Histidine phosphorylation of P-selectin upon stimulation of human platelets: a novel pathway for activation-dependent signal transduction.
Transient phosphorylation of histidine characterizes the two-component systems in prokaryotes that control important physiological functions, but analogous events have not been implicated in signal transduction in mammalian cells. To explore histidine phosphorylation during activation of human cells, stimulated platelets were analyzed for the formation of protein phosphohistidine in a model system employing P-selectin. P-selectin, a leukocyte adhesion molecule, undergoes rapid phosphorylation and selective dephosphorylation of tyrosine, serine, and threonine. We now establish that phosphorylation following platelet activation with thrombin or collagen generates phosphohistidine at histidines on the cytoplasmic tail of P-selectin. With thrombin stimulation, the kinetics of phosphohistidine appearance and disappearance of P-selectin are very rapid. Platelets exhibit a novel ligand-induced signaling pathway to generate phosphohistidine. These results provide direct biochemical evidence for the induction of rapid and reversible histidine phosphorylation in mammalian cells upon cell activation and represent a novel paradigm for mammalian cell signaling.
Crovello
C S
CS
Center for Hemostasis and Thrombosis Research, New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02111, USA.
Furie
B C
BC
Furie
B
B
D000595:Amino Acid Sequence; D001792:Blood Platelets / Q000378:metabolism / Q000502:physiology*; D015815:Cell Adhesion Molecules / Q000097:blood; D006639:Histidine / Q000031:analogs & derivatives / Q000032:analysis / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D019007:P-Selectin; D010446:Peptide Fragments / Q000737:chemistry; D010748:Phosphopeptides / Q000737:chemistry / Q000302:isolation & purification; D010766:Phosphorylation; D015539:Platelet Activation; D010980:Platelet Membrane Glycoproteins / Q000097:blood* / Q000737:chemistry / Q000302:isolation & purification; D015398:Signal Transduction; D014357:Trypsin
D015815:Cell Adhesion Molecules; D019007:P-Selectin; D010446:Peptide Fragments; D010748:Phosphopeptides; D010980:Platelet Membrane Glycoproteins; D006639:Histidine; D014357:Trypsin; C005436:phosphohistidine