordered Proteins Link Alternative Splicing and Post-translational Modifications to Complex Cell Signaling and Regulation. J Mol Biol 2018; 430:2342-2359. [DOI: 10.1016/j.jmb.2018.03.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Revised: 03/25/2018] [Accepted: 03/27/2018] [Indexed: 10/24/2022]
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14
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Guidolin D, Marcoli M, Tortorella C, Maura G, Agnati LF. G protein-coupled receptor-receptor interactions give integrative dynamics to intercellular communication. Rev Neurosci 2018; 29:703-726. [DOI: 10.1515/revneuro-2017-0087] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 01/01/2018] [Indexed: 01/14/2023]
Abstract
Abstract
The proposal of receptor-receptor interactions (RRIs) in the early 1980s broadened the view on the role of G protein-coupled receptors (GPCR) in the dynamics of the intercellular communication. RRIs, indeed, allow GPCR to operate not only as monomers but also as receptor complexes, in which the integration of the incoming signals depends on the number, spatial arrangement, and order of activation of the protomers forming the complex. The main biochemical mechanisms controlling the functional interplay of GPCR in the receptor complexes are direct allosteric interactions between protomer domains. The formation of these macromolecular assemblies has several physiologic implications in terms of the modulation of the signaling pathways and interaction with other membrane proteins. It also impacts on the emerging field of connectomics, as it contributes to set and tune the synaptic strength. Furthermore, recent evidence suggests that the transfer of GPCR and GPCR complexes between cells via the exosome pathway could enable the target cells to recognize/decode transmitters and/or modulators for which they did not express the pertinent receptors. Thus, this process may also open the possibility of a new type of redeployment of neural circuits. The fundamental aspects of GPCR complex formation and function are the focus of the present review article.
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Affiliation(s)
- Diego Guidolin
- Department of Neuroscience , University of Padova, via Gabelli 65 , I-35121 Padova , Italy
| | - Manuela Marcoli
- Department of Pharmacy and Center of Excellence for Biomedical Research , University of Genova , I-16126 Genova , Italy
| | - Cinzia Tortorella
- Department of Neuroscience , University of Padova, via Gabelli 65 , I-35121 Padova , Italy
| | - Guido Maura
- Department of Pharmacy and Center of Excellence for Biomedical Research , University of Genova , I-16126 Genova , Italy
| | - Luigi F. Agnati
- Department of Biomedical Sciences , University of Modena and Reggio Emilia , I-41121 Modena , Italy
- Department of Neuroscience , Karolinska Institutet , S-17177 Stockholm , Sweden
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15
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Kjaergaard M, Kragelund BB. Functions of intrinsic disorder in transmembrane proteins. Cell Mol Life Sci 2017; 74:3205-3224. [PMID: 28601983 PMCID: PMC11107515 DOI: 10.1007/s00018-017-2562-5] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2017] [Accepted: 06/01/2017] [Indexed: 12/19/2022]
Abstract
Intrinsic disorder is common in integral membrane proteins, particularly in the intracellular domains. Despite this observation, these domains are not always recognized as being disordered. In this review, we will discuss the biological functions of intrinsically disordered regions of membrane proteins, and address why the flexibility afforded by disorder is mechanistically important. Intrinsically disordered regions are present in many common classes of membrane proteins including ion channels and transporters; G-protein coupled receptors (GPCRs), receptor tyrosine kinases and cytokine receptors. The functions of the disordered regions are many and varied. We will discuss selected examples including: (1) Organization of receptors, kinases, phosphatases and second messenger sources into signaling complexes. (2) Modulation of the membrane-embedded domain function by ball-and-chain like mechanisms. (3) Trafficking of membrane proteins. (4) Transient membrane associations. (5) Post-translational modifications most notably phosphorylation and (6) disorder-linked isoform dependent function. We finish the review by discussing the future challenges facing the membrane protein community regarding protein disorder.
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Affiliation(s)
- Magnus Kjaergaard
- Aarhus Institute of Advanced Studies (AIAS), Aarhus University, Aarhus, Denmark.
- Department of Molecular Biology and Genetics, Aarhus University, Aarhus, Denmark.
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Aarhus, Denmark.
- The Danish Research Institute of Translational Neuroscience (DANDRITE), Aarhus, Denmark.
| | - Birthe B Kragelund
- Structural Biology and NMR Laboratory and The Linderstrøm-Lang Centre for Protein Science, Department of Biology, University of Copenhagen, Copenhagen, Denmark
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16
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Farran B. An update on the physiological and therapeutic relevance of GPCR oligomers. Pharmacol Res 2017; 117:303-327. [PMID: 28087443 DOI: 10.1016/j.phrs.2017.01.008] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2016] [Revised: 01/06/2017] [Accepted: 01/09/2017] [Indexed: 01/17/2023]
Abstract
The traditional view on GPCRs held that they function as single monomeric units composed of identical subunits. This notion was overturned by the discovery that GPCRs can form homo- and hetero-oligomers, some of which are obligatory, and can further assemble into receptor mosaics consisting of three or more protomers. Oligomerisation exerts significant impacts on receptor function and physiology, offering a platform for the diversification of receptor signalling, pharmacology, regulation, crosstalk, internalization and trafficking. Given their involvement in the modulation of crucial physiological processes, heteromers could constitute important therapeutic targets for a wide range of diseases, including schizophrenia, Parkinson's disease, substance abuse or obesity. This review aims at depicting the current developments in GPCR oligomerisation research, documenting various class A, B and C GPCR heteromers detected in vitro and in vivo using biochemical and biophysical approaches, as well as recently identified higher-order oligomeric complexes. It explores the current understanding of dimerization dynamics and the possible interaction interfaces that drive oligomerisation. Most importantly, it provides an inventory of the wide range of physiological processes and pathophysiological conditions to which GPCR oligomers contribute, surveying some of the oligomers that constitute potential drug targets. Finally, it delineates the efforts to develop novel classes of ligands that specifically target and tether to receptor oligomers instead of a single monomeric entity, thus ameliorating their ability to modulate GPCR function.
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Affiliation(s)
- Batoul Farran
- Department of Structural and Molecular Biology, University College London, Gower Street, London, WC1E 6BT, United Kingdom.
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17
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G-protein-coupled receptors mediate 14-3-3 signal transduction. Signal Transduct Target Ther 2016; 1:16018. [PMID: 29263900 PMCID: PMC5661649 DOI: 10.1038/sigtrans.2016.18] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2016] [Revised: 08/12/2016] [Accepted: 09/04/2016] [Indexed: 01/14/2023] Open
Abstract
G-protein-coupled receptor (GPCR)-interacting proteins likely participate in regulating GPCR signaling by eliciting specific signal transduction cascades, inducing cross-talk with other pathways, and fine tuning the signal. However, except for G-proteins and β-arrestins, other GPCR-interacting proteins are poorly characterized. 14-3-3 proteins are signal adaptors, and their participation in GPCR signaling is not well understood or recognized. Here we demonstrate that GPCR-mediated 14-3-3 signaling is ligand-regulated and is likely to be a more general phenomenon than suggested by the previous reports of 14-3-3 involvement with a few GPCRs. For the first time, we can pharmacologically characterize GPCR/14-3-3 signaling. We have shown that GPCR-mediated 14-3-3 signaling is phosphorylation-dependent, and that the GPCR/14-3-3 interaction likely occurs later than receptor desensitization and internalization. GPCR-mediated 14-3-3 signaling can be β-arrestin-independent, and individual agonists can have different potencies on 14-3-3 and β-arrestin signaling. GPCRs can also mediate the interaction between 14-3-3 and Raf-1. Our work opens up a new broad realm of previously unappreciated GPCR signal transduction. Linking GPCRs to 14-3-3 signal transduction creates the potential for the development of new research directions and provides a new signaling pathway for drug discovery.
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18
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Paré P, Paixão-Côrtes VR, Tovo-Rodrigues L, Vargas-Pinilla P, Viscardi LH, Salzano FM, Henkes LE, Bortolini MC. Oxytocin and arginine vasopressin receptor evolution: implications for adaptive novelties in placental mammals. Genet Mol Biol 2016; 39:646-657. [PMID: 27505307 PMCID: PMC5127151 DOI: 10.1590/1678-4685-gmb-2015-0323] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 02/28/2016] [Indexed: 11/28/2022] Open
Abstract
Oxytocin receptor (OXTR) and arginine vasopressin receptors
(AVPR1a, AVPR1b, and AVPR2) are paralogous genes
that emerged through duplication events; along the evolutionary timeline, owing to
speciation, numerous orthologues emerged as well. In order to elucidate the
evolutionary forces that shaped these four genes in placental mammals and to reveal
specific aspects of their protein structures, 35 species were selected. Specifically,
we investigated their molecular evolutionary history and intrinsic protein disorder
content, and identified the presence of short linear interaction motifs.
OXTR seems to be under evolutionary constraint in placental
mammals, whereas AVPR1a, AVPR1b, and AVPR2 exhibit
higher evolutionary rates, suggesting that they have been under relaxed or
experienced positive selection. In addition, we describe here, for the first time,
that the OXTR, AVPR1a, AVPR1b, and AVPR2 mammalian orthologues preserve their
disorder content, while this condition varies among the paralogues. Finally, our
results reveal the presence of short linear interaction motifs, indicating possible
functional adaptations related to physiological and/or behavioral taxa-specific
traits.
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Affiliation(s)
- Pamela Paré
- Programa de Pós-Graduação em Genética e Biologia Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Vanessa R Paixão-Côrtes
- Programa de Pós-Graduação em Genética e Biodiversidade, Instituto de Biologia, Universidade Federal da Bahia (UFBA), Salvador, BA, Brazil
| | - Luciana Tovo-Rodrigues
- Laboratório de Fisiologia da Reprodução Animal, Universidade Federal de Santa Catarina (UFSC), Curitibanos, SC, Brazil
| | - Pedro Vargas-Pinilla
- Programa de Pós-Graduação em Genética e Biologia Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Lucas Henriques Viscardi
- Programa de Pós-Graduação em Genética e Biologia Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Francisco Mauro Salzano
- Programa de Pós-Graduação em Genética e Biologia Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
| | - Luiz E Henkes
- Programa de Pós-Graduação em Epidemiologia, Universidade Federal de Pelotas (UFPEL), Pelotas, RS, Brazil
| | - Maria Catira Bortolini
- Programa de Pós-Graduação em Genética e Biologia Molecular, Departamento de Genética, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
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Dinkel H, Van Roey K, Michael S, Kumar M, Uyar B, Altenberg B, Milchevskaya V, Schneider M, Kühn H, Behrendt A, Dahl SL, Damerell V, Diebel S, Kalman S, Klein S, Knudsen AC, Mäder C, Merrill S, Staudt A, Thiel V, Welti L, Davey NE, Diella F, Gibson TJ. ELM 2016--data update and new functionality of the eukaryotic linear motif resource. Nucleic Acids Res 2016; 44:D294-300. [PMID: 26615199 PMCID: PMC4702912 DOI: 10.1093/nar/gkv1291] [Citation(s) in RCA: 223] [Impact Index Per Article: 27.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2015] [Revised: 11/04/2015] [Accepted: 11/05/2015] [Indexed: 01/18/2023] Open
Abstract
The Eukaryotic Linear Motif (ELM) resource (http://elm.eu.org) is a manually curated database of short linear motifs (SLiMs). In this update, we present the latest additions to this resource, along with more improvements to the web interface. ELM 2016 contains more than 240 different motif classes with over 2700 experimentally validated instances, manually curated from more than 2400 scientific publications. In addition, more data have been made available as individually searchable pages and are downloadable in various formats.
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Affiliation(s)
- Holger Dinkel
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Kim Van Roey
- Health Services Research Unit, Operational Direction Public Health and Surveillance, Scientific Institute of Public Health (WIV-ISP), 1050 Brussels, Belgium
| | - Sushama Michael
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Manjeet Kumar
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Bora Uyar
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Brigitte Altenberg
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Vladislava Milchevskaya
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | | | - Helen Kühn
- Ruprecht-Karls-Universität, Heidelberg, Germany
| | | | | | | | | | - Sara Kalman
- Ruprecht-Karls-Universität, Heidelberg, Germany
| | | | | | | | | | | | - Vera Thiel
- Ruprecht-Karls-Universität, Heidelberg, Germany
| | - Lukas Welti
- Ruprecht-Karls-Universität, Heidelberg, Germany
| | - Norman E Davey
- Conway Institute of Biomolecular and Biomedical Sciences, University College Dublin, Dublin 4, Ireland
| | - Francesca Diella
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
| | - Toby J Gibson
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany
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20
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Min L, Nie M, Zhang A, Wen J, Noel SD, Lee V, Carroll RS, Kaiser UB. Computational Analysis of Missense Variants of G Protein-Coupled Receptors Involved in the Neuroendocrine Regulation of Reproduction. Neuroendocrinology 2016; 103:230-9. [PMID: 26088945 PMCID: PMC4684493 DOI: 10.1159/000435884] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Accepted: 06/10/2015] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Many missense variants in G protein-coupled receptors (GPCRs) involved in the neuroendocrine regulation of reproduction have been identified by phenotype-driven or large-scale exome sequencing. Computational functional prediction analysis is commonly performed to evaluate their impact on receptor function. METHODS To assess the performance and outcome of functional prediction analyses for these GPCRs, we performed a statistical analysis of the prediction performance of SIFT and PolyPhen-2 for variants with documented biological function as well as variants retrieved from Ensembl. We obtained missense variants with documented biological function testing from patients with reproductive disorders from a comprehensive literature search. Missense variants from individuals with known reproductive disorders were retrieved from the Human Gene Mutation Database. Missense variants from the general population were retrieved from the Ensembl genome database. RESULTS The accuracies of SIFT and PolyPhen-2 were 83 and 85%, respectively. The performance of both prediction tools was greater in predicting loss-of-function variants (SIFT: 92%; PolyPhen-2: 95%) than in predicting variants that did not affect function (SIFT: 54%; PolyPhen-2: 57%). Concordance between SIFT and PolyPhen-2 did not improve accuracy. Surprisingly, approximately half of the variants retrieved from Ensembl were predicted as loss-of-function variants by SIFT (47%) and PolyPhen-2 (54%). CONCLUSION Our findings provide new guidance for interpreting the results and limitations of computational functional prediction analyses for GPCRs and will help to determine which variants require biological function testing. In addition, our findings raise important questions regarding the link between genotype and phenotype in the general population.
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Affiliation(s)
- Le Min
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA, 02115 USA
- To whom correspondence and reprint requests should be addressed: Le Min, M.D., Ph.D., Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, 221 Longwood Avenue, Boston, Massachusetts 02115.
| | - Min Nie
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA, 02115 USA
| | - Anna Zhang
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA, 02115 USA
| | - Junping Wen
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA, 02115 USA
| | - Sekoni D. Noel
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA, 02115 USA
| | - Vivian Lee
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA, 02115 USA
| | - Rona S. Carroll
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA, 02115 USA
| | - Ursula B. Kaiser
- Division of Endocrinology, Diabetes and Hypertension, Brigham and Women’s Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA, 02115 USA
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Jansen F, Kalbe B, Scholz P, Fränzel B, Osterloh M, Wolters D, Hatt H, Neuhaus EM, Osterloh S. Biochemical Large-Scale Interaction Analysis of Murine Olfactory Receptors and Associated Signaling Proteins with Post-Synaptic Density 95, Drosophila Discs Large, Zona-Occludens 1 (PDZ) Domains. Mol Cell Proteomics 2015; 14:2072-84. [PMID: 25979994 DOI: 10.1074/mcp.m114.045997] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2014] [Indexed: 11/06/2022] Open
Abstract
G protein-coupled receptors (GPCRs) constitute the largest family among mammalian membrane proteins and are capable of initiating numerous essential signaling cascades. Various GPCR-mediated pathways are organized into protein microdomains that can be orchestrated and regulated through scaffolding proteins, such as PSD-95/discs-large/ZO1 (PDZ) domain proteins. However, detailed binding characteristics of PDZ-GPCR interactions remain elusive because these interactions seem to be more complex than previously thought. To address this issue, we analyzed binding modalities using our established model system. This system includes the 13 individual PDZ domains of the multiple PDZ domain protein 1 (MUPP1; the largest PDZ protein), a broad range of murine olfactory receptors (a multifaceted gene cluster within the family of GPCRs), and associated olfactory signaling proteins. These proteins were analyzed in a large-scale peptide microarray approach and continuative interaction studies. As a result, we demonstrate that canonical binding motifs were not overrepresented among the interaction partners of MUPP1. Furthermore, C-terminal phosphorylation and distinct amino acid replacements abolished PDZ binding promiscuity. In addition to the described in vitro experiments, we identified new interaction partners within the murine olfactory epithelium using pull-down-based interactomics and could verify the partners through co-immunoprecipitation. In summary, the present study provides important insight into the complexity of the binding characteristics of PDZ-GPCR interactions based on olfactory signaling proteins, which could identify novel clinical targets for GPCR-associated diseases in the future.
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Affiliation(s)
- Fabian Jansen
- From the ‡Department of Cell Physiology, Faculty for Biology and Biotechnology
| | - Benjamin Kalbe
- From the ‡Department of Cell Physiology, Faculty for Biology and Biotechnology
| | - Paul Scholz
- From the ‡Department of Cell Physiology, Faculty for Biology and Biotechnology
| | - Benjamin Fränzel
- §Department of Analytical Chemistry, Faculty for Chemistry and Biochemistry, Ruhr-University Bochum, Germany
| | - Markus Osterloh
- From the ‡Department of Cell Physiology, Faculty for Biology and Biotechnology
| | - Dirk Wolters
- §Department of Analytical Chemistry, Faculty for Chemistry and Biochemistry, Ruhr-University Bochum, Germany
| | - Hanns Hatt
- From the ‡Department of Cell Physiology, Faculty for Biology and Biotechnology
| | | | - Sabrina Osterloh
- From the ‡Department of Cell Physiology, Faculty for Biology and Biotechnology,
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Guidolin D, Agnati LF, Marcoli M, Borroto-Escuela DO, Fuxe K. G-protein-coupled receptor type A heteromers as an emerging therapeutic target. Expert Opin Ther Targets 2014; 19:265-83. [PMID: 25381716 DOI: 10.1517/14728222.2014.981155] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION The discovery of receptor-receptor interactions (RRIs) in the early 1980s provided evidence that G-protein-coupled receptors (GPCRs) operate not only as monomers but also as heteromers, in which integration of the incoming signals takes place already at the plasma membrane level through allosteric RRIs. These integrative mechanisms give sophisticated dynamics to the structure and function of these receptor assemblies in terms of modulation of recognition, G-protein signaling and selectivity and switching to β-arrestin signaling. AREAS COVERED The present review briefly describes the concept of direct RRI and the available data on the mechanisms of oligomer formation. Further, pharmacological data concerning the best characterized heteromers involving type A GPCRs will be analyzed to evaluate their profile as possible targets for the treatment of various diseases, in particular of impacting diseases of the CNS. EXPERT OPINION GPCR heteromers have the potential to open a completely new field for pharmacology with likely a major impact in molecular medicine. Novel pharmacological strategies for the treatment of several pathologies have already been proposed. However, several challenges still exist to accurately characterize the role of the identified heteroreceptor complexes in pathology and to develop heteromer-specific ligands capable of efficiently exploiting their pharmacological features.
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Affiliation(s)
- Diego Guidolin
- University of Padova, Department of Molecular Medicine , via Gabelli 65, 35121 Padova , Italy +39 049 8272316 ; +39 049 8272319 ;
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Structured and disordered facets of the GPCR fold. Curr Opin Struct Biol 2014; 27:129-37. [PMID: 25198166 DOI: 10.1016/j.sbi.2014.08.002] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2014] [Revised: 07/28/2014] [Accepted: 08/05/2014] [Indexed: 01/14/2023]
Abstract
The seven-transmembrane (7TM) helix fold of G-protein coupled receptors (GPCRs) has been adapted for a wide variety of physiologically important signaling functions. Here, we discuss the diversity in the structured and disordered regions of GPCRs based on the recently published crystal structures and sequence analysis of all human GPCRs. A comparison of the structures of rhodopsin-like receptors (class A), secretin-like receptors (class B), metabotropic receptors (class C) and frizzled receptors (class F) shows that the relative arrangement of the transmembrane helices is conserved across all four GPCR classes although individual receptors can be activated by ligand binding at varying positions within and around the transmembrane helical bundle. A systematic analysis of GPCR sequences reveals the presence of disordered segments in the cytoplasmic side, abundant post-translational modification sites, evidence for alternative splicing and several putative linear peptide motifs that have the potential to mediate interactions with cytosolic proteins. While the structured regions permit the receptor to bind diverse ligands, the disordered regions appear to have an underappreciated role in modulating downstream signaling in response to the cellular state. An integrated paradigm combining the knowledge of structured and disordered regions is imperative for gaining a holistic understanding of the GPCR (un)structure-function relationship.
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