1
|
Pala D, Clark DE. Caught between a ROCK and a hard place: current challenges in structure-based drug design. Drug Discov Today 2024:104106. [PMID: 39029868 DOI: 10.1016/j.drudis.2024.104106] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2024] [Revised: 06/27/2024] [Accepted: 07/13/2024] [Indexed: 07/21/2024]
Abstract
The discipline of structure-based drug design (SBDD) is several decades old and it is tempting to think that the proliferation of experimental structures for many drug targets might make computer-aided drug design (CADD) straightforward. However, this is far from true. In this review, we illustrate some of the challenges that CADD scientists face every day in their work, even now. We use Rho-associated protein kinase (ROCK), and public domain structures and data, as an example to illustrate some of the challenges we have experienced during our project targeting this protein. We hope that this will help to prevent unrealistic expectations of what CADD can accomplish and to educate non-CADD scientists regarding the challenges still facing their CADD colleagues.
Collapse
Affiliation(s)
- Daniele Pala
- Medicinal Chemistry and Drug Design Technologies Department, Chiesi Farmaceutici S.p.A, Research Center, Largo Belloli 11/a, 43122 Parma, Italy
| | - David E Clark
- Charles River, 6-9 Spire Green Centre, Flex Meadow, Harlow, CM19 5TR, UK
| |
Collapse
|
2
|
Herneisen AL, Peters ML, Smith TA, Shortt E, Lourido S. SPARK regulates AGC kinases central to the Toxoplasma gondii asexual cycle. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2023.10.30.564746. [PMID: 37961644 PMCID: PMC10634940 DOI: 10.1101/2023.10.30.564746] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Apicomplexan parasites balance proliferation, persistence, and spread in their metazoan hosts. AGC kinases, such as PKG, PKA, and the PDK1 ortholog SPARK, integrate environmental signals to toggle parasites between replicative and motile life stages. Recent studies have cataloged pathways downstream of apicomplexan PKG and PKA; however, less is known about the global integration of AGC kinase signaling cascades. Here, conditional genetics coupled to unbiased proteomics demonstrates that SPARK complexes with an elongin-like protein to regulate the stability of PKA and PKG in the model apicomplexan Toxoplasma gondii. Defects attributed to SPARK depletion develop after PKG and PKA are down-regulated. Parasites lacking SPARK differentiate into the chronic form of infection, which may arise from reduced activity of a coccidian-specific PKA ortholog. This work delineates the signaling topology of AGC kinases that together control transitions within the asexual cycle of this important family of parasites.
Collapse
Affiliation(s)
- Alice L. Herneisen
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| | - Michelle L. Peters
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| | - Tyler A. Smith
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| | - Emily Shortt
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| | - Sebastian Lourido
- Whitehead Institute for Biomedical Research and Department of Biology, Massachusetts Institute of Technology, Cambridge, MA
| |
Collapse
|
3
|
McRee SK, Bayer AL, Pietruska J, Tsichlis PN, Hinds PW. AKT2 Loss Impairs BRAF-Mutant Melanoma Metastasis. Cancers (Basel) 2023; 15:4958. [PMID: 37894325 PMCID: PMC10605002 DOI: 10.3390/cancers15204958] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/02/2023] [Accepted: 10/10/2023] [Indexed: 10/29/2023] Open
Abstract
Despite recent advances in treatment, melanoma remains the deadliest form of skin cancer due to its highly metastatic nature. Melanomas harboring oncogenic BRAFV600E mutations combined with PTEN loss exhibit unrestrained PI3K/AKT signaling and increased invasiveness. However, the contribution of different AKT isoforms to melanoma initiation, progression, and metastasis has not been comprehensively explored, and questions remain about whether individual isoforms play distinct or redundant roles in each step. We investigate the contribution of individual AKT isoforms to melanoma initiation using a novel mouse model of AKT isoform-specific loss in a murine melanoma model, and we investigate tumor progression, maintenance, and metastasis among a panel of human metastatic melanoma cell lines using AKT isoform-specific knockdown studies. We elucidate that AKT2 is dispensable for primary tumor formation but promotes migration and invasion in vitro and metastatic seeding in vivo, whereas AKT1 is uniquely important for melanoma initiation and cell proliferation. We propose a mechanism whereby the inhibition of AKT2 impairs glycolysis and reduces an EMT-related gene expression signature in PTEN-null BRAF-mutant human melanoma cells to limit metastatic spread. Our data suggest that the elucidation of AKT2-specific functions in metastasis might inform therapeutic strategies to improve treatment options for melanoma patients.
Collapse
Affiliation(s)
- Siobhan K. McRee
- Program in Genetics, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA;
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA;
| | - Abraham L. Bayer
- Program in Immunology, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA;
- Department of Immunology, Tufts University School of Medicine, Boston, MA 02111, USA
| | - Jodie Pietruska
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA;
| | - Philip N. Tsichlis
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, OH 43210, USA;
| | - Philip W. Hinds
- Program in Genetics, Graduate School of Biomedical Sciences, Tufts University, Boston, MA 02111, USA;
- Department of Developmental, Molecular and Chemical Biology, Tufts University School of Medicine, Boston, MA 02111, USA;
| |
Collapse
|
4
|
Leroux AE, Biondi RM. The choreography of protein kinase PDK1 and its diverse substrate dance partners. Biochem J 2023; 480:1503-1532. [PMID: 37792325 DOI: 10.1042/bcj20220396] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/24/2023] [Accepted: 08/31/2023] [Indexed: 10/05/2023]
Abstract
The protein kinase PDK1 phosphorylates at least 24 distinct substrates, all of which belong to the AGC protein kinase group. Some substrates, such as conventional PKCs, undergo phosphorylation by PDK1 during their synthesis and subsequently get activated by DAG and Calcium. On the other hand, other substrates, including members of the Akt/PKB, S6K, SGK, and RSK families, undergo phosphorylation and activation downstream of PI3-kinase signaling. This review presents two accepted molecular mechanisms that determine the precise and timely phosphorylation of different substrates by PDK1. The first mechanism involves the colocalization of PDK1 with Akt/PKB in the presence of PIP3. The second mechanism involves the regulated docking interaction between the hydrophobic motif (HM) of substrates and the PIF-pocket of PDK1. This interaction, in trans, is equivalent to the molecular mechanism that governs the activity of AGC kinases through their HMs intramolecularly. PDK1 has been instrumental in illustrating the bi-directional allosteric communication between the PIF-pocket and the ATP-binding site and the potential of the system for drug discovery. PDK1's interaction with substrates is not solely regulated by the substrates themselves. Recent research indicates that full-length PDK1 can adopt various conformations based on the positioning of the PH domain relative to the catalytic domain. These distinct conformations of full-length PDK1 can influence the interaction and phosphorylation of substrates. Finally, we critically discuss recent findings proposing that PIP3 can directly regulate the activity of PDK1, which contradicts extensive in vitro and in vivo studies conducted over the years.
Collapse
Affiliation(s)
- Alejandro E Leroux
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina
| | - Ricardo M Biondi
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina
| |
Collapse
|
5
|
Sacerdoti M, Gross LZF, Riley AM, Zehnder K, Ghode A, Klinke S, Anand GS, Paris K, Winkel A, Herbrand AK, Godage HY, Cozier GE, Süß E, Schulze JO, Pastor-Flores D, Bollini M, Cappellari MV, Svergun D, Gräwert MA, Aramendia PF, Leroux AE, Potter BVL, Camacho CJ, Biondi RM. Modulation of the substrate specificity of the kinase PDK1 by distinct conformations of the full-length protein. Sci Signal 2023; 16:eadd3184. [PMID: 37311034 DOI: 10.1126/scisignal.add3184] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 05/19/2023] [Indexed: 06/15/2023]
Abstract
The activation of at least 23 different mammalian kinases requires the phosphorylation of their hydrophobic motifs by the kinase PDK1. A linker connects the phosphoinositide-binding PH domain to the catalytic domain, which contains a docking site for substrates called the PIF pocket. Here, we used a chemical biology approach to show that PDK1 existed in equilibrium between at least three distinct conformations with differing substrate specificities. The inositol polyphosphate derivative HYG8 bound to the PH domain and disrupted PDK1 dimerization by stabilizing a monomeric conformation in which the PH domain associated with the catalytic domain and the PIF pocket was accessible. In the absence of lipids, HYG8 potently inhibited the phosphorylation of Akt (also termed PKB) but did not affect the intrinsic activity of PDK1 or the phosphorylation of SGK, which requires docking to the PIF pocket. In contrast, the small-molecule valsartan bound to the PIF pocket and stabilized a second distinct monomeric conformation. Our study reveals dynamic conformations of full-length PDK1 in which the location of the linker and the PH domain relative to the catalytic domain determines the selective phosphorylation of PDK1 substrates. The study further suggests new approaches for the design of drugs to selectively modulate signaling downstream of PDK1.
Collapse
Affiliation(s)
- Mariana Sacerdoti
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET-Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina
| | - Lissy Z F Gross
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET-Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina
| | - Andrew M Riley
- Medicinal Chemistry and Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
| | - Karin Zehnder
- Department of Internal Medicine I, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Abhijeet Ghode
- Biological Sciences, National University of Singapore, Singapore 119077, Singapore
| | - Sebastián Klinke
- Fundación Instituto Leloir, IIBBA-CONICET, and Plataforma Argentina de Biología Estructural y Metabolómica PLABEM, Buenos Aires C1405BWE, Argentina
| | - Ganesh Srinivasan Anand
- Biological Sciences, National University of Singapore, Singapore 119077, Singapore
- Department of Chemistry, Huck Institutes of the Life Sciences, Pennsylvania State University, 104 Chemistry Building, University Park, PA 16802, USA
| | - Kristina Paris
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA 15260, USA
- Department of Statistics, University of Pittsburgh, WWPH 1821, Pittsburgh, PA 15213, USA
| | - Angelika Winkel
- Department of Internal Medicine I, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Amanda K Herbrand
- Department of Internal Medicine I, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - H Yasmin Godage
- Wolfson Laboratory of Medicinal Chemistry, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Gyles E Cozier
- Wolfson Laboratory of Medicinal Chemistry, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Evelyn Süß
- Department of Internal Medicine I, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Jörg O Schulze
- Department of Internal Medicine I, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
| | - Daniel Pastor-Flores
- Department of Internal Medicine I, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
- KBI Biopharma, Technologielaan 8, B-3001 Leuven, Belgium
| | - Mariela Bollini
- Centro de Investigaciones en Bionanociencias 'Elizabeth Jares-Erijman' CIBION, CONICET, Buenos Aires C1425FQD, Argentina
| | - María Victoria Cappellari
- Centro de Investigaciones en Bionanociencias 'Elizabeth Jares-Erijman' CIBION, CONICET, Buenos Aires C1425FQD, Argentina
| | - Dmitri Svergun
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, 22607 Hamburg, Germany
| | - Melissa A Gräwert
- European Molecular Biology Laboratory (EMBL), Hamburg Unit, 22607 Hamburg, Germany
| | - Pedro F Aramendia
- Centro de Investigaciones en Bionanociencias 'Elizabeth Jares-Erijman' CIBION, CONICET, Buenos Aires C1425FQD, Argentina
- Departamento de Química Inorgánica, Analítica y Química Física, FCEN, Universidad de Buenos Aires, Buenos Aires C1428EHA, Argentina
| | - Alejandro E Leroux
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET-Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina
| | - Barry V L Potter
- Medicinal Chemistry and Drug Discovery, Department of Pharmacology, University of Oxford, Mansfield Road, Oxford OX1 3QT, UK
- Wolfson Laboratory of Medicinal Chemistry, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Carlos J Camacho
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Ricardo M Biondi
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA)-CONICET-Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina
- Department of Internal Medicine I, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt, Germany
- DKTK German Cancer Consortium (DKTK), Frankfurt, Germany
- German Cancer Research Center (DKFZ), D-69120 Heidelberg, Germany
| |
Collapse
|
6
|
Martínez-Arenas L, Bayascas JR. Capturing conformational transitions of full-length PDK1 that dictate kinase substrate selectivity. Sci Signal 2023; 16:eadh5114. [PMID: 37311035 DOI: 10.1126/scisignal.adh5114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
PDK1 is a constitutively active master kinase that can phosphorylate and activate as many as 24 enzymes, all belonging to the AGC family of serine-threonine protein kinases. In this issue of Science Signaling, Sacerdoti et al. uncover how allosteric communication between different functional domains directs the selectivity of PDK1 toward particular subsets of substrates.
Collapse
Affiliation(s)
- Laura Martínez-Arenas
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| | - Jose R Bayascas
- Institut de Neurociències and Departament de Bioquímica i Biologia Molecular, Facultat de Medicina, Universitat Autònoma de Barcelona, 08193 Barcelona, Spain
| |
Collapse
|
7
|
Atiya A, Alhumaydhi FA, Sharaf SE, Al Abdulmonem W, Elasbali AM, Al Enazi MM, Shamsi A, Jawaid T, Alghamdi BS, Hashem AM, Ashraf GM, Shahwan M. Identification of 11-Hydroxytephrosin and Torosaflavone A as Potential Inhibitors of 3-Phosphoinositide-Dependent Protein Kinase 1 (PDPK1): Toward Anticancer Drug Discovery. BIOLOGY 2022; 11:1230. [PMID: 36009858 PMCID: PMC9405294 DOI: 10.3390/biology11081230] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Revised: 08/07/2022] [Accepted: 08/08/2022] [Indexed: 06/15/2023]
Abstract
The 3-phosphoinositide-dependent protein kinase 1 (PDPK1) has a significant role in cancer progression and metastasis as well as other inflammatory disorders, and has been proposed as a promising therapeutic target for several malignancies. In this work, we conducted a systematic virtual screening of natural compounds from the IMPPAT database to identify possible PDPK1 inhibitors. Primarily, the Lipinski rules, ADMET, and PAINS filter were applied and then the binding affinities, docking scores, and selectivity were carried out to find effective hits against PDPK1. Finally, we identified two natural compounds, 11-Hydroxytephrosin and Torosaflavone A, bearing substantial affinity with PDPK1. Both compounds showed drug-likeness as predicted by the ADMET analysis and their physicochemical parameters. These compounds preferentially bind to the ATP-binding pocket of PDPK1 and interact with functionally significant residues. The conformational dynamics and complex stability of PDPK1 with the selected compounds were then studied using interaction analysis and molecular dynamics (MD) simulations for 100 ns. The simulation results revealed that PDPK1 forms stable docked complexes with the elucidated compounds. The findings show that the newly discovered 11-Hydroxytephrosin and Torosaflavone A bind to PDPK1 in an ATP-competitive manner, suggesting that they could one day be used as therapeutic scaffolds against PDPK1-associated diseases including cancer.
Collapse
Affiliation(s)
- Akhtar Atiya
- Department of Pharmacognosy, College of Pharmacy, King Khalid University (KKU), Guraiger St., Abha 62529, Saudi Arabia
| | - Fahad A. Alhumaydhi
- Department of Medical Laboratories, College of Applied Medical Sciences, Qassim University, Buraydah 52571, Saudi Arabia
| | - Sharaf E. Sharaf
- Pharmaceutical Chemistry Department, College of Pharmacy Umm Al-Qura University, Makkah 21961, Saudi Arabia
- Clinical Research Administration, Executive Administration of Research and Innovation, King Abdullah Medical City in the Holy Capital, Makkah 21955, Saudi Arabia
| | - Waleed Al Abdulmonem
- Department of Pathology, College of Medicine, Qassim University, P.O. Box 6655, Buraidah 51452, Saudi Arabia
| | - Abdelbaset Mohamed Elasbali
- Department of Clinical Laboratory Science, College of Applied Sciences-Qurayyat, Jouf University, Sakaka 72388, Saudi Arabia
| | - Maher M. Al Enazi
- Department of Medical Laboratory Sciences, College of Applied Medical Sciences, Prince Sattam Bin Abdelaziz University, Al-Kharj 11942, Saudi Arabia
| | - Anas Shamsi
- Center of Medical and Bio-Allied Health Sciences Research, Ajman University, Ajman P.O. Box 346, United Arab Emirates
- Center for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, Jamia Nagar, New Delhi 110025, India
| | - Talha Jawaid
- Department of Pharmacology, College of Medicine, Al Imam Mohammad Ibn Saud Islamic University (IMSIU), Riyadh 13317, Saudi Arabia
| | - Badrah S. Alghamdi
- Neuroscience Unit, Department of Physiology, Faculty of Medicine, King Abdulaziz University, Jeddah 22254, Saudi Arabia
- Pre-Clinical Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 22254, Saudi Arabia
| | - Anwar M. Hashem
- Department of Medical Microbiology and Parasitology, Faculty of Medicine, King Abdulaziz University, Jeddah 22254, Saudi Arabia
- Vaccines and Immunotherapy Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 22254, Saudi Arabia
| | - Ghulam Md. Ashraf
- Pre-Clinical Research Unit, King Fahd Medical Research Center, King Abdulaziz University, Jeddah 22254, Saudi Arabia
- Department of Medical Laboratory Sciences, Faculty of Applied Medical Sciences, King Abdulaziz University, Jeddah 22254, Saudi Arabia
| | - Moyad Shahwan
- Center of Medical and Bio-Allied Health Sciences Research, Ajman University, Ajman P.O. Box 346, United Arab Emirates
- College of Pharmacy, Ajman University, Ajman P.O. Box 346, United Arab Emirates
| |
Collapse
|
8
|
Garcia-Viloca M, Bayascas JR, Lluch JM, González-Lafont À. Molecular Insights into the Regulation of 3-Phosphoinositide-Dependent Protein Kinase 1: Modeling the Interaction between the Kinase and the Pleckstrin Homology Domains. ACS OMEGA 2022; 7:25186-25199. [PMID: 35910176 PMCID: PMC9330272 DOI: 10.1021/acsomega.2c02020] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
The 3-phosphoinositide-dependent protein kinase 1 (PDK1) K465E mutant kinase can still activate protein kinase B (PKB) at the membrane in a phosphatidylinositol-3,4,5-trisphosphate (PIP3, PtdIns(3,4,5)P3) independent manner. To understand this new PDK1 regulatory mechanism, docking and molecular dynamics calculations were performed for the first time to simulate the wild-type kinase domain-pleckstrin homology (PH) domain complex with PH-in and PH-out conformations. These simulations were then compared to the PH-in model of the KD-PH(mutant K465E) PDK1 complex. Additionally, three KD-PH complexes were simulated, including a substrate analogue bound to a hydrophobic pocket (denominated the PIF-pocket) substrate-docking site. We find that only the PH-out conformation, with the PH domain well-oriented to interact with the cellular membrane, is active for wild-type PDK1. In contrast, the active conformation of the PDK1 K465E mutant is PH-in, being ATP-stable at the active site while the PIF-pocket is more accessible to the peptide substrate. We corroborate that both the docking-site binding and the catalytic activity are in fact enhanced in knock-in mouse samples expressing the PDK1 K465E protein, enabling the phosphorylation of PKB in the absence of PIP3 binding.
Collapse
Affiliation(s)
- Mireia Garcia-Viloca
- Departament
de Química, Universitat Autònoma
de Barcelona, Bellaterra, Barcelona 08193, Spain
| | - Jose Ramón Bayascas
- Institut
de Neurociències, Universitat Autònoma
de Barcelona, Bellaterra, Barcelona 08193, Spain
- Department
of Biochemistry and Molecular Biology, Biochemistry Unit of the School
of Medicine, Universitat Autònoma
de Barcelona, Bellaterra, Barcelona 08193, Spain
| | - José M. Lluch
- Departament
de Química, Universitat Autònoma
de Barcelona, Bellaterra, Barcelona 08193, Spain
- Institut
de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona, Bellaterra, Barcelona 08193, Spain
| | - Àngels González-Lafont
- Departament
de Química, Universitat Autònoma
de Barcelona, Bellaterra, Barcelona 08193, Spain
- Institut
de Biotecnologia i de Biomedicina (IBB), Universitat Autònoma de Barcelona, Bellaterra, Barcelona 08193, Spain
| |
Collapse
|
9
|
Levina A, Fleming KD, Burke JE, Leonard TA. Activation of the essential kinase PDK1 by phosphoinositide-driven trans-autophosphorylation. Nat Commun 2022; 13:1874. [PMID: 35387990 PMCID: PMC8986801 DOI: 10.1038/s41467-022-29368-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 03/08/2022] [Indexed: 12/18/2022] Open
Abstract
3-phosphoinositide-dependent kinase 1 (PDK1) is an essential serine/threonine protein kinase, which plays a crucial role in cell growth and proliferation. It is often referred to as a 'master' kinase due to its ability to activate at least 23 downstream protein kinases implicated in various signaling pathways. In this study, we have elucidated the mechanism of phosphoinositide-driven PDK1 auto-activation. We show that PDK1 trans-autophosphorylation is mediated by a PIP3-mediated face-to-face dimer. We report regulatory motifs in the kinase-PH interdomain linker that allosterically activate PDK1 autophosphorylation via a linker-swapped dimer mechanism. Finally, we show that PDK1 is autoinhibited by its PH domain and that positive cooperativity of PIP3 binding drives switch-like activation of PDK1. These results imply that the PDK1-mediated activation of effector kinases, including Akt, PKC, Sgk, S6K and RSK, many of whom are not directly regulated by phosphoinositides, is also likely to be dependent on PIP3 or PI(3,4)P2.
Collapse
Affiliation(s)
- Aleksandra Levina
- Department of Structural and Computational Biology, Max Perutz Labs, Campus Vienna Biocenter 5, 1030, Vienna, Austria
- Department of Medical Biochemistry, Medical University of Vienna, 1090, Vienna, Austria
| | - Kaelin D Fleming
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
| | - John E Burke
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, BC, V8W 2Y2, Canada
- Department of Biochemistry and Molecular Biology, The University of British Columbia, Vancouver, BC, V6T 1Z3, Canada
| | - Thomas A Leonard
- Department of Structural and Computational Biology, Max Perutz Labs, Campus Vienna Biocenter 5, 1030, Vienna, Austria.
- Department of Medical Biochemistry, Medical University of Vienna, 1090, Vienna, Austria.
| |
Collapse
|
10
|
S6K1-mediated phosphorylation of PDK1 impairs AKT kinase activity and oncogenic functions. Nat Commun 2022; 13:1548. [PMID: 35318320 PMCID: PMC8941131 DOI: 10.1038/s41467-022-28910-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2021] [Accepted: 02/16/2022] [Indexed: 12/13/2022] Open
Abstract
Functioning as a master kinase, 3-phosphoinositide-dependent protein kinase 1 (PDK1) plays a fundamental role in phosphorylating and activating protein kinases A, B and C (AGC) family kinases, including AKT. However, upstream regulation of PDK1 remains largely elusive. Here we report that ribosomal protein S6 kinase beta 1 (S6K1), a member of AGC kinases and downstream target of mechanistic target of rapamycin complex 1 (mTORC1), directly phosphorylates PDK1 at its pleckstrin homology (PH) domain, and impairs PDK1 interaction with and activation of AKT. Mechanistically, S6K1-mediated phosphorylation of PDK1 augments its interaction with 14-3-3 adaptor protein and homo-dimerization, subsequently dissociating PDK1 from phosphatidylinositol 3,4,5 triphosphate (PIP3) and retarding its interaction with AKT. Pathologically, tumor patient-associated PDK1 mutations, either attenuating S6K1-mediated PDK1 phosphorylation or impairing PDK1 interaction with 14-3-3, result in elevated AKT kinase activity and oncogenic functions. Taken together, our findings not only unravel a delicate feedback regulation of AKT signaling via S6K1-mediated PDK1 phosphorylation, but also highlight the potential strategy to combat mutant PDK1-driven cancers. The direct upstream regulation of PDK1 is not fully understood. Here the authors demonstrate that S6K1 directly phosphorylates PDK1 to inhibit AKT kinase activity and its ability to drive tumourigenesis.
Collapse
|
11
|
Gordon MT, Ziemba BP, Falke JJ. Single-molecule studies reveal regulatory interactions between master kinases PDK1, AKT1, and PKC. Biophys J 2021; 120:5657-5673. [PMID: 34673053 DOI: 10.1016/j.bpj.2021.10.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Revised: 09/30/2021] [Accepted: 10/13/2021] [Indexed: 12/26/2022] Open
Abstract
Leukocyte migration is controlled by a leading-edge chemosensory pathway that generates the regulatory lipid phosphatidylinositol-3,4,5-trisphosphate (PIP3), a growth signal, thereby driving leading-edge expansion up attractant gradients toward sites of infection, inflammation, or tissue damage. PIP3 also serves as an important growth signal in growing cells and oncogenesis. The kinases PDK1, AKT1 or PKB, and PKCα are key components of a plasma-membrane-based PIP3 and Ca2+ signaling circuit that regulates these processes. PDK1 and AKT1 are recruited to the membrane by PIP3, whereas PKCα is recruited to the membrane by Ca2+. All three of these master kinases phosphoregulate an array of protein targets. For example, PDK1 activates AKT1, PKCα, and other AGC kinases by phosphorylation at key sites. PDK1 is believed to form PDK1-AKT1 and PDK1-PKCα heterodimers stabilized by a PDK1-interacting fragment (PIF) interaction between the PDK1 PIF pocket and the PIF motif of the AGC binding partner. Here, we present the first, to our knowledge, single-molecule studies of full-length PDK1 and AKT1 on target membrane surfaces, as well as their interaction with full-length PKCα. These studies directly detect membrane-bound PDK1-AKT1 and PDK1-PKCα heterodimers stabilized by PIF interactions formed at physiological ligand concentrations. PKCα exhibits eightfold higher PDK1 affinity than AKT1 and can competitively displace AKT1 from PDK1-AKT1 heterodimers. Ensemble activity measurements under matched conditions reveal that PDK1 activates AKT1 via a cis mechanism by phosphorylating an AKT1 molecule in the same PDK1-AKT1 heterodimer, whereas PKCα acts as a competitive inhibitor of this phosphoactivation reaction by displacing AKT1 from PDK1. Overall, the findings provide insights into the binding and regulatory interactions of the three master kinases on their target membrane and suggest that a recently described tumor suppressor activity of PKC isoforms may arise from its ability to downregulate PDK1-AKT1 phosphoactivation in the PIP3-PDK1-AKT1-mTOR pathway linked to cell growth and oncogenesis.
Collapse
Affiliation(s)
- Moshe T Gordon
- Molecular Biophysics Program and Department of Biochemistry, University of Colorado, Boulder, Colorado
| | - Brian P Ziemba
- Molecular Biophysics Program and Department of Biochemistry, University of Colorado, Boulder, Colorado
| | - Joseph J Falke
- Molecular Biophysics Program and Department of Biochemistry, University of Colorado, Boulder, Colorado.
| |
Collapse
|
12
|
Zhang M, Jang H, Nussinov R. PI3K Driver Mutations: A Biophysical Membrane-Centric Perspective. Cancer Res 2021; 81:237-247. [PMID: 33046444 PMCID: PMC7855922 DOI: 10.1158/0008-5472.can-20-0911] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2020] [Revised: 07/24/2020] [Accepted: 10/07/2020] [Indexed: 11/16/2022]
Abstract
Ras activates its effectors at the membrane. Active PI3Kα and its associated kinases/phosphatases assemble at membrane regions enriched in signaling lipids. In contrast, the Raf kinase domain extends into the cytoplasm and its assembly is away from the crowded membrane surface. Our structural membrane-centric outlook underscores the spatiotemporal principles of membrane and signaling lipids, which helps clarify PI3Kα activation. Here we focus on mechanisms of activation driven by PI3Kα driver mutations, spotlighting the PI3Kα double (multiple) activating mutations. Single mutations can be potent, but double mutations are stronger: their combination is specific, a single strong driver cannot fully activate PI3K, and two weak drivers may or may not do so. In contrast, two strong drivers may successfully activate PI3K, where one, for example, H1047R, modulates membrane interactions facilitating substrate binding at the active site (km) and the other, for example, E542K and E545K, reduces the transition state barrier (ka), releasing autoinhibition by nSH2. Although mostly unidentified, weak drivers are expected to be common, so we ask here how common double mutations are likely to be and why PI3Kα with double mutations responds effectively to inhibitors. We provide a structural view of hotspot and weak driver mutations in PI3Kα activation, explain their mechanisms, compare these with mechanisms of Raf activation, and point to targeting cell-specific, chromatin-accessible, and parallel (or redundant) pathways to thwart the expected emergence of drug resistance. Collectively, our biophysical outlook delineates activation and highlights the challenges of drug resistance.
Collapse
Affiliation(s)
- Mingzhen Zhang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland
| | - Hyunbum Jang
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland
| | - Ruth Nussinov
- Computational Structural Biology Section, Frederick National Laboratory for Cancer Research in the Laboratory of Cancer Immunometabolism, National Cancer Institute, Frederick, Maryland.
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| |
Collapse
|
13
|
Ghode A, Gross LZF, Tee WV, Guarnera E, Berezovsky IN, Biondi RM, Anand GS. Synergistic Allostery in Multiligand-Protein Interactions. Biophys J 2020; 119:1833-1848. [PMID: 33086047 PMCID: PMC7677135 DOI: 10.1016/j.bpj.2020.09.019] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Revised: 08/31/2020] [Accepted: 09/15/2020] [Indexed: 02/07/2023] Open
Abstract
Amide hydrogen-deuterium exchange mass spectrometry is powerful for describing combinatorial coupling effects of a cooperative ligand pair binding at noncontiguous sites: adenosine at the ATP-pocket and a docking peptide (PIFtide) at the PIF-pocket, on a model protein kinase PDK1. Binding of two ligands to PDK1 reveal multiple hotspots of synergistic allostery with cumulative effects greater than the sum of individual effects mediated by each ligand. We quantified this synergism and ranked these hotspots using a difference in deuteration-based approach, which showed that the strongest synergistic effects were observed at three of the critical catalytic loci of kinases: the αB-αC helices, and HRD-motif loop, and DFG-motif. Additionally, we observed weaker synergistic effects at a distal GHI-subdomain locus. Synergistic changes in deuterium exchange observed at a distal site but not at the intermediate sites of the large lobe of the kinase reveals allosteric propagation in proteins to operate through two modes. Direct electrostatic interactions between polar and charged amino acids that mediate targeted relay of allosteric signals, and diffused relay of allosteric signals through soft matter-like hydrophobic core amino acids. Furthermore, we provide evidence that the conserved β-3 strand lysine of protein kinases (Lys111 of PDK1) functions as an integrator node to coordinate allosteric coupling of the two ligand-binding sites. It maintains indirect interactions with the ATP-pocket and mediates a critical salt bridge with a glutamate (Glu130) of αC helix, which is conserved across all kinases. In summary, allosteric propagation in cooperative, dual-liganded enzyme targets is bidirectional and synergistic and offers a strategy for combinatorial drug development.
Collapse
Affiliation(s)
- Abhijeet Ghode
- Department of Biological Sciences, National University of Singapore, Singapore
| | - Lissy Z F Gross
- Instituto de Investigación en Biomedicina de Buenos Aires - CONICET - Partner Institute of the Max Planck Society, Buenos Aires, Argentina
| | - Wei-Ven Tee
- Department of Biological Sciences, National University of Singapore, Singapore; Bioinformatics Institute, Agency for Science, Technology and Research, Matrix, Singapore
| | - Enrico Guarnera
- Bioinformatics Institute, Agency for Science, Technology and Research, Matrix, Singapore
| | - Igor N Berezovsky
- Department of Biological Sciences, National University of Singapore, Singapore; Bioinformatics Institute, Agency for Science, Technology and Research, Matrix, Singapore
| | - Ricardo M Biondi
- Instituto de Investigación en Biomedicina de Buenos Aires - CONICET - Partner Institute of the Max Planck Society, Buenos Aires, Argentina
| | - Ganesh S Anand
- Department of Biological Sciences, National University of Singapore, Singapore.
| |
Collapse
|
14
|
Kim K, Park SG, Park BC, Kim JH, Kim S. Serine 389 phosphorylation of 3-phosphoinositide-dependent kinase 1 by UNC-51-like kinase 1 affects its ability to regulate Akt and p70 S6kinase. BMB Rep 2020. [PMID: 32317083 PMCID: PMC7396916 DOI: 10.5483/bmbrep.2020.53.7.299] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Abstract
Phosphorylation of the signaling component by protein kinase often leads to a kinase cascade or feedback loop. 3-Phosphoinositide-dependent kinase 1 (PDK1) signaling pathway diverges into various kinases including Akt and p70 S6 kinase (p70S6k). However, the PDK1 feedback mechanism remains elusive. Here, we demonstrated that UNC-51-like kinase (ULK1), an autophagy initiator kinase downstream of mechanistic target of rapamycin (mTOR), directly phosphorylated PDK1 on serine 389 at the linker region. Furthermore, our data showed that this phosphorylation affected the kinase activity of PDK1 toward downstream substrates. These results suggest a possible negative feedback loop between PDK1 and ULK1.
Collapse
Affiliation(s)
- Kidae Kim
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Proteome Structural biology, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea
| | - Sung Goo Park
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea
| | - Byoung Chul Park
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Proteome Structural biology, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea
| | - Jeong-Hoon Kim
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Functional Genomics, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea
| | - Sunhong Kim
- Disease Target Structure Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Korea
- Department of Bio-Molecular Science, KRIBB School of Bioscience, Korea University of Science and Technology, Daejeon 34113, Korea
| |
Collapse
|
15
|
Heras-Martínez GDL, Calleja V, Bailly R, Dessolin J, Larijani B, Requejo-Isidro J. A Complex Interplay of Anionic Phospholipid Binding Regulates 3'-Phosphoinositide-Dependent-Kinase-1 Homodimer Activation. Sci Rep 2019; 9:14527. [PMID: 31601855 PMCID: PMC6787260 DOI: 10.1038/s41598-019-50742-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2019] [Accepted: 09/16/2019] [Indexed: 12/28/2022] Open
Abstract
3'-Phosphoinositide-dependent-Kinase-1 (PDK1) is a master regulator whereby its PI3-kinase-dependent dysregulation in human pathologies is well documented. Understanding the direct role for PtdIns(3,4,5)P3 and other anionic phospholipids in the regulation of PDK1 conformational dynamics and its downstream activation remains incomplete. Using advanced quantitative-time-resolved imaging (Fluorescence Lifetime Imaging and Fluorescence Correlation Spectroscopy) and molecular modelling, we show an interplay of antagonistic binding effects of PtdIns(3,4,5)P3 and other anionic phospholipids, regulating activated PDK1 homodimers. We demonstrate that phosphatidylserine maintains PDK1 in an inactive conformation. The dysregulation of the PI3K pathway affects the spatio-temporal and conformational dynamics of PDK1 and the activation of its downstream substrates. We have established a new anionic-phospholipid-dependent model for PDK1 regulation, depicting the conformational dynamics of multiple homodimer states. We show that the dysregulation of the PI3K pathway perturbs equilibrium between the PDK1 homodimer conformations. Our findings provide a role for the PtdSer binding site and its previously unrewarding role in PDK1 downregulation, suggesting a possible therapeutic strategy where the constitutively active dimer conformer of PDK1 may be rendered inactive by small molecules that drive it to its PtdSer-bound conformer.
Collapse
Affiliation(s)
- Gloria de Las Heras-Martínez
- Instituto Biofisika (CSIC, UPV/EHU), 48490, Leioa, Spain
- Cell Biophysics Laboratory, Ikerbasque Basque Foundation for Science, Instituto Biofisika (CSIC, UPV/EHU) & Research Centre for Experimental Marine Biology and Biotechnology (PiE), University of the Basque Country (UPV/EHU), Leioa, 48940, Spain
| | - Véronique Calleja
- Protein Phosphorylation Laboratory, The Francis Crick Institute, 1 Midland Road, NW1 1AT, London, UK
| | - Remy Bailly
- Institute of Chemistry & Biology of Membranes & Nanoobjects (UMR 5248 CBMN) CNRS - Université de Bordeaux - Bordeaux INP All. Geoffroy Saint-Hilaire, 33600, Pessac, France
| | - Jean Dessolin
- Institute of Chemistry & Biology of Membranes & Nanoobjects (UMR 5248 CBMN) CNRS - Université de Bordeaux - Bordeaux INP All. Geoffroy Saint-Hilaire, 33600, Pessac, France
| | - Banafshé Larijani
- Cell Biophysics Laboratory, Ikerbasque Basque Foundation for Science, Instituto Biofisika (CSIC, UPV/EHU) & Research Centre for Experimental Marine Biology and Biotechnology (PiE), University of the Basque Country (UPV/EHU), Leioa, 48940, Spain.
- Centre for Therapeutic Innovation (CTI-Bath); Cell Biophysics Laboratory Department of Pharmacy & Pharmacology University, Bath, Claverton Down, Bath, BA2 7AY, United Kingdom.
| | - Jose Requejo-Isidro
- Instituto Biofisika (CSIC, UPV/EHU), 48490, Leioa, Spain.
- Centro Nacional de Biotecnología (CSIC), Darwin, 3, E28049, Madrid, Spain.
- Unidad de Nanobiotecnología, CNB-CSIC-IMDEA Nanociencia Associated Unit, 28049, Madrid, Spain.
| |
Collapse
|
16
|
Lipid-dependent Akt-ivity: where, when, and how. Biochem Soc Trans 2019; 47:897-908. [PMID: 31147387 PMCID: PMC6599160 DOI: 10.1042/bst20190013] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Revised: 05/08/2019] [Accepted: 05/08/2019] [Indexed: 02/07/2023]
Abstract
Akt is an essential protein kinase activated downstream of phosphoinositide 3-kinase and frequently hyperactivated in cancer. Canonically, Akt is activated by phosphoinositide-dependent kinase 1 and mechanistic target of rapamycin complex 2, which phosphorylate it on two regulatory residues in its kinase domain upon targeting of Akt to the plasma membrane by PI(3,4,5)P3. Recent evidence, however, has shown that, in addition to phosphorylation, Akt activity is allosterically coupled to the engagement of PI(3,4,5)P3 or PI(3,4)P2 in cellular membranes. Furthermore, the active membrane-bound conformation of Akt is protected from dephosphorylation, and Akt inactivation by phosphatases is rate-limited by its dissociation. Thus, Akt activity is restricted to membranes containing either PI(3,4,5)P3 or PI(3,4)P2. While PI(3,4,5)P3 has long been associated with signaling at the plasma membrane, PI(3,4)P2 is gaining increasing traction as a signaling lipid and has been implicated in controlling Akt activity throughout the endomembrane system. This has clear implications for the phosphorylation of both freely diffusible substrates and those localized to discrete subcellular compartments.
Collapse
|
17
|
Abstract
Bruton’s tyrosine kinase (Btk) activation on the cell membrane is critical for B cell proliferation and development, and Btk inhibition is a promising treatment for several hematologic cancers and autoimmune diseases. Here, we examine Btk activation using the results of long-timescale molecular dynamics simulations. In our simulations, Btk lipid-binding modules dimerized on the membrane in a single predominant conformation. We observed that the phospholipid PIP3—in addition to its expected role of recruiting Btk to the membrane—allosterically mediated dimer formation and stability by binding at two novel sites. Our results provide strong evidence that PIP3-mediated dimerization of Btk at the cell membrane is a critical step in Btk activation and suggest a potential approach to allosteric Btk inhibitor development. Bruton’s tyrosine kinase (Btk) is critical for B cell proliferation and activation, and the development of Btk inhibitors is a vigorously pursued strategy for the treatment of various B cell malignancies. A detailed mechanistic understanding of Btk activation has, however, been lacking. Here, inspired by a previous suggestion that Btk activation might depend on dimerization of its lipid-binding PH–TH module on the cell membrane, we performed long-timescale molecular dynamics simulations of membrane-bound PH–TH modules and observed that they dimerized into a single predominant conformation. We found that the phospholipid PIP3 stabilized the dimer allosterically by binding at multiple sites, and that the effects of PH–TH mutations on dimer stability were consistent with their known effects on Btk activity. Taken together, our simulation results strongly suggest that PIP3-mediated dimerization of Btk at the cell membrane is a critical step in Btk activation.
Collapse
|
18
|
Scholz S, Pleßmann J, Enugutti B, Hüttl R, Wassmer K, Schneitz K. The AGC protein kinase UNICORN controls planar growth by attenuating PDK1 in Arabidopsis thaliana. PLoS Genet 2019; 15:e1007927. [PMID: 30742613 PMCID: PMC6386418 DOI: 10.1371/journal.pgen.1007927] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2018] [Revised: 02/22/2019] [Accepted: 01/02/2019] [Indexed: 11/19/2022] Open
Abstract
Tissue morphogenesis critically depends on the coordination of cellular growth patterns. In plants, many organs consist of clonally distinct cell layers, such as the epidermis, whose cells undergo divisions that are oriented along the plane of the layer. The developmental control of such planar growth is poorly understood. We have previously identified the Arabidopsis AGCVIII-class protein kinase UNICORN (UCN) as a central regulator of this process. Plants lacking UCN activity show spontaneous formation of ectopic multicellular protrusions in integuments and malformed petals indicating that UCN suppresses uncontrolled growth in those tissues. In the current model UCN regulates planar growth of integuments in part by directly repressing the putative transcription factor ABERRANT TESTA SHAPE (ATS). Here we report on the identification of 3-PHOSPHOINOSITIDE-DEPENDENT PROTEIN KINASE 1 (PDK1) as a novel factor involved in UCN-mediated growth control. PDK1 constitutes a basic component of signaling mediated by AGC protein kinases throughout eukaryotes. Arabidopsis PDK1 is implied in stress responses and growth promotion. Here we show that loss-of-function mutations in PDK1 suppress aberrant growth in integuments and petals of ucn mutants. Additional genetic, in vitro, and cell biological data support the view that UCN functions by repressing PDK1. Furthermore, our data indicate that PDK1 is indirectly required for deregulated growth caused by ATS overexpression. Our findings support a model proposing that UCN suppresses ectopic growth in integuments through two independent processes: the attenuation of the protein kinase PDK1 in the cytoplasm and the repression of the transcription factor ATS in the nucleus.
Collapse
Affiliation(s)
- Sebastian Scholz
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany
| | - Janys Pleßmann
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany
| | - Balaji Enugutti
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany
| | - Regina Hüttl
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany
| | - Katrin Wassmer
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany
| | - Kay Schneitz
- Entwicklungsbiologie der Pflanzen, Wissenschaftszentrum Weihenstephan, Technische Universität München, Freising, Germany
- * E-mail:
| |
Collapse
|
19
|
Pabon NA, Xia Y, Estabrooks SK, Ye Z, Herbrand AK, Süß E, Biondi RM, Assimon VA, Gestwicki JE, Brodsky JL, Camacho CJ, Bar-Joseph Z. Predicting protein targets for drug-like compounds using transcriptomics. PLoS Comput Biol 2018; 14:e1006651. [PMID: 30532261 PMCID: PMC6300300 DOI: 10.1371/journal.pcbi.1006651] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2018] [Revised: 12/19/2018] [Accepted: 11/13/2018] [Indexed: 01/07/2023] Open
Abstract
An expanded chemical space is essential for improved identification of small molecules for emerging therapeutic targets. However, the identification of targets for novel compounds is biased towards the synthesis of known scaffolds that bind familiar protein families, limiting the exploration of chemical space. To change this paradigm, we validated a new pipeline that identifies small molecule-protein interactions and works even for compounds lacking similarity to known drugs. Based on differential mRNA profiles in multiple cell types exposed to drugs and in which gene knockdowns (KD) were conducted, we showed that drugs induce gene regulatory networks that correlate with those produced after silencing protein-coding genes. Next, we applied supervised machine learning to exploit drug-KD signature correlations and enriched our predictions using an orthogonal structure-based screen. As a proof-of-principle for this regimen, top-10/top-100 target prediction accuracies of 26% and 41%, respectively, were achieved on a validation of set 152 FDA-approved drugs and 3104 potential targets. We then predicted targets for 1680 compounds and validated chemical interactors with four targets that have proven difficult to chemically modulate, including non-covalent inhibitors of HRAS and KRAS. Importantly, drug-target interactions manifest as gene expression correlations between drug treatment and both target gene KD and KD of genes that act up- or down-stream of the target, even for relatively weak binders. These correlations provide new insights on the cellular response of disrupting protein interactions and highlight the complex genetic phenotypes of drug treatment. With further refinement, our pipeline may accelerate the identification and development of novel chemical classes by screening compound-target interactions. Bioactive compounds often disrupt cellular gene expression in ways that are difficult to predict. While the correlation between a cellular response after treatment with a small molecule and the knockdown of its target protein should be simple to establish, in practice this goal has been difficult to achieve. The main challenges are that data are noisy, drugs are not intended to be active in all cell types, and signals from a bona fide target(s) may be obscured by correlations with knockdowns of other proteins in the same pathway(s). Here, we find that a random forest classification model can detect meaningful correlational patterns when gene expression profiles after compound treatment and gene knockdowns in four or more cell lines are compared. When this approach is enriched by a structure-based screen, novel drug-target interactions can be predicted. We then validated new ligand-protein interactions for four difficult targets. Although the initial compounds are not especially potent in vitro, they are capable of disrupting their target pathway in the cell to an extent that generates a significant and characteristic gene expression profile. Collectively, our studies provide insight on cell-level transcriptomic responses to pharmaceutical intervention and the use of these patterns for target identification. In addition, the method provides a novel drug discovery pipeline to test chemistries without a priori knowledge of their target(s).
Collapse
Affiliation(s)
- Nicolas A. Pabon
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Yan Xia
- Machine Learning Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
| | - Samuel K. Estabrooks
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Zhaofeng Ye
- School of Medicine, Tsinghua University, Beijing, China
| | - Amanda K. Herbrand
- Department of Internal Medicine I, Universitätsklinikum Frankfurt, Frankfurt, Germany
| | - Evelyn Süß
- Department of Internal Medicine I, Universitätsklinikum Frankfurt, Frankfurt, Germany
| | - Ricardo M. Biondi
- Department of Internal Medicine I, Universitätsklinikum Frankfurt, Frankfurt, Germany
| | - Victoria A. Assimon
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, United States of America
| | - Jason E. Gestwicki
- Department of Pharmaceutical Chemistry, University of California, San Francisco, San Francisco, California, United States of America
| | - Jeffrey L. Brodsky
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Carlos J. Camacho
- Department of Computational and Systems Biology, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (CJC); (ZBJ)
| | - Ziv Bar-Joseph
- Machine Learning Department, School of Computer Science, Carnegie Mellon University, Pittsburgh, Pennsylvania, United States of America
- * E-mail: (CJC); (ZBJ)
| |
Collapse
|
20
|
Masters TA, Marsh RJ, Blacker TS, Armoogum DA, Larijani B, Bain AJ. Polarized two-photon photoselection in EGFP: Theory and experiment. J Chem Phys 2018; 148:134311. [PMID: 29626864 DOI: 10.1063/1.5011642] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
In this work, we present a complete theoretical description of the excited state order created by two-photon photoselection from an isotropic ground state; this encompasses both the conventionally measured quadrupolar (K = 2) and the "hidden" degree of hexadecapolar (K = 4) transition dipole alignment, their dependence on the two-photon transition tensor and emission transition dipole moment orientation. Linearly and circularly polarized two-photon absorption (TPA) and time-resolved single- and two-photon fluorescence anisotropy measurements are used to determine the structure of the transition tensor in the deprotonated form of enhanced green fluorescent protein. For excitation wavelengths between 800 nm and 900 nm, TPA is best described by a single element, almost completely diagonal, two-dimensional (planar) transition tensor whose principal axis is collinear to that of the single-photon S0 → S1 transition moment. These observations are in accordance with assignments of the near-infrared two-photon absorption band in fluorescent proteins to a vibronically enhanced S0 → S1 transition.
Collapse
Affiliation(s)
- T A Masters
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - R J Marsh
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - T S Blacker
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - D A Armoogum
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - B Larijani
- Cell Biophysics Laboratory, Ikerbasque, Basque Foundation for Science and Unidad de Biofisica (CSIC-UPV/EHU), Bilbao, Spain
| | - A J Bain
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| |
Collapse
|
21
|
Masters TA, Robinson NA, Marsh RJ, Blacker TS, Armoogum DA, Larijani B, Bain AJ. Time-resolved stimulated emission depletion and energy transfer dynamics in two-photon excited EGFP. J Chem Phys 2018; 148:134312. [DOI: 10.1063/1.5011643] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- T. A. Masters
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
- CoMPLEX, University College London, London WC1E 6BT, United Kingdom
| | - N. A. Robinson
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - R. J. Marsh
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - T. S. Blacker
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
- CoMPLEX, University College London, London WC1E 6BT, United Kingdom
| | - D. A. Armoogum
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
| | - B. Larijani
- Cell Biophysics Laboratory, Ikerbasque, Basque Foundation for Science and Unidad de Biofisica (CSIC-UPV/EHU), Bilbao, Spain
| | - A. J. Bain
- Department of Physics and Astronomy, University College London, London WC1E 6BT, United Kingdom
- CoMPLEX, University College London, London WC1E 6BT, United Kingdom
| |
Collapse
|
22
|
Gagliardi PA, Puliafito A, Primo L. PDK1: At the crossroad of cancer signaling pathways. Semin Cancer Biol 2018; 48:27-35. [DOI: 10.1016/j.semcancer.2017.04.014] [Citation(s) in RCA: 92] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 03/28/2017] [Accepted: 04/26/2017] [Indexed: 12/28/2022]
|
23
|
Regulation of PI3K by PKC and MARCKS: Single-Molecule Analysis of a Reconstituted Signaling Pathway. Biophys J 2017; 110:1811-1825. [PMID: 27119641 DOI: 10.1016/j.bpj.2016.03.001] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 02/09/2016] [Accepted: 03/07/2016] [Indexed: 12/19/2022] Open
Abstract
In chemotaxing ameboid cells, a complex leading-edge signaling circuit forms on the cytoplasmic leaflet of the plasma membrane and directs both actin and membrane remodeling to propel the leading edge up an attractant gradient. This leading-edge circuit includes a putative amplification module in which Ca(2+)-protein kinase C (Ca(2+)-PKC) is hypothesized to phosphorylate myristoylated alanine-rich C kinase substrate (MARCKS) and release phosphatidylinositol-4,5-bisphosphate (PIP2), thereby stimulating production of the signaling lipid phosphatidylinositol-3,4,5-trisphosphate (PIP3) by the lipid kinase phosphoinositide-3-kinase (PI3K). We investigated this hypothesized Ca(2+)-PKC-MARCKS-PIP2-PI3K-PIP3 amplification module and tested its key predictions using single-molecule fluorescence to measure the surface densities and activities of its protein components. Our findings demonstrate that together Ca(2+)-PKC and the PIP2-binding peptide of MARCKS modulate the level of free PIP2, which serves as both a docking target and substrate lipid for PI3K. In the off state of the amplification module, the MARCKS peptide sequesters PIP2 and thereby inhibits PI3K binding to the membrane. In the on state, Ca(2+)-PKC phosphorylation of the MARCKS peptide reverses the PIP2 sequestration, thereby releasing multiple PIP2 molecules that recruit multiple active PI3K molecules to the membrane surface. These findings 1) show that the Ca(2+)-PKC-MARCKS-PIP2-PI3K-PIP3 system functions as an activation module in vitro, 2) reveal the molecular mechanism of activation, 3) are consistent with available in vivo data, and 4) yield additional predictions that are testable in live cells. More broadly, the Ca(2+)-PKC-stimulated release of free PIP2 may well regulate the membrane association of other PIP2-binding proteins, and the findings illustrate the power of single-molecule analysis to elucidate key dynamic and mechanistic features of multiprotein signaling pathways on membrane surfaces.
Collapse
|
24
|
Leroux AE, Schulze JO, Biondi RM. AGC kinases, mechanisms of regulation and innovative drug development. Semin Cancer Biol 2017; 48:1-17. [PMID: 28591657 DOI: 10.1016/j.semcancer.2017.05.011] [Citation(s) in RCA: 92] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/16/2017] [Accepted: 05/31/2017] [Indexed: 12/22/2022]
Abstract
The group of AGC kinases consists of 63 evolutionarily related serine/threonine protein kinases comprising PDK1, PKB/Akt, SGK, PKC, PRK/PKN, MSK, RSK, S6K, PKA, PKG, DMPK, MRCK, ROCK, NDR, LATS, CRIK, MAST, GRK, Sgk494, and YANK, while two other families, Aurora and PLK, are the most closely related to the group. Eight of these families are physiologically activated downstream of growth factor signalling, while other AGC kinases are downstream effectors of a wide range of signals. The different AGC kinase families share aspects of their mechanisms of inhibition and activation. In the present review, we update the knowledge of the mechanisms of regulation of different AGC kinases. The conformation of the catalytic domain of many AGC kinases is regulated allosterically through the modulation of the conformation of a regulatory site on the small lobe of the kinase domain, the PIF-pocket. The PIF-pocket acts like an ON-OFF switch in AGC kinases with different modes of regulation, i.e. PDK1, PKB/Akt, LATS and Aurora kinases. In this review, we make emphasis on how the knowledge of the molecular mechanisms of regulation can guide the discovery and development of small allosteric modulators. Molecular probes stabilizing the PIF-pocket in the active conformation are activators, while compounds stabilizing the disrupted site are allosteric inhibitors. One challenge for the rational development of allosteric modulators is the lack of complete structural information of the inhibited forms of full-length AGC kinases. On the other hand, we suggest that the available information derived from molecular biology and biochemical studies can already guide screening strategies for the identification of innovative mode of action molecular probes and the development of selective allosteric drugs for the treatment of human diseases.
Collapse
Affiliation(s)
- Alejandro E Leroux
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina.
| | - Jörg O Schulze
- Research Group PhosphoSites, Medizinische Klinik 1, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany.
| | - Ricardo M Biondi
- Instituto de Investigación en Biomedicina de Buenos Aires (IBioBA) - CONICET - Partner Institute of the Max Planck Society, Buenos Aires C1425FQD, Argentina; Research Group PhosphoSites, Medizinische Klinik 1, Universitätsklinikum Frankfurt, Theodor-Stern-Kai 7, 60590 Frankfurt am Main, Germany; German Cancer Consortium (DKTK), Heidelberg, Germany, German Cancer Research Center (DKFZ), Heidelberg, Germany.
| |
Collapse
|
25
|
Blacker T, Chen W, Avezov E, Marsh RJ, Duchen MR, Kaminski CF, Bain AJ. Investigating State Restriction in Fluorescent Protein FRET Using Time-Resolved Fluorescence and Anisotropy. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2017; 121:1507-1514. [PMID: 28217242 PMCID: PMC5309863 DOI: 10.1021/acs.jpcc.6b11235] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/23/2016] [Indexed: 05/14/2023]
Abstract
Most fluorescent proteins exhibit multiexponential fluorescence decays, indicating a heterogeneous excited state population. FRET between fluorescent proteins should therefore involve multiple energy transfer pathways. We recently demonstrated the FRET pathways between EGFP and mCherry (mC), upon the dimerization of 3-phosphoinositide dependent protein kinase 1 (PDK1), to be highly restricted. A mechanism for FRET restriction based on a highly unfavorable κ2 orientation factor arising from differences in donor-acceptor transition dipole moment angles in a far from coplanar and near static interaction geometry was proposed. Here this is tested via FRET to mC arising from the association of glutathione (GSH) and glutathione S-transferase (GST) with an intrinsically homogeneous and more mobile donor Oregon Green 488 (OG). A new analysis of the acceptor window intensity, based on the turnover point of the sensitized fluorescence, is combined with donor window intensity and anisotropy measurements which show that unrestricted FRET to mC takes place. However, a long-lived anisotropy decay component in the donor window reveals a GST-GSH population in which FRET does not occur, explaining previous discrepancies between quantitative FRET measurements of GST-GSH association and their accepted values. This reinforces the importance of the local donor-acceptor environment in mediating energy transfer and the need to perform spectrally resolved intensity and anisotropy decay measurements in the accurate quantification of fluorescent protein FRET.
Collapse
Affiliation(s)
- Thomas
S. Blacker
- Department
of Physics & Astronomy, Centre for Mathematics and Physics
in the Life Sciences and Experimental Biology, and Department of Cell & Developmental
Biology, University College London, Gower Street, London WC1E 6BT, United
Kingdom
| | - WeiYue Chen
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom
| | - Edward Avezov
- Cambridge
Institute for Medical Research, University
of Cambridge, Cambridge CB2 0XY, United Kingdom
| | - Richard J. Marsh
- Department
of Physics & Astronomy, Centre for Mathematics and Physics
in the Life Sciences and Experimental Biology, and Department of Cell & Developmental
Biology, University College London, Gower Street, London WC1E 6BT, United
Kingdom
| | - Michael R. Duchen
- Department
of Physics & Astronomy, Centre for Mathematics and Physics
in the Life Sciences and Experimental Biology, and Department of Cell & Developmental
Biology, University College London, Gower Street, London WC1E 6BT, United
Kingdom
| | - Clemens F. Kaminski
- Department
of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA, United Kingdom
| | - Angus J. Bain
- Department
of Physics & Astronomy, Centre for Mathematics and Physics
in the Life Sciences and Experimental Biology, and Department of Cell & Developmental
Biology, University College London, Gower Street, London WC1E 6BT, United
Kingdom
- E-mail:
| |
Collapse
|
26
|
A Small Molecule Inhibitor of PDK1/PLCγ1 Interaction Blocks Breast and Melanoma Cancer Cell Invasion. Sci Rep 2016; 6:26142. [PMID: 27199173 PMCID: PMC4873738 DOI: 10.1038/srep26142] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2015] [Accepted: 04/21/2016] [Indexed: 12/02/2022] Open
Abstract
Strong evidence suggests that phospholipase Cγ1 (PLCγ1) is a suitable target to counteract tumourigenesis and metastasis dissemination. We recently identified a novel signalling pathway required for PLCγ1 activation which involves formation of a protein complex with 3-phosphoinositide-dependent protein kinase 1 (PDK1). In an effort to define novel strategies to inhibit PLCγ1-dependent signals we tested here whether a newly identified and highly specific PDK1 inhibitor, 2-O-benzyl-myo-inositol 1,3,4,5,6-pentakisphosphate (2-O-Bn-InsP5), could affect PDK1/PLCγ1 interaction and impair PLCγ1-dependent cellular functions in cancer cells. Here, we demonstrate that 2-O-Bn-InsP5 interacts specifically with the pleckstrin homology domain of PDK1 and impairs formation of a PDK1/PLCγ1 complex. 2-O-Bn-InsP5 is able to inhibit the epidermal growth factor-induced PLCγ1 phosphorylation and activity, ultimately resulting in impaired cancer cell migration and invasion. Importantly, we report that 2-O-Bn-InsP5 inhibits cancer cell dissemination in zebrafish xenotransplants. This work demonstrates that the PDK1/PLCγ1 complex is a potential therapeutic target to prevent metastasis and it identifies 2-O-Bn-InsP5 as a leading compound for development of anti-metastatic drugs.
Collapse
|
27
|
Molecular characterization of the Haemonchus contortus phosphoinositide-dependent protein kinase-1 gene (Hc-pdk-1). Parasit Vectors 2016; 9:65. [PMID: 26842781 PMCID: PMC4741024 DOI: 10.1186/s13071-016-1351-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 01/28/2016] [Indexed: 12/22/2022] Open
Abstract
Background Phosphoinositide-dependent protein kinase-1 (PDK-1), which functions downstream of phosphoinositide 3-kinase (AGE-1) and activates protein kinases of the AGC family, plays critical roles in regulating biology processes, such as metabolism, growth, development and survival. In the free-living nematode Caenorhabditis elegans, PDK-1 is a key component of the insulin-like signalling pathway, regulating the entry into and exit from dauer (arrested development). Although it is proposed that similar molecular mechanisms control the transition from the free-living to the parasitic stages of nematodes, nothing is known about PDK-1 in Haemonchus contortus, a socioeconomically important gastric nematode of ruminants. Methods Here, we isolated and characterized the pdk-1 gene (Hc-pdk-1) and its inferred product (Hc-PDK-1) from H. contortus. Using in vitro and in vivo methods, we then studied the transcriptional profiles of Hc-pdk-1 and anatomical gene expression patterns of Hc-PDK-1 in different developmental stages of C. elegans. Results In silico analysis of Hc-PDK-1 displayed conserved functional domains, such as protein kinase and pleckstrin homology (PH) domains and two predicted phosphorylation sites (Thr226/Tyr229), which are crucial for the phosphorylation of downstream signalling. The Hc-pdk-1 gene is transcribed in all of the main developmental stages of H. contortus, with its highest transcription in the infective third-stage larvae (iL3) compared with other stages. Transgene constructs, in which respective promoters were fused to the coding sequence for green fluorescent protein (GFP), were used to transform C. elegans, and to localize and compare the expression of Hc-pdk-1 and Ce-pdk-1. The expression of GFP under the control of the Hc-pdk-1 promoter was localized to the intestine, and head and tail neurons, contrasting somewhat the profile for the C. elegans ortholog, which is expressed in pharynx, intestine and head and tail neurons. Conclusions This is the first characterization of pdk-1/PDK-1 from a trichostrongyloid nematode. Taken together, the findings from this study provide a first glimpse of the involvement of Hc-pdk-1 in the insulin-like signalling pathway in H. contortus. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1351-6) contains supplementary material, which is available to authorized users.
Collapse
|
28
|
Calleja V, Laguerre M, de Las Heras-Martinez G, Parker PJ, Requejo-Isidro J, Larijani B. Acute regulation of PDK1 by a complex interplay of molecular switches. Biochem Soc Trans 2014; 42:1435-40. [PMID: 25233428 DOI: 10.1042/bst20140222] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Phosphoinositide-dependent kinase 1 (PDK1) is the master regulator of at least 23 other AGC kinases whose downstream signalling has often been implicated in various diseases and in particular in cancer. Therefore there has been great interest in determining how PDK1 is controlled and how it regulates its substrates spatially and temporally. The understanding of these mechanisms could offer new possibilities for therapeutic intervention. Over the years, a more comprehensive view of the mechanisms involved in the regulation of PDK1 has emerged and these comprise serine/threonine as well as tyrosine phosphorylation, subcellular localization, regulator binding and conformation status. In the present review, we discuss how various molecular mechanisms are together responsible for the conformational regulation behind the activation of PDK1 in cells.
Collapse
Affiliation(s)
| | - Michel Laguerre
- ‡Institut Européen de Chimie et Biologie, Université de Bordeaux, UMR 5248, 2 rue Robert Escarpit, F-33607 Pessac, France
| | | | | | - Jose Requejo-Isidro
- §Biophotonics Lab, Unidad de Biofísica CSIC-UPV/EHU, Barrio de Sarriena s/n, 48940 Leioa, Spain
| | | |
Collapse
|
29
|
Voskas D, Ling LS, Woodgett JR. Signals controlling un-differentiated states in embryonic stem and cancer cells: role of the phosphatidylinositol 3' kinase pathway. J Cell Physiol 2014; 229:1312-22. [PMID: 24604594 PMCID: PMC4258093 DOI: 10.1002/jcp.24603] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2014] [Accepted: 03/04/2014] [Indexed: 12/23/2022]
Abstract
The capacity of embryonic stem (ES) cells to differentiate into cell lineages comprising the three germ layers makes them powerful tools for studying mammalian early embryonic development in vitro. The human body consists of approximately 210 different somatic cell types, the majority of which have limited proliferative capacity. However, both stem cells and cancer cells bypass this replicative barrier and undergo symmetric division indefinitely when cultured under defined conditions. Several signal transduction pathways play important roles in regulating stem cell development, and aberrant expression of components of these pathways is linked to cancer. Among signaling systems, the critical role of leukemia inhibitory factor (LIF) coupled to the Jak/STAT3 (signal transduction and activation of transcription-3) pathway in maintaining stem cell self-renewal has been extensively reviewed. This pathway additionally plays multiple roles in tumorigenesis. Likewise, the phosphatidylinositide 3-kinase (PI3K)/protein kinase B (PKB/Akt) pathway has been determined to play an important role in both stem cell maintenance and tumor development. This pathway is often induced in cancer with frequent mutational activation of the catalytic subunit of PI3K or loss of a primary PI3K antagonist, phosphatase and tensin homolog deleted on chromosome ten (PTEN). This review focusses on roles of the PI3K signal transduction pathway components, with emphasis on functions in stem cell maintenance and cancer. Since the PI3K pathway impinges on and collaborates with other signaling pathways in regulating stem cell development and/or cancer, aspects of the canonical Wnt, Ras/mitogen-activated protein kinase (MAPK), and TGF-β signaling pathways are also discussed.
Collapse
Affiliation(s)
- Daniel Voskas
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| | | | | |
Collapse
|
30
|
Swanson CJ, Ritt M, Wang W, Lang MJ, Narayan A, Tesmer JJ, Westfall M, Sivaramakrishnan S. Conserved modular domains team up to latch-open active protein kinase Cα. J Biol Chem 2014; 289:17812-29. [PMID: 24790081 DOI: 10.1074/jbc.m113.534750] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Signaling proteins comprised of modular domains have evolved along with multicellularity as a method to facilitate increasing intracellular bandwidth. The effects of intramolecular interactions between modular domains within the context of native proteins have been largely unexplored. Here we examine intra- and intermolecular interactions in the multidomain signaling protein, protein kinase Cα (PKCα). We identify three interactions between two activated PKC molecules that synergistically stabilize a nanomolar affinity homodimer. Disruption of the homodimer results in a loss of PKC-mediated ERK1/2 phosphorylation, whereas disruption of the auto-inhibited state promotes the homodimer and prolongs PKC membrane localization. These observations support a novel regulatory mechanism wherein homodimerization dictates the equilibrium between the auto-inhibited and active states of PKC by sequestering auto-inhibitory interactions. Our findings underscore the physiological importance of context-dependent modular domain interactions in cell signaling.
Collapse
Affiliation(s)
| | | | - William Wang
- Department of Cell and Developmental Biology, Department of Cardiac Surgery
| | | | - Arvind Narayan
- Department of Biomedical Engineering, Life Sciences Institute, and
| | - John J Tesmer
- From the Biophysics Program, the Departments of Pharmacology and Biological Sciences, University of Michigan, Ann Arbor, Michigan 48109
| | - Margaret Westfall
- Department of Cardiac Surgery, Department of Biomedical Engineering, Life Sciences Institute, and
| | - Sivaraj Sivaramakrishnan
- From the Biophysics Program, Department of Cell and Developmental Biology, Department of Biomedical Engineering, Life Sciences Institute, and
| |
Collapse
|
31
|
Misra UK, Pizzo SV. Activated α2-macroglobulin binding to cell surface GRP78 induces T-loop phosphorylation of Akt1 by PDK1 in association with Raptor. PLoS One 2014; 9:e88373. [PMID: 24516643 PMCID: PMC3916429 DOI: 10.1371/journal.pone.0088373] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 01/13/2014] [Indexed: 12/14/2022] Open
Abstract
PDK1 phosphorylates multiple substrates including Akt by PIP3-dependent mechanisms. In this report we provide evidence that in prostate cancer cells stimulated with activated α2-macroglobulin (α2M*) PDK1 phosphorylates Akt in the T-loop at Thr(308) by using Raptor in the mTORC1 complex as a scaffold protein. First we demonstrate that PDK1, Raptor, and mTOR co-immunoprecipitate. Silencing the expression, not only of PDK1, but also Raptor by RNAi nearly abolished Akt phosphorylation at Akt(Thr308) in Raptor-immunoprecipitates of α2M*-stimulated prostate cancer cells. Immunodepleting Raptor or PDK from cell lysates of cells treated with α2M* drastically reduced Akt phosphorylation at Thr(308), which was recovered by adding the supernatant of Raptor- or PDK1-depleted cell lysates, respectively. Studies of insulin binding to its receptor on prostate cancer cells yielded similar results. We thus demonstrate that phosphorylating the T-loop Akt residue Thr(308) by PDK1 requires Raptor of the mTORC1 complex as a platform or scaffold protein.
Collapse
Affiliation(s)
- Uma Kant Misra
- Department of Pathology, Duke University Medical Center, Durham, North Carolina, United States of America
| | - Salvatore Vincent Pizzo
- Department of Pathology, Duke University Medical Center, Durham, North Carolina, United States of America
| |
Collapse
|
32
|
Falke JJ, Ziemba BP. Interplay between phosphoinositide lipids and calcium signals at the leading edge of chemotaxing ameboid cells. Chem Phys Lipids 2014; 182:73-9. [PMID: 24451847 DOI: 10.1016/j.chemphyslip.2014.01.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Revised: 12/09/2013] [Accepted: 01/08/2014] [Indexed: 10/25/2022]
Abstract
The chemotactic migration of eukaryotic ameboid cells up concentration gradients is among the most advanced forms of cellular behavior. Chemotaxis is controlled by a complex network of signaling proteins bound to specific lipids on the cytoplasmic surface of the plasma membrane at the front of the cell, or the leading edge. The central lipid players in this leading edge signaling pathway include the phosphoinositides PI(4,5)P2 (PIP2) and PI(3,4,5)P3 (PIP3), both of which play multiple roles. The products of PI(4,5)P2 hydrolysis, diacylglycerol (DAG) and Ins(1,4,5)P3 (IP3), are also implicated as important players. Together, these leading edge phosphoinositides and their degradation products, in concert with a local Ca(2+) signal, control the recruitment and activities of many peripheral membrane proteins that are crucial to the leading edge signaling network. The present critical review summarizes the current molecular understanding of chemotactic signaling at the leading edge, including newly discovered roles of phosphoinositide lipids and Ca(2+), while highlighting key questions for future research.
Collapse
Affiliation(s)
- Joseph J Falke
- Department of Chemistry and Biochemistry and Molecular Biophysics Program, University of Colorado, Boulder, CO 80309-0596, USA.
| | - Brian P Ziemba
- Department of Chemistry and Biochemistry and Molecular Biophysics Program, University of Colorado, Boulder, CO 80309-0596, USA
| |
Collapse
|
33
|
Fyffe C, Falasca M. 3-Phosphoinositide-dependent protein kinase-1 as an emerging target in the management of breast cancer. Cancer Manag Res 2013; 5:271-80. [PMID: 24039447 PMCID: PMC3771848 DOI: 10.2147/cmar.s35026] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
It should be noted that 3-phosphoinositide-dependent protein kinase-1 (PDK1) is a protein encoded by the PDPK1 gene, which plays a key role in the signaling pathways activated by several growth factors and hormones. PDK1 is a crucial kinase that functions downstream of phosphoinositide 3-kinase activation and activates members of the AGC family of protein kinases, such as protein kinase B (Akt), protein kinase C (PKC), p70 ribosomal protein S6 kinases, and serum glucocorticoid-dependent kinase, by phosphorylating serine/threonine residues in the activation loop. AGC kinases are known to play crucial roles in regulating physiological processes relevant to metabolism, growth, proliferation, and survival. Changes in the expression and activity of PDK1 and several AGC kinases have been linked to human diseases including cancer. Recent data have revealed that the alteration of PDK1 is a critical component of oncogenic phosphoinositide 3-kinase signaling in breast cancer, suggesting that inhibition of PDK1 can inhibit breast cancer progression. Indeed, PDK1 is highly expressed in a majority of human breast cancer cell lines and both PDK1 protein and messenger ribonucleic acid are overexpressed in a majority of human breast cancers. Furthermore, overexpression of PDK1 is sufficient to transform mammary epithelial cells. PDK1 plays an essential role in regulating cell migration, especially in the context of phosphatase and tensin homologue deficiency. More importantly, downregulation of PDK1 levels inhibits migration and experimental metastasis of human breast cancer cells. Thus, targeting PDK1 may be a valuable anticancer strategy that may improve the efficacy of chemotherapeutic strategies in breast cancer patients. In this review, we summarize the evidence that has been reported to support the idea that PDK1 may be a key target in breast cancer management.
Collapse
Affiliation(s)
- Chanse Fyffe
- Queen Mary University of London, Barts and The London School of Medicine and Dentistry, Blizard Institute, Inositide Signallling Group, London, UK
| | | |
Collapse
|
34
|
Ziemba BP, Pilling C, Calleja V, Larijani B, Falke JJ. The PH domain of phosphoinositide-dependent kinase-1 exhibits a novel, phospho-regulated monomer-dimer equilibrium with important implications for kinase domain activation: single-molecule and ensemble studies. Biochemistry 2013; 52:4820-9. [PMID: 23745598 DOI: 10.1021/bi400488f] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Phosphoinositide-dependent kinase-1 (PDK1) is an essential master kinase recruited to the plasma membrane by the binding of its C-terminal PH domain to the signaling lipid phosphatidylinositol-3,4,5-trisphosphate (PIP3). Membrane binding leads to PDK1 phospho-activation, but despite the central role of PDK1 in signaling and cancer biology, this activation mechanism remains poorly understood. PDK1 has been shown to exist as a dimer in cells, and one crystal structure of its isolated PH domain exhibits a putative dimer interface. It has been proposed that phosphorylation of PH domain residue T513 (or the phospho-mimetic T513E mutation) may regulate a novel PH domain dimer-monomer equilibrium, thereby converting an inactive PDK1 dimer to an active monomer. However, the oligomeric states of the PH domain on the membrane have not yet been determined, nor whether a negative charge at position 513 is sufficient to regulate its oligomeric state. This study investigates the binding of purified wild-type (WT) and T513E PDK1 PH domains to lipid bilayers containing the PIP3 target lipid, using both single-molecule and ensemble measurements. Single-molecule analysis of the brightness of the fluorescent PH domain shows that the PIP3-bound WT PH domain on membranes is predominantly dimeric while the PIP3-bound T513E PH domain is monomeric, demonstrating that negative charge at the T513 position is sufficient to dissociate the PH domain dimer and is thus likely to play a central role in PDK1 monomerization and activation. Single-molecule analysis of two-dimensional (2D) diffusion of PH domain-PIP3 complexes reveals that the dimeric WT PH domain diffuses at the same rate as a single lipid molecule, indicating that only one of its two PIP3 binding sites is occupied and there is little penetration of the protein into the bilayer as observed for other PH domains. The 2D diffusion of T513E PH domain is slower, suggesting the negative charge disrupts local structure in a way that allows deeper insertion of the protein into the viscous bilayer, thereby increasing the diffusional friction. Ensemble measurements of PH domain affinity for PIP3 on plasma membrane-like bilayers reveal that the dimeric WT PH domain possesses a one order of magnitude higher target membrane affinity than the previously characterized monomeric PH domains, consistent with a dimerization-triggered, allosterically enhanced affinity for one PIP3 molecule (a much larger affinity enhancement would be expected for dimerization-triggered binding to two PIP3 molecules). The monomeric T513E PDK1 PH domain, like other monomeric PH domains, exhibits a PIP3 affinity and bound state lifetime that are each 1 order of magnitude lower than those of the dimeric WT PH domain, which is predicted to facilitate release of activated, monomeric PDK1 to the cytoplasm. Overall, the study yields the first molecular picture of PH domain regulation via electrostatic control of dimer-monomer conversion.
Collapse
Affiliation(s)
- Brian P Ziemba
- Department of Chemistry and Biochemistry and Molecular Biophysics Program, University of Colorado , Boulder, Colorado 80309-0596, United States
| | | | | | | | | |
Collapse
|
35
|
Masters TA, Marsh RJ, Armoogum DA, Nicolaou N, Larijani B, Bain AJ. Restricted State Selection in Fluorescent Protein Förster Resonance Energy Transfer. J Am Chem Soc 2013; 135:7883-90. [DOI: 10.1021/ja312230b] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Thomas A. Masters
- Department
of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT,
United Kingdom
- Cell Biophysics
Laboratory,
Cancer Research U.K., Lincoln’s Inn Fields Laboratories, London Research Institute, London WC2A 3LY,
United Kingdom
| | - Richard J. Marsh
- Department
of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT,
United Kingdom
| | - Daven A. Armoogum
- Department
of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT,
United Kingdom
| | - Nick Nicolaou
- Department
of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT,
United Kingdom
| | - Banafshé Larijani
- Cell Biophysics
Laboratory,
Cancer Research U.K., Lincoln’s Inn Fields Laboratories, London Research Institute, London WC2A 3LY,
United Kingdom
| | - Angus J. Bain
- Department
of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT,
United Kingdom
| |
Collapse
|
36
|
Kang JA, Jeong SP, Park D, Hayden MS, Ghosh S, Park SG. Transition from heterotypic to homotypic PDK1 homodimerization is essential for TCR-mediated NF-κB activation. THE JOURNAL OF IMMUNOLOGY 2013; 190:4508-15. [PMID: 23530144 DOI: 10.4049/jimmunol.1202923] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Strong NF-κB activation requires ligation of both the CD28 coreceptor and TCR. Phosphoinositide-dependent kinase 1 (PDK1) acts as a scaffold by binding both protein kinase Cθ (PKCθ) and CARMA1, and is therefore essential for signaling to NF-κB. In this article, we demonstrate the importance of PDK1 Thr(513) phosphorylation in regulating the intermolecular organization of PDK1 homodimers. Thr(513) is directly involved in heterotypic PDK1 homodimer formation, in which binding is mediated through the pleckstrin homology (PH) and kinase domains. Upon activation, phosphorylated Thr(513) instead mediates homotypic intermolecular binding through the PH domains. Consequently, cell-permeable peptides with a Thr(513) to Ile derivative (protein transduction domain [PTD]-PDK1-Thr(513)-Ile) bound the kinase domain, whereas a Thr(513)-to-Asp peptide (PTD-PDK1-Thr(513)-Asp) bound the PH domain. PTD-PDK1-Thr(513)-Ile blocked binding between PDK1 and PKCθ, phosphorylation of PKCθ Thr(538), and activation of both NF-κB and AKT. In contrast, PTD-PDK1- Thr(513)-Asp selectively inhibited binding between PDK1 and CARMA1, and blocked TCR/CD28-induced NF-κB activation. Therefore, Thr(513) phosphorylation regulates a critical intermolecular switch governing PDK1 homodimer structure and the capacity to interact with downstream signaling pathway components. Given the pleiotropic functions of PDK1, these data may open the door to the development of immunosuppressive therapies that selectively target the PDK1 to NF-κB pathway in T cell activation.
Collapse
Affiliation(s)
- Jung-Ah Kang
- School of Life Sciences, Gwangju Institute of Science and Technology, Gwangju 500-712, Republic of Korea
| | | | | | | | | | | |
Collapse
|
37
|
Akt is efficiently activated by PIF-pocket- and PtdIns(3,4,5)P3-dependent mechanisms leading to resistance to PDK1 inhibitors. Biochem J 2013; 448:285-95. [PMID: 23030823 DOI: 10.1042/bj20121287] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Mutations leading to inappropriate activation of Akt isoforms contribute to proliferation and survival of a significant proportion of human cancers. Akt is activated by phosphorylation of its T-loop residue (Thr(308)) by PDK1 (3-phosphoinositide-dependent kinase-1) and its C-terminal hydrophobic motif (Ser(473)) by mTORC2 [mTOR (mammalian target of rapamycin) complex 2]. Potent PDK1 inhibitors such as GSK2334470 have recently been elaborated as potential anti-cancer agents. However, these compounds were surprisingly ineffective at suppressing Akt activation. In the present study we demonstrate that resistance to PDK1 inhibitors results from Akt being efficiently recruited to PDK1 via two alternative mechanisms. The first involves ability of Akt and PDK1 to mutually interact with the PI3K (phosphoinositide 3-kinase) second messenger PtdIns(3,4,5)P3. The second entails recruitment of PDK1 to Akt after its phosphorylation at Ser(473) by mTORC2, via a substrate-docking motif termed the PIF-pocket. We find that disruption of either the PtdIns(3,4,5)P3 or the Ser(473) phosphorylation/PIF-pocket mechanism only moderately impacts on Akt activation, but induces marked sensitization to PDK1 inhibitors. These findings suggest that suppression of Ser(473) phosphorylation by using mTOR inhibitors would disrupt the PIF-pocket mechanism and thereby sensitize Akt to PDK1 inhibitors. Consistent with this, we find combing PDK1 and mTOR inhibitors reduced Akt activation to below basal levels and markedly inhibited proliferation of all of the cell lines tested. Our results suggest further work is warranted to explore the utility of combining PDK1 and mTOR inhibitors as a therapeutic strategy for treatment of cancers that harbour mutations elevating Akt activity.
Collapse
|
38
|
Stieglitz B, Haire LF, Dikic I, Rittinger K. Structural analysis of SHARPIN, a subunit of a large multi-protein E3 ubiquitin ligase, reveals a novel dimerization function for the pleckstrin homology superfold. J Biol Chem 2012; 287:20823-9. [PMID: 22549881 PMCID: PMC3375506 DOI: 10.1074/jbc.m112.359547] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2012] [Revised: 04/17/2012] [Indexed: 11/06/2022] Open
Abstract
SHARPIN (SHANK-associated RH domain interacting protein) is part of a large multi-protein E3 ubiquitin ligase complex called LUBAC (linear ubiquitin chain assembly complex), which catalyzes the formation of linear ubiquitin chains and regulates immune and apoptopic signaling pathways. The C-terminal half of SHARPIN contains ubiquitin-like domain and Npl4-zinc finger domains that mediate the interaction with the LUBAC subunit HOIP and ubiquitin, respectively. In contrast, the N-terminal region does not show any homology with known protein interaction domains but has been suggested to be responsible for self-association of SHARPIN, presumably via a coiled-coil region. We have determined the crystal structure of the N-terminal portion of SHARPIN, which adopts the highly conserved pleckstrin homology superfold that is often used as a scaffold to create protein interaction modules. We show that in SHARPIN, this domain does not appear to be used as a ligand recognition domain because it lacks many of the surface properties that are present in other pleckstrin homology fold-based interaction modules. Instead, it acts as a dimerization module extending the functional applications of this superfold.
Collapse
Affiliation(s)
- Benjamin Stieglitz
- From the Division of Molecular Structure, Medical Research Council National Institute for Medical Research, The Ridgeway, London NW7 1AA, United Kingdom and
| | - Lesley F. Haire
- From the Division of Molecular Structure, Medical Research Council National Institute for Medical Research, The Ridgeway, London NW7 1AA, United Kingdom and
| | - Ivan Dikic
- the Buchmann Institute for Molecular Life Sciences and Institute of Biochemistry II, Goethe University School of Medicine, D-60590 Frankfurt, Germany
| | - Katrin Rittinger
- From the Division of Molecular Structure, Medical Research Council National Institute for Medical Research, The Ridgeway, London NW7 1AA, United Kingdom and
| |
Collapse
|
39
|
Bauer AF, Sonzogni S, Meyer L, Zeuzem S, Piiper A, Biondi RM, Neimanis S. Regulation of protein kinase C-related protein kinase 2 (PRK2) by an intermolecular PRK2-PRK2 interaction mediated by Its N-terminal domain. J Biol Chem 2012; 287:20590-602. [PMID: 22511787 DOI: 10.1074/jbc.m111.327437] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Protein kinase C-related protein kinases (PRKs) are effectors of the Rho family of small GTPases and play a role in the development of diseases such as prostate cancer and hepatitis C. Here we examined the mechanism underlying the regulation of PRK2 by its N-terminal region. We show that the N-terminal region of PRK2 prevents the interaction with its upstream kinase, the 3-phosphoinositide-dependent kinase 1 (PDK1), which phosphorylates the activation loop of PRK2. We confirm that the N-terminal region directly inhibits the kinase activity of PRK2. However, in contrast to previous models, our data indicate that this inhibition is mediated in trans through an intermolecular PRK2-PRK2 interaction. Our results also suggest that amino acids 487-501, located in the linker region between the N-terminal domains and the catalytic domain, contribute to the PRK2-PRK2 dimer formation. This dimerization is further supported by other N-terminal domains. Additionally, we provide evidence that the region C-terminal to the catalytic domain intramolecularly activates PRK2. Finally, we discovered that the catalytic domain mediates a cross-talk between the inhibitory N-terminal region and the activating C-terminal region. The results presented here describe a novel mechanism of regulation among AGC kinases and offer new insights into potential approaches to pharmacologically regulate PRK2.
Collapse
Affiliation(s)
- Angelika F Bauer
- Department of Internal Medicine I, Research Group PhosphoSites, Goethe University Hospital Frankfurt, Frankfurt 60590, Germany
| | | | | | | | | | | | | |
Collapse
|
40
|
Re-examination of the dimerization state of leucine-rich repeat kinase 2: predominance of the monomeric form. Biochem J 2012; 441:987-94. [PMID: 22047502 DOI: 10.1042/bj20111215] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Mutations in the LRRK2 (leucine-rich repeat kinase 2) gene have been identified in PARK8, a major form of autosomal-dominantly inherited familial Parkinson's disease, although the biochemical properties of LRRK2 are not fully understood. It has been proposed that LRRK2 predominantly exists as a homodimer on the basis of the observation that LRRK2, with a theoretical molecular mass of 280 kDa, migrates at 600 kDa (p600 LRRK2) on native polyacrylamide gels. In the present study, we biochemically re-examined the nature of p600 LRRK2 and found that p600 LRRK2 was fractionated with a single peak at ~272 kDa by ultracentrifugation on a glycerol gradient. In addition, p600 LRRK2 behaved similarly to monomeric proteins upon two-dimensional electrophoretic separation. These results suggested a monomeric composition of p600 LRRK2 within cells. The p600 LRRK2 exhibited kinase activity as well as GTP-binding activity, and forced dimerization of LRRK2 neither upregulated its kinase activity nor altered its subcellular localization. Collectively, we conclude that the monomer form of LRRK2 is predominant within cells, and that dimerization is dispensable for its enzymatic activity.
Collapse
|
41
|
Rademacher EH, Offringa R. Evolutionary Adaptations of Plant AGC Kinases: From Light Signaling to Cell Polarity Regulation. FRONTIERS IN PLANT SCIENCE 2012; 3:250. [PMID: 23162562 PMCID: PMC3499706 DOI: 10.3389/fpls.2012.00250] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Accepted: 10/22/2012] [Indexed: 05/19/2023]
Abstract
Signaling and trafficking over membranes involves a plethora of transmembrane proteins that control the flow of compounds or relay specific signaling events. Next to external cues, internal stimuli can modify the activity or abundance of these proteins at the plasma membrane (PM). One such regulatory mechanism is protein phosphorylation by membrane-associated kinases, several of which are AGC kinases. The AGC kinase family is one of seven kinase families that are conserved in all eukaryotic genomes. In plants evolutionary adaptations introduced specific structural changes within the AGC kinases that most likely allow modulation of kinase activity by external stimuli (e.g., light). Starting from the well-defined structural basis common to all AGC kinases we review the current knowledge on the structure-function relationship in plant AGC kinases. Nine of the 39 Arabidopsis AGC kinases have now been shown to be involved in the regulation of auxin transport. In particular, AGC kinase-mediated phosphorylation of the auxin transporters ABCB1 and ABCB19 has been shown to regulate their activity, while auxin transporters of the PIN family are located to different positions at the PM depending on their phosphorylation status, which is a result of counteracting AGC kinase and PP6 phosphatase activities. We therefore focus on regulation of AGC kinase activity in this context. Identified structural adaptations of the involved AGC kinases may provide new insight into AGC kinase functionality and demonstrate their position as central hubs in the cellular network controlling plant development and growth.
Collapse
Affiliation(s)
- Eike H. Rademacher
- Molecular and Developmental Genetics, Institute Biology Leiden, Leiden UniversityLeiden, Netherlands
| | - Remko Offringa
- Molecular and Developmental Genetics, Institute Biology Leiden, Leiden UniversityLeiden, Netherlands
- *Correspondence: Remko Offringa, Molecular and Developmental Genetics, Institute Biology Leiden, Leiden University, Sylviusweg 72, 2333BE Leiden, Netherlands. e-mail:
| |
Collapse
|
42
|
Calleja V, Leboucher P, Larijani B. Protein activation dynamics in cells and tumor micro arrays assessed by time resolved Förster resonance energy transfer. Methods Enzymol 2012; 506:225-46. [PMID: 22341227 DOI: 10.1016/b978-0-12-391856-7.00036-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022]
Abstract
Analytical time resolved Förster resonance energy transfer (FRET) can be exploited for assessing, in cells and tumor micro arrays, the activation status and dynamics of oncoproteins such as epidermal growth factor receptor (EGFR1) and their downstream effectors such as protein kinase B (PKB) and 3-phosphoinositide-dependent protein kinase 1 (PDK1). The outcome of our research involving the application of quantitative imaging for investigating molecular mechanisms of phosphoinositide-dependant enzymes, such as PKB and PDK1, has resulted in a refined model describing the dynamics and regulation of these two oncoproteins in live cells. Our translational research exploits a quantitative FRET method for establishing the activation status of predictive biomarkers in tumor micro arrays. We developed a two-site FRET assay monitored by automated frequency domain Fluorescence lifetime imaging microscopy (FLIM). As a proof of principle, we tested our methodology by assessing EGFR1 activation status in tumor micro arrays from head and neck patients. Our two-site FRET assay, by high-throughput frequency domain FLIM, has great potential to provide prognostic and perhaps predictive biomarkers.
Collapse
Affiliation(s)
- Véronique Calleja
- Cell Biophysics Laboratory, Cancer Research UK, London Research Institute, London, United Kingdom
| | | | | |
Collapse
|
43
|
Meuillet EJ. Novel inhibitors of AKT: assessment of a different approach targeting the pleckstrin homology domain. Curr Med Chem 2011; 18:2727-42. [PMID: 21649580 DOI: 10.2174/092986711796011292] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2011] [Accepted: 05/13/2011] [Indexed: 12/21/2022]
Abstract
Protein kinase B/AKT plays a central role in cancer. The serine/threonine kinase is overexpressed or constitutively active in many cancers and has been validated as a therapeutic target for cancer treatment. However, targeting the kinase activity has revealed itself to be a challenge due to non-selectivity of the compounds towards other kinases. This review summarizes other approaches scientists have developed to inhibit the activity and function of AKT. They consist in targeting the pleckstrin homology (PH) domain of AKT. Indeed, upon the generation of 3-phosphorylated phosphatidylinositol phosphates (PI3Ps) by PI3-kinase (PI3K), AKT translocates from the cytosol to the plasma membrane and binds to the PI3Ps via its PH domain. Thus, several analogs of PI3Ps (PI Analogs or PIAs), alkylphospholipids (APLs), such as edelfosine or inositol phophates (IPs) have been described that inhibit the binding of the PH domain to PI3Ps. Recent allostertic inhibitors and small molecules that do not bind the kinase domain but affect the kinase activity of AKT, presumably by interacting with the PH domain, have been also identified. Finally, several drug screening studies spawned novel chemical scaffolds that bind the PH domain of AKT. Together, these approaches have been more or less sucessfull in vitro and to some extent translated in preclinical studies. Several of these new AKT PH domain inhibitors exhibit promising anti-tumor activity in mouse models and some of them show synergy with ionizing radiation and chemotherapy. Early clinical trials have started and results will attest to the validity and efficacy of such approaches in the near future.
Collapse
Affiliation(s)
- E J Meuillet
- Department of Nutritional Sciences, The University of Arizona, Tucson, Arizona, USA.
| |
Collapse
|
44
|
PI3K/Akt signaling requires spatial compartmentalization in plasma membrane microdomains. Proc Natl Acad Sci U S A 2011; 108:14509-14. [PMID: 21873248 DOI: 10.1073/pnas.1019386108] [Citation(s) in RCA: 159] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Spatial compartmentalization of signaling pathway components generally defines the specificity and enhances the efficiency of signal transduction. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway is known to be compartmentalized within plasma membrane microdomains; however, the underlying mechanisms and functional impact of this compartmentalization are not well understood. Here, we show that phosphoinositide-dependent kinase 1 is activated in membrane rafts in response to growth factors, whereas the negative regulator of the pathway, phosphatase and tensin homolog deleted on chromosome 10 (PTEN), is primarily localized in nonraft regions. Alteration of this compartmentalization, either by genetic targeting or ceramide-induced recruitment of PTEN to rafts, abolishes the activity of the entire pathway. These findings reveal critical steps in raft-mediated PI3K/Akt activation and demonstrate the essential role of membrane microdomain compartmentalization in enabling PI3K/Akt signaling. They further suggest that dysregulation of this compartmentalization may underlie pathological complications such as insulin resistance.
Collapse
|