The 650-kDa 12(S)-hydroxyeicosatetraenoic acid binding complex: occurrence in human platelets, identification of hsp90 as a constituent, and binding properties of its 50-kDa subunit.
A cytosolic 650-kDa complex which binds 12(S)-hydroxy-5,8,10, 14-eicosatetraenoic acid (12(S)-HETE) with high affinity and specificity has been found in various cell lines but not until now in platelet cytosol. After incubation of human platelets with 12(S)-[3H]HETE, a labeled cytosolic 650-kDa complex was isolated. As previously shown for the binding complex in Lewis lung carcinoma (LLC) cells, ATP treatment transformed the platelet complex into a 50-kDa ligand-binding subunit. These results are of interest for two reasons: (a) 12(S)-HETE is a major arachidonic acid metabolite in platelets, and (b) platelets contain large amounts of the cell adhesion molecule GpIIb/IIIa, the activation of which is regulated by 12(S)-HETE. Hsp90 was found to be a component of the 12(S)-HETE binding complex in Lewis lung carcinoma cells, and the 50-kDa ligand-binding subunit itself bound 12(S)-HETE with high affinity. Competition experiments showed that 12(R)-HETE, 15-deoxy-Delta12, 14-prostaglandin J2, and 5(S)-HETE had lower affinity for the 50-kDa subunit than 12(S)-HETE. The 12(S)-HETE binding protein appears to be distinct from known members of the steroid hormone receptor superfamily of nuclear receptors.
Herbertsson
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Division of Cell Biology, Linköping University, Linköping, S-581 85, Sweden.
Kühme
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Hammarström
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D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism*; D015117:5,8,11,14-Eicosatetraynoic Acid / Q000494:pharmacology; D000255:Adenosine Triphosphate / Q000494:pharmacology; D001667:Binding, Competitive; D001792:Blood Platelets / Q000737:chemistry* / Q000166:cytology / Q000378:metabolism; D002478:Cells, Cultured; D002850:Chromatography, Gel; D003600:Cytosol / Q000737:chemistry / Q000187:drug effects; D018840:HSP70 Heat-Shock Proteins / Q000032:analysis / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000032:analysis* / Q000378:metabolism; D006801:Humans; D020128:Inhibitory Concentration 50; D007975:Leukotriene B4 / Q000378:metabolism; D008024:Ligands; D008970:Molecular Weight; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000378:metabolism; D011233:Precipitin Tests; D015230:Prostaglandin D2 / Q000031:analogs & derivatives / Q000378:metabolism; D011485:Protein Binding / Q000187:drug effects; D014407:Tumor Cells, Cultured
C097240:15-deoxy-delta(12,14)-prostaglandin J2; D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D008024:Ligands; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D015117:5,8,11,14-Eicosatetraynoic Acid; D007975:Leukotriene B4; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D000255:Adenosine Triphosphate; D015230:Prostaglandin D2