Abstract:
:The fluorogenic sulfhydryl probe 7-diethylamino-3-(4'-maleimidylphenyl)-4-methylcoumarin (CPM) (1-50 nM) is used to characterize the functional role and location of highly reactive thiol groups on the ryanodine-sensitive Ca2+ release channel complex [i.e., ryanodine receptors (RyRs)] of skeletal and cardiac junctional sarcoplasmic reticulum (SR). The kinetics of forming fluorescent CPM adducts with junctional but not longitudinal SR membrane proteins (0.02-1 pmol of CPM/microgram of SR protein) are found to be markedly dependent on the presence of physiological and pharmacological modulators of the RyR Ca2+ channel. RyR agonists, micromolar Ca2+, and nanomolar ryanodine promote a slow SR thiol-CPM reaction, with an apparent rate constant k of 0.0021 +/- 0.0002 sec-1, and > 89% of the fluorescence is associated with the 110-kDa Ca2+ pump, which constitutes 68% of the protein in the SR preparations. However, in the presence of Ca2+ channel antagonists (millimolar Mg2+, millimolar Ca2+, or micromolar ryanodine), CPM rapidly forms adducts with a single class of highly reactive (hyperreactive) SR thiols (k = 0.025 +/- 0.002 sec-1). Nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis of CPM-labeled SR protein and Western blot analyses with antiryanodine or antitriadin antibodies reveal that the hyperreactive thiols labeled by CPM under conditions favoring channel closure are localized principally to the RyR protomer and triadin, which constitute < 6% of the protein in the SR preparation. Immunoprecipitation experiments with antiryanodine and antitriadin monoclonal antibodies confirm the location of CPM-labeled thiol groups on RyR and triadin, respectively. The results indicate that the RyR and triadin contain a small number of highly reactive cysteine residues that selectively conjugate with CPM only when channel closure is favored. It is shown that either 1) the redox state (sulfhydryl/disulfide status) or 2) the accessibility of the hyperreactive thiols on the RyR and triadin is determined by the conformational state of the channel. Covalent modification of hyperreactive thiols with nanomolar CPM inhibits both Ca(2+)-induced Ca2+ release and the gating activity of single channels reconstituted in bilayers, revealing the essential functional importance of hyperreactive thiols on channel-associated proteins. 1,4-Naphthoquinone (0.4-40 pmol/micrograms of protein) selectively oxidizes hyperreactive thiols on RyR and triadin and releases Ca2+ from SR vesicles, without inhibiting Ca(2+)-ATPase activity. The results provide direct evidence of the existence and functional role of hyperreactive cysteine residues on the RyR and triadin in regulating the gating of ryanodine-sensitive intracellular Ca2+ channels and strongly suggest that these important Ca2+ regulatory channels may be an important target for oxidative cell damage mediated by quinones.
journal_name
Mol Pharmacoljournal_title
Molecular pharmacologyauthors
Liu G,Abramson JJ,Zable AC,Pessah INsubject
Has Abstractpub_date
1994-02-01 00:00:00pages
189-200issue
2eissn
0026-895Xissn
1521-0111journal_volume
45pub_type
杂志文章abstract::Tetrahydroimidazo[4,5,1-jk][1,4]benzodiazepin-2(1H)-one and -thione (TIBO) derivatives (e.g., R82150) are potent, human immunodeficiency virus-1 (HIV-1)-specific, inhibitors of reverse transcriptase (RT) that are undergoing initial evaluation in clinical trials. Because HIV-1 has become resistant to other RT inhibitor...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1993-01-01 00:00:00
abstract::The compound 4-(5-(4-bromophenyl)-3-(6-methyl-2-oxo-4-phenyl-1,2-dihydroquinolin-3-yl)-4,5-dihydro-1H-pyrazol-1-yl)-4-oxobutanoic acid (DQP-1105) is a representative member of a new class of N-methyl-d-aspartate (NMDA) receptor antagonists. DQP-1105 inhibited GluN2C- and GluN2D-containing receptors with IC(50) values ...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.111.073239
更新日期:2011-11-01 00:00:00
abstract::Prokaryotes produce a variety of toxins that affect genomic function of both eukaryotes and prokaryotes. The 375-base pair bacterial gene Streptoalloteichus hindustanus (Sh) ble encodes a small protein, Streptoalloteichus hindustanus bleomycin resistance protein (BRP), that inhibits in vitro DNA cleavage by the prokar...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1993-12-01 00:00:00
abstract::The intracellular pathways taken by galactose-terminal glycoproteins were examined following endocytosis by the asialoglycoprotein receptor in monolayers of the human hepatoma cell line, Hep G2. In addition to a pathway leading to lysosomal degradation, single cohort kinetics revealed that up to 28% of surface-bound a...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1984-11-01 00:00:00
abstract::Guinea pig lung microsomes converted arachidonic acid (AA) to two classes of cytochrome P450 (P450)-dependent metabolites, 16- through 20-hydroxyeicosatetraenoic acids [(16-20)-OH-AA] and epoxyeicosatrienoic acids (EETs). The rate of formation of (16-20)-OH-AA was approximately 3-fold higher in microsomes from beta-na...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1994-06-01 00:00:00
abstract::Activation of endothelial nitric-oxide synthase (eNOS) has been shown to occur through various pathways involving increases in the cytosolic Ca(2+) concentration, activation of the phosphatidylinositol-3' kinase/Akt pathway, as well as regulation by other kinases and by protein-protein interactions. We have recently r...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.63.4.886
更新日期:2003-04-01 00:00:00
abstract::Electrical recordings were made in Xenopus oocytes to study the modulatory effects of steroids on gamma-aminobutyric acid (GABA) receptors expressed by RNA from mammalian brain and retina. GABA responses expressed by rat cerebral cortex poly(A)+ RNA were bicuculline-sensitive Cl- currents mediated by GABAA receptors. ...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1992-01-01 00:00:00
abstract::The cannabinoid analog abnormal cannabidiol [abn-cbd; (-)-4-(3-3,4-trans-p-menthadien-[1,8]-yl)-olivetol] does not bind to CB(1) or CB(2) receptors, yet it acts as a full agonist in relaxing rat isolated mesenteric artery segments. Vasorelaxation by abn-cbd is endothelium-dependent, pertussis toxin-sensitive, and is i...
journal_title:Molecular pharmacology
pub_type: 评论,杂志文章
doi:10.1124/mol.63.3.699
更新日期:2003-03-01 00:00:00
abstract::Multidrug resistance-associated protein 1 (Mrp1; Abcc1) is expressed in sarcolemma of murine heart, where it probably protects the cardiomyocyte by mediating efflux of endo- and xenobiotics. We used doxorubicin (DOX), a chemotherapeutic drug known to induce oxidative stress and thereby cardiac injury, as a model cardi...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.108.052209
更新日期:2009-05-01 00:00:00
abstract::When expressed via an inducible promoter in human embryonic kidney 293 cells, the rat Mas-related gene D (rMrgD) receptor responded to beta-alanine but not L-alanine by elevating intracellular [Ca(2+)], stimulating phosphorylation of the mitogenactivated protein kinases known as extracellular signal-regulated kinase (...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.105.018788
更新日期:2006-02-01 00:00:00
abstract::In the hippocampus, two distinct forms of GABAergic inhibition have been identified, phasic inhibitory postsynaptic currents that are the consequence of the vesicular release of GABA and a tonic conductance that is activated by low ambient concentrations of extracellular GABA. It is not known what accounts for the dis...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.63.1.2
更新日期:2003-01-01 00:00:00
abstract::The epithelial sodium channel (ENaC) is believed to represent the rate-limiting step for sodium absorption in the renal collecting duct. Consequently, ENaC is a central effector affecting systemic blood volume and pressure. Sodium and water transport are dysregulated in diabetes mellitus. Peroxisome proliferator-activ...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.109.056911
更新日期:2009-12-01 00:00:00
abstract::The co-transfection assay is a novel functional assay using cells transiently transfected with plasmids encoding intracellular receptors and corresponding reporter genes. Using this assay, natural product extracts were tested to identify compounds that modulate intracellular receptor activity, measured as changes in r...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1995-03-01 00:00:00
abstract::Cidofovir [(S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine; (S)-HPMPC] is an antiviral drug that has been approved for the treatment of cytomegalovirus retinitis in patients with AIDS. Cidofovir also possesses potent activity against human papillomavirus-induced tumors in animal models and patients. We have recent...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.106.026559
更新日期:2007-03-01 00:00:00
abstract::C57BL/6J (C57) and DBA/JBOMf (DBA) mice were used to study the role of adipose tissue as a modifier of tissue distribution, biological effects, and elimination of a lipophilic foreign chemical, 2,4,5,2',4',5'-hexachlorobiphenyl (HCB). As an indication of biological potency of the model compound, the activities of hepa...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1983-11-01 00:00:00
abstract::The X-ray and NMR structural study of 3-carbomethoxy rifamycin S5 was undertaken in order to determine whether its low antimicrobial activity was related to a conformation of the molecule which was unfavorable for interaction with bacterial DNA-dependent RNA polymerase. However, the molecule assumes a conformation sim...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1982-03-01 00:00:00
abstract::We demonstrate that gastrin-releasing peptide (GRP) can inhibit the proliferation of human immortal nontumorigenic (184-B5) mammary epithelial cells ectopically expressing the human GRP receptor. Growth of Balb 3T3 cells ectopically expressing relatively high levels of the GRP receptor was also inhibited by GRP; howev...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1996-03-01 00:00:00
abstract::Aldosterone synthase (AS) regulates blood volume by synthesizing the mineralocorticoid aldosterone. Overproduction of aldosterone in the adrenal gland can lead to hypertension, a major cause of heart disease and stroke. Aldosterone production depends upon stimulation of AS expression by the renin-angiotensin system, w...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.111.076471
更新日期:2012-03-01 00:00:00
abstract::As a member of the transient receptor potential (TRP) ion channel superfamily, the ligand-gated ion channel TRPA1 has been implicated in nociceptive function and pain states. The endogenous ligands that activate TRPA1 remain unknown. However, various agonists have been identified, including environmental irritants (e....
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.106.033621
更新日期:2007-05-01 00:00:00
abstract::We investigated the mechanisms of MDR1 gene activation by CCAAT/enhancer binding protein beta (C/EBPbeta, or nuclear factor for interleukin 6) in human cancer cells. Transfection of the breast cancer cell line MCF-7 and its doxorubicin-selected variant MCF-7/ADR by either C/EBPbeta or C/EBPbeta-LIP (a dominant-negativ...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.65.4.906
更新日期:2004-04-01 00:00:00
abstract::Previous studies showed that lapatinib and obatoclax interact in a greater-than-additive fashion to cause cell death and do so through a toxic form of autophagy. The present studies sought to extend our analyses. Lapatinib and obatoclax killed multiple tumor cell types, and cells lacking phosphatase and tensin homolog...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.112.081539
更新日期:2012-12-01 00:00:00
abstract::Cyclic nucleotide analogs were used to study relaxation of pig coronary arteries and guinea pig tracheal smooth muscle in an attempt to determine the roles of cAMP- and cGMP-dependent protein kinases (cA-K and cG-K). In pig coronary artery strips, cGMP analogs were generally more effective than cAMP analogs in promoti...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1988-10-01 00:00:00
abstract::The dissociation constants (Kd values) of substance P (SP), physalaemin, kassinin, and SP analogues acting on SP receptors in guinea pig ileal longitudinal muscle strips were determined by the pharmacological procedures of Furchgott [Adv. Drug Res. 3:21-55 (1966)]. This method involves analysis of the concentration-re...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1983-05-01 00:00:00
abstract::Multidrug resistance protein 1 (MRP1) is a member of the "C" branch of the ATP-binding cassette transporter superfamily. The NH(2)-proximal nucleotide-binding domain (NBD1) of MRP1 differs functionally from its COOH-proximal domain (NBD2). NBD1 displays intrinsic high-affinity ATP binding and little ATPase activity. I...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.104.007708
更新日期:2005-06-01 00:00:00
abstract::The cDNA for the rat alpha 1c-adrenergic receptor (AR) has been cloned using a probe derived from the bovine alpha 1c-AR sequence. Clone rB7a has a 2.6-kilobase insert with a 1390-base pair open reading frame and encodes a receptor of 466 amino acids. The cloned receptor has 91% amino acid identity with the bovine alp...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1994-09-01 00:00:00
abstract::Batrachotoxin (BTX), from South American frogs of the genus Phyllobates, irreversibly activates voltage-gated sodium channels. Previous work demonstrated that a phenylalanine residue approximately halfway through pore-lining transmembrane segment IVS6 is a critical determinant of channel sensitivity to BTX. In this st...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.61.4.905
更新日期:2002-04-01 00:00:00
abstract::The 5-hydroxytryptamine3 receptor 5-HT3R has been implicated in gut and cardiac motility and in behavioral disorders. Characteristics of 5-HT3Rs appear to be heterogeneous among species, but human 5-HT3R cDNA has not been identified. We isolated a cDNA encoding 5-HT3R from human hippocampus. The mouse 5-HT3R gene has ...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1995-09-01 00:00:00
abstract::The ADP-sensitive and K+ -sensitive phosphorylated forms of Na,K-ATPase (E1P and E2P, respectively) are believed to be the main phosphorylated intermediates of Na,K-ATPase. In the presence of 100 mM Na+, E2P is the major component of the phosphorylated form in all native Na,K-ATPase preparations known, including the m...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1982-11-01 00:00:00
abstract::Ro 11-2465 is a cyanide derivative of imipramine. In cerebral cortex homogenates, [3H] Ro 11-2465 displays a binding profile similar to that of [3H]imipramine. Agents compete with binding of [3H]Ro 11-2465 in an order of potency similar to their ability to block serotonin uptake, and raphe lesions greatly decrease the...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:
更新日期:1983-05-01 00:00:00
abstract::We have observed that rodent cell lines (mouse, hamster) contain approximately 10 times the levels of dihydrofolate reductase as human cell lines, yet the sensitivity to methotrexate (ED(50)), the folate antagonist that targets this enzyme, is similar. Our previous studies showed that dihydrofolate reductase protein l...
journal_title:Molecular pharmacology
pub_type: 杂志文章
doi:10.1124/mol.109.055772
更新日期:2009-10-01 00:00:00