Platelet adenylate cyclase and phospholipase C are affected differentially by ADP-ribosylation. Effects on thrombin-mediated responses.
نویسندگان
چکیده
Thrombin stimulates phospholipase C and inhibits adenylate cyclase in human platelets. We have studied the effect of purified S1 monomer, the ADP-ribosylating subunit of pertussis toxin, on these receptor-coupled G-protein-dependent activities. ADP-ribosylation of a 41 kDa protein is associated with a marked decrease in the ability of thrombin to inhibit cyclic AMP formation, but has little effect on phospholipase C. Therefore adenylate cyclase and phospholipase C appear to be modulated by different G-proteins.
منابع مشابه
Molecular identification and characterization of the platelet ADP receptor targeted by thienopyridine antithrombotic drugs.
ADP plays a critical role in modulating thrombosis and hemostasis. ADP initiates platelet aggregation by simultaneous activation of two G protein-coupled receptors, P2Y1 and P2Y12. Activation of P2Y1 activates phospholipase C and triggers shape change, while P2Y12 couples to Gi to reduce adenylyl cyclase activity. P2Y12 has been shown to be the target of the thienopyridine drugs, ticlopidine an...
متن کاملAmarogentin, a Secoiridoid Glycoside, Abrogates Platelet Activation through PLCγ2-PKC and MAPK Pathways
Amarogentin, an active principle of Gentiana lutea, possess antitumorigenic, antidiabetic, and antioxidative properties. Activation of platelets is associated with intravascular thrombosis and cardiovascular diseases. The present study examined the effects of amarogentin on platelet activation. Amarogentin treatment (15~60 μM) inhibited platelet aggregation induced by collagen, but not thrombi...
متن کاملADP-ribosylation factor-dependent phospholipase D activation by VPAC receptors and a PAC(1) receptor splice variant.
The VPAC(1) and VPAC(2) receptors for vasoactive intestinal polypeptide and the PAC(1) receptor for pituitary adenylate cyclase-activating polypeptide are members of a subfamily of G protein-coupled receptors (GPCRs). We recently reported that phospholipase D (PLD) activation by members of the rhodopsin group of GPCRs occurs by at least two routes, one of which seems to involve the small G prot...
متن کاملADP-induced platelet shape change and mobilization of cytoplasmic ionized calcium are mediated by distinct binding sites on platelets: 5'-p-fluorosulfonylbenzoyladenosine is a weak platelet agonist.
Platelet stimulation with ADP results in several responses, including shape change, increase in cytoplasmic ionized calcium concentration [Ca2+]i, an inhibition of adenylate cyclase. 5'-p-Fluorosulphonyl benzoyladenosine (FSBA), which covalently labels an ADP binding site on platelets, blocks platelet shape change but not the inhibition of cyclic AMP levels by ADP, whereas p-chloromercuribenzen...
متن کاملADP induces partial platelet aggregation without shape change and potentiates collagen-induced aggregation in the absence of Galphaq.
Platelets from Galphaq knockout mice are unable to aggregate in response to physiological agonists like adenosine 5'-diphosphate (ADP), thromboxane A(2), thrombin, or collagen, although shape change still occurs in response to all of these agonists except ADP. ADP-induced platelet aggregation results from simultaneous activation of the purinergic P2Y(1) receptor coupled to calcium mobilization ...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
عنوان ژورنال:
- The Biochemical journal
دوره 252 1 شماره
صفحات -
تاریخ انتشار 1988