Glycoprotein IIb-IIIa and the translocation of Rap2B to the platelet cytoskeleton.
Torti, M, Ramaschi, G, Sinigaglia, F, Lapetina, E G, Balduini, C
The stimulation of human platelets with physiological agonists results in the incorporation of several proteins into the cytoskeleton, fibrinogen binding, and platelet aggregation. We recently...
Torti, M, Ramaschi, G, Sinigaglia, F, Lapetina, E G, Balduini, C
The intracellular distribution of the low-molecular-weight GTP-binding protein rap2B was investigated in resting and agonist-activated human platelets. In both cases, platelets were lysed by Triton...
Glyceraldehyde-3-phosphate dehydrogenase is required for the transport of nitric oxide in platelets.
McDonald, B, Reep, B, Lapetina, E G, Molina Y Vedia, L
Nitric oxide (NO) or NO-generating compounds like sodium nitroprusside (SNP) increase cellular levels of cGMP and produce S-nitrosylation of glyceraldehyde-3-phosphate dehydrogenase [GAPDH;...
Epinephrine suppresses rap1B.GAP-activated GTPase activity in human platelets.
Lysate from quiescent platelets promotes rapid hydrolysis of [gamma-32P]GTP bound to rap1B. Various platelet agonists, including platelet-activating factor, phorbol 12,13-dibutyrate, alpha-thrombin,...
Thrombin activates phospholipase C in human platelets, but the specific isoenzymes activated and the signal pathway used are unknown. Using specific antibodies, we found that phospholipase C-gamma 1...
Sahyoun, N, McDonald, O B, Farrell, F, Lapetina, E G
A neuron-specific Ca2+/calmodulin-dependent protein kinase, CaM kinase Gr, phosphorylates selectively a Ras-related GTP-binding protein (Rap-1b) that is enriched in brain tissue. The phosphorylation...
Association of p21ras with phosphatidylinositol 3-kinase.
Sjölander, A, Yamamoto, K, Huber, B E, Lapetina, E G
In mammalian cells, ras genes code for 21-kDa GTP-binding proteins. Increased expression and mutations in specific amino acids have been closely linked to alterations of normal cell morphology,...
White, T E, Lacal, J C, Reep, B, Fischer, T H, Lapetina, E G, White, G C
Platelet inhibition by agents that increase intracellular levels of cAMP is associated with cAMP-dependent phosphorylation of specific intracellular proteins, including a membrane-associated 22-kDa...
Agonist-induced ADP-ribosylation of a cytosolic protein in human platelets.
Brüne, B, Molina Y Vedia, L, Lapetina, E G
alpha-Thrombin and phorbol 12,13-dibutyrate stimulated the mono(ADP-ribosyl)ation of a 42-kDa cytosolic protein of human platelets. This effect was mediated by protein kinase C activation and was...
RAP2B: a RAS-related GTP-binding protein from platelets.
Ohmstede, C A, Farrell, F X, Reep, B R, Clemetson, K J, Lapetina, E G
A platelet cDNA expression library was screened with the monoclonal antibody M90, which recognizes a specific epitope on RAS-encoded p21 proteins (amino acids 107-130). DNA sequence analysis of one...
Molina Y Vedia, L M, Reep, B R, Lapetina, E G
ADP-ribosylation induced by cholera toxin and pertussis toxin was studied in particulate and cytosolic fractions of human platelets. Platelets were disrupted by a cycle of freezing and thawing in the...
Iloprost-induced translocation of a 23-kDa protein that is recognized by a Gs alpha antiserum.
Molina Y Vedia, L, Lapetina, E G
We have observed that iloprost, a prostacyclin analog, causes the translocation of a 23-kDa protein from the membrane to the cytosol of human platelets. This 23-kDa protein is recognized by a Gs...
Crouch, M F, Winegar, D A, Lapetina, E G
By using antibodies specific for alpha subunits of inhibitory GTP-binding proteins (Gi alpha polypeptides) to probe Western blots of whole platelet protein, we detected Gi alpha-2 as the predominant...
Lapetina, E G, Lacal, J C, Reep, B R, Molina Y Vedia, L
The antigenicity of platelet proteins was assayed against various monoclonal antibodies (mAbs) that recognize specific epitopes of the ras-encoded p21 protein. mAb M90, which detects the region of...
We have assessed the binding of [alpha-32P]GTP to platelet proteins from cytosolic and membrane fractions. Proteins were separated by NaDodSO4/PAGE and electrophoretically transferred to...
May, W S, Lapetina, E G, Cuatrecasas, P
The effect of the synthetic diacylglycerol, sn-1,2-dioctanoylglycerol (diC8), on the expression of the surface transferrin receptor reveals that exogenous diC8 can act as an intracellular activator...
Protease and cyclooxygenase inhibitors synergistically prevent activation of human platelets.
Thrombin induces platelet aggregation and formation of a fibrin clot in platelet-rich plasma; leupeptin, a protease inhibitor, partially inhibits platelet aggregation, but it does not inhibit fibrin...
Cytochalasins inhibit arachidonic acid metabolism in thrombin-stimulated platelets.
Siess, W, Lapetina, E G, Cuatrecasas, P
Low concentrations (0.5-1 microM) of cytochalasins inhibit the thrombin-stimulated polymerization of monomeric actin to filamentous actin in platelets. Similar concentrations of cytochalasin B...
Rapid inactivation of cyclooxygenase activity after stimulation of intact platelets
Lapetina, E. G., Cuatrecasas, P.
Trypsin, thrombin, and ionophore A23187 activate phospholipid breakdown of platelets that have been labeled with [14C]arachidonate, releasing their cyclooxygenase and lipoxygenase products. Intact...
Lapetina, E G, Reep, B, Chang, K J
Permeabilization of human platelets with saponin (15-25 micrograms/ml) allows the determination of the ADP-ribosylation of a 41-kDa protein by pertussis toxin. The ADP-ribosylated protein is present...
Lapetina, E G, Watson, S P, Cuatrecasas, P
In an attempt to establish a system with physiological substrates and phospholipid surfaces to investigate Ca2+- and 1,2-diacylglycerol-dependent protein kinase C activation, saponized platelets were...
Stimulation of horse platelets with platelet-activating factor (PAF) induces a rapid degradation of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2]. Addition of 0.1 microM PAF for 5 sec to...
The present study has demonstrated that pretreatment of human platelets with either phorbol ester or 1,2-diacylglycerol inhibits agonist-induced formation of inositol phosphates; this inhibition can...
Brandt, S J, Dougherty, R W, Lapetina, E G, Niedel, J E
The binding of the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine to its cell surface receptor rapidly elicits the hydrolysis of phosphatidylinositol 4,5-bisphosphate by phospholipase C...
Action of corticosteroids in regulation of prostaglandin biosynthesis in cultured fibroblasts.
Chandrabose, K A, Lapetina, E G, Schmitges, C J, Siegel, M I, Cuatrecasas, P
Various vasoactive agents (e.g., thrombin and bradykinin) and serum stimulate arachidonate production and thus prostaglandin biosynthesis in cultured fibroblasts. Treatment of 3T3 cells with the...
Lapetina, E G, Chandrabose, K A, Cuatrecasas, P
Stimulation of platelets labeled with [14C]-arachidonate by ionophore A23187 or thrombin produces rapid degradation of specific membrane phospholipids. This is also reflected by the release of...
Farrell, F X, Yamamoto, K, Lapetina, E G
Rap proteins comprise a subset of the large family of ras-related proteins. They contain the C-terminal tetrapeptide sequence motif Cys-Ali-Ali-Xaa (Ali is an aliphatic amino acid and X is any amino...
Adrenaline or UK 14304 (a specific alpha 2-adrenoceptor agonist) and phorbol ester (phorbol 12,13-dibutyrate; PdBu) or bioactive diacylglycerols (sn-1,2-dioctanoylglycerol; DiC8) synergistically...
Microinjection of Rap2B protein or RNA induces rearrangement of pigment granules in Xenopus oocytes.
Campa, M J, Farrell, F X, Lapetina, E G, Chang, K J
Rap2B, a member of the ras superfamily of low-molecular-mass GTP-binding proteins, induced a characteristic rearrangement of the pigment granules in Xenopus oocytes following its microinjection,...
Low concentrations of Ca2+-mobilizing agonists such as vasopressin, platelet-activating factor, ADP, the endoperoxide analogue U44069 and the Ca2+ ionophore A23187 enhance the binding of [3H]phorbol...
Molina Y Vedia, L, Nolan, R D, Lapetina, E G
The phosphatase-induced hydrolysis of [3H]inositol 1,4-bisphosphate [Ins(1,4)P2)] and [3H]inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] was studied in platelet subcellular fractions. The activity that...
Giesberts, A N, Van Willigen, G, Lapetina, E G, Akkerman, J W
Binding sites on glycoprotein (GP) IIb/IIIa exposed by 0.5 unit/ml alpha-thrombin are insensitive to prostaglandin I2 (PGI2), in contrast with sites exposed by ADP or platelet-activating factor. Here...
Suspensions of aspirin-treated, 32P-prelabelled, washed platelets containing ADP scavengers in the buffer were activated with either phorbol 12,13-dibutyrate (PdBu) or the Ca2+ ionophore A23187. High...
The effect of iloprost on the ADP-ribosylation of Gs alpha (the alpha-subunit of Gs).
Molina Y Vedia, L, Nolan, R D, Lapetina, E G
Treatment of platelets with a prostacyclin analogue, iloprost, decreased the cholera-toxin-induced ADP-ribosylation of membrane-bound Gs alpha (alpha-subunit of G-protein that stimulates adenylate...
Collagen stimulates [3H]inositol trisphosphate formation in indomethacin-treated human platelets.
Watson, S P, Reep, B, McConnell, R T, Lapetina, E G
The present study investigates the pathway of metabolism of inositol phospholipids in human platelets exposed to collagen. Platelet activation by collagen was preceded by a lag phase usually lasting...
Exposure of human platelets to prostacyclin (PGI2), iloprost or prostaglandin E1 (PGE1) elicits the cyclic AMP-dependent phosphorylation of proteins of 22, 24, 30, 39, 50, 60 and 250 kDa (P22, P24...
Watson, S P, McConnell, R T, Lapetina, E G
Platelets rapidly convert 1,2-didecanoyl-sn-glycerol into its corresponding phosphatidic acid and lysophosphatidic acid derivatives, thereby providing a means of introducing these two compounds into...
The diglyceride kinase of rat cerebral cortex
Lapetina, E. G., Hawthorne, J. N.
1. Formation of phosphatidic acid by diglyceride kinase (EC 2.7.1.-) in the presence of ATP and Mg2+ was shown in a homogenate and subcellular fractions of rat cerebral cortex. 2. The kinase was...
Heat shock proteins and macrophage resistance to the toxic effects of nitric oxide.
Hirvonen, M R, Brüne, B, Lapetina, E G
Nitric oxide (NO) functions as a pathophysiological mediator in mammalian tissues. Activated macrophages produce NO as a non-specific immune response directed against invading bacteria or...
Regulation of hormone-induced Ca2+ mobilization in the human platelets.
alpha-Thrombin, gamma-thrombin, and platelet-activating factor each stimulated the mobilization of intracellular Ca2+ stores in aspirin-treated human platelets. This was followed by desensitization...
Glycoprotein IIb-IIIa and the translocation of Rap2B to the platelet cytoskeleton.
Torti, M, Ramaschi, G, Sinigaglia, F, Lapetina, E G, Balduini, C
The stimulation of human platelets with physiological agonists results in the incorporation of several proteins into the cytoskeleton, fibrinogen binding, and platelet aggregation. We recently...
Torti, M, Ramaschi, G, Sinigaglia, F, Lapetina, E G, Balduini, C
The intracellular distribution of the low-molecular-weight GTP-binding protein rap2B was investigated in resting and agonist-activated human platelets. In both cases, platelets were lysed by Triton...
Glyceraldehyde-3-phosphate dehydrogenase is required for the transport of nitric oxide in platelets.
McDonald, B, Reep, B, Lapetina, E G, Molina Y Vedia, L
Nitric oxide (NO) or NO-generating compounds like sodium nitroprusside (SNP) increase cellular levels of cGMP and produce S-nitrosylation of glyceraldehyde-3-phosphate dehydrogenase [GAPDH;...
Epinephrine suppresses rap1B.GAP-activated GTPase activity in human platelets.
Lysate from quiescent platelets promotes rapid hydrolysis of [gamma-32P]GTP bound to rap1B. Various platelet agonists, including platelet-activating factor, phorbol 12,13-dibutyrate, alpha-thrombin,...
Thrombin activates phospholipase C in human platelets, but the specific isoenzymes activated and the signal pathway used are unknown. Using specific antibodies, we found that phospholipase C-gamma 1...
Sahyoun, N, McDonald, O B, Farrell, F, Lapetina, E G
A neuron-specific Ca2+/calmodulin-dependent protein kinase, CaM kinase Gr, phosphorylates selectively a Ras-related GTP-binding protein (Rap-1b) that is enriched in brain tissue. The phosphorylation...
Association of p21ras with phosphatidylinositol 3-kinase.
Sjölander, A, Yamamoto, K, Huber, B E, Lapetina, E G
In mammalian cells, ras genes code for 21-kDa GTP-binding proteins. Increased expression and mutations in specific amino acids have been closely linked to alterations of normal cell morphology,...
White, T E, Lacal, J C, Reep, B, Fischer, T H, Lapetina, E G, White, G C
Platelet inhibition by agents that increase intracellular levels of cAMP is associated with cAMP-dependent phosphorylation of specific intracellular proteins, including a membrane-associated 22-kDa...
Agonist-induced ADP-ribosylation of a cytosolic protein in human platelets.
Brüne, B, Molina Y Vedia, L, Lapetina, E G
alpha-Thrombin and phorbol 12,13-dibutyrate stimulated the mono(ADP-ribosyl)ation of a 42-kDa cytosolic protein of human platelets. This effect was mediated by protein kinase C activation and was...
RAP2B: a RAS-related GTP-binding protein from platelets.
Ohmstede, C A, Farrell, F X, Reep, B R, Clemetson, K J, Lapetina, E G
A platelet cDNA expression library was screened with the monoclonal antibody M90, which recognizes a specific epitope on RAS-encoded p21 proteins (amino acids 107-130). DNA sequence analysis of one...
Molina Y Vedia, L M, Reep, B R, Lapetina, E G
ADP-ribosylation induced by cholera toxin and pertussis toxin was studied in particulate and cytosolic fractions of human platelets. Platelets were disrupted by a cycle of freezing and thawing in the...
Iloprost-induced translocation of a 23-kDa protein that is recognized by a Gs alpha antiserum.
Molina Y Vedia, L, Lapetina, E G
We have observed that iloprost, a prostacyclin analog, causes the translocation of a 23-kDa protein from the membrane to the cytosol of human platelets. This 23-kDa protein is recognized by a Gs...
Crouch, M F, Winegar, D A, Lapetina, E G
By using antibodies specific for alpha subunits of inhibitory GTP-binding proteins (Gi alpha polypeptides) to probe Western blots of whole platelet protein, we detected Gi alpha-2 as the predominant...
Lapetina, E G, Lacal, J C, Reep, B R, Molina Y Vedia, L
The antigenicity of platelet proteins was assayed against various monoclonal antibodies (mAbs) that recognize specific epitopes of the ras-encoded p21 protein. mAb M90, which detects the region of...
We have assessed the binding of [alpha-32P]GTP to platelet proteins from cytosolic and membrane fractions. Proteins were separated by NaDodSO4/PAGE and electrophoretically transferred to...
May, W S, Lapetina, E G, Cuatrecasas, P
The effect of the synthetic diacylglycerol, sn-1,2-dioctanoylglycerol (diC8), on the expression of the surface transferrin receptor reveals that exogenous diC8 can act as an intracellular activator...
Protease and cyclooxygenase inhibitors synergistically prevent activation of human platelets.
Thrombin induces platelet aggregation and formation of a fibrin clot in platelet-rich plasma; leupeptin, a protease inhibitor, partially inhibits platelet aggregation, but it does not inhibit fibrin...
Cytochalasins inhibit arachidonic acid metabolism in thrombin-stimulated platelets.
Siess, W, Lapetina, E G, Cuatrecasas, P
Low concentrations (0.5-1 microM) of cytochalasins inhibit the thrombin-stimulated polymerization of monomeric actin to filamentous actin in platelets. Similar concentrations of cytochalasin B...
Rapid inactivation of cyclooxygenase activity after stimulation of intact platelets
Lapetina, E. G., Cuatrecasas, P.
Trypsin, thrombin, and ionophore A23187 activate phospholipid breakdown of platelets that have been labeled with [14C]arachidonate, releasing their cyclooxygenase and lipoxygenase products. Intact...
Lapetina, E G, Reep, B, Chang, K J
Permeabilization of human platelets with saponin (15-25 micrograms/ml) allows the determination of the ADP-ribosylation of a 41-kDa protein by pertussis toxin. The ADP-ribosylated protein is present...
Lapetina, E G, Watson, S P, Cuatrecasas, P
In an attempt to establish a system with physiological substrates and phospholipid surfaces to investigate Ca2+- and 1,2-diacylglycerol-dependent protein kinase C activation, saponized platelets were...
Stimulation of horse platelets with platelet-activating factor (PAF) induces a rapid degradation of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2]. Addition of 0.1 microM PAF for 5 sec to...
The present study has demonstrated that pretreatment of human platelets with either phorbol ester or 1,2-diacylglycerol inhibits agonist-induced formation of inositol phosphates; this inhibition can...
Brandt, S J, Dougherty, R W, Lapetina, E G, Niedel, J E
The binding of the chemotactic peptide N-formyl-methionyl-leucyl-phenylalanine to its cell surface receptor rapidly elicits the hydrolysis of phosphatidylinositol 4,5-bisphosphate by phospholipase C...
Action of corticosteroids in regulation of prostaglandin biosynthesis in cultured fibroblasts.
Chandrabose, K A, Lapetina, E G, Schmitges, C J, Siegel, M I, Cuatrecasas, P
Various vasoactive agents (e.g., thrombin and bradykinin) and serum stimulate arachidonate production and thus prostaglandin biosynthesis in cultured fibroblasts. Treatment of 3T3 cells with the...
Lapetina, E G, Chandrabose, K A, Cuatrecasas, P
Stimulation of platelets labeled with [14C]-arachidonate by ionophore A23187 or thrombin produces rapid degradation of specific membrane phospholipids. This is also reflected by the release of...
Farrell, F X, Yamamoto, K, Lapetina, E G
Rap proteins comprise a subset of the large family of ras-related proteins. They contain the C-terminal tetrapeptide sequence motif Cys-Ali-Ali-Xaa (Ali is an aliphatic amino acid and X is any amino...
Adrenaline or UK 14304 (a specific alpha 2-adrenoceptor agonist) and phorbol ester (phorbol 12,13-dibutyrate; PdBu) or bioactive diacylglycerols (sn-1,2-dioctanoylglycerol; DiC8) synergistically...
Microinjection of Rap2B protein or RNA induces rearrangement of pigment granules in Xenopus oocytes.
Campa, M J, Farrell, F X, Lapetina, E G, Chang, K J
Rap2B, a member of the ras superfamily of low-molecular-mass GTP-binding proteins, induced a characteristic rearrangement of the pigment granules in Xenopus oocytes following its microinjection,...
Low concentrations of Ca2+-mobilizing agonists such as vasopressin, platelet-activating factor, ADP, the endoperoxide analogue U44069 and the Ca2+ ionophore A23187 enhance the binding of [3H]phorbol...
Molina Y Vedia, L, Nolan, R D, Lapetina, E G
The phosphatase-induced hydrolysis of [3H]inositol 1,4-bisphosphate [Ins(1,4)P2)] and [3H]inositol 1,4,5-trisphosphate [Ins(1,4,5)P3] was studied in platelet subcellular fractions. The activity that...
Giesberts, A N, Van Willigen, G, Lapetina, E G, Akkerman, J W
Binding sites on glycoprotein (GP) IIb/IIIa exposed by 0.5 unit/ml alpha-thrombin are insensitive to prostaglandin I2 (PGI2), in contrast with sites exposed by ADP or platelet-activating factor. Here...
Suspensions of aspirin-treated, 32P-prelabelled, washed platelets containing ADP scavengers in the buffer were activated with either phorbol 12,13-dibutyrate (PdBu) or the Ca2+ ionophore A23187. High...
The effect of iloprost on the ADP-ribosylation of Gs alpha (the alpha-subunit of Gs).
Molina Y Vedia, L, Nolan, R D, Lapetina, E G
Treatment of platelets with a prostacyclin analogue, iloprost, decreased the cholera-toxin-induced ADP-ribosylation of membrane-bound Gs alpha (alpha-subunit of G-protein that stimulates adenylate...
Collagen stimulates [3H]inositol trisphosphate formation in indomethacin-treated human platelets.
Watson, S P, Reep, B, McConnell, R T, Lapetina, E G
The present study investigates the pathway of metabolism of inositol phospholipids in human platelets exposed to collagen. Platelet activation by collagen was preceded by a lag phase usually lasting...
Exposure of human platelets to prostacyclin (PGI2), iloprost or prostaglandin E1 (PGE1) elicits the cyclic AMP-dependent phosphorylation of proteins of 22, 24, 30, 39, 50, 60 and 250 kDa (P22, P24...
Watson, S P, McConnell, R T, Lapetina, E G
Platelets rapidly convert 1,2-didecanoyl-sn-glycerol into its corresponding phosphatidic acid and lysophosphatidic acid derivatives, thereby providing a means of introducing these two compounds into...
The diglyceride kinase of rat cerebral cortex
Lapetina, E. G., Hawthorne, J. N.
1. Formation of phosphatidic acid by diglyceride kinase (EC 2.7.1.-) in the presence of ATP and Mg2+ was shown in a homogenate and subcellular fractions of rat cerebral cortex. 2. The kinase was...
Heat shock proteins and macrophage resistance to the toxic effects of nitric oxide.
Hirvonen, M R, Brüne, B, Lapetina, E G
Nitric oxide (NO) functions as a pathophysiological mediator in mammalian tissues. Activated macrophages produce NO as a non-specific immune response directed against invading bacteria or...
Regulation of hormone-induced Ca2+ mobilization in the human platelets.
alpha-Thrombin, gamma-thrombin, and platelet-activating factor each stimulated the mobilization of intracellular Ca2+ stores in aspirin-treated human platelets. This was followed by desensitization...