Association of a phospholipase A2 (14-3-3 protein) with the platelet glycoprotein Ib-IX complex.
Platelet adhesion to subendothelial von Willebrand factor involves receptor recognition by the platelet glycoprotein (GP) Ib-IX and initiates activation signals that contribute to primary hemostasis. We show here that GPIb-IX is specifically associated with an intracellular 29-kDa protein. The physicochemical characteristics and amino acid sequence of this protein indicate that it is identical to the human zeta-isoform 14-3-3 protein, previously characterized as a platelet phospholipase A2 (PLA2). As activation of PLA2 is an early event in GPIb-IX-mediated signaling, this result suggests that ligand occupancy of GPIb-IX may directly activate PLA2, leading to platelet activation.
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X
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Department of Vascular Biology, Scripps Research Institute, La Jolla, California 92037.
Harris
S J
SJ
Tetaz
T J
TJ
Ginsberg
M H
MH
Berndt
M C
MC
D048948:14-3-3 Proteins; D000595:Amino Acid Sequence; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D015151:Immunoblotting; D008969:Molecular Sequence Data; D008970:Molecular Weight; D009419:Nerve Tissue Proteins / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification; D010741:Phospholipases A / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification; D054467:Phospholipases A2; D010980:Platelet Membrane Glycoproteins / Q000302:isolation & purification / Q000378:metabolism*; D011485:Protein Binding; D017386:Sequence Homology, Amino Acid; D014446:Tyrosine 3-Monooxygenase
D048948:14-3-3 Proteins; D009419:Nerve Tissue Proteins; D010980:Platelet Membrane Glycoproteins; D014446:Tyrosine 3-Monooxygenase; D010741:Phospholipases A; D054467:Phospholipases A2