1
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Novel Binding Partners for CCT and PhLP1 Suggest a Common Folding Mechanism for WD40 Proteins with a 7-Bladed Beta-Propeller Structure. Proteomes 2021; 9:proteomes9040040. [PMID: 34698247 PMCID: PMC8544692 DOI: 10.3390/proteomes9040040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2021] [Revised: 09/15/2021] [Accepted: 09/27/2021] [Indexed: 11/25/2022] Open
Abstract
This study investigates whether selected WD40 proteins with a 7-bladed β-propeller structure, similar to that of the β subunit of the G protein heterotrimer, interact with the cytosolic chaperonin CCT and its known binding partner, PhLP1. Previous studies have shown that CCT is required for the folding of the Gβ subunit and other WD40 proteins. The role of PhLP1 in the folding of Gβ has also been established, but it is unknown if PhLP1 assists in the folding of other Gβ-like proteins. The binding of three Gβ-like proteins, TBL2, MLST8 and CDC20, to CCT and PhLP1, was demonstrated in this study. Co-immunoprecipitation assays identified one novel binding partner for CCT and three new interactors for PhLP1. All three of the studied proteins interact with CCT and PhLP1, suggesting that these proteins may have a folding machinery in common with that of Gβ and that the well-established Gβ folding mechanism may have significantly broader biological implications than previously thought. These findings contribute to continuous efforts to determine common traits and unique differences in the folding mechanism of the WD40 β-propeller protein family, and the role PhLP1 has in this process.
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2
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Young BD, Sha J, Vashisht AA, Wohlschlegel JA. Human Multisubunit E3 Ubiquitin Ligase Required for Heterotrimeric G-Protein β-Subunit Ubiquitination and Downstream Signaling. J Proteome Res 2021; 20:4318-4330. [PMID: 34342229 DOI: 10.1021/acs.jproteome.1c00292] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
G-protein-coupled receptors (GPCRs) initiate intracellular signaling events through heterotrimeric G-protein α-subunits (Gα) and the βγ-subunit dimer (Gβγ). In this study, we utilized mass spectrometry to identify novel regulators of Gβγ signaling in human cells. This prompted our characterization of KCTD2 and KCTD5, two related potassium channel tetramerization domain (KCTD) proteins that specifically recognize Gβγ. We demonstrated that these KCTD proteins are substrate adaptors for a multisubunit CUL3-RING ubiquitin ligase, in which a KCTD2-KCTD5 hetero-oligomer associates with CUL3 through KCTD5 subunits and recruits Gβγ through both KCTD proteins in response to G-protein activation. These KCTD proteins promote monoubiquitination of lysine-23 within Gβ1/2 in vitro and in HEK-293 cells. Depletion of these adaptors from cancer cell lines sharply impairs downstream signaling. Together, our studies suggest that a KCTD2-KCTD5-CUL3-RING E3 ligase recruits Gβγ in response to signaling, monoubiquitinates lysine-23 within Gβ1/2, and regulates Gβγ effectors to modulate downstream signal transduction.
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Affiliation(s)
- Brian D Young
- Department of Biological Chemistry, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States.,Molecular Biology Institute, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
| | - Jihui Sha
- Department of Biological Chemistry, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
| | - Ajay A Vashisht
- Department of Biological Chemistry, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
| | - James A Wohlschlegel
- Department of Biological Chemistry, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States.,Molecular Biology Institute, David Geffen School of Medicine, UCLA, Los Angeles, California 90095, United States
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3
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Horta MAC, Thieme N, Gao Y, Burnum-Johnson KE, Nicora CD, Gritsenko MA, Lipton MS, Mohanraj K, de Assis LJ, Lin L, Tian C, Braus GH, Borkovich KA, Schmoll M, Larrondo LF, Samal A, Goldman GH, Benz JP. Broad Substrate-Specific Phosphorylation Events Are Associated With the Initial Stage of Plant Cell Wall Recognition in Neurospora crassa. Front Microbiol 2019; 10:2317. [PMID: 31736884 PMCID: PMC6838226 DOI: 10.3389/fmicb.2019.02317] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2019] [Accepted: 09/23/2019] [Indexed: 12/26/2022] Open
Abstract
Fungal plant cell wall degradation processes are governed by complex regulatory mechanisms, allowing the organisms to adapt their metabolic program with high specificity to the available substrates. While the uptake of representative plant cell wall mono- and disaccharides is known to induce specific transcriptional and translational responses, the processes related to early signal reception and transduction remain largely unknown. A fast and reversible way of signal transmission are post-translational protein modifications, such as phosphorylations, which could initiate rapid adaptations of the fungal metabolism to a new condition. To elucidate how changes in the initial substrate recognition phase of Neurospora crassa affect the global phosphorylation pattern, phospho-proteomics was performed after a short (2 min) induction period with several plant cell wall-related mono- and disaccharides. The MS/MS-based peptide analysis revealed large-scale substrate-specific protein phosphorylation and de-phosphorylations. Using the proteins identified by MS/MS, a protein-protein-interaction (PPI) network was constructed. The variance in phosphorylation of a large number of kinases, phosphatases and transcription factors indicate the participation of many known signaling pathways, including circadian responses, two-component regulatory systems, MAP kinases as well as the cAMP-dependent and heterotrimeric G-protein pathways. Adenylate cyclase, a key component of the cAMP pathway, was identified as a potential hub for carbon source-specific differential protein interactions. In addition, four phosphorylated F-Box proteins were identified, two of which, Fbx-19 and Fbx-22, were found to be involved in carbon catabolite repression responses. Overall, these results provide unprecedented and detailed insights into a so far less well known stage of the fungal response to environmental cues and allow to better elucidate the molecular mechanisms of sensory perception and signal transduction during plant cell wall degradation.
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Affiliation(s)
- Maria Augusta C. Horta
- Holzforschung München, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Nils Thieme
- Holzforschung München, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
| | - Yuqian Gao
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States
| | | | - Carrie D. Nicora
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Marina A. Gritsenko
- Biological Sciences Division, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Mary S. Lipton
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, WA, United States
| | - Karthikeyan Mohanraj
- The Institute of Mathematical Sciences (IMSc), Homi Bhabha National Institute (HBNI), Chennai, India
| | - Leandro José de Assis
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
| | - Liangcai Lin
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Chaoguang Tian
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China
| | - Gerhard H. Braus
- Department of Molecular Microbiology and Genetics, Institute of Microbiology and Genetics, Göttingen Center for Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Katherine A. Borkovich
- Department of Microbiology & Plant Pathology, Institute for Integrative Genome Biology, University of California, Riverside, Riverside, CA, United States
| | - Monika Schmoll
- AIT - Austrian Institute of Technology GmbH, Center for Health & Bioresources, Tulln, Austria
| | - Luis F. Larrondo
- Millennium Institute for Integrative Biology (iBio), Departamento Genética Molecular y Microbiología, Facultad de Ciencias Biológicas, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Areejit Samal
- The Institute of Mathematical Sciences (IMSc), Homi Bhabha National Institute (HBNI), Chennai, India
| | - Gustavo H. Goldman
- Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, Brazil
- Institute for Advanced Study, Technical University of Munich, Garching, Germany
| | - J. Philipp Benz
- Holzforschung München, TUM School of Life Sciences Weihenstephan, Technical University of Munich, Freising, Germany
- Institute for Advanced Study, Technical University of Munich, Garching, Germany
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4
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Mutual action by Gγ and Gβ for optimal activation of GIRK channels in a channel subunit-specific manner. Sci Rep 2019; 9:508. [PMID: 30679535 PMCID: PMC6346094 DOI: 10.1038/s41598-018-36833-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2018] [Accepted: 11/29/2018] [Indexed: 01/06/2023] Open
Abstract
The tetrameric G protein-gated K+ channels (GIRKs) mediate inhibitory effects of neurotransmitters that activate Gi/o-coupled receptors. GIRKs are activated by binding of the Gβγ dimer, via contacts with Gβ. Gγ underlies membrane targeting of Gβγ, but has not been implicated in channel gating. We observed that, in Xenopus oocytes, expression of Gγ alone activated homotetrameric GIRK1* and heterotetrameric GIRK1/3 channels, without affecting the surface expression of GIRK or Gβ. Gγ and Gβ acted interdependently: the effect of Gγ required the presence of ambient Gβ and was enhanced by low doses of coexpressed Gβ, whereas excess of either Gβ or Gγ imparted suboptimal activation, possibly by sequestering the other subunit “away” from the channel. The unique distal C-terminus of GIRK1, G1-dCT, was important but insufficient for Gγ action. Notably, GIRK2 and GIRK1/2 were not activated by Gγ. Our results suggest that Gγ regulates GIRK1* and GIRK1/3 channel’s gating, aiding Gβ to trigger the channel’s opening. We hypothesize that Gγ helps to relax the inhibitory effect of a gating element (“lock”) encompassed, in part, by the G1-dCT; GIRK2 acts to occlude the effect of Gγ, either by setting in motion the same mechanism as Gγ, or by triggering an opposing gating effect.
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5
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Papasergi-Scott MM, Stoveken HM, MacConnachie L, Chan PY, Gabay M, Wong D, Freeman RS, Beg AA, Tall GG. Dual phosphorylation of Ric-8A enhances its ability to mediate G protein α subunit folding and to stimulate guanine nucleotide exchange. Sci Signal 2018; 11:11/532/eaap8113. [PMID: 29844055 DOI: 10.1126/scisignal.aap8113] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Resistance to inhibitors of cholinesterase-8A (Ric-8A) and Ric-8B are essential biosynthetic chaperones for heterotrimeric G protein α subunits. We provide evidence for the direct regulation of Ric-8A cellular activity by dual phosphorylation. Using proteomics, Western blotting, and mutational analyses, we determined that Ric-8A was constitutively phosphorylated at five serines and threonines by the protein kinase CK2. Phosphorylation of Ser435 and Thr440 in rat Ric-8A (corresponding to Ser436 and Thr441 in human Ric-8A) was required for high-affinity binding to Gα subunits, efficient stimulation of Gα subunit guanine nucleotide exchange, and mediation of Gα subunit folding. The CK2 consensus sites that contain Ser435 and Thr440 are conserved in Ric-8 homologs from worms to mammals. We found that the homologous residues in mouse Ric-8B, Ser468 and Ser473, were also phosphorylated. Mutation of the genomic copy of ric-8 in Caenorhabditis elegans to encode alanine in the homologous sites resulted in characteristic ric-8 reduction-of-function phenotypes that are associated with defective Gq and Gs signaling, including reduced locomotion and defective egg laying. The C. elegans ric-8 phosphorylation site mutant phenotypes were partially rescued by chemical stimulation of Gq signaling. These results indicate that dual phosphorylation represents a critical form of conserved Ric-8 regulation and demonstrate that Ric-8 proteins are needed for effective Gα signaling. The position of the CK2-phosphorylated sites within a structural model of Ric-8A reveals that these sites contribute to a key acidic and negatively charged surface that may be important for its interactions with Gα subunits.
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Affiliation(s)
- Makaía M Papasergi-Scott
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Hannah M Stoveken
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Lauren MacConnachie
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Pui-Yee Chan
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Meital Gabay
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Dorothy Wong
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Robert S Freeman
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Asim A Beg
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Gregory G Tall
- Department of Pharmacology, University of Michigan Medical School, Ann Arbor, MI 48109, USA.
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6
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Martemyanov KA, Sampath AP. The Transduction Cascade in Retinal ON-Bipolar Cells: Signal Processing and Disease. Annu Rev Vis Sci 2017; 3:25-51. [PMID: 28715957 DOI: 10.1146/annurev-vision-102016-061338] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Our robust visual experience is based on the reliable transfer of information from our photoreceptor cells, the rods and cones, to higher brain centers. At the very first synapse of the visual system, information is split into two separate pathways, ON and OFF, which encode increments and decrements in light intensity, respectively. The importance of this segregation is borne out in the fact that receptive fields in higher visual centers maintain a separation between ON and OFF regions. In the past decade, the molecular mechanisms underlying the generation of ON signals have been identified, which are unique in their use of a G-protein signaling cascade. In this review, we consider advances in our understanding of G-protein signaling in ON-bipolar cell (BC) dendrites and how insights about signaling have emerged from visual deficits, mostly night blindness. Studies of G-protein signaling in ON-BCs reveal an intricate mechanism that permits the regulation of visual sensitivity over a wide dynamic range.
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Affiliation(s)
| | - Alapakkam P Sampath
- Jules Stein Eye Institute, University of California, Los Angeles, California 90095;
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7
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8
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Xie K, Masuho I, Shih CC, Cao Y, Sasaki K, Lai CWJ, Han PL, Ueda H, Dessauer CW, Ehrlich ME, Xu B, Willardson BM, Martemyanov KA. Stable G protein-effector complexes in striatal neurons: mechanism of assembly and role in neurotransmitter signaling. eLife 2015; 4. [PMID: 26613416 PMCID: PMC4728126 DOI: 10.7554/elife.10451] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2015] [Accepted: 11/26/2015] [Indexed: 12/23/2022] Open
Abstract
In the striatum, signaling via G protein-coupled neurotransmitter receptors is essential for motor control. Critical to this process is the effector enzyme adenylyl cyclase type 5 (AC5) that produces second messenger cAMP upon receptor-mediated activation by G protein Golf. However, the molecular organization of the Golf-AC5 signaling axis is not well understood. In this study, we report that in the striatum AC5 exists in a stable pre-coupled complex with subunits of Golf heterotrimer. We use genetic mouse models with disruption in individual components of the complex to reveal hierarchical order of interactions required for AC5-Golf stability. We further identify that the assembly of AC5-Golf complex is mediated by PhLP1 chaperone that plays central role in neurotransmitter receptor coupling to cAMP production motor learning. These findings provide evidence for the existence of stable G protein-effector signaling complexes and identify a new component essential for their assembly.
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Affiliation(s)
- Keqiang Xie
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
| | - Ikuo Masuho
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
| | - Chien-Cheng Shih
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States.,Department of Pharmacology and Physiology, Georgetown University Medical Center, Washington, United States
| | - Yan Cao
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
| | - Keita Sasaki
- Department of Pharmacology and Therapeutic Innovation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Chun Wan J Lai
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, United States
| | - Pyung-Lim Han
- Department of Brain and Cognitive Sciences, Ewha Womans University, Seoul, Republic of Korea
| | - Hiroshi Ueda
- Department of Pharmacology and Therapeutic Innovation, Graduate School of Biomedical Sciences, Nagasaki University, Nagasaki, Japan
| | - Carmen W Dessauer
- Department of Integrative Biology and Pharmacology, The University of Texas Health Science Center, Houston, United States
| | - Michelle E Ehrlich
- Department of Neurology, Icahn School of Medicine at Mount Sinai, New York, United States.,Department of Pediatrics, Icahn School of Medicine at Mount Sinai, New York, United States.,Department of Genetics and Genomic Sciences, Icahn School of Medicine at Mount Sinai, New York, United States
| | - Baoji Xu
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
| | - Barry M Willardson
- Department of Chemistry and Biochemistry, Brigham Young University, Provo, United States
| | - Kirill A Martemyanov
- Department of Neuroscience, The Scripps Research Institute, Jupiter, United States
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9
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Zhang P, Kofron CM, Mende U. Heterotrimeric G protein-mediated signaling and its non-canonical regulation in the heart. Life Sci 2015; 129:35-41. [PMID: 25818188 PMCID: PMC4415990 DOI: 10.1016/j.lfs.2015.02.029] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2014] [Revised: 01/31/2015] [Accepted: 02/11/2015] [Indexed: 11/20/2022]
Abstract
Heterotrimeric guanine nucleotide-binding proteins (G proteins) regulate a multitude of signaling pathways in mammalian cells by transducing signals from G protein-coupled receptors (GPCRs) to effectors, which in turn regulate cellular function. In the myocardium, G protein signaling occurs in all cardiac cell types and is centrally involved in the regulation of heart rate, pump function, and vascular tone and in the response to hemodynamic stress and injury. Perturbations in G protein-mediated signaling are well known to contribute to cardiac hypertrophy, failure, and arrhythmias. Most of the currently used drugs for cardiac and other diseases target GPCR signaling. In the canonical G protein signaling paradigm, G proteins that are located at the cytoplasmic surface of the plasma membrane become activated after an agonist-induced conformational change of GPCRs, which then allows GTP-bound Gα and free Gβγ subunits to activate or inhibit effector proteins. Research over the past two decades has markedly broadened the original paradigm with a GPCR-G protein-effector at the cell surface at its core by revealing novel binding partners and additional subcellular localizations for heterotrimeric G proteins that facilitate many previously unrecognized functional effects. In this review, we focus on non-canonical and epigenetic-related mechanisms that regulate heterotrimeric G protein expression, activation, and localization and discuss functional consequences using cardiac examples where possible. Mechanisms reviewed involve microRNAs, histone deacetylases, chaperones, alternative modes of G protein activation, and posttranslational modifications. Some of these newly characterized mechanisms may be further developed into novel strategies for the treatment of cardiac disease and beyond.
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Affiliation(s)
- Peng Zhang
- Cardiovascular Research Center, Cardiology Division, Rhode Island Hospital, Providence, RI, USA; Alpert Medical School of Brown University, Providence, RI, USA
| | - Celinda M Kofron
- Cardiovascular Research Center, Cardiology Division, Rhode Island Hospital, Providence, RI, USA; Alpert Medical School of Brown University, Providence, RI, USA
| | - Ulrike Mende
- Cardiovascular Research Center, Cardiology Division, Rhode Island Hospital, Providence, RI, USA; Alpert Medical School of Brown University, Providence, RI, USA.
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10
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Structures of the Gβ-CCT and PhLP1-Gβ-CCT complexes reveal a mechanism for G-protein β-subunit folding and Gβγ dimer assembly. Proc Natl Acad Sci U S A 2015; 112:2413-8. [PMID: 25675501 DOI: 10.1073/pnas.1419595112] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
G-protein signaling depends on the ability of the individual subunits of the G-protein heterotrimer to assemble into a functional complex. Formation of the G-protein βγ (Gβγ) dimer is particularly challenging because it is an obligate dimer in which the individual subunits are unstable on their own. Recent studies have revealed an intricate chaperone system that brings Gβ and Gγ together. This system includes cytosolic chaperonin containing TCP-1 (CCT; also called TRiC) and its cochaperone phosducin-like protein 1 (PhLP1). Two key intermediates in the Gβγ assembly process, the Gβ-CCT and the PhLP1-Gβ-CCT complexes, were isolated and analyzed by a hybrid structural approach using cryo-electron microscopy, chemical cross-linking coupled with mass spectrometry, and unnatural amino acid cross-linking. The structures show that Gβ interacts with CCT in a near-native state through interactions of the Gγ-binding region of Gβ with the CCTγ subunit. PhLP1 binding stabilizes the Gβ fold, disrupting interactions with CCT and releasing a PhLP1-Gβ dimer for assembly with Gγ. This view provides unique insight into the interplay between CCT and a cochaperone to orchestrate the folding of a protein substrate.
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11
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Retinal cone photoreceptors require phosducin-like protein 1 for G protein complex assembly and signaling. PLoS One 2015; 10:e0117129. [PMID: 25659125 PMCID: PMC4319785 DOI: 10.1371/journal.pone.0117129] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 12/19/2014] [Indexed: 12/24/2022] Open
Abstract
G protein β subunits (Gβ) play essential roles in phototransduction as part of G protein βγ (Gβγ) and regulator of G protein signaling 9 (RGS9)-Gβ5 heterodimers. Both are obligate dimers that rely on the cytosolic chaperone CCT and its co-chaperone PhLP1 to form complexes from their nascent polypeptides. The importance of PhLP1 in the assembly process was recently demonstrated in vivo in a retinal rod-specific deletion of the Phlp1 gene. To test whether this is a general mechanism that also applies to other cell types, we disrupted the Phlp1 gene specifically in mouse cones and measured the effects on G protein expression and cone visual signal transduction. In PhLP1-deficient cones, expression of cone transducin (Gt2) and RGS9-Gβ5 subunits was dramatically reduced, resulting in a 27-fold decrease in sensitivity and a 38-fold delay in cone photoresponse recovery. These results demonstrate the essential role of PhLP1 in cone G protein complex formation. Our findings reveal a common mechanism of Gβγ and RGS9-Gβ5 assembly in rods and cones, highlighting the importance of PhLP1 and CCT-mediated Gβ complex formation in G protein signaling.
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12
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Yoda A, Adelmant G, Tamburini J, Chapuy B, Shindoh N, Yoda Y, Weigert O, Kopp N, Wu SC, Kim SS, Liu H, Tivey T, Christie AL, Elpek KG, Card J, Gritsman K, Gotlib J, Deininger MW, Makishima H, Turley SJ, Javidi-Sharifi N, Maciejewski JP, Jaiswal S, Ebert BL, Rodig SJ, Tyner JW, Marto JA, Weinstock DM, Lane AA. Mutations in G protein β subunits promote transformation and kinase inhibitor resistance. Nat Med 2014; 21:71-5. [PMID: 25485910 PMCID: PMC4289115 DOI: 10.1038/nm.3751] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2014] [Accepted: 10/17/2014] [Indexed: 12/18/2022]
Abstract
Activating mutations in genes encoding G protein α (Gα) subunits occur in 4-5% of all human cancers, but oncogenic alterations in Gβ subunits have not been defined. Here we demonstrate that recurrent mutations in the Gβ proteins GNB1 and GNB2 confer cytokine-independent growth and activate canonical G protein signaling. Multiple mutations in GNB1 affect the protein interface that binds Gα subunits as well as downstream effectors and disrupt Gα interactions with the Gβγ dimer. Different mutations in Gβ proteins clustered partly on the basis of lineage; for example, all 11 GNB1 K57 mutations were in myeloid neoplasms, and seven of eight GNB1 I80 mutations were in B cell neoplasms. Expression of patient-derived GNB1 variants in Cdkn2a-deficient mouse bone marrow followed by transplantation resulted in either myeloid or B cell malignancies. In vivo treatment with the dual PI3K-mTOR inhibitor BEZ235 suppressed GNB1-induced signaling and markedly increased survival. In several human tumors, mutations in the gene encoding GNB1 co-occurred with oncogenic kinase alterations, including the BCR-ABL fusion protein, the V617F substitution in JAK2 and the V600K substitution in BRAF. Coexpression of patient-derived GNB1 variants with these mutant kinases resulted in inhibitor resistance in each context. Thus, GNB1 and GNB2 alterations confer transformed and resistance phenotypes across a range of human tumors and may be targetable with inhibitors of G protein signaling.
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Affiliation(s)
- Akinori Yoda
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Guillaume Adelmant
- 1] Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA. [2] Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - Jerome Tamburini
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Bjoern Chapuy
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Nobuaki Shindoh
- 1] Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA. [2] Drug Discovery Research, Astellas Pharma Inc., Tsukuba, Ibaraki, Japan
| | - Yuka Yoda
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Oliver Weigert
- Department of Medicine III, Campus Grosshadern, Ludwig-Maximilians-University, and Helmholtz Center, Munich, Germany
| | - Nadja Kopp
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Shuo-Chieh Wu
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Sunhee S Kim
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Huiyun Liu
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Trevor Tivey
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Amanda L Christie
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Kutlu G Elpek
- 1] Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA. [2] Jounce Therapeutics, Inc., Cambridge, Massachusetts, USA
| | - Joseph Card
- Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Kira Gritsman
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Jason Gotlib
- Division of Hematology, Stanford Cancer Institute, Stanford University School of Medicine, Stanford, California, USA
| | - Michael W Deininger
- Division of Hematology and Hematologic Malignancies, Huntsman Cancer Institute, The University of Utah, Salt Lake City, Utah, USA
| | - Hideki Makishima
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Shannon J Turley
- Department of Cancer Immunology and AIDS, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
| | - Nathalie Javidi-Sharifi
- Department of Cell, Developmental and Cancer Biology, Oregon Health and Science University, Knight Cancer Institute, Portland, Oregon, USA
| | - Jaroslaw P Maciejewski
- Department of Translational Hematology and Oncology Research, Taussig Cancer Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Siddhartha Jaiswal
- 1] Department of Pathology, Massachusetts General Hospital, Boston, Massachusetts, USA. [2] Division of Hematology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Benjamin L Ebert
- 1] Division of Hematology, Brigham and Women's Hospital, Boston, Massachusetts, USA. [2] Broad Institute, Cambridge, Massachusetts, USA
| | - Scott J Rodig
- Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Jeffrey W Tyner
- Department of Cell, Developmental and Cancer Biology, Oregon Health and Science University, Knight Cancer Institute, Portland, Oregon, USA
| | - Jarrod A Marto
- 1] Department of Cancer Biology and Blais Proteomics Center, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA. [2] Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, Boston, Massachusetts, USA
| | - David M Weinstock
- 1] Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA. [2] Broad Institute, Cambridge, Massachusetts, USA
| | - Andrew A Lane
- Department of Medical Oncology, Dana-Farber Cancer Institute, Harvard Medical School, Boston, Massachusetts, USA
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