C-terminal modifications of pertussis toxin-sensitive G-protein α-subunits differentially affect immunoreactivity

Böhm, Michael; Gräbel, Claudia; Kirchmayr, Rita; Lensche, Herbert; Erdmann, Erland; Gierschik, Peter

doi:10.1016/0006-2952(93)90603-t

Cited by 6 publications

(2 citation statements)

References 24 publications

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“…This observation may reflect the redistribution of some G␣ i2 from the cytoplasmic space to the cell periphery. However, others have shown, using Western blotting, that compared with native G␣ i2 , ADP-ribosylated G␣ i2 has a higher affinity for the anti-G␣ i antibody employed in the present studies (44). Therefore, some of the substantial increase in G␣ i2 immunofluorescence at the cortex of pertussis toxin-treated hepatocytes may be due to an enhanced affinity of the anti-G␣ i antibody for ADP-ribosylated G␣ i2 (compared with native G␣ i2 ).…”

Section: Fig 8 the Localization Of F-actin And G␣ I2 In Hepatocytesmentioning

confidence: 53%

Regulation of F-actin and Endoplasmic Reticulum Organization by the Trimeric G-protein Gi2 in Rat Hepatocytes

Wang¹,

Gregory

Barritt

2000

Journal of Biological Chemistry

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The roles of the heterotrimeric G-protein, G i2 , in regulating the actin cytoskeleton and the activation of store-operated Ca 2؉ channels in rat hepatocytes were investigated. G␣ i2 was principally associated with the plasma membrane and microsomes. Both F-actin and G␣ i2 were detected by Western blot analysis in a purified plasma membrane preparation, the supernatant and pellet obtained by treating the plasma membrane with Triton X-100, and after depolymerization and repolymerization of F-actin in the Triton X-100-insoluble pellet. Actin in the Triton X-100-soluble supernatant coprecipitated with G␣ i2 using either anti-G␣ i2 or antiactin antibodies. The principally cortical location of F-actin in hepatocytes cultured for 0.5 h changed to a pericanalicular distribution over a further 3.5 h. Some G␣ i2 co-localized with F-actin at the plasma membrane. Pretreatment with pertussis toxin ADP-ribosylated 70 -80% of G␣ i2 in the plasma membrane and microsomes, prevented the redistribution of F-actin, caused redistribution and fragmentation of the endoplasmic reticulum, and inhibited vasopressin-stimulated Ca 2؉ inflow. It is concluded that (i) a significant portion of hepatocyte G␣ i2 associates with, and regulates the arrangement of, cortical F-actin and the endoplasmic reticulum and (ii) either or both of these regulatory roles are likely to be required for normal vasopressin activation of Ca 2؉ inflow.

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Section: Fig 8 the Localization Of F-actin And G␣ I2 In Hepatocytesmentioning

confidence: 53%

Regulation of F-actin and Endoplasmic Reticulum Organization by the Trimeric G-protein Gi2 in Rat Hepatocytes

Wang¹,

Gregory

Barritt

2000

Journal of Biological Chemistry

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“…Ligand binding to the high‐ and low‐affinity state of the receptor was studied under control conditions and after uncoupling of the receptor from the G protein with sulphydryl alkylating agent N‐ethylmaleimide (NEM). NEM alkylates the same cysteine residue in G i and G o α subunits which is ADP‐ribosylated by pertussis toxin ( Böhm et al ., 1993 ). Ligand binding mechanisms under control conditions and after receptor‐G protein‐uncoupling were compared to the binding mechanism in the presence of GDP, MgCl 2 and NaCl as described previously ( Lorenzen et al ., 1996 ).…”

Section: Introductionmentioning

confidence: 99%

Thermodynamically distinct high and low affinity states of the A₁ adenosine receptor induced by G protein coupling and guanine nucleotide ligation states of G proteins

Lorenzen

Guerra

Campi

et al. 2000

British J Pharmacology

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1 The in¯uence of the receptor-G protein coupling state and the guanine nucleotide ligation state of the G protein on the binding mechanism of A 1 adenosine receptor ligands has been investigated in [ 3 H]-1,3-dipropyl-8-cyclopentylxanthine ([ 3 H]-DPCPX) binding studies in rat brain membranes. Thermodynamic parameters of binding of A 1 adenosine receptor ligands of di erent intrinsic activities were determined in the absence or presence of GDP and compared to the binding mechanism after receptor-G protein uncoupling. 2 In agreement with previous studies, it was found that xanthine and non-xanthine antagonists showed an enthalpy-or enthalpy-and entropy-driven binding mechanism under all conditions. 3 In contrast to antagonists, the binding mechanism of agonists was strongly a ected by the G protein coupling state or the absence or presence of guanine nucleotides. Binding of full and partial agonists to the high-a nity state of the A 1 receptor was entropy-driven in the absence of GDP, and a good correlation between intrinsic activities and the contribution of entropy was observed. In the absence of GDP, binding of full and partial agonists and antagonists to the high a nity state of the receptor was thermodynamically discriminated. In contrast, no such discrimination was found in the presence of GDP. 4 The binding mechanism of agonists to the low-a nity state of the receptor was identical to that of antagonists only after uncoupling of the receptor from G proteins by pretreatment with Nethylmaleimide or guanosine-5'-(g-thio)-triphosphate (GTPgS). 5 These results indicate the existence of two thermodynamically distinct high-and low-a nity states of the A 1 adenosine receptor.

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Modulation of agonist responses at the A1 adenosine receptor by an irreversible antagonist, receptor–G protein uncoupling and by the G protein activation state

Lorenzen¹,

Beukers²,

Graaf³

et al. 2002

Biochemical Pharmacology

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C-terminal modifications of pertussis toxin-sensitive G-protein α-subunits differentially affect immunoreactivity

Cited by 6 publications

References 24 publications

Regulation of F-actin and Endoplasmic Reticulum Organization by the Trimeric G-protein Gi2 in Rat Hepatocytes

Regulation of F-actin and Endoplasmic Reticulum Organization by the Trimeric G-protein Gi2 in Rat Hepatocytes

Thermodynamically distinct high and low affinity states of the A₁ adenosine receptor induced by G protein coupling and guanine nucleotide ligation states of G proteins

Modulation of agonist responses at the A1 adenosine receptor by an irreversible antagonist, receptor–G protein uncoupling and by the G protein activation state

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C-terminal modifications of pertussis toxin-sensitive G-protein α-subunits differentially affect immunoreactivity

Cited by 6 publications

References 24 publications

Regulation of F-actin and Endoplasmic Reticulum Organization by the Trimeric G-protein Gi2 in Rat Hepatocytes

Regulation of F-actin and Endoplasmic Reticulum Organization by the Trimeric G-protein Gi2 in Rat Hepatocytes

Thermodynamically distinct high and low affinity states of the A1 adenosine receptor induced by G protein coupling and guanine nucleotide ligation states of G proteins

Modulation of agonist responses at the A1 adenosine receptor by an irreversible antagonist, receptor–G protein uncoupling and by the G protein activation state

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Product

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Thermodynamically distinct high and low affinity states of the A₁ adenosine receptor induced by G protein coupling and guanine nucleotide ligation states of G proteins