[Effect of protein kinase C activation on platelet Na+/H+ exchanger].
Protein kinase C activation in human platelets has a modulatory role in maintaining intracellular pH (pHi), by adjusting pHi at a particular value (pH 7.22). Changes in pHi induced by protein kinase C appeared to depend upon differences between H+ efflux catalyzed by Na+/H+ exchanger and H+ production. The pHi recovery after acid loading was significantly facilitated by protein kinase C activation. Analysis of the rate constant for pHi recovery suggested that the turnover rate or the apparent affinity of the Na+/H+ exchanger for H+ was increased. Protein kinase C also decreased the Km value of the Na+/H+ exchanger for extracellular Na+. It is suggested that the role of protein kinase C in platelet pHi regulation is dual, adjusting the pHi value at a certain set-point, on the one hand, and increasing the rate constant of the Na+/H+, on the other.
Ozaki
Y
Y
Department of Clinical and Laboratory Medicine, Yamanashi Medical College.
D001792:Blood Platelets / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011493:Protein Kinase C / Q000097:blood / Q000502:physiology*; D012964:Sodium / Q000097:blood
D002352:Carrier Proteins; D012964:Sodium; D011493:Protein Kinase C