1
|
Malik F, Li Z. Is there a common allosteric binding site for G-protein coupled receptors? J Comput Aided Mol Des 2022; 36:405-413. [PMID: 35507106 PMCID: PMC10150935 DOI: 10.1007/s10822-022-00454-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 04/19/2022] [Indexed: 11/30/2022]
Abstract
Targeting the allosteric sites on G-protein coupled receptors (GPCRs) for drug discovery is attracting increased interest. Given a GPCR target, identifying the allosteric binding sites in it remains a challenge. Previous works from our and other labs suggest the intracellular region below the middle of the transmembrane (TM) domain that spatially overlaps with the G-protein binding site could contain a common allosteric site for all GPCRs. We performed several bioinformatics analyses on this site for more than 100 representative human GPCR structures. Results of the studies confirmed that the proposed region contains an allosteric site that is druggable for 89% of the GPCRs and is not 100% identical between a GPCR and its most similar homolog for 94% of the GPCRs. The physico-chemical properties and amino acid composition of this site vary among and within GPCR classes. Since this proposed region occupies the space existing in all GPCRs of known structure, it could represent a common host of an allosteric site for all GPCRs that can be targeted for structure-based allosteric drug design.
Collapse
Affiliation(s)
- Faisal Malik
- Department of Chemistry & Biochemistry, University of the Sciences in Philadelphia, Philadelphia, PA, 19104, USA
| | - Zhijun Li
- Department of Chemistry & Biochemistry, University of the Sciences in Philadelphia, Philadelphia, PA, 19104, USA.
| |
Collapse
|
2
|
Kuznetsov A, Arukuusk P, Härk H, Juronen E, Ustav M, Langel Ü, Järv J. ACE2 Peptide Fragment Interaction with Different S1 Protein Sites. Int J Pept Res Ther 2021; 28:7. [PMID: 34867130 PMCID: PMC8634746 DOI: 10.1007/s10989-021-10324-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/21/2021] [Indexed: 11/25/2022]
Abstract
We study the effect of the peptide QAKTFLDKFNHEAEDLFYQ on the kinetics of the SARS-CoV-2 spike protein S1 binding to angiotensin-converting enzyme 2 (ACE2), with the aim to characterize the interaction mechanism of the SARS-CoV2 virus with its host cell. This peptide corresponds to the sequence 24–42 of the ACE2 α1 domain, which marks the binding site for the S1 protein. The kinetics of S1-ACE2 complex formation was measured in the presence of various concentrations of the peptide using bio-layer interferometry. Formation of the S1-ACE2 complex was inhibited by the peptide in cases where it was preincubated with S1 protein before the binding experiment. The kinetic analysis of S1-ACE2 complex dissociation revealed that preincubation stabilized this complex, and this effect was dependent on the peptide concentration as well as the preincubation time. The results point to the formation of the ternary complex of S1 with ACE2 and the peptide. This is possible in the presence of another binding site for the S1 protein beside the receptor-binding domain for ACE2, which binds the peptide QAKTFLDKFNHEAEDLFYQ. Therefore, we conducted computational mapping of the S1 protein surface, revealing two additional binding sites located at some distance from the main receptor-binding domain on S1. We suggest the possibility to predict and test the short protein derived peptides for development of novel strategies in inhibiting virus infections.
Collapse
Affiliation(s)
| | - Piret Arukuusk
- Institute of Technology, University of Tartu, Tartu, Estonia
| | - Heleri Härk
- Institute of Technology, University of Tartu, Tartu, Estonia
| | | | - Mart Ustav
- Institute of Technology, University of Tartu, Tartu, Estonia.,Icosagen Cell Factory OÜ, Tartu, Estonia
| | - Ülo Langel
- Institute of Technology, University of Tartu, Tartu, Estonia.,Department of Biochemistry and Biophysics, Stockholm University, Stockholm, Sweden
| | - Jaak Järv
- Institute of Chemistry, University of Tartu, Tartu, Estonia
| |
Collapse
|
3
|
Kopytova AE, Rychkov GN, Nikolaev MA, Baydakova GV, Cheblokov AA, Senkevich KA, Bogdanova DA, Bolshakova OI, Miliukhina IV, Bezrukikh VA, Salogub GN, Sarantseva SV, Usenko TC, Zakharova EY, Emelyanov AK, Pchelina SN. Ambroxol increases glucocerebrosidase (GCase) activity and restores GCase translocation in primary patient-derived macrophages in Gaucher disease and Parkinsonism. Parkinsonism Relat Disord 2021; 84:112-121. [PMID: 33609962 DOI: 10.1016/j.parkreldis.2021.02.003] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 01/11/2021] [Accepted: 02/01/2021] [Indexed: 12/24/2022]
Abstract
Mutations in the glucocerebrosidase gene (GBA) encoding the lysosomal enzyme glucocerebrosidase (GCase) cause Gaucher disease (GD) and are the most commonly known genetic risk factor for Parkinson disease (PD). Ambroxol is one of the most effective pharmacological chaperones of GCase. Fourteen GD patients, six PD patients with mutations in the GBA gene (GBA-PD), and thirty controls were enrolled. GCase activity and hexosylsphingosine (HexSph) concentration were measured in dried blood and macrophage spots using liquid chromatography coupled with tandem mass spectrometry. The effect of ambroxol on GCase translocation to lysosomes was assessed using confocal microscopy. The results showed that ambroxol treatment significantly increased GCase activity in cultured macrophages derived from patient blood monocytic cell (PBMC) of GD (by 3.3-fold) and GBA-PD patients (by 3.5-fold) compared to untreated cells (p < 0.0001 and p < 0.0001, respectively) four days after cultivation. Ambroxol treatment significantly reduced HexSph concentration in GD (by 2.1-fold) and GBA-PD patients (by 1.6-fold) (p < 0.0001 and p < 0.0001, respectively). GD macrophage treatment resulted in increased GCase level and increased enzyme colocalization with the lysosomal marker LAMP2. The possible binding modes of ambroxol to mutant GCase carrying N370S amino acid substitution at pH 4.7 were examined using molecular docking and molecular dynamics simulations. The ambroxol position characterized by minimal binding free energy was observed in close vicinity to the residue, at position 370. Taken together, these data showed that PBMC-derived macrophages could be used for assessing ambroxol therapy response for GD patients and also for GBA-PD patients.
Collapse
Affiliation(s)
- A E Kopytova
- Petersburg Nuclear Physics Institute Named By B.P. Konstantinov of National Research Center «Kurchatov Institute», Gatchina, Russia.
| | - G N Rychkov
- Petersburg Nuclear Physics Institute Named By B.P. Konstantinov of National Research Center «Kurchatov Institute», Gatchina, Russia; Peter the Great St.Petersburg Polytechnic University, Saint-Petersburg, Russia; Kurchatov Genome Center - PNPI, Gatchina, Russia
| | - M A Nikolaev
- Petersburg Nuclear Physics Institute Named By B.P. Konstantinov of National Research Center «Kurchatov Institute», Gatchina, Russia; First Pavlov State Medical University of St. Petersburg, Saint-Petersburg, Russia
| | - G V Baydakova
- Research Center for Medical Genetics, Moscow, Russia
| | - A A Cheblokov
- Petersburg Nuclear Physics Institute Named By B.P. Konstantinov of National Research Center «Kurchatov Institute», Gatchina, Russia
| | - K A Senkevich
- Petersburg Nuclear Physics Institute Named By B.P. Konstantinov of National Research Center «Kurchatov Institute», Gatchina, Russia; First Pavlov State Medical University of St. Petersburg, Saint-Petersburg, Russia
| | - D A Bogdanova
- Petersburg Nuclear Physics Institute Named By B.P. Konstantinov of National Research Center «Kurchatov Institute», Gatchina, Russia
| | - O I Bolshakova
- Petersburg Nuclear Physics Institute Named By B.P. Konstantinov of National Research Center «Kurchatov Institute», Gatchina, Russia
| | - I V Miliukhina
- Petersburg Nuclear Physics Institute Named By B.P. Konstantinov of National Research Center «Kurchatov Institute», Gatchina, Russia; Institute of Experimental Medicine, Saint-Petersburg, Russia; First Pavlov State Medical University of St. Petersburg, Saint-Petersburg, Russia
| | - V A Bezrukikh
- Almazov National Medical Research Centre, Saint-Petersburg, Russia
| | - G N Salogub
- Almazov National Medical Research Centre, Saint-Petersburg, Russia
| | - S V Sarantseva
- Petersburg Nuclear Physics Institute Named By B.P. Konstantinov of National Research Center «Kurchatov Institute», Gatchina, Russia
| | - T C Usenko
- Petersburg Nuclear Physics Institute Named By B.P. Konstantinov of National Research Center «Kurchatov Institute», Gatchina, Russia; First Pavlov State Medical University of St. Petersburg, Saint-Petersburg, Russia
| | - E Y Zakharova
- Research Center for Medical Genetics, Moscow, Russia
| | - A K Emelyanov
- Petersburg Nuclear Physics Institute Named By B.P. Konstantinov of National Research Center «Kurchatov Institute», Gatchina, Russia; Institute of Experimental Medicine, Saint-Petersburg, Russia; First Pavlov State Medical University of St. Petersburg, Saint-Petersburg, Russia
| | - S N Pchelina
- Petersburg Nuclear Physics Institute Named By B.P. Konstantinov of National Research Center «Kurchatov Institute», Gatchina, Russia; Institute of Experimental Medicine, Saint-Petersburg, Russia; First Pavlov State Medical University of St. Petersburg, Saint-Petersburg, Russia
| |
Collapse
|
4
|
Kim N, Kang JH, Lee WK, Kim SG, Lee JS, Lee SH, Park JB, Kim KH, Gong YD, Hwang KY, Kim SY. Allosteric inhibition site of transglutaminase 2 is unveiled in the N terminus. Amino Acids 2018; 50:1583-1594. [PMID: 30105541 DOI: 10.1007/s00726-018-2635-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 08/09/2018] [Indexed: 12/22/2022]
Abstract
Previously we have demonstrated transglutaminase 2 (TGase 2) inhibition abrogated renal cell carcinoma (RCC) using GK921 (3-(phenylethynyl)-2-(2-(pyridin-2-yl)ethoxy)pyrido[3,2-b]pyrazine), although the mechanism of TGase 2 inhibition remains unsolved. Recently, we found that the increase of TGase 2 expression is required for p53 depletion in RCC by transporting the TGase 2 (1-139 a.a)-p53 complex to the autophagosome, through TGase 2 (472-687 a.a) binding p62. In this study, mass analysis revealed that GK921 bound to the N terminus of TGase 2 (81-116 a.a), which stabilized p53 by blocking TGase 2 binding. This suggests that RCC survival can be stopped by p53-induced cell death through blocking the p53-TGase 2 complex formation using GK921. Although GK921 does not bind to the active site of TGase 2, GK921 binding to the N terminus of TGase 2 also inactivated TGase 2 activity through acceleration of non-covalent self-polymerization of TGase 2 via conformational change. This suggests that TGase 2 has an allosteric binding site (81-116 a.a) which changes the conformation of TGase 2 enough to accelerate inactivation through self-polymer formation.
Collapse
Affiliation(s)
- Nayeon Kim
- Tumor Microenvironment Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang, 10408, Republic of Korea
| | - Joon Hee Kang
- Tumor Microenvironment Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang, 10408, Republic of Korea
| | - Won-Kyu Lee
- New Drug Development Center, Osong Medical Innovation Foundation, Cheongju, Chungbuk, 28160, Republic of Korea
| | - Seul-Gi Kim
- Tumor Microenvironment Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang, 10408, Republic of Korea
| | - Jae-Seon Lee
- Tumor Microenvironment Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang, 10408, Republic of Korea
| | - Seon-Hyeong Lee
- Tumor Microenvironment Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang, 10408, Republic of Korea
| | - Jong Bae Park
- Department of System Cancer Science, Graduate School of Cancer Science and Policy, National Cancer Center, Goyang, 10408, Republic of Korea
| | - Kyung-Hee Kim
- Omics Core Lab, Research Institute, National Cancer Center, Goyang, 10408, Republic of Korea
| | - Young-Dae Gong
- Department of Chemistry, College of Science, Dongguk University, Seoul, 04620, Republic of Korea
| | - Kwang Yeon Hwang
- Institute of Life Science and Natural Resources, Korea University, Seoul, 02841, Republic of Korea
| | - Soo-Youl Kim
- Tumor Microenvironment Branch, Division of Cancer Biology, Research Institute, National Cancer Center, Goyang, 10408, Republic of Korea.
| |
Collapse
|
5
|
Kim BK, Cho JH, Jeong P, Lee Y, Lim JJ, Park KR, Eom SH, Kim YC. Benserazide, the first allosteric inhibitor of Coxsackievirus B3 3C protease. FEBS Lett 2015; 589:1795-801. [PMID: 26022398 PMCID: PMC7094222 DOI: 10.1016/j.febslet.2015.05.027] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2015] [Revised: 04/30/2015] [Accepted: 05/07/2015] [Indexed: 01/20/2023]
Abstract
Coxsackievirus B3 is the main cause of human viral myocarditis and cardiomyopathy. Virally encoded Coxsackievirus 3C protease (3C(pro)) plays an essential role in viral proliferation. Here, benserazide was discovered as a novel inhibitor from a drug library screen targeting Coxsackievirus 3C(pro) using a FRET-based enzyme assay. Benserazide, whose chemical structure has no electrophilic functional groups, was characterized as a non-competitive inhibitor by enzyme kinetic studies. A molecular docking study with benserazide and its analogs indicated that a novel putative allosteric binding site was involved. Specifically, a 2,3,4-trihydroxybenzyl moiety was determined to be a key pharmacophore for the enzyme's inhibitory activity. We suggest that the putative allosteric binding site may be a novel target for future therapeutic strategies.
Collapse
Affiliation(s)
- Bo-Kyoung Kim
- School of Life Sciences, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju (GIST) 500-712, Republic of Korea
| | - Joong-Heui Cho
- New Drug Development Center (NDDC), Daegu-Gyeongbuk Medical Innovation Foundation (DGMIF), 80 Cheombok-ro, Dong-gu, Daegu 701-310, Republic of Korea
| | - Pyeonghwa Jeong
- Department of Medical System Engineering (DMSE), Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 500-712, Republic of Korea
| | - Youngjin Lee
- School of Life Sciences, Steitz Center for Structural Biology, Systems Biology Research Center and Department of Chemistry, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 500-712, Republic of Korea
| | - Jia Jia Lim
- School of Life Sciences, Steitz Center for Structural Biology, Systems Biology Research Center and Department of Chemistry, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 500-712, Republic of Korea
| | - Kyoung Ryoung Park
- School of Life Sciences, Steitz Center for Structural Biology, Systems Biology Research Center and Department of Chemistry, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 500-712, Republic of Korea
| | - Soo Hyun Eom
- School of Life Sciences, Steitz Center for Structural Biology, Systems Biology Research Center and Department of Chemistry, Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 500-712, Republic of Korea
| | - Yong-Chul Kim
- School of Life Sciences, Gwangju Institute of Science and Technology, 123 Cheomdangwagi-ro, Buk-gu, Gwangju (GIST) 500-712, Republic of Korea; Department of Medical System Engineering (DMSE), Gwangju Institute of Science and Technology (GIST), 123 Cheomdangwagi-ro, Buk-gu, Gwangju 500-712, Republic of Korea.
| |
Collapse
|
6
|
Potempa M, Nalivaika E, Ragland D, Lee SK, Schiffer CA, Swanstrom R. A Direct Interaction with RNA Dramatically Enhances the Catalytic Activity of the HIV-1 Protease In Vitro. J Mol Biol 2015; 427:2360-78. [PMID: 25986307 DOI: 10.1016/j.jmb.2015.05.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Revised: 05/08/2015] [Accepted: 05/08/2015] [Indexed: 01/09/2023]
Abstract
Though the steps of human immunodeficiency virus type 1 (HIV-1) virion maturation are well documented, the mechanisms regulating the proteolysis of the Gag and Gag-Pro-Pol polyproteins by the HIV-1 protease (PR) remain obscure. One proposed mechanism argues that the maturation intermediate p15NC must interact with RNA for efficient cleavage by the PR. We investigated this phenomenon and found that processing of multiple substrates by the HIV-1 PR was enhanced in the presence of RNA. The acceleration of proteolysis occurred independently from the substrate's ability to interact with nucleic acid, indicating that a direct interaction between substrate and RNA is not necessary for enhancement. Gel-shift assays demonstrated the HIV-1 PR is capable of interacting with nucleic acids, suggesting that RNA accelerates processing reactions by interacting with the PR rather than the substrate. All HIV-1 PRs examined have this ability; however, the HIV-2 PR does not interact with RNA and does not exhibit enhanced catalytic activity in the presence of RNA. No specific sequence or structure was required in the RNA for a productive interaction with the HIV-1 PR, which appears to be principally, though not exclusively, driven by electrostatic forces. For a peptide substrate, RNA increased the kinetic efficiency of the HIV-1 PR by an order of magnitude, affecting both turnover rate (k(cat)) and substrate affinity (K(m)). These results suggest that an allosteric binding site exists on the HIV-1 PR and that HIV-1 PR activity during maturation could be regulated in part by the juxtaposition of the enzyme with virion-packaged RNA.
Collapse
Affiliation(s)
- Marc Potempa
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Ellen Nalivaika
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Debra Ragland
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Sook-Kyung Lee
- Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA
| | - Celia A Schiffer
- Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Ronald Swanstrom
- Department of Microbiology and Immunology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Department of Biochemistry and Biophysics, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA; Center for AIDS Research, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599, USA.
| |
Collapse
|
7
|
Del Cadia M, De Rienzo F, Weston DA, Thompson AJ, Menziani MC, Lummis SC. Exploring a potential palonosetron allosteric binding site in the 5-HT(3) receptor. Bioorg Med Chem 2013; 21:7523-8. [PMID: 24128813 PMCID: PMC3898987 DOI: 10.1016/j.bmc.2013.09.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2013] [Revised: 09/10/2013] [Accepted: 09/11/2013] [Indexed: 11/26/2022]
Abstract
Palonosetron (Aloxi) is a potent second generation 5-HT(3) receptor antagonist whose mechanism of action is not yet fully understood. Palonosetron acts at the 5-HT(3) receptor binding site but recent computational studies indicated other possible sites of action in the extracellular domain. To test this hypothesis we mutated a series of residues in the 5-HT3A receptor subunit (Tyr(73), Phe(130), Ser(163), and Asp(165)) and in the 5-HT3B receptor subunit (His(73), Phe(130), Glu(170), and Tyr(143)) that were previously predicted by in silico docking studies to interact with palonosetron. Homomeric (5-HT(3)A) and heteromeric (5-HT(3)AB) receptors were then expressed in HEK293 cells to determine the potency of palonosetron using both fluorimetric and radioligand methods to test function and ligand binding, respectively. The data show that the substitutions have little or no effect on palonosetron inhibition of 5-HT-evoked responses or binding. In contrast, substitutions in the orthosteric binding site abolish palonosetron binding. Overall, the data support a binding site for palonosetron at the classic orthosteric binding pocket between two 5-HT3A receptor subunits but not at allosteric sites previously identified by in silico modelling and docking.
Collapse
Affiliation(s)
- Marta Del Cadia
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | - Francesca De Rienzo
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | - David A. Weston
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Andrew J. Thompson
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| | - Maria Cristina Menziani
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy
| | - Sarah C.R. Lummis
- Dipartimento di Scienze Chimiche e Geologiche, Università degli Studi di Modena e Reggio Emilia, Via Campi 183, 41100 Modena, Italy
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK
| |
Collapse
|
8
|
Lummis SCR, Thompson AJ. Agonists and antagonists induce different palonosetron dissociation rates in 5-HT₃A and 5-HT₃AB receptors. Neuropharmacology 2013; 73:241-6. [PMID: 23747573 PMCID: PMC3778450 DOI: 10.1016/j.neuropharm.2013.05.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 04/19/2013] [Accepted: 05/08/2013] [Indexed: 11/30/2022]
Abstract
Palonosetron is a potent 5-HT3 receptor antagonist with a unique structure and some unusual properties. Here we explore the properties of palonosetron at heterologously expressed 5-HT3A and 5-HT3AB receptors. We used receptors expressed in HEK293 cells, and functionally analysed them using a membrane potential sensitive dye in a Flexstation, which revealed IC50s of 0.24 nM and 0.18 nM for 5-HT3A and 5-HT3AB receptors respectively. Radioligand binding studies with [3H]palonosetron revealed similar Kds: 0.34 nM for 5-HT3A and 0.15 nM for 5-HT3AB receptors. Kinetic studies showed palonosetron association and dissociation rates were slightly faster in 5-HT3AB than 5-HT3A receptors, and for both subtypes dissociation rates were ligand-dependent, with antagonists causing more rapid dissociation than agonists. Similar ligand effects were not observed for [3H]granisetron dissociation studies. These data support previous studies which show palonosetron has actions distinct to other 5-HT3 receptor antagonists, and the slow rates observed for agonist induced dissociation (t1/2 > 10 h) could at least partly explain the long duration of palonosetron effects in vivo. Palonosetron IC50s and Kds for 5-HT3A and 5-HT3AB receptors in HEK293 cells are similar. Palonosetron association and dissociation rates are slower at 5-HT3A than 5-HT3AB receptors. Agonist-induced palonosetron dissociation rates are slower than those for antagonists in both 5-HT3A and 5-HT3AB receptors. Agonist- and antagonist-induced granisetron dissociation rates are similar in both 5-HT3A and 5-HT3AB receptors. Palonosetron and granisetron have distinct actions.
Collapse
Affiliation(s)
- Sarah C R Lummis
- Department of Biochemistry, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK.
| | | |
Collapse
|