1
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Baffi TR, Lordén G, Wozniak JM, Feichtner A, Yeung W, Kornev AP, King CC, Del Rio JC, Limaye AJ, Bogomolovas J, Gould CM, Chen J, Kennedy EJ, Kannan N, Gonzalez DJ, Stefan E, Taylor SS, Newton AC. mTORC2 controls the activity of PKC and Akt by phosphorylating a conserved TOR interaction motif. Sci Signal 2021; 14:eabe4509. [PMID: 33850054 PMCID: PMC8208635 DOI: 10.1126/scisignal.abe4509] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The complex mTORC2 is accepted to be the kinase that controls the phosphorylation of the hydrophobic motif, a key regulatory switch for AGC kinases, although whether mTOR directly phosphorylates this motif remains controversial. Here, we identified an mTOR-mediated phosphorylation site that we termed the TOR interaction motif (TIM; F-x3-F-pT), which controls the phosphorylation of the hydrophobic motif of PKC and Akt and the activity of these kinases. The TIM is invariant in mTORC2-dependent AGC kinases, is evolutionarily conserved, and coevolved with mTORC2 components. Mutation of this motif in Akt1 and PKCβII abolished cellular kinase activity by impairing activation loop and hydrophobic motif phosphorylation. mTORC2 directly phosphorylated the PKC TIM in vitro, and this phosphorylation event was detected in mouse brain. Overexpression of PDK1 in mTORC2-deficient cells rescued hydrophobic motif phosphorylation of PKC and Akt by a mechanism dependent on their intrinsic catalytic activity, revealing that mTORC2 facilitates the PDK1 phosphorylation step, which, in turn, enables autophosphorylation. Structural analysis revealed that PKC homodimerization is driven by a TIM-containing helix, and biophysical proximity assays showed that newly synthesized, unphosphorylated PKC dimerizes in cells. Furthermore, disruption of the dimer interface by stapled peptides promoted hydrophobic motif phosphorylation. Our data support a model in which mTORC2 relieves nascent PKC dimerization through TIM phosphorylation, recruiting PDK1 to phosphorylate the activation loop and triggering intramolecular hydrophobic motif autophosphorylation. Identification of TIM phosphorylation and its role in the regulation of PKC provides the basis for AGC kinase regulation by mTORC2.
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Affiliation(s)
- Timothy R Baffi
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, USA
- Biomedical Sciences Graduate Program, University of California at San Diego, La Jolla, CA 92093, USA
| | - Gema Lordén
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, USA
| | - Jacob M Wozniak
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, USA
- Biomedical Sciences Graduate Program, University of California at San Diego, La Jolla, CA 92093, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, CA 92093, USA
| | - Andreas Feichtner
- Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, Innsbruck A-6020, Austria
| | - Wayland Yeung
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - Alexandr P Kornev
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, USA
| | - Charles C King
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, USA
| | - Jason C Del Rio
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, USA
- Biomedical Sciences Graduate Program, University of California at San Diego, La Jolla, CA 92093, USA
| | - Ameya J Limaye
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602, USA
| | - Julius Bogomolovas
- Department of Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Christine M Gould
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, USA
- Biomedical Sciences Graduate Program, University of California at San Diego, La Jolla, CA 92093, USA
| | - Ju Chen
- Department of Medicine, University of California at San Diego, La Jolla, CA 92093, USA
| | - Eileen J Kennedy
- Department of Pharmaceutical and Biomedical Sciences, College of Pharmacy, University of Georgia, Athens, GA 30602, USA
| | - Natarajan Kannan
- Institute of Bioinformatics, University of Georgia, Athens, GA 30602, USA
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA
| | - David J Gonzalez
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, USA
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California at San Diego, La Jolla, CA 92093, USA
| | - Eduard Stefan
- Institute of Biochemistry and Center for Molecular Biosciences, University of Innsbruck, Innsbruck A-6020, Austria
| | - Susan S Taylor
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, USA
- Department of Chemistry and Biochemistry, University of California at San Diego, La Jolla, CA 92093, USA
| | - Alexandra C Newton
- Department of Pharmacology, University of California at San Diego, La Jolla, CA 92093, USA.
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2
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Lippert LG, Ma N, Ritt M, Jain A, Vaidehi N, Sivaramakrishnan S. Kinase inhibitors allosterically disrupt a regulatory interaction to enhance PKCα membrane translocation. J Biol Chem 2021; 296:100339. [PMID: 33508318 PMCID: PMC7949123 DOI: 10.1016/j.jbc.2021.100339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2020] [Revised: 01/14/2021] [Accepted: 01/22/2021] [Indexed: 10/28/2022] Open
Abstract
The eukaryotic kinase domain has multiple intrinsically disordered regions whose conformation dictates kinase activity. Small molecule kinase inhibitors (SMKIs) rely on disrupting the active conformations of these disordered regions to inactivate the kinase. While SMKIs are selected for their ability to cause this disruption, the allosteric effects of conformational changes in disordered regions is limited by a lack of dynamic information provided by traditional structural techniques. In this study, we integrated multiscale molecular dynamics simulations with FRET sensors to characterize a novel allosteric mechanism that is selectively triggered by SMKI binding to the protein kinase Cα domain. The indole maleimide inhibitors BimI and sotrastaurin were found to displace the Gly-rich loop (G-loop) that normally shields the ATP-binding site. Displacement of the G-loop interferes with a newly identified, structurally conserved binding pocket for the C1a domain on the N lobe of the kinase domain. This binding pocket, in conjunction with the N-terminal regulatory sequence, masks a diacylglycerol (DAG) binding site on the C1a domain. SMKI-mediated displacement of the G-loop released C1a and exposed the DAG binding site, enhancing protein kinase Cα translocation both to synthetic lipid bilayers and to live cell membranes in the presence of DAG. Inhibitor chemotype determined the extent of the observed allosteric effects on the kinase domain and correlated with the extent of membrane recruitment. Our findings demonstrate the allosteric effects of SMKIs beyond the confines of kinase catalytic conformation and provide an integrated computational-experimental paradigm to investigate parallel mechanisms in other kinases.
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Affiliation(s)
- Lisa G Lippert
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, USA
| | - Ning Ma
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, California, USA
| | - Michael Ritt
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, USA
| | - Abhinandan Jain
- The Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California, USA
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine, Beckman Research Institute of the City of Hope, Duarte, California, USA.
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, USA.
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3
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Gupte TM, Ritt M, Sivaramakrishnan S. ER/K-link-Leveraging a native protein linker to probe dynamic cellular interactions. Methods Enzymol 2020; 647:173-208. [PMID: 33482988 PMCID: PMC8009693 DOI: 10.1016/bs.mie.2020.10.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
ER/K α-helices are a subset of single alpha helical domains, which exhibit unusual stability as isolated protein secondary structures. They adopt an elongated structural conformation, while regulating the frequency of interactions between proteins or polypeptides fused to their ends. Here we review recent advances on the structure, stability and function of ER/K α-helices as linkers (ER/K linkers) in native proteins. We describe methodological considerations in the molecular cloning, protein expression and measurement of interaction strengths, using sensors incorporating ER/K linkers. We highlight biological insights obtained over the last decade by leveraging distinct biophysical features of ER/K-linked sensors. We conclude with the outlook for the use of ER/K linkers in the selective modulation of dynamic cellular interactions.
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Affiliation(s)
- Tejas M Gupte
- Department of Genetics, Cell Biology, and Development, College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States
| | - Michael Ritt
- Department of Genetics, Cell Biology, and Development, College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development, College of Biological Sciences, University of Minnesota, Minneapolis, MN, United States.
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4
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Heckman CA, Biswas T, Dimick DM, Cayer ML. Activated Protein Kinase C (PKC) Is Persistently Trafficked with Epidermal Growth Factor (EGF) Receptor. Biomolecules 2020; 10:E1288. [PMID: 32906765 PMCID: PMC7563713 DOI: 10.3390/biom10091288] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 09/02/2020] [Accepted: 09/05/2020] [Indexed: 12/22/2022] Open
Abstract
Protein kinase Cs (PKCs) are activated by lipids in the plasma membrane and bind to a scaffold assembled on the epidermal growth factor (EGF) receptor (EGFR). Understanding how this complex is routed is important, because this determines whether EGFR is degraded, terminating signaling. Here, cells were preincubated in EGF-tagged gold nanoparticles, then allowed to internalize them in the presence or absence of a phorbol ester PKC activator. PKC colocalized with EGF-tagged nanoparticles within 5 min and migrated with EGFR-bearing vesicles into the cell. Two conformations of PKC-epsilon were distinguished by different primary antibodies. One, thought to be enzymatically active, was on endosomes and displayed a binding site for antibody RR (R&D). The other, recognized by Genetex green (GG), was soluble, on actin-rich structures, and loosely bound to vesicles. During a 15-min chase, EGF-tagged nanoparticles entered large, perinuclear structures. In phorbol ester-treated cells, vesicles bearing EGF-tagged nanoparticles tended to enter this endocytic recycling compartment (ERC) without the GG form. The correlation coefficient between the GG (inactive) and RR conformations on vesicles was also lower. Thus, active PKC has a Charon-like function, ferrying vesicles to the ERC, and inactivation counteracts this function. The advantage conferred on cells by aggregating vesicles in the ERC is unclear.
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Affiliation(s)
- Carol A. Heckman
- Department of Biological Sciences, 217 Life Science Building, Bowling Green State University, Bowling Green, OH 43403, USA;
| | - Tania Biswas
- Department of Biological Sciences, 217 Life Science Building, Bowling Green State University, Bowling Green, OH 43403, USA;
| | - Douglas M. Dimick
- Department of Physics & Astronomy, 104 Overman Hall, Bowling Green State University, Bowling Green, OH 43403, USA;
| | - Marilyn L. Cayer
- Center for Microscopy & Microanalysis, 217 Life Science Building, Bowling Green State University, Bowling Green, OH 43403, USA;
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5
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Barnes CA, Shen Y, Ying J, Takagi Y, Torchia DA, Sellers JR, Bax A. Remarkable Rigidity of the Single α-Helical Domain of Myosin-VI As Revealed by NMR Spectroscopy. J Am Chem Soc 2019; 141:9004-9017. [PMID: 31117653 PMCID: PMC6556874 DOI: 10.1021/jacs.9b03116] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2019] [Indexed: 11/29/2022]
Abstract
Although the α-helix has long been recognized as an all-important element of secondary structure, it generally requires stabilization by tertiary interactions with other parts of a protein's structure. Highly charged single α-helical (SAH) domains, consisting of a high percentage (>75%) of Arg, Lys, and Glu residues, are exceptions to this rule but have been difficult to characterize structurally. Our study focuses on the 68-residue medial tail domain of myosin-VI, which is found to contain a highly ordered α-helical structure extending from Glu-6 to Lys-63. High hydrogen exchange protection factors (15-150), small (ca. 4 Hz) 3 JHNHα couplings, and a near-perfect fit to an ideal model α-helix for its residual dipolar couplings (RDCs), measured in a filamentous phage medium, support the high regularity of this helix. Remarkably, the hydrogen exchange rates are far more homogeneous than the protection factors derived from them, suggesting that for these transiently broken helices the intrinsic exchange rates derived from the amino acid sequence are not appropriate reference values. 15N relaxation data indicate a very high degree of rotational diffusion anisotropy ( D∥/ D⊥ ≈ 7.6), consistent with the hydrodynamic behavior predicted for such a long, nearly straight α-helix. Alignment of the helix by a paramagnetic lanthanide ion attached to its N-terminal region shows a decrease in alignment as the distance from the tagging site increases. This decrease yields a precise measure for the persistence length of 224 ± 10 Å at 20 °C, supporting the idea that the role of the SAH helix is to act as an extension of the myosin-VI lever arm.
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6
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Ma N, Lippert LG, Devamani T, Levy B, Lee S, Sandhu M, Vaidehi N, Sivaramakrishnan S. Bitopic Inhibition of ATP and Substrate Binding in Ser/Thr Kinases through a Conserved Allosteric Mechanism. Biochemistry 2018; 57:6387-6390. [PMID: 30339352 DOI: 10.1021/acs.biochem.8b00729] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Protein kinases achieve substrate selective phosphorylation through their conformational flexibility and dynamic interaction with the substrate. Designing substrate selective or kinase selective small molecule inhibitors remains a challenge because of a lack of understanding of the dynamic mechanism by which substrates are selected by the kinase. Using a combination of all-atom molecular dynamics simulations and FRET sensors, we have delineated an allosteric mechanism that results in interaction among the DFG motif, G-loop, and activation loop and structurally links the nucleotide and substrate binding interfaces in protein kinase Cα and three other Ser/Thr kinases. ATP-competitive staurosporine analogues engage this allosteric switch region located just outside the ATP binding site to displace substrate binding to varying degrees. These inhibitors function as bitopic ligands by occupying the ATP binding site and interacting with the allosteric switch region. The conserved mechanism identified in this study can be exploited to select and design bitopic inhibitors for kinases.
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Affiliation(s)
- Ning Ma
- Department of Computational and Quantitative Medicine , Beckman Research Institute of the City of Hope , Duarte , California 91010 , United States
| | - Lisa G Lippert
- Department of Genetics, Cell Biology, and Development , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Titu Devamani
- Department of Genetics, Cell Biology, and Development , University of Minnesota , Minneapolis , Minnesota 55455 , United States
| | - Benjamin Levy
- Department of Computational and Quantitative Medicine , Beckman Research Institute of the City of Hope , Duarte , California 91010 , United States
| | - Sangbae Lee
- Department of Computational and Quantitative Medicine , Beckman Research Institute of the City of Hope , Duarte , California 91010 , United States
| | - Manbir Sandhu
- Department of Computational and Quantitative Medicine , Beckman Research Institute of the City of Hope , Duarte , California 91010 , United States
| | - Nagarajan Vaidehi
- Department of Computational and Quantitative Medicine , Beckman Research Institute of the City of Hope , Duarte , California 91010 , United States
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development , University of Minnesota , Minneapolis , Minnesota 55455 , United States
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7
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Rosenberg S, Simeonova I, Bielle F, Verreault M, Bance B, Le Roux I, Daniau M, Nadaradjane A, Gleize V, Paris S, Marie Y, Giry M, Polivka M, Figarella-Branger D, Aubriot-Lorton MH, Villa C, Vasiljevic A, Lechapt-Zalcman E, Kalamarides M, Sharif A, Mokhtari K, Pagnotta SM, Iavarone A, Lasorella A, Huillard E, Sanson M. A recurrent point mutation in PRKCA is a hallmark of chordoid gliomas. Nat Commun 2018; 9:2371. [PMID: 29915258 PMCID: PMC6006150 DOI: 10.1038/s41467-018-04622-w] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2017] [Accepted: 05/14/2018] [Indexed: 12/31/2022] Open
Abstract
Chordoid glioma (ChG) is a characteristic, slow growing, and well-circumscribed diencephalic tumor, whose mutational landscape is unknown. Here we report the analysis of 16 ChG by whole-exome and RNA-sequencing. We found that 15 ChG harbor the same PRKCAD463H mutation. PRKCA encodes the Protein kinase C (PKC) isozyme alpha (PKCα) and is mutated in a wide range of human cancers. However the hot spot PRKCAD463H mutation was not described in other tumors. PRKCAD463H is strongly associated with the activation of protein translation initiation (EIF2) pathway. PKCαD463H mRNA levels are more abundant than wild-type PKCα transcripts, while PKCαD463H is less stable than the PCKαWT protein. Compared to PCKαWT, the PKCαD463H protein is depleted from the cell membrane. The PKCαD463H mutant enhances proliferation of astrocytes and tanycytes, the cells of origin of ChG. In conclusion, our study identifies the hallmark mutation for chordoid gliomas and provides mechanistic insights on ChG oncogenesis. Chordoid glioma is a slow growing diencephalic tumor whose mutational landscape is poorly characterized. Here, the authors perform whole-exome and RNA-sequencing and find that 15 of 16 chordoid glioma cases studied harbor the same PRKCA mutation which results in enhanced proliferation.
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Affiliation(s)
- Shai Rosenberg
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France.,Gaffin Center for Neuro-oncology, Sharett Institute for Oncology, Hadassah - Hebrew University Medical Center, 91120, Jerusalem, Israel
| | - Iva Simeonova
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France
| | - Franck Bielle
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France.,Laboratoire R Escourolle, AP-HP, Hôpital de la Pitié-Salpêtrière, F-75013, Paris, France
| | - Maite Verreault
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France
| | - Bertille Bance
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France
| | - Isabelle Le Roux
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France
| | - Mailys Daniau
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France
| | - Arun Nadaradjane
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France
| | - Vincent Gleize
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France
| | - Sophie Paris
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France
| | - Yannick Marie
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France.,Onconeurotek Tumor Bank, Institut du Cerveau et de la Moelle épinère-ICM, F-75013, Paris, France
| | - Marine Giry
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France
| | - Marc Polivka
- Department of Pathology, AP-HP, Hôpital Lariboisière, F-75010, Paris, France
| | - Dominique Figarella-Branger
- Pathology and Neuropathology Department, Assistance Publique-Hôpitaux de Marseille (AP-HM), CHU Timone, 13005, Marseille, France
| | | | - Chiara Villa
- Department of Pathological Cytology and Anatomy, Foch Hospital, Suresnes, F-92151, Paris, France
| | - Alexandre Vasiljevic
- Centre de Biologie et Pathologie Est, Groupement Hospitalier Est, Hospices Civils de Lyon, 69500, Bron, France
| | - Emmanuèle Lechapt-Zalcman
- Department of Pathology, CHU de Caen, Caen, France Normandie Univ, UNICAEN, CEA, CNRS, ISTCT/LDM-TEP Group, 14000, Caen, France
| | - Michel Kalamarides
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France.,Service de Neurochirurgie, AP-HP, Hôpital de la Pitié-Salpêtrière, F-75013, Paris, France
| | - Ariane Sharif
- INSERM U1172, "Development and Plasticity of the Neuroendocrine Brain", F-59045, Lille, France
| | - Karima Mokhtari
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France.,Laboratoire R Escourolle, AP-HP, Hôpital de la Pitié-Salpêtrière, F-75013, Paris, France
| | - Stefano Maria Pagnotta
- Dipartimento di Scienze e Tecnologie, Università degli Studi del Sannio, 82100, Benevento, Italy.,Institute for Cancer Genetics, Columbia University Medical Center, New York City, NY, 10032, USA
| | - Antonio Iavarone
- Institute for Cancer Genetics, Columbia University Medical Center, New York City, NY, 10032, USA.,Departments of Neurology and Pathology, Institute for Cancer Genetics, Irving Comprehensive Research Center, New York, NY, 10032, USA
| | - Anna Lasorella
- Institute for Cancer Genetics, Columbia University Medical Center, New York City, NY, 10032, USA.,Departments of Pediatrics and Pathology, Institute for Cancer Genetics, Irving Comprehensive Research Center, New York, NY, 10032, USA
| | - Emmanuelle Huillard
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France
| | - Marc Sanson
- Inserm U 1127, CNRS UMR 7225, Sorbonne Universités, UPMC Univ Paris 06 UMR S 1127, ICM, F-75013, Paris, France. .,Onconeurotek Tumor Bank, Institut du Cerveau et de la Moelle épinère-ICM, F-75013, Paris, France. .,AP-HP, Hôpital de la Pitié-Salpêtrière, Service de Neurologie 2, F-75013, Paris, France. .,Site de Recherche Intégrée sur le Cancer (SiRIC) "CURAMUS", F-75013, Paris, France.
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8
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Lee S, Devamani T, Song HD, Sandhu M, Larsen A, Sommese R, Jain A, Vaidehi N, Sivaramakrishnan S. Distinct structural mechanisms determine substrate affinity and kinase activity of protein kinase Cα. J Biol Chem 2017; 292:16300-16309. [PMID: 28821615 PMCID: PMC5625059 DOI: 10.1074/jbc.m117.804781] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2017] [Revised: 08/04/2017] [Indexed: 11/06/2022] Open
Abstract
Protein kinase Cα (PKCα) belongs to the family of AGC kinases that phosphorylate multiple peptide substrates. Although the consensus sequence motif has been identified and used to explain substrate specificity for PKCα, it does not inform the structural basis of substrate-binding and kinase activity for diverse substrates phosphorylated by this kinase. The transient, dynamic, and unstructured nature of this protein-protein interaction has limited structural mapping of kinase-substrate interfaces. Here, using multiscale MD simulation-based predictions and FRET sensor-based experiments, we investigated the conformational dynamics of the kinase-substrate interface. We found that the binding strength of the kinase-substrate interaction is primarily determined by long-range columbic interactions between basic (Arg/Lys) residues located N-terminally to the phosphorylated Ser/Thr residues in the substrate and by an acidic patch in the kinase catalytic domain. Kinase activity stemmed from conformational flexibility in the region C-terminal to the phosphorylated Ser/Thr residues. Flexibility of the substrate-kinase interaction enabled an Arg/Lys two to three amino acids C-terminal to the phosphorylated Ser/Thr to prime a catalytically active conformation, facilitating phosphoryl transfer to the substrate. The structural mechanisms determining substrate binding and catalytic activity formed the basis of diverse binding affinities and kinase activities of PKCα for 14 substrates with varying degrees of sequence conservation. Our findings provide insight into the dynamic properties of the kinase-substrate interaction that govern substrate binding and turnover. Moreover, this study establishes a modeling and experimental method to elucidate the structural dynamics underlying substrate selectivity among eukaryotic kinases.
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Affiliation(s)
- Sangbae Lee
- From the Department of Molecular Immunology, Beckman Research Institute of the City of Hope, Duarte, California 91010
| | - Titu Devamani
- the Department of Genetics, Cell Biology, and Development, University of Minnesota, Twin Cities, Minneapolis, Minnesota 55455, and
| | - Hyun Deok Song
- From the Department of Molecular Immunology, Beckman Research Institute of the City of Hope, Duarte, California 91010
| | - Manbir Sandhu
- From the Department of Molecular Immunology, Beckman Research Institute of the City of Hope, Duarte, California 91010
| | - Adrien Larsen
- From the Department of Molecular Immunology, Beckman Research Institute of the City of Hope, Duarte, California 91010
| | - Ruth Sommese
- the Department of Genetics, Cell Biology, and Development, University of Minnesota, Twin Cities, Minneapolis, Minnesota 55455, and
| | - Abhinandan Jain
- the Jet Propulsion Laboratory, California Institute of Technology, Pasadena, California 91109
| | - Nagarajan Vaidehi
- From the Department of Molecular Immunology, Beckman Research Institute of the City of Hope, Duarte, California 91010,
| | - Sivaraj Sivaramakrishnan
- the Department of Genetics, Cell Biology, and Development, University of Minnesota, Twin Cities, Minneapolis, Minnesota 55455, and
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9
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Malik RU, Dysthe M, Ritt M, Sunahara RK, Sivaramakrishnan S. ER/K linked GPCR-G protein fusions systematically modulate second messenger response in cells. Sci Rep 2017; 7:7749. [PMID: 28798477 PMCID: PMC5552854 DOI: 10.1038/s41598-017-08029-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 07/05/2017] [Indexed: 12/20/2022] Open
Abstract
FRET and BRET approaches are well established for detecting ligand induced GPCR-G protein interactions in cells. Currently, FRET/BRET assays rely on co-expression of GPCR and G protein, and hence depend on the stoichiometry and expression levels of the donor and acceptor probes. On the other hand, GPCR-G protein fusions have been used extensively to understand the selectivity of GPCR signaling pathways. However, the signaling properties of fusion proteins are not consistent across GPCRs. In this study, we describe and characterize novel sensors based on the Systematic Protein Affinity Strength Modulation (SPASM) technique. Sensors consist of a GPCR and G protein tethered by an ER/K linker flanked by FRET probes. SPASM sensors are tested for the β2-, α1-, and α2- adrenergic receptors, and adenosine type 1 receptor (A1R), tethered to Gαs-XL, Gαi2, or Gαq subunits. Agonist stimulation of β2-AR and α2-AR increases FRET signal comparable to co-expressed FRET/BRET sensors. SPASM sensors also retain signaling through the endogenous G protein milieu. Importantly, ER/K linker length systematically tunes the GPCR-G protein interaction, with consequent modulation of second messenger signaling for cognate interactions. SPASM GPCR sensors serve the dual purpose of detecting agonist-induced changes in GPCR-G protein interactions, and linking these changes to downstream signaling.
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Affiliation(s)
- Rabia U Malik
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Matthew Dysthe
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Michael Ritt
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Roger K Sunahara
- Department of Pharmacology, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, 55455, USA.
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10
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Heckman CA, Pandey P, Cayer ML, Biswas T, Zhang Z, Boudreau NS. The tumor promoter-activated protein kinase Cs are a system for regulating filopodia. Cytoskeleton (Hoboken) 2017; 74:297-314. [PMID: 28481056 PMCID: PMC5575509 DOI: 10.1002/cm.21373] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2016] [Revised: 04/28/2017] [Accepted: 05/01/2017] [Indexed: 01/02/2023]
Abstract
Different protein kinase C (PKC) isoforms have distinct roles in regulating cell functions. The conventional (α, β, γ) and novel (δ, ɛ, η, θ) classes are targets of phorbol ester tumor promoters, which are surrogates of endogenous second messenger, diacylglycerol. The promoter-stimulated disappearance of filopodia was investigated by use of blocking peptides (BPs) that inhibit PKC maturation and/or docking. Filopodia were partially rescued by a peptide representing PKC ɛ hydrophobic sequence, but also by a myristoylated PKC α/β pseudosubstrate sequence, and an inhibitor of T-cell protein tyrosine phosphatase (TC-PTP). The ability to turn over filopodia was widely distributed among PKC isoforms. PKC α and η hydrophobic sequences enhanced filopodia in cells in the absence of tumor promoter treatment. With transcriptional knockdown of PKC α, the content of PKC ɛ predominated over other isoforms. PKC ɛ could decrease filopodia significantly in promoter-treated cells, and this was attributed to ruffling. The presence of PKC α counteracted the PKC ɛ-mediated enhancement of ruffling. The results showed that there were two mechanisms of filopodia downregulation. One operated in the steady-state and relied on PKC α and η. The other was stimulated by tumor promoters and relied on PKC ɛ. Cycles of protrusion and retraction are characteristic of filopodia and are essential for the cell to orient itself during chemotaxis and haptotaxis. By suppressing filopodia, PKC ɛ can create a long-term "memory" of an environmental signal that may act in nature as a mnemonic device to mark the direction of a repulsive signal.
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Affiliation(s)
- Carol A. Heckman
- Department of Biological SciencesBowling Green State UniversityLife Sciences Building Room 217Bowling GreenOhio43403
| | - Pratima Pandey
- Department of Biological SciencesBowling Green State UniversityLife Sciences Building Room 217Bowling GreenOhio43403
| | - Marilyn L. Cayer
- Center for Microscopy and MicroanalysisBowling Green State UniversityLife Sciences Building Room 217Bowling GreenOhio43403
| | - Tania Biswas
- Department of Biological SciencesBowling Green State UniversityLife Sciences Building Room 217Bowling GreenOhio43403
| | - Zhong‐Yin Zhang
- Department of Medicinal Chemistry and Molecular PharmacologyPurdue UniversityRobert E. Heine Pharmacy Building, Room 202A, 575 Stadium Mall DriveWest LafayetteIndiana47907
| | - Nancy S. Boudreau
- Department of Applied Statistics and Operations ResearchBowling Green State University344 Business Administration BuildingBowling GreenOhio43403
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11
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Morales KA, Yang Y, Cole TR, Igumenova TI. Dynamic Response of the C2 Domain of Protein Kinase Cα to Ca 2+ Binding. Biophys J 2017; 111:1655-1667. [PMID: 27760353 DOI: 10.1016/j.bpj.2016.09.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Revised: 09/04/2016] [Accepted: 09/07/2016] [Indexed: 11/28/2022] Open
Abstract
Ca2+-dependent conserved-region 2 (C2) domains target their host signaling proteins to anionic membranes. The Ca2+-binding event is a prerequisite for membrane association. Here, we investigate multiscale metal-ion-dependent dynamics of the C2 domain of protein kinase Cα (C2α) using NMR spectroscopy. Interactions with metal ions attenuate microsecond-timescale motions of the loop regions, indicating that preorganization of the metal-binding loops occurs before membrane insertion. Binding of a full complement of Ca2+ ions has a profound effect on the millisecond-timescale dynamics of the N- and C-terminal regions of C2α. We propose that Ca2+ binding allosterically destabilizes the terminal regions of C2α and thereby facilitates the conformational rearrangement necessary for full membrane insertion and activation of protein kinase Cα.
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Affiliation(s)
- Krystal A Morales
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Yuan Yang
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Taylor R Cole
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas
| | - Tatyana I Igumenova
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas.
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12
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Rennella E, Sekhar A, Kay LE. Self-Assembly of Human Profilin-1 Detected by Carr-Purcell-Meiboom-Gill Nuclear Magnetic Resonance (CPMG NMR) Spectroscopy. Biochemistry 2017; 56:692-703. [PMID: 28052669 DOI: 10.1021/acs.biochem.6b01263] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Protein oligomerization in the cell has important implications for both health and disease, and an understanding of the mechanisms by which proteins can self-associate is, therefore, of critical interest. Initial stages of the oligomerization process can be hard to detect, as they often involve the formation of sparsely populated and transient states that are difficult to characterize by standard biophysical approaches. Using relaxation dispersion nuclear magnetic resonance spectroscopy, we study the oligomerization of human profilin-1, a protein that regulates the polymerization of actin. We show that in solution and at millimolar concentrations profilin-1 is predominantly monomeric. However, fits of concentration-dependent relaxation data are consistent with the formation of a higher-order oligomer that is generated via a multistep process. Together with crystallographic data for profilin-2, a homologue of the protein studied here, our results suggest that profilin-1 forms a sparsely populated tetrameric conformer in solution.
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Affiliation(s)
- Enrico Rennella
- Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto , Toronto, Ontario M5S 1A8, Canada
| | - Ashok Sekhar
- Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto , Toronto, Ontario M5S 1A8, Canada
| | - Lewis E Kay
- Departments of Molecular Genetics, Biochemistry and Chemistry, The University of Toronto , Toronto, Ontario M5S 1A8, Canada.,Program in Molecular Structure and Function, Hospital for Sick Children , 555 University Avenue, Toronto, Ontario M5G 1X8, Canada
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13
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Sommese RF, Ritt M, Swanson CJ, Sivaramakrishnan S. The Role of Regulatory Domains in Maintaining Autoinhibition in the Multidomain Kinase PKCα. J Biol Chem 2017; 292:2873-2880. [PMID: 28049730 DOI: 10.1074/jbc.m116.768457] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Revised: 12/30/2016] [Indexed: 11/06/2022] Open
Abstract
Resolving the conformational dynamics of large multidomain proteins has proven to be a significant challenge. Here we use a variety of techniques to dissect the roles of individual protein kinase Cα (PKCα) regulatory domains in maintaining catalytic autoinhibition. We find that whereas the pseudosubstrate domain is necessary for autoinhibition it is not sufficient. Instead, each regulatory domain (C1a, C1b, and C2) appears to strengthen the pseudosubstrate-catalytic domain interaction in a nucleotide-dependent manner. The pseudosubstrate and C1a domains, however, are minimally essential for maintaining the inactivated state. Furthermore, disrupting known interactions between the C1a and other regulatory domains releases the autoinhibited interaction and increases basal activity. Modulating this interaction between the catalytic and regulatory domains reveals a direct correlation between autoinhibition and membrane translocation following PKC activation.
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Affiliation(s)
- Ruth F Sommese
- From the Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455 and
| | - Michael Ritt
- From the Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455 and
| | - Carter J Swanson
- the Biophysics Program, University of Michigan, Ann Arbor, Michigan 48109
| | - Sivaraj Sivaramakrishnan
- From the Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455 and
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14
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Bonny M, Hui X, Schweizer J, Kaestner L, Zeug A, Kruse K, Lipp P. C2-domain mediated nano-cluster formation increases calcium signaling efficiency. Sci Rep 2016; 6:36028. [PMID: 27808106 PMCID: PMC5093555 DOI: 10.1038/srep36028] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2016] [Accepted: 08/18/2016] [Indexed: 01/31/2023] Open
Abstract
Conventional protein kinase Cs (cPKCs) are key signaling proteins for transducing intracellular Ca2+ signals into downstream phosphorylation events. However, the lifetime of individual membrane-bound activated cPKCs is an order of magnitude shorter than the average time needed for target-protein phosphorylation. Here, we employed intermolecular Förster resonance energy transfer (FRET) in living cells combined with computational analysis to study the spatial organization of cPKCs bound to the plasma membrane. We discovered Ca2+-dependent cPKC nano-clusters that significantly extend cPKC’s plasma-membrane residence time. These protein patterns resulted from self-assembly mediated by Ca2+-binding C2-domains, which are widely used for membrane-targeting of Ca2+-sensing proteins. We also established clustering of other unrelated C2-domain containing proteins, suggesting that nano-cluster formation is a key step for efficient cellular Ca2+-signaling.
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Affiliation(s)
- Mike Bonny
- Theoretical Physics, Saarland University, Saarbrücken, Germany
| | - Xin Hui
- Institute for Molecular Cell Biology, Medical Faculty, Saarland University, Homburg/Saar, Germany
| | - Julia Schweizer
- Institute for Molecular Cell Biology, Medical Faculty, Saarland University, Homburg/Saar, Germany
| | - Lars Kaestner
- Institute for Molecular Cell Biology, Medical Faculty, Saarland University, Homburg/Saar, Germany
| | - André Zeug
- Cellular Neurophysiology, Center of Physiology, Hannover Medical School, Hannover, Germany
| | - Karsten Kruse
- Theoretical Physics, Saarland University, Saarbrücken, Germany
| | - Peter Lipp
- Institute for Molecular Cell Biology, Medical Faculty, Saarland University, Homburg/Saar, Germany
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15
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Swanson CJ, Sommese RF, Petersen KJ, Ritt M, Karslake J, Thomas DD, Sivaramakrishnan S. Calcium Stimulates Self-Assembly of Protein Kinase C α In Vitro. PLoS One 2016; 11:e0162331. [PMID: 27706148 PMCID: PMC5051681 DOI: 10.1371/journal.pone.0162331] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 08/22/2016] [Indexed: 11/18/2022] Open
Abstract
Protein kinase C α (PKCα) is a nodal regulator in several intracellular signaling networks. PKCα is composed of modular domains that interact with each other to dynamically regulate spatial-temporal function. We find that PKCα specifically, rapidly and reversibly self-assembles in the presence of calcium in vitro. This phenomenon is dependent on, and can be modulated by an intramolecular interaction between the C1a and C2 protein domains of PKCα. Next, we monitor self-assembly of PKC—mCitrine fusion proteins using time-resolved and steady-state homoFRET. HomoFRET between full-length PKCα molecules is observed when in solution with both calcium and liposomes containing either diacylglycerol (DAG) or phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2). Surprisingly, the C2 domain is sufficient to cluster on liposomes containing PI(4,5)P2, indicating the C1a domain is not required for self-assembly in this context. We conclude that three distinct clustered states of PKCα can be formed depending on what combination of cofactors are bound, but Ca2+ is minimally required and sufficient for clustering.
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Affiliation(s)
- Carter J. Swanson
- Biophysics Program, University of Michigan, Ann Arbor, 48109, United States of America
| | - Ruth F. Sommese
- Dept. of Genetics, Cell Biology and Development, University of Minnesota, Twin Cities, 55455, United States of America
| | - Karl J. Petersen
- Dept. of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Twin Cities, 55455, United States of America
| | - Michael Ritt
- Dept. of Genetics, Cell Biology and Development, University of Minnesota, Twin Cities, 55455, United States of America
| | - Joshua Karslake
- Biophysics Program, University of Michigan, Ann Arbor, 48109, United States of America
| | - David D. Thomas
- Dept. of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Twin Cities, 55455, United States of America
| | - Sivaraj Sivaramakrishnan
- Dept. of Genetics, Cell Biology and Development, University of Minnesota, Twin Cities, 55455, United States of America
- * E-mail:
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16
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Sommese RF, Hariadi RF, Kim K, Liu M, Tyska MJ, Sivaramakrishnan S. Patterning protein complexes on DNA nanostructures using a GFP nanobody. Protein Sci 2016; 25:2089-2094. [PMID: 27538185 DOI: 10.1002/pro.3020] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Revised: 08/15/2016] [Accepted: 08/15/2016] [Indexed: 11/06/2022]
Abstract
DNA nanostructures have become an important and powerful tool for studying protein function over the last 5 years. One of the challenges, though, has been the development of universal methods for patterning protein complexes on DNA nanostructures. Herein, we present a new approach for labeling DNA nanostructures by functionalizing them with a GFP nanobody. We demonstrate the ability to precisely control protein attachment via our nanobody linker using two enzymatic model systems, namely adenylyl cyclase activity and myosin motility. Finally, we test the power of this attachment method by patterning unpurified, endogenously expressed Arp2/3 protein complex from cell lysate. By bridging DNA nanostructures with a fluorescent protein ubiquitous throughout cell and developmental biology and protein biochemistry, this approach significantly streamlines the application of DNA nanostructures as a programmable scaffold in biological studies.
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Affiliation(s)
- R F Sommese
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, 55455
| | - R F Hariadi
- Department of Physics, Arizona State University, Tempe, Arizona, 85287.,Biodesign Center for Molecular Design and Biomimetics, Arizona State University, Tempe, Arizona, 85287
| | - K Kim
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, 55455
| | - M Liu
- Biodesign Center for Molecular Design and Biomimetics, Arizona State University, Tempe, Arizona, 85287.,School of Molecular Sciences, Arizona State University, Tempe, Arizona, 85287
| | - M J Tyska
- Department of Cell and Developmental Biology, Vanderbilt University Medical Center, Nashville, Tennessee, 37232
| | - S Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota, 55455.
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17
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Sommese RF, Sivaramakrishnan S. Substrate Affinity Differentially Influences Protein Kinase C Regulation and Inhibitor Potency. J Biol Chem 2016; 291:21963-21970. [PMID: 27555323 DOI: 10.1074/jbc.m116.737601] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Indexed: 02/05/2023] Open
Abstract
The overlapping network of kinase-substrate interactions provides exquisite specificity in cell signaling pathways, but also presents challenges to our ability to understand the mechanistic basis of biological processes. Efforts to dissect kinase-substrate interactions have been particularly limited by their inherently transient nature. Here, we use a library of FRET sensors to monitor these transient complexes, specifically examining weak interactions between the catalytic domain of protein kinase Cα and 14 substrate peptides. Combining results from this assay platform with those from standard kinase activity assays yields four novel insights into the kinase-substrate interaction. First, preferential binding of non-phosphorylated versus phosphorylated substrates leads to enhanced kinase-specific activity. Second, kinase-specific activity is inversely correlated with substrate binding affinity. Third, high affinity substrates can suppress phosphorylation of their low affinity counterparts. Finally, the substrate-competitive inhibitor bisindolylmaleimide I displaces low affinity substrates more potently leading to substrate selective inhibition of kinase activity. Overall, our approach complements existing structural and biophysical approaches to provide generalizable insights into the regulation of kinase activity.
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Affiliation(s)
- Ruth F Sommese
- From the Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455
| | - Sivaraj Sivaramakrishnan
- From the Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, Minnesota 55455
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18
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Termini CM, Lidke KA, Gillette JM. Tetraspanin CD82 Regulates the Spatiotemporal Dynamics of PKCα in Acute Myeloid Leukemia. Sci Rep 2016; 6:29859. [PMID: 27417454 PMCID: PMC4945921 DOI: 10.1038/srep29859] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2016] [Accepted: 06/22/2016] [Indexed: 02/08/2023] Open
Abstract
Patients with acute myeloid leukemia (AML) have increased myeloid cells within their bone marrow that exhibit aberrant signaling. Therefore, therapeutic targets that modulate disrupted signaling cascades are of significant interest. In this study, we demonstrate that the tetraspanin membrane scaffold, CD82, regulates protein kinase c alpha (PKCα)-mediated signaling critical for AML progression. Utilizing a palmitoylation mutant form of CD82 with disrupted membrane organization, we find that the CD82 scaffold controls PKCα expression and activation. Combining single molecule and ensemble imaging measurements, we determine that CD82 stabilizes PKCα activation at the membrane and regulates the size of PKCα membrane clusters. Further evaluation of downstream effector signaling identified robust and sustained activation of ERK1/2 upon CD82 overexpression that results in enhanced AML colony formation. Together, these data propose a mechanism where CD82 membrane organization regulates sustained PKCα signaling that results in an aggressive leukemia phenotype. These observations suggest that the CD82 scaffold may be a potential therapeutic target for attenuating aberrant signal transduction in AML.
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Affiliation(s)
- Christina M Termini
- Department of Pathology, University of New Mexico Health Sciences Center, University of New Mexico, MSC 08-4640, Albuquerque, NM 87131, USA
| | - Keith A Lidke
- Department of Physics and Astronomy, University of New Mexico, MSC 07-4220, Albuquerque, NM 87131, USA
| | - Jennifer M Gillette
- Department of Pathology, University of New Mexico Health Sciences Center, University of New Mexico, MSC 08-4640, Albuquerque, NM 87131, USA
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19
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Abstract
Protein kinase C (PKC) is a family of Ser/Thr kinases that regulate a multitude of cellular processes through participation in the phosphoinositide signaling pathway. Significant research efforts have been directed at understanding the structure, function, and regulatory modes of the enzyme since its discovery and identification as the first receptor for tumor-promoting phorbol esters. The activation of PKC involves a transition from the cytosolic autoinhibited latent form to the membrane-associated active form. The membrane recruitment step is accompanied by the conformational rearrangement of the enzyme, which relieves autoinhibitory interactions and thereby allows PKC to phosphorylate its targets. The multidomain structure and intrinsic flexibility of PKC present remarkable challenges and opportunities for the biophysical and structural biology studies of this class of enzymes and their interactions with membranes, the major focus of this Current Topic. I will highlight the recent advances in the field, outline the current challenges, and identify areas where biophysics and structural biology approaches can provide insight into the isoenzyme-specific regulation of PKC activity.
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20
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Abstract
Precise control of the amplitude of protein kinase C (PKC) signalling is essential for cellular homoeostasis, and disruption of this control leads to pathophysiological states such as cancer, neurodegeneration and diabetes. For conventional and novel PKC, this amplitude is meticulously tuned by multiple inputs that regulate the amount of enzyme in the cell, its ability to sense its allosteric activator diacylglycerol, and protein scaffolds that co-ordinate access to substrates. Key to regulation of the signalling output of most PKC isoenzymes is the ability of cytosolic enzyme to respond to the membrane-embedded lipid second messenger, diacylglycerol, in a dynamic range that prevents signalling in the absence of agonists but allows efficient activation in response to small changes in diacylglycerol levels. The present review discusses the regulatory inputs that control the spatiotemporal dynamics of PKC signalling, with a focus on conventional and novel PKC isoenzymes.
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21
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Sinha C, Arora K, Moon CS, Yarlagadda S, Woodrooffe K, Naren AP. Förster resonance energy transfer - an approach to visualize the spatiotemporal regulation of macromolecular complex formation and compartmentalized cell signaling. Biochim Biophys Acta Gen Subj 2014; 1840:3067-72. [PMID: 25086255 DOI: 10.1016/j.bbagen.2014.07.015] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2014] [Revised: 07/17/2014] [Accepted: 07/21/2014] [Indexed: 01/09/2023]
Abstract
BACKGROUND Signaling messengers and effector proteins provide an orchestrated molecular machinery to relay extracellular signals to the inside of cells and thereby facilitate distinct cellular behaviors. Formations of intracellular macromolecular complexes and segregation of signaling cascades dynamically regulate the flow of a biological process. SCOPE OF REVIEW In this review, we provide an overview of the development and application of FRET technology in monitoring cyclic nucleotide-dependent signalings and protein complexes associated with these signalings in real time and space with brief mention of other important signaling messengers and effector proteins involved in compartmentalized signaling. MAJOR CONCLUSIONS The preciseness, rapidity and specificity of cellular responses indicate restricted alterations of signaling messengers, particularly in subcellular compartments rather than globally. Not only the physical confinement and selective depletion, but also the intra- and inter-molecular interactions of signaling effectors modulate the direction of signal transduction in a compartmentalized fashion. To understand the finer details of various intracellular signaling cascades and crosstalk between proteins and other effectors, it is important to visualize these processes in live cells. Förster Resonance Energy Transfer (FRET) has been established as a useful tool to do this, even with its inherent limitations. GENERAL SIGNIFICANCE FRET technology remains as an effective tool for unraveling the complex organization and distribution of various endogenous signaling proteins, as well as the spatiotemporal dynamics of second messengers inside a single cell to distinguish the heterogeneity of cell signaling under normal physiological conditions and during pathological events.
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Affiliation(s)
- Chandrima Sinha
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, MLC2120 3333 Burnet Avenue Cincinnati, OH 45229, USA; Department of Physiology, University of Tennessee Health Science Center, 426 Nash Research Building, 894 Union Avenue, Memphis, TN 38163, USA
| | - Kavisha Arora
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, MLC2120 3333 Burnet Avenue Cincinnati, OH 45229, USA
| | - Chang Suk Moon
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, MLC2120 3333 Burnet Avenue Cincinnati, OH 45229, USA
| | - Sunitha Yarlagadda
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, MLC2120 3333 Burnet Avenue Cincinnati, OH 45229, USA
| | - Koryse Woodrooffe
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, MLC2120 3333 Burnet Avenue Cincinnati, OH 45229, USA
| | - Anjaparavanda P Naren
- Division of Pulmonary Medicine, Department of Pediatrics, Cincinnati Children's Hospital Medical Center, MLC2120 3333 Burnet Avenue Cincinnati, OH 45229, USA; Department of Physiology, University of Tennessee Health Science Center, 426 Nash Research Building, 894 Union Avenue, Memphis, TN 38163, USA.
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22
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Swanson CJ, Sivaramakrishnan S. Harnessing the unique structural properties of isolated α-helices. J Biol Chem 2014; 289:25460-7. [PMID: 25059657 DOI: 10.1074/jbc.r114.583906] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The α-helix is a ubiquitous secondary structural element that is almost exclusively observed in proteins when stabilized by tertiary or quaternary interactions. However, beginning with the unexpected observations of α-helix formation in the isolated C-peptide in ribonuclease A, there is growing evidence that a significant percentage (0.2%) of all proteins contain isolated stable single α-helical domains (SAH). These SAH domains provide unique structural features essential for normal protein function. A subset of SAH domains contain a characteristic ER/K motif, composed of a repeating sequence of ∼4 consecutive glutamic acids followed by ∼4 consecutive basic arginine or lysine (R/K) residues. The ER/K α-helix, also termed the ER/K linker, has been extensively characterized in the context of the myosin family of molecular motors and is emerging as a versatile structural element for protein and cellular engineering applications. Here, we review the structure and function of SAH domains, as well as the tools to identify them in natural proteins. We conclude with a discussion of recent studies that have successfully used the modular ER/K linker for engineering chimeric myosin proteins with altered mechanical properties, as well as synthetic polypeptides that can be used to monitor and systematically modulate protein interactions within cells.
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Affiliation(s)
| | - Sivaraj Sivaramakrishnan
- From the Departments of Biophysics, Cell and Developmental Biology, and Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109
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