Interaction of Bivalent Ligand KDN21 with Heterodimeric δ-κ Opioid Receptors in Human Embryonic Kidney 293 Cells

2005 ◽  
Vol 68 (4) ◽  
pp. 1079-1086 ◽  
Author(s):  
Zhihua Xie ◽  
Rashmi G. Bhushan ◽  
David J. Daniels ◽  
Philip S. Portoghese
Keyword(s):  
Opioid Receptors ◽  
Human Embryonic Kidney ◽  
Bivalent Ligand ◽  
293 Cells

Hetero-oligomers of α2A-adrenergic and μ-opioid receptors do not lead to transactivation of G-proteins or altered endocytosis profiles

2004 ◽  
Vol 32 (5) ◽  
pp. 856-860 ◽  
Author(s):  
Y.Q. Zhang ◽  
L.E. Limbird
Keyword(s):  
Opioid Receptors ◽  
Pertussis Toxin ◽  
Adrenergic Receptors ◽  
Functional Communication ◽  
Human Embryonic Kidney ◽  
Hek 293 ◽  
293 Cells ◽  
Μ Opioid Receptors ◽  
Transmembrane Span ◽  
In Cells

Complexes of α2A-ARs (α2A-adrenergic receptors) and MORs (μ-opioid receptors), probably hetero-oligomers, were detected by co-immunoisolation after extraction from HEK-293 cells (human embryonic kidney 293 cells). Functional communication between these receptors is revealed by α2A-AR activation of a pertussis toxin-insensitive Giα subunit (termed as Gi1) when fused with the MOR and evaluated in membranes from pertussis toxin-treated cells. However, the α2A-AR does not require transactivation through MOR, since quantitatively indistinguishable results were observed in cells co-expressing α2A-AR and a fusion protein of Gi1 with the first transmembrane span of MOR (myc–MOR-TM1). Functional cross-talk among these α2A-AR–MOR complexes does not occur for internalization profiles; incubation with adrenaline (epinephrine) leads to endocytosis of α2A-AR but not MOR, while incubation with DAMGO ([D-Ala,NMe-Phe,Gly-ol]enkephalin) leads to endocytosis of MOR but not α2A-AR in cells co-expressing both the receptors. Hence, α2A-AR and MOR hetero-oligomers, although they occur, do not have an obligatory functional influence on one another in the paradigms studied.

scholarly journals Exploring the first Rimonabant analog-opioid peptide hybrid compound, as bivalent ligand for CB1 and opioid receptors

2017 ◽  
Vol 32 (1) ◽  
pp. 444-451 ◽  
Author(s):  
Adriano Mollica ◽  
Sveva Pelliccia ◽  
Valeria Famiglini ◽  
Azzurra Stefanucci ◽  
Giorgia Macedonio ◽  
...  
Keyword(s):  
Opioid Receptors ◽  
Opioid Peptide ◽  
Hybrid Compound ◽  
Bivalent Ligand

scholarly journals Reduced Expression of EXTL2, a Member of the Exostosin (EXT) Family of Glycosyltransferases, in Human Embryonic Kidney 293 Cells Results in Longer Heparan Sulfate Chains

2015 ◽  
Vol 290 (21) ◽  
pp. 13168-13177 ◽  
Author(s):  
Kirankumar Katta ◽  
Tabasum Imran ◽  
Marta Busse-Wicher ◽  
Mona Grønning ◽  
Szymon Czajkowski ◽  
...  
Keyword(s):  
Heparan Sulfate ◽  
Human Embryonic Kidney ◽  
293 Cells

Regulation of Human Neuronal Calcium Channels by G Protein βγ Subunits Expressed in Human Embryonic Kidney 293 Cells

1997 ◽  
Vol 52 (2) ◽  
pp. 282-291 ◽  
Author(s):  
Lee R. Shekter ◽  
Ronald Taussig ◽  
Samantha E. Gillard ◽  
Richard J. Miller
Keyword(s):  
Calcium Channels ◽  
G Protein ◽  
Human Embryonic Kidney ◽  
293 Cells ◽  
Neuronal Calcium Channels

scholarly journals Bupivacaine inhibits a small conductance calcium‐activated potassium type 2 channel in human embryonic kidney 293 cells

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Hongfei Chen ◽  
Zhousheng Jin ◽  
Fangfang Xia ◽  
Zhijian Fu
Keyword(s):  
Free Calcium ◽  
Heart Cells ◽  
Dependent Manner ◽  
Human Embryonic Kidney ◽  
Patch Clamp Technique ◽  
Hek 293 ◽  
293 Cells ◽  
Ic50 Value ◽  
Small Conductance

Abstract Background Bupivacaine blocks many ion channels in the heart muscle, causing severe cardiotoxicity. Small-conductance calcium-activated potassium type 2 channels (SK2 channels) are widely distributed in the heart cells and are involved in relevant physiological functions. However, whether bupivacaine can inhibit SK2 channels is still unclear. This study investigated the effect of bupivacaine on SK2 channels. Methods The SK2 channel gene was transfected into human embryonic kidney 293 cells (HEK-293 cells) with Lipofectamine 2000. The whole-cell patch-clamp technique was used to examine the effect of bupivacaine on SK2 channels. The concentration–response relationship of bupivacaine for inhibiting SK2 currents (0 mV) was fitted to a Hill equation, and the half-maximal inhibitory concentration (IC50) value was determined. Results Bupivacaine inhibited the SK2 channels reversibly in a dose-dependent manner. The IC50 value of bupivacaine, ropivacaine, and lidocaine on SK2 currents was 16.5, 46.5, and 77.8µM, respectively. The degree of SK2 current inhibition by bupivacaine depended on the intracellular concentration of free calcium. Conclusions The results of this study suggested the inhibitory effect of bupivacaine on SK2 channels. Future studies should explore the effects of SK2 on bupivacaine cardiotoxicity.

scholarly journals Proteasome Involvement in Agonist-induced Down-regulation of μ and δ Opioid Receptors

2001 ◽  
Vol 276 (15) ◽  
pp. 12345-12355 ◽  
Author(s):  
Kirti Chaturvedi ◽  
Persis Bandari ◽  
Norihiro Chinen ◽  
Richard D. Howells
Keyword(s):  
Opioid Receptor ◽  
Opioid Receptors ◽  
Proteasome Inhibitors ◽  
Metabolic Labeling ◽  
Down Regulation ◽  
Hek 293 ◽  
293 Cells ◽  
Ubiquitin Proteasome ◽  
Μ Opioid Receptor ◽  
Δ Opioid Receptor

This study investigated the mechanism of agonist-induced opioid receptor down-regulation. Incubation of HEK 293 cells expressing FLAG-tagged δ and μ receptors with agonists caused a time-dependent decrease in opioid receptor levels assayed by immunoblotting. Pulse-chase experiments using [35S]methionine metabolic labeling indicated that the turnover rate of δ receptors was accelerated 5-fold following agonist stimulation. Inactivation of functional Giand Goproteins by pertussis toxin-attenuated down-regulation of the μ opioid receptor, while down-regulation of the δ opioid receptor was unaffected. Pretreatment of cells with inhibitors of lysosomal proteases, calpain, and caspases had little effect on μ and δ opioid receptor down-regulation. In marked contrast, pretreatment with proteasome inhibitors attenuated agonist-induced μ and δ receptor down-regulation. In addition, incubation of cells with proteasome inhibitors in the absence of agonists increased steady-state μ and δ opioid receptor levels. Immunoprecipitation of μ and δ opioid receptors followed by immunoblotting with ubiquitin antibodies suggested that preincubation with proteasome inhibitors promoted accumulation of polyubiquitinated receptors. These data provide evidence that the ubiquitin/proteasome pathway plays a role in agonist-induced down-regulation and basal turnover of opioid receptors.

Endothelin-B receptors activate Gα13

1999 ◽  
Vol 276 (4) ◽  
pp. C930-C937 ◽  
Author(s):  
Kenichiro Kitamura ◽  
Naoki Shiraishi ◽  
William D. Singer ◽  
Mary E. Handlogten ◽  
Kimio Tomita ◽  
...  
Keyword(s):  
G Protein ◽  
G Proteins ◽  
Guanine Nucleotides ◽  
Heterotrimeric G Proteins ◽  
Human Embryonic Kidney ◽  
Cellular Effects ◽  
293 Cells ◽  
Specific Antagonist ◽  
Α Chain ◽  
Endothelin B

Endothelin (ET) receptors activate heterotrimeric G proteins that are members of the Gi, Gq, and Gs families but may also activate members of other families such as Gα12/13. Gα13 has multiple complex cellular effects that are similar to those of ET. We studied the ability of ET receptors to activate Gα13 using an assay for G protein α-chain activation that is based on the fact that an activated (GTP-bound) α-chain is resistant to trypsinization compared with an inactive (GDP-bound) α-chain. Nonhydrolyzable guanine nucleotides and AlMgF protected Gα13 from degradation by trypsin. In membranes from human embryonic kidney 293 cells that coexpress ETB receptors and α13, ET-3 and 5′-guanylylimidodiphosphate [Gpp(NH)p] increased the protection of α13 compared with Gpp(NH)p alone. The specificity of ETBreceptor-α13 coupling was documented by showing that β2receptors and isoproterenol or ETAreceptors and ET-1 did not activate α13 and that a specific antagonist for ETB receptors blocked ET-3-dependent activation of α13.

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