What question did this study set out to answer?

To compare the biochemical properties of pertussis toxin-sensitive G proteins (Gi and Gp) in platelets and examine their receptor coupling to adenylyl cyclase and phospholipase C.

April 1, 1988Journal of Biological ChemistryOpen Access

Interactions in platelets between G proteins and the agonists that stimulate phospholipase C and inhibit adenylyl cyclase.

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Authors

LBLawrence F. BrassCross-Cutting Cardiology MWMarílyn J. WoolkalísThe Wistar Institute DMDavid R. ManningSydney Children’s Hospitals Network

Discussion

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Implication

In vitro study reveals a shared pertussis toxin-sensitive G protein mediates diverse receptor signaling in platelets, indicating dual regulation of adenylyl cyclase and phospholipase C.

Key Points

To compare the biochemical properties of pertussis toxin-sensitive G proteins (Gi and Gp) in platelets and examine their receptor coupling to adenylyl cyclase and phospholipase C.
Measured pertussis toxin-catalyzed [32P]ADP-ribosylation of the alpha 41 G protein subunit in permeabilized platelets and isolated platelet membranes pretreated with agonist compounds.
Characterized alpha 41 heterogeneity using two-dimensional gel electrophoresis, isoelectric focusing, and peptide mapping following chymotrypsin and Staphylococcus aureus V8 protease digestion.
Assayed adenylyl cyclase inhibition and phosphoinositide hydrolysis across intact platelets and isolated membranes challenged with thrombin, epinephrine, vasopressin, platelet-activating factor, or U46619.
Agonist exposure selectively inhibited [32P]ADP-ribosylation of alpha 41: thrombin reduced radiolabeling by >90%, epinephrine, vasopressin, and platelet-activating factor each reduced it by 50%, whereas U46619 had no effect.
Two-dimensional electrophoresis separated alpha 41 into two distinct subspecies that yielded identical proteolytic fragments and demonstrated equivalent agonist-dependent decreases in [32P]ADP-ribosylation.
Platelet-activating factor and vasopressin produced pertussis toxin-sensitive inhibition of adenylyl cyclase in isolated membrane preparations despite failing to inhibit cyclic AMP formation in intact platelets.

Cite This Study

Brass et al. (1988) studied this question.

synapsesocial.com/papers/6a702e638031ec7bb1dc2c3e https://doi.org/10.1016/s0021-9258(18)60722-7

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Implication

In vitro study reveals a shared pertussis toxin-sensitive G protein mediates diverse receptor signaling in platelets, indicating dual regulation of adenylyl cyclase and phospholipase C.

Interactions in platelets between G proteins and the agonists that stimulate phospholipase C and inhibit adenylyl cyclase.

Discussion

Member takes

Implication

Key Points

Cite This Study

Interactions in platelets between G proteins and the agonists that stimulate phospholipase C and inhibit adenylyl cyclase.

Discussion

Member takes

Implication

Key Points

Cite This Study

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