Mutation of tyrosine-350 impairs the coupling of the .beta.2-adrenergic receptor to the stimulatory guanine nucleotide binding protein without interfering with receptor down-regulation

Biochemistry ◽  
1993 ◽  
Vol 32 (19) ◽  
pp. 4979-4985 ◽  
Author(s):  
Manon Valiquette ◽  
Helene Bonin ◽  
Michel Bouvier
Keyword(s):  
Adrenergic Receptor ◽  
Binding Protein ◽  
Nucleotide Binding ◽  
Guanine Nucleotide ◽  
Down Regulation ◽  
Guanine Nucleotide Binding Protein ◽  
Beta 2 ◽  
Guanine Nucleotide Binding ◽  
Nucleotide Binding Protein

scholarly journals Cholera toxin treatment produces down-regulation of the α-subunit of the stimulatory guanine-nucleotide-binding protein (Gs)

1989 ◽  
Vol 262 (2) ◽  
pp. 643-649 ◽  
Author(s):  
G Milligan ◽  
C G Unson ◽  
M J Wakelam
Keyword(s):  
Plasma Membrane ◽  
Cholera Toxin ◽  
Binding Protein ◽  
Nucleotide Binding ◽  
Guanine Nucleotide ◽  
Down Regulation ◽  
Guanine Nucleotide Binding Protein ◽  
Adp Ribosylation ◽  
Guanine Nucleotide Binding ◽  
Nucleotide Binding Protein

The effect of activation of the alpha-subunit(s) of the stimulatory guanine-nucleotide-binding protein, Gs, on levels of this polypeptide(s) associated with the plasma membrane of L6 skeletal myoblasts was ascertained. Incubation of these cells with cholera toxin led to a time- and concentration-dependent ‘down-regulation’ of both 44 and 42 kDa forms of Gs alpha as assessed by immunoblotting with an anti-peptide antiserum (CS1) able to identify the extreme C-terminus of Gs. The effect of cholera toxin was specific for Gs; levels of Gi alpha in membranes of cholera toxin-treated cells were not different from untreated cells. Down-regulation of Gs was absolutely dependent upon prior ADP-ribosylation, and hence activation of Gs and was not mimicked by other agents which elevate intracellular levels of cyclic AMP. Pretreatment with pertussis toxin, which catalyses ADP-ribosylation of Gi but not of Gs, did not down-regulate either Gi or Gs, demonstrating that covalent modification by ADP-ribosylation is alone not a signal for removal of G-proteins from the plasma membrane.

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