1
|
Haga T. Molecular properties of muscarinic acetylcholine receptors. PROCEEDINGS OF THE JAPAN ACADEMY. SERIES B, PHYSICAL AND BIOLOGICAL SCIENCES 2013; 89:226-256. [PMID: 23759942 PMCID: PMC3749793 DOI: 10.2183/pjab.89.226] [Citation(s) in RCA: 86] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2013] [Accepted: 04/30/2013] [Indexed: 05/28/2023]
Abstract
Muscarinic acetylcholine receptors, which comprise five subtypes (M1-M5 receptors), are expressed in both the CNS and PNS (particularly the target organs of parasympathetic neurons). M1-M5 receptors are integral membrane proteins with seven transmembrane segments, bind with acetylcholine (ACh) in the extracellular phase, and thereafter interact with and activate GTP-binding regulatory proteins (G proteins) in the intracellular phase: M1, M3, and M5 receptors interact with Gq-type G proteins, and M2 and M4 receptors with Gi/Go-type G proteins. Activated G proteins initiate a number of intracellular signal transduction systems. Agonist-bound muscarinic receptors are phosphorylated by G protein-coupled receptor kinases, which initiate their desensitization through uncoupling from G proteins, receptor internalization, and receptor breakdown (down regulation). Recently the crystal structures of M2 and M3 receptors were determined and are expected to contribute to the development of drugs targeted to muscarinic receptors. This paper summarizes the molecular properties of muscarinic receptors with reference to the historical background and bias to studies performed in our laboratories.
Collapse
|
2
|
Cholinergic modulation on spike timing-dependent plasticity in hippocampal CA1 network. Neuroscience 2011; 192:91-101. [DOI: 10.1016/j.neuroscience.2011.06.064] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2011] [Revised: 06/17/2011] [Accepted: 06/22/2011] [Indexed: 11/22/2022]
|
3
|
Wang H, Yu YQ, Liao WJ, Wang ZR, Lv YJ, Zhang YG, Gao TW. Negative regulation of endogenous protein kinase Calpha on the dynamic change of carbachol-induced intracellular calcium response in different melanoma cells. J Cell Physiol 2009; 221:276-82. [PMID: 19626679 DOI: 10.1002/jcp.21881] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Regulations of intracellular protein kinase C (PKC) on carbachol (CCh)-induced intracellular calcium ([Ca(2+)]i) responses were investigated in different stages of melanoma cells. We found that CCh (1 mM) significantly increased [Ca(2+)]i with 6-, 4-, 4-, and 25-folds intensities in WM793B, 451Lu, SK-MEL-5, and A2058 melanoma cells, respectively. Pretreatment of phorbol 12, 13-dibutyrate (PDBu, 2 microM), an activator of intracellular PKC, significantly suppressed CCh-induced peak reactions in WM793B, SK-MEL-5, and A2058 cells. RT-PCR data showed that mRNA levels of PKCalpha were 12-, 4-, 6-, and 0.9-folds higher in above four melanoma cells. Short interfering RNA (siRNA) targeting to PKCalpha in WM793B cells enhanced CCh-induced peak calcium reactions. Present data indicated that CCh-induced [Ca(2+)]i responses were dynamically changed in different stages of melanoma progression. Moreover, intracellular PKCalpha activated by exogenous agonist and expressed through endogenous gene transcription negatively regulated CCh-induced calcium responses. The functional analysis on the relationship between CCh-induced calcium response and endogenous PKCalpha expression might be helpful to predict the development of melanoma.
Collapse
Affiliation(s)
- Huan Wang
- Department of Dermatology, Center of Dermatology of Chinese PLA, Xijing Hospital, Fourth Military Medical University, Xi'an, China
| | | | | | | | | | | | | |
Collapse
|
4
|
Yamanushi TT, Shui Z, Leach RN, Dobrzynski H, Claydon TW, Boyett MR. Role of internalization of M2muscarinic receptor via clathrin-coated vesicles in desensitization of the muscarinic K+current in heart. Am J Physiol Heart Circ Physiol 2007; 292:H1737-46. [PMID: 17012364 DOI: 10.1152/ajpheart.01287.2005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In the heart, ACh activates the ACh-activated K+current ( IK,ACh) via the M2muscarinic receptor. The relationship between desensitization of IK,AChand internalization of the M2receptor has been studied in rat atrial cells. On application of the stable muscarinic agonist carbachol for 2 h, IK,AChdeclined by ∼62% with time constants of 1.5 and 26.9 min, whereas ∼83% of the M2receptor was internalized from the cell membrane with time constants of 2.9 and 51.6 min. Transfection of the cells with β-adrenergic receptor kinase 1 (G protein-receptor kinase 2) and β-arrestin 2 significantly increased IK,AChdesensitization and M2receptor internalization during a 3-min application of agonist. Internalized M2receptor in cells exposed to carbachol for 2 h was colocalized with clathrin and not caveolin. It is concluded that a G protein-receptor kinase 2- and β-arrestin 2-dependent internalization of the M2receptor into clathrin-coated vesicles could play a major role in IK,AChdesensitization.
Collapse
Affiliation(s)
- T T Yamanushi
- Cardiovascular Research Group, School of Medicine, University of Manchester, Manchester, United Kingdom
| | | | | | | | | | | |
Collapse
|
5
|
Oishi K, Sakurai A, Seki N, Yoshizumi T, Uchida MK. Carbachol-induced secretion and homologous desensitization in rat basophilic leukemia (RBL-2H3) cells transfected with human m2 muscarinic acetylcholine receptors. J Pharmacol Sci 2004; 96:73-83. [PMID: 15359086 DOI: 10.1254/jphs.fp0040337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
Carbachol (CCh) caused a dose-dependent release of beta-hexosaminidase and an increase in the production of inositol 1,4,5-trisphosphate (IP3) in RBL-2H3 cells transfected with m2 mAChR cDNA (RBL-m2 cells). The secretion was completely inhibited by LaCl3 and pertussis toxin. The secretion was dependent on extracellular Ca2+ and mediated through the pertussis toxin-sensitive G protein. Exposing RBL-m2 cells to 100 microM CCh for 30 min in Ca2+ -free medium (desensitizing treatment) inhibited the secretion induced by the subsequent addition of 10 microM CCh plus Ca2+, but not by stimulating the high affinity IgE receptor (FcepsilonRI). Desensitizing treatment of RBL-m2 cells reduced the affinity of the lipophilic ligand [3H]quinuclidinyl benzilate to m2 mAChR without a reduction of the total m2 mAChR number. The treatment also decreased the cell surface mAChR number to 14% with a slight reduction in its affinity. Desensitizing treatment of RBL-m2 cells inhibited the CCh-induced transient increase in levels of IP3 and intracellular Ca2+ concentration. The results suggested that the CCh-induced desensitization of m2 mAChR-mediated secretion is due to the receptor sequestration followed by blocking the increase in [Ca2+]i and that this desensitizing mechanism is receptor-subtype-specific.
Collapse
MESH Headings
- Animals
- Carbachol/pharmacology
- Cell Line, Tumor
- Dose-Response Relationship, Drug
- Humans
- Inositol 1,4,5-Trisphosphate/metabolism
- Leukemia, Basophilic, Acute/genetics
- Leukemia, Basophilic, Acute/metabolism
- Rats
- Receptor, Muscarinic M2/agonists
- Receptor, Muscarinic M2/genetics
- Receptor, Muscarinic M2/metabolism
- Transfection/methods
- beta-N-Acetylhexosaminidases/metabolism
Collapse
Affiliation(s)
- Kazuhiko Oishi
- Department of Pharmacology, Meiji Pharmaceutical University, Kiyose, Tokyo, Japan.
| | | | | | | | | |
Collapse
|
6
|
Abstract
Multiple mechanisms regulate the signaling of the five members of the family of the guanine nucleotide binding protein (G protein)-coupled muscarinic acetylcholine (ACh) receptors (mAChRs). Following activation by classical or allosteric agonists, mAChRs can be phosphorylated by a variety of receptor kinases and second messenger-regulated kinases. The phosphorylated mAChR subtypes can interact with beta-arrestin and presumably other adaptor proteins as well. As a result, the various mAChR signaling pathways may be differentially altered, leading to short-term or long-term desensitization of a particular signaling pathway, receptor-mediated activation of the mitogen-activated protein kinase pathway downstream of mAChR phosphorylation, as well as long-term potentiation of mAChR-mediated phospholipase C stimulation. Agonist activation of mAChRs may also induce receptor internalization and down-regulation, which proceed in a highly regulated manner, depending on receptor subtype and cell type. In this review, our current understanding of the complex regulatory processes that underlie signaling of mAChR is summarized.
Collapse
Affiliation(s)
- Chris J van Koppen
- Institut für Pharmakologie, Universitätsklinikum Essen, Hufelandstrasse 55, D-45122, Essen, Germany.
| | | |
Collapse
|
7
|
Shui Z, Khan IA, Tsuga H, Dobrzynski H, Haga T, Henderson Z, Boyett MR. Role of receptor kinase in long-term desensitization of the cardiac muscarinic receptor-K+ channel system. Am J Physiol Heart Circ Physiol 2002; 283:H819-28. [PMID: 12124232 DOI: 10.1152/ajpheart.00515.2001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Desensitization of the cardiac muscarinic K+ channel was studied in cultured neonatal rat atrial cells and in Chinese hamster ovary (CHO) cells transfected with muscarinic receptor (HM(2)), G protein-coupled inward rectifying K+ channels 1 and 4, and G protein-coupled receptor kinase 2. In atrial cells incubated in 10 microM carbachol for 24 h, channel activity in cell-attached patches was substantially reduced as a result of long-term desensitization. The long-term desensitization was also observed in CHO cells transfected with the wild-type receptor and receptor kinase (as well as the channel). However, long-term desensitization was greatly reduced or abolished if the cells were 1) not transfected with the receptor kinase, 2) transfected with a mutant receptor lacking phosphorylation sites (rather than the wild-type receptor), or 3) transfected with a mutant receptor kinase lacking kinase activity (rather than the wild-type receptor kinase). We suggest that long-term desensitization of the cardiac muscarinic receptor-K+ channel system to muscarinic agonist may involve phosphorylation of the receptor by receptor kinase.
Collapse
Affiliation(s)
- Z Shui
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | | | | | | | | | | | | |
Collapse
|
8
|
Shui Z, Yamanushi TT, Boyett MR. Evidence of involvement of GIRK1/GIRK4 in long-term desensitization of cardiac muscarinic K+ channels. Am J Physiol Heart Circ Physiol 2001; 280:H2554-62. [PMID: 11356610 DOI: 10.1152/ajpheart.2001.280.6.h2554] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The cardiac M2 muscarinic receptor/G protein/K+ channel system was studied in neonatal rat atrial cells cultured with and without 10 microM carbachol (CCh) for 24 h. Channel activity in CCh-pretreated cells was substantially reduced as a result of long-term desensitization regardless of whether the channel was activated by ACh in cell-attached patches or GTP in inside-out patches. Channel activity in CCh-pretreated cells was also low when the receptor was bypassed and the G protein and channel were directly activated by [gamma-S]GTP or both the receptor and G protein were bypassed and the channel was directly activated by trypsin. Finally, in CCh-pretreated cells, the whole cell K+ current was low when the channel was activated via the independent adenosine receptor. This suggests that the channel is involved in long-term desensitization. However, in CCh-pretreated cells, although the receptor was internalized, there was no internalization of the channel. We suggest that the function of the muscarinic K+ channel declines in long-term desensitization of the cardiac M2 muscarinic receptor/G protein/K+ channel system.
Collapse
Affiliation(s)
- Z Shui
- School of Biomedical Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom
| | | | | |
Collapse
|
9
|
Lee KB, Ptasienski JA, Bunemann M, Hosey MM. Acidic amino acids flanking phosphorylation sites in the M2 muscarinic receptor regulate receptor phosphorylation, internalization, and interaction with arrestins. J Biol Chem 2000; 275:35767-77. [PMID: 10952973 DOI: 10.1074/jbc.m002225200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The studies reported here address the molecular events underlying the interactions of arrestins with the M(2) muscarinic acetylcholine receptor (mAChR). In particular, we focused on the role of receptor phosphorylation in this process. Agonist-dependent phosphorylation of the M(2) mAChR can occur at clusters of serines and threonines at positions 286-290 (site P1) or 307-311 (site P2) in the third intracellular loop (Pals-Rylaarsdam, R., and Hosey, M. M. (1997) J. Biol. Chem. 272, 14152-14158). Phosphorylation at either P1 or P2 can support agonist-dependent internalization. However, phosphorylation at P2 is required for receptor interaction with arrestins (Pals-Rylaarsdam, R., Gurevich, V. V., Lee, K. B., Ptasienski, J. A., Benovic, J. L., and Hosey, M. M. (1997) J. Biol. Chem. 272, 23682-26389). The present study investigated the role of acidic amino acids between P1 and P2 in regulating receptor phosphorylation, internalization, and receptor/arrestin interactions. Mutation of the acidic amino acids at positions 298-300 (site A1) and/or 304-305 (site A2) to alanines had significant effects on agonist-dependent phosphorylation. P2 was identified as the preferred site of agonist-dependent phosphorylation, and full phosphorylation at P2 required the acidic amino acids at A1 or their neutral counterparts. In contrast, phosphorylation at site P1 was dependent on site A2. In addition, sites A1 and A2 significantly affected the ability of the wild type and P1 and P2 mutant receptors to internalization and to interact with arrestin2. Substitution of asparagine and glutamine for the aspartates and glutamates at sites A1 or A2 did not influence receptor phosphorylation but did influence arrestin interaction with the receptor. We propose that the amino acids at sites A1 and A2 play important roles in agonist-dependent phosphorylation at sites P2 and P1, respectively, and also play an important role in arrestin interactions with the M(2) mAChR.
Collapse
Affiliation(s)
- K B Lee
- Department of Molecular Pharmacology and Biological Chemistry, the Institute for Neuroscience, Northwestern University Medical School, Evanston, Illinois 60208, USA.
| | | | | | | |
Collapse
|
10
|
Palmer TM, Stiles GL. Identification of Threonine Residues Controlling the Agonist-Dependent Phosphorylation and Desensitization of the Rat A3Adenosine Receptor. Mol Pharmacol 2000. [DOI: 10.1124/mol.57.3.539] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
11
|
Abstract
G-protein coupled receptors (GPCRs) comprise one of the largest classes of signalling molecules. A wide diversity of activating ligands induce the active conformation of GPCRs and lead to signalling via heterotrimeric G-proteins and downstream effectors. In addition, a complex series of reactions participate in the 'turn-off' of GPCRs in both physiological and pharmacological settings. Some key players in the inactivation or 'desensitization' of GPCRs have been identified, whereas others remain the target of ongoing studies. G-protein coupled receptor kinases (GRKs) specifically phosphorylate activated GPCRs and initiate homologous desensitization. Uncoupling proteins, such as members of the arrestin family, bind to the phosphorylated and activated GPCRs and cause desensitization by precluding further interactions of the GPCRs and G-proteins. Adaptor proteins, including arrestins, and endocytic machinery participate in the internalization of GPCRs away from their normal signalling milieu. In this review we discuss the roles of these regulatory molecules as modulators of GPCR signalling.
Collapse
Affiliation(s)
- M Bünemann
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, 303 East Chicago Avenue S215, Chicago, IL 60611, USA
| | | |
Collapse
|
12
|
Hosey MM, Benovic JL, DebBurman SK, Richardson RM. Multiple mechanisms involving protein phosphorylation are linked to desensitization of muscarinic receptors. Life Sci 1999; 56:951-5. [PMID: 10188798 DOI: 10.1016/0024-3205(95)00033-3] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
Agonists induce phosphorylation of m2 muscarinic receptors (mAChR) in several cell types. This phosphorylation correlates with desensitization. The mechanisms underlying mAChR phosphorylation have been investigated using several in vitro approaches. Protein kinase C phosphorylated the purified and reconstituted m2 mAChR to a stoichiometry of approximately 5 mols P/mol receptor; this phosphorylation resulted in the decreased ability of receptors to activate G-proteins. Although the phosphorylation by PKC was not modulated by agonist binding to the mAChR, heterotrimeric G-proteins were able to completely block the PKC-mediated effects. If significant receptor/G-protein coupling occurs in vivo, agonists would be required to promote dissociation of the G-proteins from the receptors and reveal the phosphorylation sites for PKC. Members of the G-protein coupled receptor kinase (GRK) family also phosphorylated the purified and reconstituted m2 mAChR. In contrast to PKC, the GRKs phosphorylated the m2 mAChR strictly in an agonist-dependent manner. GRK mediated phosphorylation perturbed receptor/G-protein coupling. In addition, phosphorylation allowed for arrestin binding to the m2 mAChR which should further contribute to desensitization. Using a new strategy that does not require purification and reconstitution of receptors for GRK studies, the m3 mAChR were revealed as substrates for the GRKs. For both the m2 and m3 receptor subtypes, the most effective kinases were GRK 2 and 3. Phosphorylation of the receptors by these enzymes was stimulated by low concentrations of G-proteins and by membrane phospholipids. Thus, multiple mechanisms involving protein phosphorylation appear to contribute to the overall process of mAChR desensitization.
Collapse
Affiliation(s)
- M M Hosey
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, Chicago, IL 60611, USA
| | | | | | | |
Collapse
|
13
|
Bünemann M, Lee KB, Pals-Rylaarsdam R, Roseberry AG, Hosey MM. Desensitization of G-protein-coupled receptors in the cardiovascular system. Annu Rev Physiol 1999; 61:169-92. [PMID: 10099686 DOI: 10.1146/annurev.physiol.61.1.169] [Citation(s) in RCA: 105] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Multiple mechanisms exist to control the signaling and density of G-protein-coupled receptors (GPRs). Upon agonist binding and receptor activation, a series of reactions participate in the turn off or desensitization of GPRs. Many GPRs are phosphorylated by protein kinases and consequently uncoupled from G proteins. In addition, many GPRs are sequestered from the cell surface and become inaccessible to their activating ligands. Both receptor:G protein uncoupling and receptor sequestration may involve the participation of arrestins or other proteins. A model for receptor regulation has been developed from studies of the beta-adrenergic receptor. However, recent studies suggest that other GPRs important in the cardiovascular system, such as the muscarinic cholinergic receptors that regulate heart rate, might be regulated by mechanisms other than those that regulate the beta-adrenergic receptors. This review summarizes our current understanding of the processes involved in the desensitization of GPRs.
Collapse
Affiliation(s)
- M Bünemann
- Department of Molecular Pharmacology & Biological Chemistry, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | | | | | | | | |
Collapse
|
14
|
Abstract
Protein phosphorylation acts a pivotal mechanism in regulating the contractile state of the heart by modulating particular levels of autonomic control on cardiac force/length relationships. Early studies of changes in cardiac protein phosphorylation focused on key components of the excitation-coupling process, namely phospholamban of the sarcoplasmic reticulum and myofibrillar troponin I. In more recent years the emphasis has shifted towards the identification of other phosphoproteins, and more importantly, the delineation of the mechanistic and signaling pathways regulating the various known phosphoproteins. In addition to cAMP- and Ca(2+)-calmodulin-dependent kinase processes, these have included regulation by protein kinase C and the ever-emerging family of growth factor-related kinases such as the tyrosine-, mitogen- and stress-activated protein kinases. Similarly, the role of protein dephosphorylation by protein phosphatases has been recognized as integral in modulating normal cardiac cellular function. Recent studies involving a variety of cardiovascular pathologies have demonstrated that changes in the phosphorylation states of key cardiac regulatory proteins may underlie cardiac dysfunction in disease states. The emphasis of this comprehensive review will be on discussing the role of cardiac phosphoproteins in regulating myocardial function and pathophysiology based not only on in vitro data, but more importantly, from ex vivo experiments with corroborative physiological and biochemical evidence.
Collapse
Affiliation(s)
- S T Rapundalo
- Department of Biochemistry, Parke-Davis Pharmaceutical Research, Division of Warner-Lambert, Ann Arbor, MI 48105, USA.
| |
Collapse
|
15
|
Minshall RD, Tan F, Nakamura F, Rabito SF, Becker RP, Marcic B, Erdös EG. Potentiation of the actions of bradykinin by angiotensin I-converting enzyme inhibitors. The role of expressed human bradykinin B2 receptors and angiotensin I-converting enzyme in CHO cells. Circ Res 1997; 81:848-56. [PMID: 9351459 DOI: 10.1161/01.res.81.5.848] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Part of the beneficial effects of angiotensin I-converting enzyme (ACE) inhibitors are due to augmenting the actions of bradykinin (BK). We studied this effect of enalaprilat on the binding of [3H]BK to Chinese hamster ovary (CHO) cells stably transfected to express the human BK B2 receptor alone (CHO-3B) or in combination with ACE (CHO-15AB). In CHO-15AB cells, enalaprilat (1 mumol/L) increased the total number of low-affinity [3H]BK binding sites on the cells at 37 degrees C, but not at 4 degrees C, from 18.4 +/- 4.3 to 40.3 +/- 11.9 fmol/10(6) cells (P < .05; Kd, 2.3 +/- 0.8 and 5.9 +/- 1.3 nmol/L; n = 4). Enalaprilat preserved a portion of the receptors in high-affinity conformation (Kd, 0.17 +/- 0.08 nmol/L; 8.1 +/- 0.9 fmol/10(6) cells). Enalaprilat decreased the IC50 of [Hyp3-Tyr(Me)8]BK, the BK analogue more resistant to ACE, from 3.2 +/- 0.8 to 0.41 +/- 0.16 nmol/L (P < .05, n = 3). The biphasic displacement curve of the binding of [3H]BK also suggested the presence of high-affinity BK binding sites. Enalaprilat (5 nmol to 1 mumol/L) potentiated the release of [3H]arachidonic acid and the liberation of inositol 1,4,5-trisphosphate (IP3) induced by BK and [Hyp3-Tyr(Me)8]BK. Moreover, enalaprilat (1 mumol/L) completely and immediately restored the response of the B2 receptor, desensitized by the agonist (1 mumol/L [Hyp3-Tyr(Me)8]BK); this effect was blocked by the antagonist, HOE 140. Finally, enalaprilat, but not the prodrug enalapril, decreased internalization of the receptor from 70 +/- 9% to 45 +/- 9% (P < .05, n = 7). In CHO-3B cells, enalaprilat was ineffective. ACE inhibitors in the presence of both the B2 receptor and ACE enhance BK binding, protect high-affinity receptors, block receptor desensitization, and decrease internalization, thereby potentiating BK beyond blocking its hydrolysis.
Collapse
Affiliation(s)
- R D Minshall
- Department of Pharmacology, University of Illinois College of Medicine, Chicago, USA
| | | | | | | | | | | | | |
Collapse
|
16
|
Mita M, Satoh-Akimoto K, Oishi K, Hashimoto T, Uchida MK. Inhibition of muscarinic receptor-operated Ca2+ sensitization by short-term desensitization of alpha-toxin-permeabilized smooth muscle cells from guinea pig stomach. GENERAL PHARMACOLOGY 1997; 29:753-61. [PMID: 9347321 DOI: 10.1016/s0306-3623(97)00033-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
1. Isolated single smooth muscle cells from the guinea pig stomach were permeabilized with Staphylococcus aureus alpha-toxin. 2. The permeabilized single cells showed a shortening in response to Ca2+ in an all-or-none manner. Moreover, the addition of acetylcholine (ACh) or guanosine 5'-triphosphate (GTP) resulted in a decrease in concentration of Ca2+ required to trigger a threshold response, suggesting that Ca2+ sensitization is induced by the stimulation of muscarinic acetylcholine receptors (mAChRs) or GTP-binding protein(s). 3. Short-term desensitization was induced by incubating the permeabilized cells with 100 microM ACh for 10 min. 4. In desensitized cells, the concentration of Ca2+ required to trigger a threshold response in the presence of ACh was increased, however, the cell shortening in response to Ca2+ in the absence of ACh and GTP-induced Ca2+ sensitization was not affected by short-term desensitization. 5. These results suggest that the receptor-operated augmentation of Ca2+ sensitivity is inhibited by short-term desensitization and that the development of short-term desensitization is due to an uncoupling of mAChR/GTP-binding protein(s).
Collapse
Affiliation(s)
- M Mita
- Department of Pharmacology, Meiji College of Pharmacy, Tokyo, Japan
| | | | | | | | | |
Collapse
|
17
|
Minshall RD, Erdös EG, Vogel SM. Angiotensin I-converting enzyme inhibitors potentiate bradykinin's inotropic effects independently of blocking its inactivation. Am J Cardiol 1997; 80:132A-136A. [PMID: 9293966 DOI: 10.1016/s0002-9149(97)00468-2] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The positive inotropic effects of bradykinin (BK) and 2 analogs resistant to angiotensin I-converting enzyme (ACE) were potentiated on isolated guinea pig atrial preparations by enalaprilat. The stable BK analogs, dextran-BK and [Hyp3-Tyr(Me)8]-BK, were as active as BK. Pretreatment for 5 min with enalaprilat augmented the maximal positive inotropic effect of [Hyp3-Tyr(Me)8]-BK 2.8-fold, from 19% to 53% and that of BK from 28% to 42% over baseline; inotropic responses to dextran-BK (1 microM) were similarly increased. The activity of atrial ACE, a zinc-requiring enzyme, was completely inhibited by 8-hydroxyquinoline-5-sulfonic acid (QSA, 10 mM), which raised the maximal inotropic effect of BK to 39% above baseline. This value rose to 67% when in addition to QSA, 1 microM enalaprilat was added; enalaprilat thus, potentiated the effects of BK independently of enzyme inhibition. The positive inotropic effects to BK and its analogs decline with time in the presence of these agonists. After 10 min of exposure, the response to 1 microM [Hyp3-Tyr(Me)8]-BK decreased to about half, and after 20 min, to 0. Enalaprilat, when present in the tissue bath, prevented the decline in inotropy; even after tachyphylaxis occurred, it reversed this decrease in activity when added. The effects of 1 microM [Hyp3-Tyr(Me)8]-BK, in the absence or presence of enalaprilat, were abolished by the BK B2 receptor antagonist icatibant (0.75 microM). The results indicate that ACE inhibitors, by potentiating the BK effects and blocking BK B2-receptor desensitization, may contribute to the beneficial cardiac effects of BK independently of blocking its inactivation.
Collapse
Affiliation(s)
- R D Minshall
- Department of Pharmacology, University of Illinois College of Medicine at Chicago, 60612, USA
| | | | | |
Collapse
|
18
|
Leiros CP, Sterin-Borda L, Borda ES, Goin JC, Hosey MM. Desensitization and sequestration of human m2 muscarinic acetylcholine receptors by autoantibodies from patients with Chagas' disease. J Biol Chem 1997; 272:12989-93. [PMID: 9148906 DOI: 10.1074/jbc.272.20.12989] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Chronic Chagas' disease is associated with pathologic changes of the cardiovascular, digestive, and autonomic nervous system, culminating in autonomic denervation and congestive heart failure. Previously, circulating autoantibodies that activate signaling by cardiac muscarinic acetylcholine receptors (mAChRs) have been described. However, it remains unclear whether the chagasic IgGs directly interact with the m2 mAChRs (predominant cardiac subtype), and, if so, whether chronic exposure of the mAChRs to such activating IgGs would result in receptor desensitization. Here we performed studies with purified and reconstituted hm2 mAChRs and demonstrate that IgGs from chagasic serum immunoprecipitated the mAChRs in a manner similar to an anti-m2 mAChR monoclonal antibody tested in parallel. The chagasic antibodies did not directly interact with the ligand binding site, because the binding of radiolabeled antagonist was unchanged by the addition of the chagasic IgG. In intact cells stably expressing the hm2 mAChR, the chagasic IgGs, but not normal IgGs, mimicked the ability of the agonist acetylcholine to induce two effects associated with agonist-induced receptor desensitization: a decrease in affinity for agonist binding to m2 mAChR and sequestration of the hm2 mAChRs from the cell surface. The results demonstrate that the chagasic IgGs can directly interact with and desensitize m2 mAChRs and provide support for the hypothesis of autoimmune mechanisms having a role in the pathogenesis of Chagas' cardioneuromyopathy.
Collapse
Affiliation(s)
- C P Leiros
- Centro de Estudios Farmacologicos y Botanicos, Consejo Nacional de Investigaciones Cientificas y Tecnicas, Buenos Aires 1414, Argentina
| | | | | | | | | |
Collapse
|
19
|
Harper EA, Roberts SP, Shankley NP, Black JW. Analysis of variation in L-365,260 competition curves in radioligand binding assays. Br J Pharmacol 1996; 118:1717-26. [PMID: 8842437 PMCID: PMC1909838 DOI: 10.1111/j.1476-5381.1996.tb15597.x] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
1. For several years, we have used the cholecystokinin (CCK)B/gastrin receptor selective antagonist, L-365,260, as a reference compound in a variety of studies in CCKB/gastrin receptor radioligand binding assays. Here, we have analysed the competition curve data sets obtained between L-365,260 and [125I]-BH-CCK8S in guinea-pig gastric gland and mouse and rat cerebral cortex preparations. 2. Competition curves obtained for L-365,260 in the mouse cortex assay were not different from rectangular hyperbolae (slope = 1.01 +/- 0.02) implying the presence of a single population of binding sites (pKI = 8.41 +/- 0.01; data from 47 experiments, slope constrained to unity). However, in the rat cortex and guinea-pig gastric gland assays, the mean slope of the competition curves was significantly less than one and the mean apparent pKI significantly lower than that obtained in the mouse cortex (slope = 0.85 +/- 0.03, 0.90 +/- 0.03; apparent pKI = 7.98 +/- 0.05, 8.07 +/- 0.05; 48 and 45 experiments, in rat and guinea-pig, respectively). The distribution of the individual pKI and slope estimates of the competition curves in these two assays was consistent with expectations for the variable expression (in terms of absolute number and proportion) of two binding sites. The two sites were characterized by pKI values for L-365,260 of 8.50 +/- 0.04 and 8.48 +/- 0.04 for the high affinity site and 7.32 +/- 0.04 and 7.22 +/- 0.06 for the low affinity site in guinea-pig and rat, respectively. 3. The affinity estimates for L-365,260, although obtained on different tissues, are consistent with data obtained from the analysis of L-365,260 antagonism of pentagastrin-stimulated responses in mouse and rat stomach (acid secretion) and guinea-pig gastric muscle (isotonic contraction) assays. To this extent, these data suggest the existence of two CCKB/gastrin receptor subtypes.
Collapse
|
20
|
Sterin-Borda L, Cremaschi G, Genaro AM, Echagüe AV, Goin JC, Borda E. Involvement of nitric oxide synthase and protein kinase C activation on chagasic antibodies action upon cardiac contractility. Mol Cell Biochem 1996; 160-161:75-82. [PMID: 8901458 DOI: 10.1007/bf00240034] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
We have already demonstrated the presence of antibodies in the sera of chagasic patients with the ability to interact with neurotransmitter receptors triggering several intracellular pathways of transduction signals. Here we show that, chagasic IgG induced protein kinase C (PKC) translocation to rat cardiac membranes and this effect was inhibited by muscarinic cholinergic blockers atropine and AF-DX 116 pointing to the participation of M2 receptors in this effect. It was also able to stimulate nitric oxide synthase (NOS) activity and this action was blunted by phospholipase C (PLC) and PKC inhibitors indicating that the production of nitric oxide (NO) would be the consequence of the cascade of enzymatic pathways triggered by mAChR activation. PKC and NOS activities were involved in chagasic IgG negative inotropic actions on rat isolated myocardium as its effects were blunted by staurosporine and L-N-monomethyl arginine. Furthermore, low concentrations of chagasic IgG inhibited the cardiac mechanical action of carbachol in a non-competitive manner. These data suggested that PKC activation in myocardium by chagasic IgG would be involved in its physiological actions by modulating NOS activity. The participation of PKC-mediated phosphorylation of mAChR leading to receptor desensitization as one of the causes of dysautonomia is also discussed.
Collapse
|
21
|
Hosey MM, DebBurman SK, Pals-Rylaarsdam R, Richardson RM, Benovic JL. The role of G-protein coupled receptor kinases in the regulation of muscarinic cholinergic receptors. PROGRESS IN BRAIN RESEARCH 1996; 109:169-79. [PMID: 9009704 DOI: 10.1016/s0079-6123(08)62099-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Affiliation(s)
- M M Hosey
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, Chicago, IL 60611, USA
| | | | | | | | | |
Collapse
|
22
|
Pals-Rylaarsdam R, Xu Y, Witt-Enderby P, Benovic JL, Hosey MM. Desensitization and internalization of the m2 muscarinic acetylcholine receptor are directed by independent mechanisms. J Biol Chem 1995; 270:29004-11. [PMID: 7499433 DOI: 10.1074/jbc.270.48.29004] [Citation(s) in RCA: 135] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
The phenomenon of acute desensitization of G-protein-coupled receptors has been associated with several events, including receptor phosphorylation, loss of high affinity agonist binding, receptor:G-protein uncoupling, and receptor internalization. However, the biochemical events underlying these processes are not fully understood, and their contributions to the loss of signaling remain correlative. In addition, the nature of the kinases and the receptor domains which are involved in modulation of activity have only begun to be investigated. In order to directly measure the role of G-protein-coupled receptor kinases (GRKs) in the desensitization of the m2 muscarinic acetylcholine receptor (m2 mAChR), a dominant-negative allele of GRK2 was used to inhibit receptor phosphorylation by endogenous GRK activity in a human embryonic kidney cell line. The dominant-negative GRK2K220R reduced agonist-dependent phosphorylation of the m2 mAChR by approximately 50% and prevented acute desensitization of the receptor as measured by the ability of the m2 mAChR to attenuate adenylyl cyclase activity. In contrast, the agonist-induced internalization of the m2 mAChR was unaffected by the GRK2K220R construct. Further evidence linking receptor phosphorylation to acute receptor desensitization was obtained when two deletions of the third intracellular loop were made which created m2 mAChRs that did not become phosphorylated in an agonist-dependent manner and did not desensitize. However, the mutant mAChRs retained the ability to internalize. These data provide the first direct evidence that GRK-mediated receptor phosphorylation is necessary for m2 mAChR desensitization; the likely sites of in vivo phosphorylation are in the central portion of the third intracellular loop (amino acids 282-323). These results also indicate that internalization of the m2 receptor is not a key event in desensitization and is mediated by mechanisms distinct from GRK phosphorylation of the receptor.
Collapse
Affiliation(s)
- R Pals-Rylaarsdam
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, Chicago, Illinois 60611, USA
| | | | | | | | | |
Collapse
|
23
|
DebBurman SK, Ptasienski J, Boetticher E, Lomasney JW, Benovic JL, Hosey MM. Lipid-mediated regulation of G protein-coupled receptor kinases 2 and 3. J Biol Chem 1995; 270:5742-7. [PMID: 7890702 DOI: 10.1074/jbc.270.11.5742] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
G protein-coupled receptor-mediated signaling is attenuated by a process referred to as desensitization, wherein agonist-dependent phosphorylation of receptors by G protein-coupled receptor kinases (GRKs) is proposed to be a key initial event. However, mechanisms that activate GRKs are not fully understood. In one scenario, beta gamma-subunits of G proteins (G beta gamma) activate certain GRKs (beta-adrenergic receptor kinases 1 and 2, or GRK2 and GRK3), via a pleckstrin homology domain in the COOH terminus. This interaction has been proposed to translocate cytosolic beta-adrenergic receptor kinases (beta ARKs) to the plasma membrane and facilitate interaction with receptor substrates. Here, we report a novel finding that membrane lipids modulate beta ARK activity in vitro in a manner that is analogous and competitive with G beta gamma. Several lipids, including phosphatidylserine (PS), stimulated, whereas phosphatidylinositol 4,5-bisphosphate inhibited, the ability of these GRKs to phosphorylate agonist-occupied m2 muscarinic acetylcholine receptors. Furthermore, both PS and phosphatidylinositol 4,5-bisphosphate specifically bound to beta ARK1, whereas phosphatidylcholine, a lipid that did not modulate beta ARK activity, did not bind to beta ARK1. The lipid regulation of beta ARKs did not occur via a modulation of its autophosphorylation state. PS- and G beta gamma-mediated stimulation of beta ARK1 was compared and found strikingly similar; moreover, their effects together were not additive (except at initial stages of reaction), which suggests that PS and G beta gamma employed a common interaction and activation mechanism with the kinase. The effects of these lipids were prevented by two well known G beta gamma-binding proteins, phosducin and GST-beta ARK-(466-689) fusion protein, suggesting that the G beta gamma-binding domain (possibly the pleckstrin homology domain) of the GRKs is also a site for lipid:protein interaction. We submit the intriguing possibility that both lipids and G proteins co-regulate the function of GRKs.
Collapse
Affiliation(s)
- S K DebBurman
- Department of Molecular Pharmacology and Biological Chemistry, Northwestern University Medical School, Chicago, Illinois 60611
| | | | | | | | | | | |
Collapse
|
24
|
Tsuga H, Kameyama K, Haga T, Kurose H, Nagao T. Sequestration of muscarinic acetylcholine receptor m2 subtypes. Facilitation by G protein-coupled receptor kinase (GRK2) and attenuation by a dominant-negative mutant of GRK2. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(18)31665-x] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
25
|
Koenig J, Edwardson J. Kinetic analysis of the trafficking of muscarinic acetylcholine receptors between the plasma membrane and intracellular compartments. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)32537-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
26
|
Shapiro M, Koshland D. Mutagenic studies of the interaction between the aspartate receptor and methyltransferase from Escherichia coli. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(19)78090-9] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
27
|
Maloteaux JM, Hermans E. Agonist-induced muscarinic cholinergic receptor internalization, recycling and degradation in cultured neuronal cells. Cellular mechanisms and role in desensitization. Biochem Pharmacol 1994; 47:77-88. [PMID: 8311846 DOI: 10.1016/0006-2952(94)90439-1] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Short-term incubation of intact neuronal cells with muscarinic cholinergic agonists resulted in a rapid decrease of the specific binding of [3H]methylscopolamine to cell surface receptors indicative of receptor internalization. The agonists induced the internalization of both the muscarinic receptor subtypes coupled to adenylyl cyclase and those coupled to phosphoinositide turnover. Receptor internalization, which was inhibited at 0-4 degrees and by depletion of intracellular K+, is thought to occur through coated pits formation and was rapidly reversible. Receptor recycling did not imply protein synthesis. Down-regulation of muscarinic receptors occurred slowly in the presence of agonists, needed intact cytoskeleton (demonstrated by the inhibitory effect of colchicine) and involved lysosomal activity. Both receptor internalization and down-regulation were prevented by muscarinic receptor antagonists. Receptor internalization and down-regulation are agonist-induced cellular mechanisms that with receptor phosphorylation and uncoupling, may induce desensitization. These processes may contribute to complex intracellular regulatory processes and may be involved in some of the long-term effects of neurotransmitters (mainly neuropeptides and growth hormones) or drugs.
Collapse
Affiliation(s)
- J M Maloteaux
- Laboratoire de Neurochimie, Université Catholique de Louvain, Brussels, Belgium
| | | |
Collapse
|
28
|
Fraser CM, Lee NH, Pellegrino SM, Kerlavage AR. Molecular properties and regulation of G-protein-coupled receptors. PROGRESS IN NUCLEIC ACID RESEARCH AND MOLECULAR BIOLOGY 1994; 49:113-56. [PMID: 7863005 DOI: 10.1016/s0079-6603(08)60049-5] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Affiliation(s)
- C M Fraser
- Institute for Genomic Research, Gaithersburg, Maryland 20878
| | | | | | | |
Collapse
|
29
|
Tsunoda Y. Receptor-operated Ca2+ signaling and crosstalk in stimulus secretion coupling. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1154:105-56. [PMID: 8218335 DOI: 10.1016/0304-4157(93)90008-c] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In the cells of higher eukaryotic organisms, there are several messenger pathways of intracellular signal transduction, such as the inositol 1,4,5-trisphosphate/Ca2+ signal, voltage-dependent and -independent Ca2+ channels, adenylate cyclase/cyclic adenosine 3',5'-monophosphate, guanylate cyclase/cyclic guanosine 3',5'-monophosphate, diacylglycerol/protein kinase C, and growth factors/tyrosine kinase/tyrosine phosphatase. These pathways are present in different cell types and impinge on each other for the modulation of the cell function. Ca2+ is one of the most ubiquitous intracellular messengers mediating transcellular communication in a wide variety of cell types. Over the last decades it has become clear that the activation of many types of cells is accompanied by an increase in cytosolic free Ca2+ concentration ([Ca2+]i) that is thought to play an important part in the sequence of events occurring during cell activation. The Ca2+ signal can be divided into two categories: receptor- and voltage-operated Ca2+ signal. This review describes and integrates some recent views of receptor-operated Ca2+ signaling and crosstalk in the context of stimulus-secretion coupling.
Collapse
Affiliation(s)
- Y Tsunoda
- Department of Faculty Science, Hokkaido University, Sapporo, Japan
| |
Collapse
|
30
|
Doi R, Chowdhury P, Rayford P. Agonist-regulated alteration of the affinity of pancreatic muscarinic cholinergic receptors. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)41548-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
31
|
Phosphorylation and desensitization of human m2 muscarinic cholinergic receptors by two isoforms of the beta-adrenergic receptor kinase. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)38697-1] [Citation(s) in RCA: 85] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
|
32
|
Hishinuma S, Matsumoto Y, Uchida MK, Kurokawa M. Novel regulation of muscarinic receptors and their coupling with G proteins in smooth muscle: transient resensitization during desensitizing process. Br J Pharmacol 1993; 109:330-5. [PMID: 8358538 PMCID: PMC2175686 DOI: 10.1111/j.1476-5381.1993.tb13574.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
1. Muscarinic stimulation of the smooth muscle of guinea-pig taenia caeci was produced with 10(-4) M carbachol for 15 s, 30 s, 1 min, 2 min and 30 min, and the time course of developing desensitization was studied by measuring the muscle contractility and the binding characteristics of muscarinic receptors. 2. The contractile response to carbachol was analyzed using dose-response curves. The response to 10(-7) M carbachol was reduced by treatment for 15 s with 10(-4) M carbachol (fast desensitization), but recovered partially after 30 s treatment and completely after 1 min treatment (resensitization). Contractility was reduced again after 2 min and 30 min treatment (re-desensitization). 3. The affinity of carbachol for muscarinic receptors was changed by the carbachol treatment in a manner similar to the contractility. Thus, the affinity was reduced at 15 s, restored slightly at 30 s and completely at 1 and 2 min, and was reduced again at 30 min. 4. 5'-Guanylylimidodiphosphate (GppNHp), a non-hydrolysable analogue of guanosine triphosphate (GTP) reduced the affinity of muscarinic receptors for carbachol via guanine nucleotide-binding regulatory proteins (G proteins). A similar effect was observed in tissues desensitized by 15 s carbachol treatment. This effect disappeared after 30 s, recovered completely after 1 and 2 min, and disappeared again after 30 min carbachol treatment. 5. Neither the dissociation constant (Kd value) nor the maximal binding (Bmax) of [3H]-quinuclidinyl benzilate ([3H]-QNB) to muscarinic receptors were changed by the carbachol treatment. 6. These results indicate that the whole process of desensitization, resensitization and re-desensitization are related to changes in the binding ability of muscarinic receptors, in their coupling with G proteins and in the post-receptor steps of the signal transduction. We emphasize that the desensitizing process involves an early transient phase of resensitization that could be caused by restoration of both the affinity of carbachol for muscarinic receptors and their coupling with G proteins. This novel resensitization mechanism may have some physiological significance for cellular homoeostasis by modulating cellular responsiveness transiently or even in an oscillatory manner during the process of desensitization.
Collapse
Affiliation(s)
- S Hishinuma
- Department of Pharmacology, Meiji College of Pharmacy, Tanashi, Tokyo, Japan
| | | | | | | |
Collapse
|
33
|
Tobin A, Nahorski S. Rapid agonist-mediated phosphorylation of m3-muscarinic receptors revealed by immunoprecipitation. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)98420-6] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
34
|
|
35
|
Richardson R, Hosey M. Agonist-induced phosphorylation and desensitization of human m2 muscarinic cholinergic receptors in Sf9 insect cells. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41662-6] [Citation(s) in RCA: 62] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
|
36
|
Affiliation(s)
- Y Kurachi
- Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905
| | | | | | | |
Collapse
|
37
|
Richardson R, Ptasienski J, Hosey M. Functional effects of protein kinase C-mediated phosphorylation of chick heart muscarinic cholinergic receptors. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50209-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
|
38
|
Mita M, Uchida MK. The change in the threshold for short-term desensitization in isolated smooth muscle cells showing an all-or-none response to acetylcholine. Br J Pharmacol 1991; 104:603-8. [PMID: 1797324 PMCID: PMC1908226 DOI: 10.1111/j.1476-5381.1991.tb12476.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
1. Isolated smooth muscle cells from guinea-pig taenia caecum were prepared by collagenase digestion. The cells showed an all-or-none response to acetylcholine (ACh) under our experimental conditions. 2. Desensitized cells showed an all-or-none response but required a higher concentration of ACh for induction of contraction, indicating that the desensitization was due to a change in the threshold concentration. 3. In [3H]-quinuclidinyl benzilate ([3H]-QNB) binding to the desensitized cells, KD and Bmax were not significantly different from those estimated in the control cells. The competitive inhibition curve for specific binding of [3H]-QNB by ACh in the desensitized cells was in agreement with that of control cells. 4. The ACh-stimulated increase of the 45Ca2+ influx was very rapid and correlated well with the contraction of the cells. The concentrations of ACh inducing the maximal 45Ca2+ influx were increased by desensitization. 5. These results indicated that although the binding of ACh to the receptor was not changed by desensitization, the threshold concentration of ACh for their contraction was raised by desensitization, and the 45Ca2+ influx accompanying the contraction was shifted to the side of high concentration of ACh. 6. These results suggest that the development of short-term desensitization is due to an uncoupling of the receptor from the mechanism for initiation of the contraction.
Collapse
Affiliation(s)
- M Mita
- Department of Pharmacology, Meiji College of Pharmacy, Tokyo, Japan
| | | |
Collapse
|
39
|
Sakuta H, Sekiguchi M, Okamoto K, Sakai Y. Desensitization of endogenous angiotensin II receptors in Xenopus oocytes: a role of protein kinase C. Eur J Pharmacol 1991; 208:41-7. [PMID: 1657620 DOI: 10.1016/0922-4106(91)90049-n] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
The inward chloride current induced by angiotensin II (AII) in Xenopus oocytes shows strong and homologous desensitization, and was suggested to be mediated by phosphatidylinositol (PI) hydrolysis (Sakuta et al., 1991, Eur. J. Pharmacol. Mol. Pharmacol. 208, 31). As a model of agonist-induced desensitization of receptors coupled with PI hydrolysis, the mechanism of the desensitization of endogenous AII receptors in oocytes was investigated. Incubation of collagenase-treated oocytes with staurosporine significantly augmented the peak amplitude of AII responses, prolonged their duration, and increased the ratio of oocytes responsive to AII. Moreover, staurosporine-pretreatment made oocytes be consistently responsive to every application of AII. These effects of staurosporine were inhibited by incubation of staurosporine-treated oocytes with 12-O-tetradecanoylphorbol 13-acetate (TPA) but not with dibutyryl cAMP. TPA also attenuated AII responses in staurosporine-untreated control oocytes. These results suggest that staurosporine suppresses the desensitization of endogenous AII receptors in oocytes by blocking protein kinase C (PKC), and the desensitization is likely to be due to phosphorylation by PKC of the receptors or the molecules comprising an AII receptor complex.
Collapse
Affiliation(s)
- H Sakuta
- Department of Pharmacology, National Defense Medical College, Saitama, Japan
| | | | | | | |
Collapse
|
40
|
Shimada T, Hamada E, Terano A, Sugimoto T, Kurachi Y. Beta-angonists modulate ACh-inhibition of a K current in intestinal smooth muscle cells. Biochem Biophys Res Commun 1991; 179:327-32. [PMID: 1652953 DOI: 10.1016/0006-291x(91)91373-k] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
ACh causes a long-lasting inhibition of STOCs via G proteins in intestinal smooth muscle cells. We examined the effects of isoproterenol (Iso) on the ACh-induced inhibition of STOCs in isolated ileal smooth muscle cells using the G omega-seal whole cell clamp technique. In control, ACh (1 microM) completely suppressed STOCs, which did not desensitize over a period lasting 20 minutes. When Iso (10 microM) was added to the bath in the presence of ACh, the ACh-induced inhibition of STOCs was gradually removed. This effect of Iso was prevented by propranolol (10 microM). Application of Db-cAMP (500 microM) mimicked the Iso effects. Intracellulary applied GTP-gamma S (100 microM) gradually suppressed STOCs in the absence of ACh, which could not be removed by either Iso or Db-cAMP. These results suggest that beta-adrenergic stimulation causes a removal of the muscarinic inhibition of STOCs via a cAMP-dependent process.
Collapse
Affiliation(s)
- T Shimada
- 2nd Department of Internal Medicine, Faculty of Medicine, University of Tokyo, Japan
| | | | | | | | | |
Collapse
|
41
|
Benovic J, Onorato J, Arriza J, Stone W, Lohse M, Jenkins N, Gilbert D, Copeland N, Caron M, Lefkowitz R. Cloning, expression, and chromosomal localization of beta-adrenergic receptor kinase 2. A new member of the receptor kinase family. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)98568-6] [Citation(s) in RCA: 165] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
|
42
|
Richardson RM, Hosey MM. Agonist-independent phosphorylation of purified cardiac muscarinic cholinergic receptors by protein kinase C. Biochemistry 1990; 29:8555-61. [PMID: 2125467 DOI: 10.1021/bi00489a008] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The results of several studies have suggested that muscarinic cholinergic receptors (mAChR) may be regulated by multiple pathways involving phosphorylation of the receptors. Previous studies have demonstrated that chick heart mAChR are phosphorylated by the beta-adrenergic receptor kinase (beta-AR kinase) in an agonist-dependent manner, and it has been suggested that this process may be linked to receptor desensitization. In this work, we present evidence that protein kinase C can phosphorylate the purified, reconstituted chick heart mAChR and can modify the interaction of the receptors with GTP binding proteins (G-proteins) that couple the receptors to effectors. Phosphorylation of the mAChR with protein kinase C occurred to an extent of approximately 5 mol of P/mol of receptor. Neither the rate nor the extent of the protein kinase C mediated phosphorylation of mAChR was agonist-dependent. Under the conditions tested, the initial rate of phosphorylation of the mAChR by protein kinase C was significantly more rapid than that obtained with the beta-AR kinase. At equilibrium, phosphorylation of mAChR by protein kinase C and beta-AR kinase was partially additive. The functional effects of protein kinase C mediated phosphorylation of the mAChR were assessed by comparing the abilities of purified G-proteins (Gi and Go) to reconstitute high-affinity agonist binding to phosphorylated and nonphosphorylated receptors. A significantly larger percentage of the receptors phosphorylated with protein kinase C exhibited G-protein-dependent high-affinity agonist binding, suggesting that phosphorylation of the receptors by protein kinase C modulates receptor function in a positive manner.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- R M Richardson
- Department of Pharmacology, Northwestern University Medical School, Chicago, Illinois 60611
| | | |
Collapse
|
43
|
Scherer NM, Nathanson NM. Differential regulation by agonist and phorbol ester of cloned m1 and m2 muscarinic acetylcholine receptors in mouse Y1 adrenal cells and in Y1 cells deficient in cAMP-dependent protein kinase. Biochemistry 1990; 29:8475-83. [PMID: 2174702 DOI: 10.1021/bi00488a039] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Cloned muscarinic acetylcholine m1 and m2 receptors were expressed in stably transfected mouse Y1 adrenal cells and in a variant Y1 line, Kin-8, which is deficient in cAMP-dependent protein kinase activity (PKA-). m1 and m2 receptors were rapidly internalized following exposure of transfected PKA+ or PKA- cells to the muscarinic agonist carbachol. Thus, agonist-dependent internalization of m1 and m2 did not require PKA activity. A differential effect of PKA on regulation by agonist of the m2 receptor, but not the m1 receptor, was unmasked in PKA- cells. The m2 receptor was more sensitive to agonist-dependent internalization, and its rate of internalization was faster in PKA- cells than it was in PKA+ cells. Treatment of PKA+ cells with 8-(4-chlorophenylthio)-cAMP or forskolin did not result in internalization of either m1 or m2 receptors and did not alter the extent of agonist-dependent internalization of m2. These data indicate that the basal activity of PKA may modulate the agonist-dependent internalization of the m2 receptor, but not the m1 receptor. The internalization of the m1 and m2 receptors in both PKA+ and PKA- cells was accompanied by desensitization of functional responses. Exposure of PKA+ cells to 10(-7) M phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C, resulted in a 30 +/- 9% decrease in the number of m1 receptors on the cell surface. However, treatment of PKA- cells expressing the m1 receptor did not result in internalization, suggesting that PKA was required for some aspect of PMA-dependent internalization.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- N M Scherer
- Department of Pharmacology, University of Washington, Seattle 98195
| | | |
Collapse
|
44
|
Haga K, Haga T. Dual regulation by G proteins of agonist-dependent phosphorylation of muscarinic acetylcholine receptors. FEBS Lett 1990; 268:43-7. [PMID: 2116980 DOI: 10.1016/0014-5793(90)80968-o] [Citation(s) in RCA: 70] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Muscarinic acetylcholine receptors purified from porcine atrium were phosphorylated, depending on the presence of agonists, by a protein kinase partially purified from porcine brain, which had similar properties to the beta-adrenergic receptor kinase. GTP-binding regulatory proteins (Go) had dual effects on the phosphorylation of muscarinic receptors, i.e. stimulation at lower concentrations and inhibition at higher concentrations. The stimulatory effect was reproduced with the beta gamma subunit of Go and the inhibitory effect with the combination of the alpha and beta gamma subunits.
Collapse
Affiliation(s)
- K Haga
- Department of Biochemistry, Faculty of Medicine, University of Tokyo, Japan
| | | |
Collapse
|
45
|
Abstract
Muscarinic acetylcholine receptors purified from porcine cerebrum were phosphorylated by protein kinase C purified from the same tissue. More than 1 mol of phosphate was incorporated per mole of receptor, with both serine and threonine residues being phosphorylated. Neither the degree nor the rate of the phosphorylation was affected by the presence or absence of acetylcholine. GTP-sensitive high-affinity binding with acetylcholine was observed for muscarinic receptors reconstituted with GTP-binding proteins (Gi or Go), irrespective of whether muscarinic receptors or the GTP-binding proteins had been phosphorylated by protein kinase C or not. This indicates that the interaction between purified muscarinic receptors and purified GTP-binding proteins in vitro is not affected by their phosphorylation.
Collapse
Affiliation(s)
- K Haga
- Department of Biochemistry, Hamamatsu University School of Medicine, Japan
| | | | | |
Collapse
|
46
|
Lefkowitz RJ, Hausdorff WP, Caron MG. Role of phosphorylation in desensitization of the beta-adrenoceptor. Trends Pharmacol Sci 1990; 11:190-4. [PMID: 2188401 DOI: 10.1016/0165-6147(90)90113-m] [Citation(s) in RCA: 239] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Regulation of receptors allows their responses to be modified rapidly and appropriately according to the needs of the environment. Multiple mechanisms are involved in the loss of sensitivity that follows exposure to agonists. Receptor sequestration, a rapid and transient event, and receptor downregulation, which requires more prolonged agonist exposure, contribute to this effect. However, in this article Bob Lefkowitz and colleagues focus primarily on the recent developments in understanding mechanisms of rapid desensitization involving receptor phosphorylation. Various molecular biological techniques have been used to demonstrate the important roles of two particular kinases--beta ARK and protein kinase A--in this regard.
Collapse
Affiliation(s)
- R J Lefkowitz
- Department of Medicine, Howard Hughes Medical Institute, Duke University Medical Center, Durham, NC 27710
| | | | | |
Collapse
|
47
|
Hosey MM, Kwatra MM, Ptasienski J, Richardson RM. Regulation of receptor function by protein phosphorylation. Ann N Y Acad Sci 1990; 588:155-63. [PMID: 2192639 DOI: 10.1111/j.1749-6632.1990.tb13206.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- M M Hosey
- Department of Biological Chemistry and Structure, University of Health Sciences, Chicago Medical School, Illinois 60064
| | | | | | | |
Collapse
|
48
|
Himpens B, Casteels R. Different effects of depolarization and muscarinic stimulation on the Ca2+/force relationship during the contraction-relaxation cycle in the guinea pig ileum. Pflugers Arch 1990; 416:28-35. [PMID: 2352839 DOI: 10.1007/bf00370218] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The effects of K+ depolarization and of the muscarinic agonist carbachol on [Ca2+]i and force were investigated in smooth muscle sheets of the longitudinal layer of the ileum loaded with Fura-2. K(+)-rich solutions increased [Ca2+]i and force to an initial peak value, which was determined by the concentration of [K+]o. Thereafter, [Ca2+]i and force declined to a lower maintained level. The Ca2+/force relationship observed during this contraction-relaxation cycle is represented by a clockwise hysteresis loop. At 140 mM [K+]o, this loop consisted of three components while at lower [K+]o a two-component loop was observed. The stimulation with 0.1 mM carbachol resulted in a transient increase of [Ca2+]i and force followed by a continuous decline of these parameters despite the presence of the drug. Its EC50 of relaxation was around 270 nM [Ca2+]i. The Ca2+/force relationship proceeded along a counterclockwise hysteresis loop during the contraction-relaxation cycle. The extent of this loop decreased but remained unaltered in its direction during repeated stimulation with carbachol. These results suggest that (a) both agonists increase force and [Ca2+]i during stimulation; (b) during depolarization with K+, desensitization to CA2+ occurs resulting in a clockwise hysteresis loop; (c) during carbachol stimulation, a counterclockwise hysteresis is observed. This could be due to an increased sensitivity to Ca2+ mainly in tonic smooth muscle. These observations might be explained by a modulation of the Ca2+ sensitivity by sensitizing and desensitizing mechanisms. These modulations during different stimuli could be due to different myosin light-chain kinase/myosin light-chain phosphatase ratios.
Collapse
Affiliation(s)
- B Himpens
- Laboratory of Physiology, K.U. Leuven, Belgium
| | | |
Collapse
|
49
|
Abstract
Bradykinin binds to specific cell surface receptors on Rat13 fibroblasts with a high affinity (2.1 nM). Prolonged exposure of cells to the ligand causes a concentration-dependent decline in surface levels of the 2.1 nM receptor from 40,000 receptors per cell to undetectable levels with a t1/2 of approximately 2 h. The decline occurs in parallel with the appearance of an equal number of lower affinity binding sites (40 nM), suggesting that ligand exposure causes desensitization by an alteration in receptor affinity. The affinity change is characterized by a faster rate of ligand dissociation while the rate of association remains unaltered. The observed desensitization is dependent on the presence of active cellular metabolism since (i) it does not occur in whole cells maintained at 4 degrees C and (ii) membranes prepared from Rat13 cells retain their high-affinity sites at 37 degrees C despite extensive ligand exposure.
Collapse
Affiliation(s)
- R A Roberts
- Imperial Cancer Research Fund, Hammersmith Hospital, London, United Kingdom
| | | |
Collapse
|
50
|
Affiliation(s)
- M I Schimerlik
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis 97331-6503
| |
Collapse
|