Abstract
The saliva of Triatoma pallidipennis, a blood-sucking triatomine bug (Hemiptera, family Reduviidae, subfamily Triatominae) was found to contain a factor that specifically inhibits collagen-induced platelet aggregation. The 19-kDa protein was purified to homogeneity and named pallidipin. Collagen-mediated aggregation of platelets in plasma and of washed platelets was inhibited with the same efficacy. No inhibition of aggregation stimulated by other effectors (ADP, thrombin, thromboxane A2 mimetic U46619, phorbol ester) was detected. Pallidipin had no effect on platelet adhesion to collagen but inhibited ATP release from platelets. It interacted reversibly with platelets and may share with collagen a common target on them. The protein exhibits a unique primary structure (predicted from cDNA clones) with no significant similarity to other previously described sequences. The protein produced in recombinant baby hamster kidney cells had antiaggregatory effects similar to those of native pallidipin. Availability of recombinant pallidipin will allow further investigation of the precise mechanism of action.
MeSH terms
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15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid
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Adenosine Diphosphate / pharmacology
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Adenosine Triphosphate / blood
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Amino Acid Sequence
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Animals
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Base Sequence
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Blood Platelets / drug effects
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Blood Platelets / metabolism*
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Cell Line
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Collagen / pharmacology*
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Cricetinae
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Gene Expression
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Humans
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Kidney
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Kinetics
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Molecular Sequence Data
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Molecular Weight
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Phorbol Esters / pharmacology
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Platelet Adhesiveness / drug effects
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Platelet Aggregation / drug effects
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Platelet Aggregation Inhibitors / isolation & purification*
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Platelet Aggregation Inhibitors / pharmacology
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Prostaglandin Endoperoxides, Synthetic / pharmacology
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Recombinant Proteins / biosynthesis
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Recombinant Proteins / isolation & purification
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Recombinant Proteins / pharmacology
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Saliva
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Salivary Proteins and Peptides / biosynthesis
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Salivary Proteins and Peptides / isolation & purification*
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Salivary Proteins and Peptides / pharmacology
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Thrombin / pharmacology
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Thromboxane A2 / analogs & derivatives
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Thromboxane A2 / pharmacology
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Transfection
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Triatominae / metabolism*
Substances
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Phorbol Esters
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Platelet Aggregation Inhibitors
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Prostaglandin Endoperoxides, Synthetic
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Recombinant Proteins
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Salivary Proteins and Peptides
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pallidipin
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Thromboxane A2
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Adenosine Diphosphate
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15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid
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Adenosine Triphosphate
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Collagen
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Thrombin