Heat-shock protein 90 complexes in resting and thrombin-activated platelets.
Heat-shock protein 90 (hsp90) is a chaperone important for the function of many signaling proteins. In this study, we show that hsp90 exists in resting platelets as a complex with the heat-shock cognate protein 70 (hsc70), the alpha- and beta-subunits of protein kinase CK2, and other unidentified phosphoproteins. Platelet activation by thrombin caused the rapid dissociation of hsc70 and CK2alpha from the hsp90 complex, the ex vivo phosphorylation of many protein components, and the stimulation of protein kinase(s) associated with the hsp90 complex. These results suggest that the hsp90 complex, with its associated protein kinase(s), which may include CK2, and their substrates, is involved in thrombin-induced platelet activation.
Suttitanamongkol
Sudawadee
S
Department of Biochemistry and Molecular Genetics, University of Virginia, Jordan Hall, Box 440, Charlottesville, VA 22908, USA.
Polanowska-Grabowska
Renata
R
Gear
Adrian R L
AR
D001792:Blood Platelets / Q000378:metabolism*; D047390:Casein Kinase II; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation; D015539:Platelet Activation / Q000502:physiology*; D011494:Protein Kinases / Q000378:metabolism; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D013917:Thrombin / Q000378:metabolism*
D018840:HSP70 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; D010750:Phosphoproteins; D011494:Protein Kinases; D047390:Casein Kinase II; D017346:Protein Serine-Threonine Kinases; D013917:Thrombin