1
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Chandra Jena B, Flaherty DP, O'Brien VP, Watts VJ. Biochemical pharmacology of adenylyl cyclases in cancer. Biochem Pharmacol 2024:116160. [PMID: 38522554 DOI: 10.1016/j.bcp.2024.116160] [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: 01/20/2024] [Revised: 03/11/2024] [Accepted: 03/21/2024] [Indexed: 03/26/2024]
Abstract
Globally, despite extensive research and pharmacological advancement, cancer remains one of the most common causes of mortality. Understanding the signaling pathways involved in cancer progression is essential for the discovery of new drug targets. The adenylyl cyclase (AC) superfamily comprises glycoproteins that regulate intracellular signaling and convert ATP into cyclic AMP, an important second messenger. The present review highlights the involvement of ACs in cancer progression and suppression, broken down for each specific mammalian AC isoform. The precise mechanisms by which ACs contribute to cancer cell proliferation and invasion are not well understood and are variable among cancer types; however, AC overactivation, along with that of downstream regulators, presents a potential target for novel anticancer therapies. The expression patterns of ACs in numerous cancers are discussed. In addition, we highlight inhibitors of AC-related signaling that are currently under investigation, with a focus on possible anti-cancer strategies. Recent discoveries with small molecules regarding more direct modulation AC activity are also discussed in detail. A more comprehensive understanding of different components in AC-related signaling could potentially lead to the development of novel therapeutic strategies for personalized oncology and might enhance the efficacy of chemoimmunotherapy in the treatment of various cancers.
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Affiliation(s)
- Bikash Chandra Jena
- Borch Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, USA
| | - Daniel P Flaherty
- Borch Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, USA
| | - Valerie P O'Brien
- Borch Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, USA.
| | - Val J Watts
- Borch Department of Medicinal Chemistry and Molecular Pharmacology, College of Pharmacy, Purdue University, West Lafayette, Indiana 47907, USA.
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2
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Sapienza PJ, Bonin JP, Jinasena HD, Li K, Dieckhaus H, Popov KI, Aubé J, Lee AL. Mixed, nonclassical behavior in a classic allosteric protein. Proc Natl Acad Sci U S A 2023; 120:e2308338120. [PMID: 37695919 PMCID: PMC10515163 DOI: 10.1073/pnas.2308338120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2023] [Accepted: 07/27/2023] [Indexed: 09/13/2023] Open
Abstract
Allostery is a major driver of biological processes requiring coordination. Thus, it is one of the most fundamental and remarkable phenomena in nature, and there is motivation to understand and manipulate it to a multitude of ends. Today, it is often described in terms of two phenomenological models proposed more than a half-century ago involving only T(tense) or R(relaxed) conformations. Here, methyl-based NMR provides extensive detail on a dynamic T to R switch in the classical dimeric allosteric protein, yeast chorismate mutase (CM), that occurs in the absence of substrate, but only with the activator bound. Switching of individual subunits is uncoupled based on direct observation of mixed TR states in the dimer. This unique finding excludes both classic models and solves the paradox of a coexisting hyperbolic binding curve and highly skewed substrate-free T-R equilibrium. Surprisingly, structures of the activator-bound and effector-free forms of CM appear the same by NMR, providing another example of the need to account for dynamic ensembles. The apo enzyme, which has a sigmoidal activity profile, is shown to switch, not to R, but to a related high-energy state. Thus, the conformational repertoire of CM does not just change as a matter of degree depending on the allosteric input, be it effector and/or substrate. Rather, the allosteric model appears to completely change in different contexts, which is only consistent with modern ensemble-based frameworks.
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Affiliation(s)
- Paul J. Sapienza
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - Jeffrey P. Bonin
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - H.P. Dinusha Jinasena
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - Kelin Li
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - Henry Dieckhaus
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - Konstantin I. Popov
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - Jeffrey Aubé
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
| | - Andrew L. Lee
- Division of Chemical Biology and Medicinal Chemistry, Eshelman School of Pharmacy, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
- Department of Biochemistry and Biophysics, School of Medicine, University of North Carolina at Chapel Hill, Chapel Hill, NC27599
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3
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Sartre C, Peurois F, Ley M, Kryszke MH, Zhang W, Courilleau D, Fischmeister R, Ambroise Y, Zeghouf M, Cianferani S, Ferrandez Y, Cherfils J. Membranes prime the RapGEF EPAC1 to transduce cAMP signaling. Nat Commun 2023; 14:4157. [PMID: 37438343 DOI: 10.1038/s41467-023-39894-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 06/30/2023] [Indexed: 07/14/2023] Open
Abstract
EPAC1, a cAMP-activated GEF for Rap GTPases, is a major transducer of cAMP signaling and a therapeutic target in cardiac diseases. The recent discovery that cAMP is compartmentalized in membrane-proximal nanodomains challenged the current model of EPAC1 activation in the cytosol. Here, we discover that anionic membranes are a major component of EPAC1 activation. We find that anionic membranes activate EPAC1 independently of cAMP, increase its affinity for cAMP by two orders of magnitude, and synergize with cAMP to yield maximal GEF activity. In the cell cytosol, where cAMP concentration is low, EPAC1 must thus be primed by membranes to bind cAMP. Examination of the cell-active chemical CE3F4 in this framework further reveals that it targets only fully activated EPAC1. Together, our findings reformulate previous concepts of cAMP signaling through EPAC proteins, with important implications for drug discovery.
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Affiliation(s)
- Candice Sartre
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - François Peurois
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Marie Ley
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, IPHC, CNRS UMR 7178, Infrastructure Nationale de Protéomique ProFI - FR2048, 67087, Strasbourg, France
| | - Marie-Hélène Kryszke
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Wenhua Zhang
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Delphine Courilleau
- Université Paris-Saclay, IPSIT-CIBLOT, Inserm US31, CNRS UAR3679, 91400, Orsay, France
| | | | - Yves Ambroise
- Université Paris-Saclay, CEA, Service de Chimie Bioorganique et de Marquage, 91191, Gif-sur-Yvette, France
| | - Mahel Zeghouf
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Sarah Cianferani
- Laboratoire de Spectrométrie de Masse BioOrganique, Université de Strasbourg, IPHC, CNRS UMR 7178, Infrastructure Nationale de Protéomique ProFI - FR2048, 67087, Strasbourg, France
| | - Yann Ferrandez
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France
| | - Jacqueline Cherfils
- Université Paris-Saclay, Ecole Normale Supérieure Paris-Saclay, CNRS, 91190, Gif-sur-Yvette, France.
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4
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Slika H, Mansour H, Nasser SA, Shaito A, Kobeissy F, Orekhov AN, Pintus G, Eid AH. Epac as a tractable therapeutic target. Eur J Pharmacol 2023; 945:175645. [PMID: 36894048 DOI: 10.1016/j.ejphar.2023.175645] [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: 08/21/2022] [Revised: 02/26/2023] [Accepted: 03/06/2023] [Indexed: 03/09/2023]
Abstract
In 1957, cyclic adenosine monophosphate (cAMP) was identified as the first secondary messenger, and the first signaling cascade discovered was the cAMP-protein kinase A (PKA) pathway. Since then, cAMP has received increasing attention given its multitude of actions. Not long ago, a new cAMP effector named exchange protein directly activated by cAMP (Epac) emerged as a critical mediator of cAMP's actions. Epac mediates a plethora of pathophysiologic processes and contributes to the pathogenesis of several diseases such as cancer, cardiovascular disease, diabetes, lung fibrosis, neurological disorders, and others. These findings strongly underscore the potential of Epac as a tractable therapeutic target. In this context, Epac modulators seem to possess unique characteristics and advantages and hold the promise of providing more efficacious treatments for a wide array of diseases. This paper provides an in-depth dissection and analysis of Epac structure, distribution, subcellular compartmentalization, and signaling mechanisms. We elaborate on how these characteristics can be utilized to design specific, efficient, and safe Epac agonists and antagonists that can be incorporated into future pharmacotherapeutics. In addition, we provide a detailed portfolio for specific Epac modulators highlighting their discovery, advantages, potential concerns, and utilization in the context of clinical disease entities.
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Affiliation(s)
- Hasan Slika
- Department of Pharmacology and Toxicology, American University of Beirut, Beirut, P.O. Box 11-0236, Lebanon.
| | - Hadi Mansour
- Department of Pharmacology and Toxicology, American University of Beirut, Beirut, P.O. Box 11-0236, Lebanon.
| | | | - Abdullah Shaito
- Biomedical Research Center, Qatar University, Doha, P.O. Box: 2713, Qatar.
| | - Firas Kobeissy
- Department of Neurobiology and Neuroscience, Morehouse School of Medicine, Atlanta, Georgia, USA.
| | - Alexander N Orekhov
- Laboratory of Cellular and Molecular Pathology of Cardiovascular System, Institute of Human Morphology, 3 Tsyurupa Street, Moscow, 117418, Russia; Laboratory of Angiopathology, Institute of General Pathology and Pathophysiology, 8 Baltiiskaya Street, Moscow, 125315, Russia; Institute for Atherosclerosis Research, Skolkovo Innovative Center, Osennyaya Street 4-1-207, Moscow, 121609, Russia.
| | - Gianfranco Pintus
- Department of Biomedical Sciences, University of Sassari, 07100, Sassari, Italy.
| | - Ali H Eid
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, P.O. Box 2713, Qatar.
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5
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Meneses-Sagrero SE, Rascón-Valenzuela LA, García-Ramos JC, Vilegas W, Arvizu-Flores AA, Sotelo-Mundo RR, Robles-Zepeda RE. Calotropin and corotoxigenin 3-O-glucopyranoside from the desert milkweed Asclepias subulata inhibit the Na +/K +-ATPase activity. PeerJ 2022; 10:e13524. [PMID: 35673388 PMCID: PMC9167584 DOI: 10.7717/peerj.13524] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Accepted: 05/10/2022] [Indexed: 01/17/2023] Open
Abstract
Na+/K+-ATPase is an essential transmembrane enzyme found in all mammalian cells with critical functions for cell ion homeostasis. The inhibition of this enzyme by several cardiotonic steroids (CTS) has been associated with the cytotoxic effect on cancer cell lines of phytochemicals such as ouabain and digitoxin. This study evaluated the inhibitory capacity of cardenolides calotropin and corotoxigenin 3-O-glucopyranoside (C3OG) from Asclepias subulata over the Na+/K+-ATPase activity in vitro and silico. The inhibitory assays showed that calotropin and C3OG decreased the Na+/K+-ATPase activity with IC50 values of 0.27 and 0.87 μM, respectively. Furthermore, the molecules presented an uncompetitive inhibition on Na+/K+-ATPase activity, with Ki values of 0.2 μM to calotropin and 0.5 μM to C3OG. Furthermore, the molecular modeling indicated that calotropin and C3OG might interact with the Thr797 and Gln111 residues, considered essential to the interaction with the Na+/K+-ATPase. Besides, these cardenolides can interact with amino acid residues such as Phe783, Leu125, and Ala323, to establish hydrophobic interactions on the binding site. Considering the results, these provide novel evidence about the mechanism of action of cardenolides from A. subulata, proposing that C3OG is a novel cardenolide that deserves further consideration for in vitro cellular antiproliferative assays and in vivo studies as an anticancer molecule.
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Affiliation(s)
| | | | - Juan C. García-Ramos
- Escuela de Ciencias de la Salud, Universidad Autónoma de Baja California, Ensenada, Baja California, México
| | - Wagner Vilegas
- Instituto de Biociências, São Paulo State University, Sao Paulo, Brasil
| | | | - Rogerio R. Sotelo-Mundo
- Laboratorio de Estructura Molecular, Centro de Investigación en Alimentación y Desarrollo AC, Hermosillo, Sonora, México
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6
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Identification of Core Allosteric Sites through Temperature- and Nucleus-Invariant Chemical Shift Covariance. Biophys J 2022; 121:2035-2045. [PMID: 35538664 DOI: 10.1016/j.bpj.2022.05.004] [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: 11/16/2021] [Revised: 04/11/2022] [Accepted: 05/04/2022] [Indexed: 11/22/2022] Open
Abstract
Allosteric regulation is essential to control biological function. In addition, allosteric sites offer a promising venue for selective drug targeting. However, accurate mapping of allosteric sites remains challenging since allostery relies on often subtle, yet functionally relevant, structural and dynamical changes. A viable approach proposed to overcome such challenge is the chemical shift covariance analysis (CHESCA). Although CHESCA offers an exhaustive map of allosteric networks, it is critical to define the core allosteric sites to be prioritized in subsequent functional studies or the design of allosteric drugs. Here we propose two new CHESCA-based methodologies, called temperature CHESCA (T-CHESCA) and CLASS-CHESCA, aimed at narrowing down allosteric maps to the core allosteric residues. Both T- and CLASS-CHESCAs rely on the invariance of core inter-residue correlations to changes in the chemical shifts of the active and inactive conformations interconverting in fast exchange. In the T-CHESCA the chemical shifts of such states are modulated through temperature changes, while in the CLASS-CHESCA through variations in the spin-active nuclei involved in pairwise correlations. The T- and CLASS-CHESCAs as well as complete-linkage CHESCA were applied to the cAMP-binding domain of the exchange protein directly activated by cAMP (EPAC), which serves as a prototypical allosteric switch. Residues consistently identified by the three CHESCA methods were found in previously identified EPAC allosteric core sites. Hence, the T-, CLASS- and CL-CHESCA provide a toolset to establish allosteric site hierarchy and triage allosteric sites to be further analyzed by mutations and functional assays. Furthermore, the core allosteric networks selectively revealed through T- and CLASS-CHESCA are expected to facilitate the mechanistic understanding of disease-related mutations and the design of selective allosteric modulators.
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7
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Allosteric pluripotency: challenges and opportunities. Biochem J 2022; 479:825-838. [PMID: 35403669 DOI: 10.1042/bcj20210528] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 03/17/2022] [Accepted: 03/21/2022] [Indexed: 12/11/2022]
Abstract
Allosteric pluripotency arises when the functional response of an allosteric receptor to an allosteric stimulus depends on additional allosteric modulators. Here, we discuss allosteric pluripotency as observed in the prototypical Protein Kinase A (PKA) as well as in other signaling systems, from typical multidomain signaling proteins to bacterial enzymes. We identify key drivers of pluripotent allostery and illustrate how hypothesizing allosteric pluripotency may solve apparent discrepancies currently present in the literature regarding the dual nature of known allosteric modulators. We also outline the implications of allosteric pluripotency for cellular signaling and allosteric drug design, and analyze the challenges and opportunities opened by the pluripotent nature of allostery.
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8
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Martinez Pomier K, Akimoto M, Byun JA, Khamina M, Melacini G. Allosteric Regulation of Cyclic Nucleotide Dependent Protein Kinases. CAN J CHEM 2022. [DOI: 10.1139/cjc-2021-0359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Kinases include a wide variety of valuable drug targets, but full therapeutic exploitation requires a high degree of selectivity. A promising avenue to engineer the desired kinase selectivity relies on allosteric sites. Here we provide a focused minireview of recent progress in allosteric modulation of cyclic nucleotide-dependent kinases, including protein kinases A and G. We show how apparently diverse emerging concepts such as allosteric pluripotency, allosteric non-additive binding and uncompetitive allosteric inhibition are all manifestations of complex conformational ensembles. Such ensembles include not only the typical apo-inactive and effector-bound-active states, but also mixed intermediates that feature attributes of the former states within a single molecule. We also discuss how allosteric responses are amplified by aggregation processes, thus establishing a novel interface between the signaling and amyloid fields. Finally, we critically evaluate the challenges and opportunities for clinical translation opened by these emerging allosteric concepts.
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Affiliation(s)
| | | | - Jung Ah Byun
- McMaster University, 3710, Hamilton, Ontario, Canada
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9
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Zhang Q, Chen Y, Ni D, Huang Z, Wei J, Feng L, Su JC, Wei Y, Ning S, Yang X, Zhao M, Qiu Y, Song K, Yu Z, Xu J, Li X, Lin H, Lu S, Zhang J. Targeting a cryptic allosteric site of SIRT6 with small-molecule inhibitors that inhibit the migration of pancreatic cancer cells. Acta Pharm Sin B 2022; 12:876-889. [PMID: 35256952 PMCID: PMC8897208 DOI: 10.1016/j.apsb.2021.06.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2021] [Revised: 06/17/2021] [Accepted: 06/23/2021] [Indexed: 02/07/2023] Open
Abstract
SIRT6 belongs to the conserved NAD+-dependent deacetylase superfamily and mediates multiple biological and pathological processes. Targeting SIRT6 by allosteric modulators represents a novel direction for therapeutics, which can overcome the selectivity problem caused by the structural similarity of orthosteric sites among deacetylases. Here, developing a reversed allosteric strategy AlloReverse, we identified a cryptic allosteric site, Pocket Z, which was only induced by the bi-directional allosteric signal triggered upon orthosteric binding of NAD+. Based on Pocket Z, we discovered an SIRT6 allosteric inhibitor named JYQ-42. JYQ-42 selectively targets SIRT6 among other histone deacetylases and effectively inhibits SIRT6 deacetylation, with an IC50 of 2.33 μmol/L. JYQ-42 significantly suppresses SIRT6-mediated cancer cell migration and pro-inflammatory cytokine production. JYQ-42, to our knowledge, is the most potent and selective allosteric SIRT6 inhibitor. This study provides a novel strategy for allosteric drug design and will help in the challenging development of therapeutic agents that can selectively bind SIRT6.
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Key Words
- ADPr, ADP-ribose
- Allosteric inhibitor
- BSA, bull serum albumin
- CCK-8, Cell Counting Kit-8
- Cell migration
- Cytokine production
- DMSO, dimethyl sulfoxide
- FBS, fetal bovine serum
- FDL, Fluor de Lys
- H3K18, histone 3 lysine 18
- H3K56, histone 3 lysine 56
- H3K9, histone 3 lysine 9
- HDAC, histone deacetylase
- HPLC, high-performance liquid chromatography
- IC50, half-maximum inhibitory concentration
- IPTG, isopropyl-β-d-thiogalactoside
- MD, molecular dynamics
- Molecular dynamics simulations
- NAD+, nicotinamide adenine dinucleotide
- NAM, nicotinamide
- PBS, phosphate buffer saline
- PMA, phorbol 12-myristate 13-acetate
- PMSF, phenylmethanesulfonyl fluoride
- Pancreatic cancer
- RMSD, root-mean-square deviation
- RT-qPCR, real-time quantitative PCR
- Reversed allostery
- SDS-PAGE, SDS-polyacrylamide gel electrophoresis
- SIRT6
- SIRT6, sirtuin 6
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Mohamed H, Shao H, Akimoto M, Darveau P, MacKinnon MR, Magolan J, Melacini G. QSAR models reveal new EPAC-selective allosteric modulators. RSC Chem Biol 2022; 3:1230-1239. [PMID: 36320893 PMCID: PMC9533425 DOI: 10.1039/d2cb00106c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 08/02/2022] [Indexed: 11/23/2022] Open
Abstract
Exchange proteins directly activated by cAMP (EPAC) are guanine nucleotide exchange factors for the small GTPases, Rap1 and Rap2. They regulate several physiological functions and mitigation of their activity has been suggested as a possible treatment for multiple diseases such as cardiomyopathy, diabetes, chronic pain, and cancer. Several EPAC-specific modulators have been developed, however studies that quantify their structure–activity relationships are still lacking. Here we propose a quantitative structure–activity relationship (QSAR) model for a series of EPAC-specific compounds. The model demonstrated high reproducibility and predictivity and the predictive ability of the model was tested against a series of compounds that were unknown to the model. The compound with the highest predicted affinity was validated experimentally through fluorescence-based competition assays and NMR experiments revealed its mode of binding and mechanism of action as a partial agonist. The proposed QSAR model can, therefore, serve as an effective screening tool to identify promising EPAC-selective drug leads with enhanced potency. QSAR models of EPAC-specific allosteric ligands predict the affinity of a promising analogue.![]()
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Affiliation(s)
- Hebatallah Mohamed
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
| | - Hongzhao Shao
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
| | - Madoka Akimoto
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
| | - Patrick Darveau
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
| | - Marc R. MacKinnon
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
| | - Jakob Magolan
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
| | - Giuseppe Melacini
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, L8S 4L8, Canada
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11
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Byun JA, VanSchouwen B, Parikh N, Akimoto M, McNicholl ET, Melacini G. State-selective frustration as a key driver of allosteric pluripotency. Chem Sci 2021; 12:11565-11575. [PMID: 34667558 PMCID: PMC8447923 DOI: 10.1039/d1sc01753e] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Accepted: 07/12/2021] [Indexed: 12/13/2022] Open
Abstract
Allosteric pluripotency arises when an allosteric effector switches from agonist to antagonist depending on the experimental conditions. For example, the Rp-cAMPS ligand of Protein Kinase A (PKA) switches from agonist to antagonist as the MgATP concentration increases and/or the kinase substrate affinity or concentration decreases. Understanding allosteric pluripotency is essential to design effective allosteric therapeutics with minimal side effects. Allosteric pluripotency of PKA arises from divergent allosteric responses of two homologous tandem cAMP-binding domains, resulting in a free energy landscape for the Rp-cAMPS-bound PKA regulatory subunit R1a in which the ground state is kinase inhibition-incompetent and the kinase inhibition-competent state is excited. The magnitude of the free energy difference between the ground non-inhibitory and excited inhibitory states (ΔGR,Gap) relative to the effective free energy of R1a binding to the catalytic subunit of PKA (ΔGR:C) dictates whether the antagonism-to-agonism switch occurs. However, the key drivers of ΔGR,Gap are not fully understood. Here, by analyzing an R1a mutant that selectively silences allosteric pluripotency, we show that a major determinant of ΔGR,Gap unexpectedly arises from state-selective frustration in the ground inhibition-incompetent state of Rp-cAMPS-bound R1a. Such frustration is caused by steric clashes between the phosphate-binding cassette and the helices preceding the lid, which interact with the phosphate and base of Rp-cAMPS, respectively. These clashes are absent in the excited inhibitory state, thus reducing the ΔGR,Gap to values comparable to ΔGR:C, as needed for allosteric pluripotency to occur. The resulting model of allosteric pluripotency is anticipated to assist the design of effective allosteric modulators. The Rp-cAMPS ligand of protein kinase A switches from agonist to antagonist depending on metabolite and proteomic contexts. We show that the state-selective frustration is a key driver of this allosteric pluripotency phenomenon.![]()
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Affiliation(s)
- Jung Ah Byun
- Department of Biochemistry and Biomedical Sciences, McMaster University Hamilton ON L8S 4M1 Canada
| | - Bryan VanSchouwen
- Department of Chemistry and Chemical Biology, McMaster University Hamilton ON L8S 4M1 Canada
| | - Nishi Parikh
- Department of Chemistry and Chemical Biology, McMaster University Hamilton ON L8S 4M1 Canada
| | - Madoka Akimoto
- Department of Chemistry and Chemical Biology, McMaster University Hamilton ON L8S 4M1 Canada
| | - Eric Tyler McNicholl
- Department of Chemistry and Chemical Biology, McMaster University Hamilton ON L8S 4M1 Canada
| | - Giuseppe Melacini
- Department of Biochemistry and Biomedical Sciences, McMaster University Hamilton ON L8S 4M1 Canada .,Department of Chemistry and Chemical Biology, McMaster University Hamilton ON L8S 4M1 Canada
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12
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Verkhivker GM. Making the invisible visible: Toward structural characterization of allosteric states, interaction networks, and allosteric regulatory mechanisms in protein kinases. Curr Opin Struct Biol 2021; 71:71-78. [PMID: 34237520 DOI: 10.1016/j.sbi.2021.06.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 05/27/2021] [Accepted: 06/03/2021] [Indexed: 02/07/2023]
Abstract
Despite the established view of protein kinases as dynamic and versatile allosteric regulatory machines, our knowledge of allosteric functional states, allosteric interaction networks, and the intrinsic folding energy landscapes is surprisingly limited. We discuss the latest developments in structural characterization of allosteric molecular events underlying protein kinase dynamics and functions using structural, biophysical, and computational biology approaches. The recent studies highlighted progress in making the invisible aspects of protein kinase 'life' visible, including the determination of hidden allosteric states and mapping of allosteric energy landscapes, discovery of new mechanisms underlying ligand-induced modulation of allosteric activity, evolutionary adaptation of kinase allostery, and characterization of allosteric interaction networks as the intrinsic driver of kinase adaptability and signal transmission in the regulatory assemblies.
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Affiliation(s)
- Gennady M Verkhivker
- Keck Center for Science and Engineering, Schmid College of Science and Technology, Chapman University, One University Drive, Orange, CA, 92866, USA; Department of Biomedical and Pharmaceutical Sciences, Chapman University School of Pharmacy, 9401 Jeronimo Road, Irvine, CA, 92618, USA.
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13
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Huang J, Byun JA, VanSchouwen B, Henning P, Herberg FW, Kim C, Melacini G. Dynamical Basis of Allosteric Activation for the Plasmodium falciparum Protein Kinase G. J Phys Chem B 2021; 125:6532-6542. [PMID: 34115498 DOI: 10.1021/acs.jpcb.1c03622] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The Plasmodium falciparum cGMP-dependent protein kinase (PfPKG) is required for the progression of the Plasmodium's life cycle and is therefore a promising malaria drug target. PfPKG includes four cGMP-binding domains (CBD-A to CBD-D). CBD-D plays a crucial role in PfPKG regulation as it is the primary determinant for the inhibition and cGMP-dependent activation of the catalytic domain. Hence, it is critical to understand how CBD-D is allosterically regulated by cGMP. Although the apo versus holo conformational changes of CBD-D have been reported, information on the intermediates of the activation pathway is currently lacking. Here, we employed molecular dynamics simulations to model four key states along the thermodynamic cycle for the cGMP-dependent activation of the PfPKG CBD-D domain. The simulations were compared to NMR data, and they revealed that the PfPKG CBD-D activation pathway samples a compact intermediate in which the N- and C-terminal helices approach the central β-barrel. In addition, by comparing the cGMP-bound active and inactive states, the essential binding interactions that differentiate these states were identified. The identification of structural and dynamical features unique to the cGMP-bound inactive state provides a promising basis to design PfPKG-selective allosteric inhibitors as a viable treatment for malaria.
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Affiliation(s)
- Jinfeng Huang
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Jung Ah Byun
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Bryan VanSchouwen
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada
| | - Philipp Henning
- Department of Biochemistry, University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
| | - Friedrich W Herberg
- Department of Biochemistry, University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
| | - Choel Kim
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, United States.,Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas 77030, United States.,Center for Drug Discovery, Baylor College of Medicine, Houston, Texas 77030, United States
| | - Giuseppe Melacini
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4M1, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4M1, Canada
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14
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Rufer AC. Drug discovery for enzymes. Drug Discov Today 2021; 26:875-886. [PMID: 33454380 DOI: 10.1016/j.drudis.2021.01.006] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Revised: 12/21/2020] [Accepted: 01/07/2021] [Indexed: 02/06/2023]
Abstract
Enzymes are essential, physiological catalysts involved in all processes of life, including metabolism, cellular signaling and motility, as well as cell growth and division. They are attractive drug targets because of the presence of defined substrate-binding pockets, which can be exploited as binding sites for pharmaceutical enzyme inhibitors. Understanding the reaction mechanisms of enzymes and the molecular mode of action of enzyme inhibitors is indispensable for the discovery and development of potent, efficacious, and safe novel drugs. The combination of classical concepts of enzymology with new experimental and data analysis methods opens new routes for drug discovery.
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Affiliation(s)
- Arne Christian Rufer
- Pharma Research and Early Development, Roche Innovation Center Basel, F. Hoffmann-La Roche Ltd, Grenzacherstrasse 124, 065/208A, 4070 Basel, Switzerland.
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15
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GRKs and Epac1 Interaction in Cardiac Remodeling and Heart Failure. Cells 2021; 10:cells10010154. [PMID: 33466800 PMCID: PMC7830799 DOI: 10.3390/cells10010154] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2020] [Revised: 01/06/2021] [Accepted: 01/08/2021] [Indexed: 12/25/2022] Open
Abstract
β-adrenergic receptors (β-ARs) play a major role in the physiological regulation of cardiac function through signaling routes tightly controlled by G protein-coupled receptor kinases (GRKs). Although the acute stimulation of β-ARs and the subsequent production of cyclic AMP (cAMP) have beneficial effects on cardiac function, chronic stimulation of β-ARs as observed under sympathetic overdrive promotes the development of pathological cardiac remodeling and heart failure (HF), a leading cause of mortality worldwide. This is accompanied by an alteration in cAMP compartmentalization and the activation of the exchange protein directly activated by cAMP 1 (Epac1) signaling. Among downstream signals of β-ARs, compelling evidence indicates that GRK2, GRK5, and Epac1 represent attractive therapeutic targets for cardiac disease. Here, we summarize the pathophysiological roles of GRK2, GRK5, and Epac1 in the heart. We focus on their signalosome and describe how under pathological settings, these proteins can cross-talk and are part of scaffolded nodal signaling systems that contribute to a decreased cardiac function and HF development.
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16
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Byun JA, VanSchouwen B, Akimoto M, Melacini G. Allosteric inhibition explained through conformational ensembles sampling distinct "mixed" states. Comput Struct Biotechnol J 2020; 18:3803-3818. [PMID: 33335680 PMCID: PMC7720024 DOI: 10.1016/j.csbj.2020.10.026] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Revised: 10/24/2020] [Accepted: 10/25/2020] [Indexed: 11/29/2022] Open
Abstract
Allosteric modulation provides an effective avenue for selective and potent enzyme inhibition. Here, we summarize and critically discuss recent advances on the mechanisms of allosteric partial agonists for three representative signalling enzymes activated by cyclic nucleotides: the cAMP-dependent protein kinase (PKA), the cGMP-dependent protein kinase (PKG), and the exchange protein activated by cAMP (EPAC). The comparative analysis of partial agonism in PKA, PKG and EPAC reveals a common emerging theme, i.e. the sampling of distinct “mixed” conformational states, either within a single domain or between distinct domains. Here, we show how such “mixed” states play a crucial role in explaining the observed functional response, i.e. partial agonism and allosteric pluripotency, as well as in maximizing inhibition while minimizing potency losses. In addition, by combining Nuclear Magnetic Resonance (NMR), Molecular Dynamics (MD) simulations and Ensemble Allosteric Modeling (EAM), we also show how to map the free-energy landscape of conformational ensembles containing “mixed” states. By discussing selected case studies, we illustrate how MD simulations and EAM complement NMR to quantitatively relate protein dynamics to function. The resulting NMR- and MD-based EAMs are anticipated to inform not only the design of new generations of highly selective allosteric inhibitors, but also the choice of multidrug combinations.
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Affiliation(s)
- Jung Ah Byun
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Bryan VanSchouwen
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, Canada
| | - Madoka Akimoto
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, Canada
| | - Giuseppe Melacini
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada.,Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario, Canada
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17
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Formoso K, Lezoualc'h F, Mialet-Perez J. Role of EPAC1 Signalosomes in Cell Fate: Friends or Foes? Cells 2020; 9:E1954. [PMID: 32854274 PMCID: PMC7563956 DOI: 10.3390/cells9091954] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/21/2020] [Accepted: 08/22/2020] [Indexed: 02/06/2023] Open
Abstract
The compartmentation of signaling processes is accomplished by the assembly of protein complexes called signalosomes. These signaling platforms colocalize enzymes, substrates, and anchoring proteins into specific subcellular compartments. Exchange protein directly activated by cAMP 1 (EPAC1) is an effector of the second messenger, 3',5'-cyclic adenosine monophosphate (cAMP) that is associated with multiple roles in several pathologies including cardiac diseases. Both EPAC1 intracellular localization and molecular partners are key players in the regulation of cell fate, which may have important therapeutic potential. In this review, we summarize the recent findings on EPAC1 structure, regulation, and pharmacology. We describe the importance of EPAC1 subcellular distribution in its biological action, paying special attention to its nuclear localization and mechanism of action leading to cardiomyocyte hypertrophy. In addition, we discuss the role of mitochondrial EPAC1 in the regulation of cell death. Depending on the cell type and stress condition, we present evidence that supports either a protective or detrimental role of EPAC1 activation.
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Affiliation(s)
- Karina Formoso
- INSERM UMR-1048, Institute of Metabolic and Cardiovascular Diseases, and Université de Toulouse III-Paul Sabatier, 31432 Toulouse, France
| | - Frank Lezoualc'h
- INSERM UMR-1048, Institute of Metabolic and Cardiovascular Diseases, and Université de Toulouse III-Paul Sabatier, 31432 Toulouse, France
| | - Jeanne Mialet-Perez
- INSERM UMR-1048, Institute of Metabolic and Cardiovascular Diseases, and Université de Toulouse III-Paul Sabatier, 31432 Toulouse, France
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18
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Boulton S, Van K, VanSchouwen B, Augustine J, Akimoto M, Melacini G. Allosteric Mechanisms of Nonadditive Substituent Contributions to Protein-Ligand Binding. Biophys J 2020; 119:1135-1146. [PMID: 32882185 DOI: 10.1016/j.bpj.2020.07.038] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/30/2020] [Accepted: 07/06/2020] [Indexed: 02/07/2023] Open
Abstract
Quantifying chemical substituent contributions to ligand-binding free energies is challenging due to nonadditive effects. Protein allostery is a frequent cause of nonadditivity, but the underlying allosteric mechanisms often remain elusive. Here, we propose a general NMR-based approach to elucidate such mechanisms and we apply it to the HCN4 ion channel, whose cAMP-binding domain is an archetypal conformational switch. Using NMR, we show that nonadditivity arises not only from concerted conformational transitions, but also from conformer-specific effects, such as steric frustration. Our results explain how affinity-reducing functional groups may lead to affinity gains if combined. Surprisingly, our approach also reveals that nonadditivity depends markedly on the receptor conformation. It is negligible for the inhibited state but highly significant for the active state, opening new opportunities to tune potency and agonism of allosteric effectors.
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Affiliation(s)
- Stephen Boulton
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Katherine Van
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Bryan VanSchouwen
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Canada
| | - Jerry Augustine
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Madoka Akimoto
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Canada
| | - Giuseppe Melacini
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada; Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Canada.
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19
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Zhang T, Lai Z, Yuan S, Huang YY, Dong G, Sheng C, Ke H, Luo HB. Discovery of Evodiamine Derivatives as Highly Selective PDE5 Inhibitors Targeting a Unique Allosteric Pocket. J Med Chem 2020; 63:9828-9837. [DOI: 10.1021/acs.jmedchem.0c00983] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Tianhua Zhang
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, P. R. China
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, The University of North Carolina, Chapel Hill, North Carolina 27599-7260, United States
| | - Zengwei Lai
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, P. R. China
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, China
| | - Suying Yuan
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Yi-You Huang
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, P. R. China
| | - Guoqiang Dong
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, China
| | - Chunquan Sheng
- School of Pharmacy, Second Military Medical University, 325 Guohe Road, Shanghai 200433, China
| | - Hengming Ke
- Department of Biochemistry and Biophysics and Lineberger Comprehensive Cancer Center, The University of North Carolina, Chapel Hill, North Carolina 27599-7260, United States
| | - Hai-Bin Luo
- School of Pharmaceutical Sciences, Sun Yat-Sen University, Guangzhou 510006, P. R. China
- Key Laboratory of Tropical Biological Resources of Ministry of Education, School of Life and Pharmaceutical Sciences, Hainan University, Haikou 570228, Hainan, China
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20
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Akimoto M, Yu T, Moleschi K, Van K, Anand GS, Melacini G. An NMR based phosphodiesterase assay. Chem Commun (Camb) 2020; 56:8091-8094. [PMID: 32555789 DOI: 10.1039/d0cc01673j] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
We propose a phosphodiesterase assay based on 1D 1H NMR to monitor the hydrolysis of cyclic nucleotides directly, without requiring tags or the addition of exogenous reagents. The method is suitable to measure phosphodiesterase KM and kcat parameters and to identify phosphodiesterase inhibitors.
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Affiliation(s)
- Madoka Akimoto
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Canada.
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21
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Byun JA, Akimoto M, VanSchouwen B, Lazarou TS, Taylor SS, Melacini G. Allosteric pluripotency as revealed by protein kinase A. SCIENCE ADVANCES 2020; 6:eabb1250. [PMID: 32596469 PMCID: PMC7304965 DOI: 10.1126/sciadv.abb1250] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2020] [Accepted: 05/08/2020] [Indexed: 05/03/2023]
Abstract
The functional response of a signaling system to an allosteric stimulus often depends on subcellular conditions, a phenomenon known as pluripotent allostery. For example, a single allosteric modulator, Rp-cAMPS, of the prototypical protein kinase A (PKA) switches from antagonist to agonist depending on MgATP levels. However, the mechanism underlying such pluripotent allostery has remained elusive for decades. Using nuclear magnetic resonance spectroscopy, ensemble models, kinase assays, and molecular dynamics simulations, we show that allosteric pluripotency arises from surprisingly divergent responses of highly homologous tandem domains. The differential responses perturb domain-domain interactions and remodel the free-energy landscape of inhibitory excited states sampled by the regulatory subunit of PKA. The resulting activation threshold values are comparable to the effective free energy of regulatory and catalytic subunit binding, which depends on metabolites, substrates, and mutations, explaining pluripotent allostery and warranting a general redefinition of allosteric targets to include specific subcellular environments.
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Affiliation(s)
- J. A. Byun
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4M1, Canada
| | - M. Akimoto
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada
| | - B. VanSchouwen
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada
| | - T. S. Lazarou
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada
| | - S. S. Taylor
- Departments of Chemistry and Biochemistry and Pharmacology, University of California San Diego, La Jolla, CA 92093, USA
| | - G. Melacini
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4M1, Canada
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4M1, Canada
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22
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Byun JA, Van K, Huang J, Henning P, Franz E, Akimoto M, Herberg FW, Kim C, Melacini G. Mechanism of allosteric inhibition in the Plasmodium falciparum cGMP-dependent protein kinase. J Biol Chem 2020; 295:8480-8491. [PMID: 32317283 DOI: 10.1074/jbc.ra120.013070] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Revised: 04/16/2020] [Indexed: 11/06/2022] Open
Abstract
Most malaria deaths are caused by the protozoan parasite Plasmodium falciparum Its life cycle is regulated by a cGMP-dependent protein kinase (PfPKG), whose inhibition is a promising antimalaria strategy. Allosteric kinase inhibitors, such as cGMP analogs, offer enhanced selectivity relative to competitive kinase inhibitors. However, the mechanisms underlying allosteric PfPKG inhibition are incompletely understood. Here, we show that 8-NBD-cGMP is an effective PfPKG antagonist. Using comparative NMR analyses of a key regulatory domain, PfD, in its apo, cGMP-bound, and cGMP analog-bound states, we elucidated its inhibition mechanism of action. Using NMR chemical shift analyses, molecular dynamics simulations, and site-directed mutagenesis, we show that 8-NBD-cGMP inhibits PfPKG not simply by reverting a two-state active versus inactive equilibrium, but by sampling also a distinct inactive "mixed" intermediate. Surface plasmon resonance indicates that the ability to stabilize a mixed intermediate provides a means to effectively inhibit PfPKG, without losing affinity for the cGMP analog. Our proposed model may facilitate the rational design of PfPKG-selective inhibitors for improved management of malaria.
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Affiliation(s)
- Jung Ah Byun
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Katherine Van
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Jinfeng Huang
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Philipp Henning
- Department of Biochemistry, University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
| | - Eugen Franz
- Biaffin GmbH & Co. KG, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
| | - Madoka Akimoto
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Friedrich W Herberg
- Department of Biochemistry, University of Kassel, Heinrich-Plett-Strasse 40, 34132 Kassel, Germany
| | - Choel Kim
- Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030.,Department of Pharmacology and Chemical Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Giuseppe Melacini
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4L8, Canada .,Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4L8, Canada
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23
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Shao H, Mohamed H, Boulton S, Huang J, Wang P, Chen H, Zhou J, Luchowska-Stańska U, Jentsch NG, Armstrong AL, Magolan J, Yarwood S, Melacini G. Mechanism of Action of an EPAC1-Selective Competitive Partial Agonist. J Med Chem 2020; 63:4762-4775. [PMID: 32297742 DOI: 10.1021/acs.jmedchem.9b02151] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The exchange protein activated by cAMP (EPAC) is a promising drug target for a wide disease range, from neurodegeneration and infections to cancer and cardiovascular conditions. A novel partial agonist of the EPAC isoform 1 (EPAC1), I942, was recently discovered, but its mechanism of action remains poorly understood. Here, we utilize NMR spectroscopy to map the I942-EPAC1 interactions at atomic resolution and propose a mechanism for I942 partial agonism. We found that I942 interacts with the phosphate binding cassette (PBC) and base binding region (BBR) of EPAC1, similar to cyclic adenosine monophosphate (cAMP). These results not only reveal the molecular basis for the I942 vs cAMP mimicry and competition, but also suggest that the partial agonism of I942 arises from its ability to stabilize an inhibition-incompetent activation intermediate distinct from both active and inactive EPAC1 states. The mechanism of action of I942 may facilitate drug design for EPAC-related diseases.
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Affiliation(s)
| | | | | | | | - Pingyuan Wang
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Haiying Chen
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Jia Zhou
- Chemical Biology Program, Department of Pharmacology and Toxicology, University of Texas Medical Branch, Galveston, Texas 77555, United States
| | - Urszula Luchowska-Stańska
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh Campus, Edinburgh EH14 4AS, United Kingdom
| | | | | | | | - Stephen Yarwood
- Institute of Biological Chemistry, Biophysics and Bioengineering, School of Engineering and Physical Sciences, Heriot-Watt University, Edinburgh Campus, Edinburgh EH14 4AS, United Kingdom
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24
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White MA, Tsalkova T, Mei FC, Cheng X. Conformational States of Exchange Protein Directly Activated by cAMP (EPAC1) Revealed by Ensemble Modeling and Integrative Structural Biology. Cells 2019; 9:cells9010035. [PMID: 31877746 PMCID: PMC7016869 DOI: 10.3390/cells9010035] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 12/16/2019] [Accepted: 12/18/2019] [Indexed: 02/08/2023] Open
Abstract
Exchange proteins directly activated by cAMP (EPAC1 and EPAC2) are important allosteric regulators of cAMP-mediated signal transduction pathways. To understand the molecular mechanism of EPAC activation, we performed detailed Small-Angle X-ray Scattering (SAXS) analysis of EPAC1 in its apo (inactive), cAMP-bound, and effector (Rap1b)-bound states. Our study demonstrates that we can model the solution structures of EPAC1 in each state using ensemble analysis and homology models derived from the crystal structures of EPAC2. The N-terminal domain of EPAC1, which is not conserved between EPAC1 and EPAC2, appears folded and interacts specifically with another component of EPAC1 in each state. The apo-EPAC1 state is a dynamic mixture of a compact (Rg = 32.9 Å, 86%) and a more extended (Rg = 38.5 Å, 13%) conformation. The cAMP-bound form of EPAC1 in the absence of Rap1 forms a dimer in solution; but its molecular structure is still compatible with the active EPAC1 conformation of the ternary complex model with cAMP and Rap1. Herein, we show that SAXS can elucidate the conformational states of EPAC1 activation as it proceeds from the compact, inactive apo conformation through a previously unknown intermediate-state, to the extended cAMP-bound form, and then binds to its effector (Rap1b) in a ternary complex.
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Affiliation(s)
- Mark Andrew White
- Sealy Center for Structural Biology and Molecular Biophysics, The University of Texas Medical Branch, Galveston, TX 77555, USA
- Department of Biochemistry and Molecular Biology, The University of Texas Medical Branch, Galveston, TX 77555, USA
- Correspondence: (M.A.W.); (X.C.); Tel.: +409-747-4747 (M.A.W.); +713-500-7487 (X.C.)
| | - Tamara Tsalkova
- Department of Pharmacology and Toxicology, The University of Texas Medical Branch, Galveston, TX 77555, USA;
| | - Fang C. Mei
- Department of Integrative Biology & Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA;
- Texas Therapeutics Institute, Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Xiaodong Cheng
- Department of Integrative Biology & Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA;
- Texas Therapeutics Institute, Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
- Correspondence: (M.A.W.); (X.C.); Tel.: +409-747-4747 (M.A.W.); +713-500-7487 (X.C.)
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25
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The Epac1 Protein: Pharmacological Modulators, Cardiac Signalosome and Pathophysiology. Cells 2019; 8:cells8121543. [PMID: 31795450 PMCID: PMC6953115 DOI: 10.3390/cells8121543] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/22/2019] [Accepted: 11/24/2019] [Indexed: 12/11/2022] Open
Abstract
The second messenger 3′,5′-cyclic adenosine monophosphate (cAMP) is one of the most important signalling molecules in the heart as it regulates many physiological and pathophysiological processes. In addition to the classical protein kinase A (PKA) signalling route, the exchange proteins directly activated by cAMP (Epac) mediate the intracellular functions of cAMP and are now emerging as a new key cAMP effector in cardiac pathophysiology. In this review, we provide a perspective on recent advances in the discovery of new chemical entities targeting the Epac1 isoform and illustrate their use to study the Epac1 signalosome and functional characterisation in cardiac cells. We summarize the role of Epac1 in different subcompartments of the cardiomyocyte and discuss how cAMP–Epac1 specific signalling networks may contribute to the development of cardiac diseases. We also highlight ongoing work on the therapeutic potential of Epac1-selective small molecules for the treatment of cardiac disorders.
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26
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Ahmed A, Boulton S, Shao H, Akimoto M, Natarajan A, Cheng X, Melacini G. Recent Advances in EPAC-Targeted Therapies: A Biophysical Perspective. Cells 2019; 8:E1462. [PMID: 31752286 PMCID: PMC6912387 DOI: 10.3390/cells8111462] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/12/2019] [Accepted: 11/13/2019] [Indexed: 02/07/2023] Open
Abstract
The universal second messenger cAMP regulates diverse intracellular processes by interacting with ubiquitously expressed proteins, such as Protein Kinase A (PKA) and the Exchange Protein directly Activated by cAMP (EPAC). EPAC is implicated in multiple pathologies, thus several EPAC-specific inhibitors have been identified in recent years. However, the mechanisms and molecular interactions underlying the EPAC inhibition elicited by such compounds are still poorly understood. Additionally, being hydrophobic low molecular weight species, EPAC-specific inhibitors are prone to forming colloidal aggregates, which result in non-specific aggregation-based inhibition (ABI) in aqueous systems. Here, we review from a biophysical perspective the molecular basis of the specific and non-specific interactions of two EPAC antagonists-CE3F4R, a non-competitive inhibitor, and ESI-09, a competitive inhibitor of EPAC. Additionally, we discuss the value of common ABI attenuators (e.g., TX and HSA) to reduce false positives at the expense of introducing false negatives when screening aggregation-prone compounds. We hope this review provides the EPAC community effective criteria to evaluate similar compounds, aiding in the optimization of existing drug leads, and informing the development of the next generation of EPAC-specific inhibitors.
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Affiliation(s)
- Alveena Ahmed
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada; (A.A.); (S.B.)
| | - Stephen Boulton
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada; (A.A.); (S.B.)
| | - Hongzhao Shao
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4L8, Canada; (H.S.); (M.A.)
| | - Madoka Akimoto
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4L8, Canada; (H.S.); (M.A.)
| | - Amarnath Natarajan
- Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68198, USA;
| | - Xiaodong Cheng
- Department of Integrative Biology & Pharmacology, University of Texas Health Science Center at Houston, Houston, TX 77030, USA;
- Texas Therapeutics Institute, Institute of Molecular Medicine, University of Texas Health Science Center at Houston, Houston, TX 77030, USA
| | - Giuseppe Melacini
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4L8, Canada; (A.A.); (S.B.)
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, ON L8S 4L8, Canada; (H.S.); (M.A.)
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27
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Vallurupalli P, Tiwari VP, Ghosh S. A Double-Resonance CEST Experiment To Study Multistate Protein Conformational Exchange: An Application to Protein Folding. J Phys Chem Lett 2019; 10:3051-3056. [PMID: 31081645 DOI: 10.1021/acs.jpclett.9b00985] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Despite the importance of protein dynamics to function, studying exchange between multiple conformational states remains a challenge because sparsely populated states are invisible to conventional techniques. CEST NMR experiments can detect minor states with lifetimes between 5 and 200 ms populated to a level of just ∼1%. However, CEST often cannot provide the exchange mechanism for processes involving three or more states, leaving the role of the detected minor states unknown. Here a double-resonance CEST experiment to determine the kinetics of multistate exchange is presented. The approach that involves irradiating resonances from two minor states simultaneously is used to study the exchange of T4 lysozyme (T4L) between the dominant native state and two minor states, the unfolded state and a second minor state (B), each populated to only ∼4%. Regular CEST does not provide the folding mechanism, but double-resonance CEST clearly shows that T4L can fold directly without going through B.
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Affiliation(s)
- Pramodh Vallurupalli
- TIFR Centre for Interdisciplinary Sciences , Tata Institute of Fundamental Research Hyderabad , 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District , Hyderabad , Telangana 500107 , India
| | - Ved Prakash Tiwari
- TIFR Centre for Interdisciplinary Sciences , Tata Institute of Fundamental Research Hyderabad , 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District , Hyderabad , Telangana 500107 , India
| | - Shamasree Ghosh
- TIFR Centre for Interdisciplinary Sciences , Tata Institute of Fundamental Research Hyderabad , 36/P, Gopanpally Village, Serilingampally Mandal, Ranga Reddy District , Hyderabad , Telangana 500107 , India
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28
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Boulton S, Selvaratnam R, Ahmed R, Van K, Cheng X, Melacini G. Mechanisms of Specific versus Nonspecific Interactions of Aggregation-Prone Inhibitors and Attenuators. J Med Chem 2019; 62:5063-5079. [PMID: 31074269 PMCID: PMC7255057 DOI: 10.1021/acs.jmedchem.9b00258] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
A common source of false positives in drug discovery is ligand self-association into large colloidal assemblies that nonspecifically inhibit target proteins. However, the mechanisms of aggregation-based inhibition (ABI) and ABI-attenuation by additives, such as Triton X-100 (TX) and human serum albumin (HSA), are not fully understood. Here, we investigate the molecular basis of ABI and ABI-attenuation through the lens of NMR and coupled thermodynamic cycles. We unexpectedly discover a new class of aggregating ligands that exhibit negligible interactions with proteins but act as competitive sinks for the free inhibitor, resulting in bell-shaped dose-response curves. TX attenuates ABI by converting inhibitory, protein-binding aggregates into nonbinding coaggregates, whereas HSA minimizes nonspecific ligand interactions by functioning as a reservoir for free inhibitor and preventing self-association. Hence, both TX and HSA are useful tools to minimize false positives arising from nonspecific binding but at the cost of potentially introducing false negatives due to suppression of specific interactions.
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Affiliation(s)
- Stephen Boulton
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Rajeevan Selvaratnam
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4L8, Canada
- Department of Laboratory Medicine, University Health Network, Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario M5G 2C4, Canada
| | - Rashik Ahmed
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Katherine Van
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Xiaodong Cheng
- Department of Integrative Biology and Pharmacology and Texas Therapeutics Institute, McGovern Medical School, University of Texas Health Science Center, Houston, Texas 77030, United States
| | - Giuseppe Melacini
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario L8S 4L8, Canada
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Ontario L8S 4L8, Canada
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