Creatine kinase is required for swelling-activated K-Cl cotransport in dog red blood cells.
K-Cl cotransport in resealed dog red cell ghosts requires the incorporation of creatine phosphate before resealing; incorporation of ATP has no effect [Colclasure and Parker. Am. J. Physiol. 265 (Cell Physiol. 34): C1648-C1652, 1993]. A role for creatine kinase (CK) in swelling-activated K-Cl cotransport was investigated. 2,4-Dinitrofluorobenzene (DNFB), an inhibitor of CK, inhibited K-Cl cotransport in intact red blood cells and resealed ghosts from DNFB-treated cells. Incorporation of exogenous CK into ghosts of DNFB-treated cells restored K-Cl cotransport. Therefore DNFB inhibits CK and not the cotransporter. Inhibition of native CK in ghosts by DNFB and the incorporation of CK into the ghosts were demonstrated in electrophoretic gels. In a dose-response experiment, approximately 770 molecules CK/ghost restored 50% of control cotransport. Since creatine phosphate is a substrate only for CK, CK provides ATP to a site inaccessible to cytoplasmic ATP. The nature of this site and its role in K-Cl cotransport are uncertain, but an essential function for CK is established.
Colclasure
G C
GC
Department of Medicine, University of North Carolina, Chapel Hill 27599.
Parker
J C
JC
Dunham
P B
PB
D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D002352:Carrier Proteins / Q000037:antagonists & inhibitors / Q000097:blood*; D003402:Creatine Kinase / Q000037:antagonists & inhibitors / Q000097:blood*; D004139:Dinitrofluorobenzene / Q000494:pharmacology; D004285:Dogs; D004910:Erythrocyte Membrane / Q000187:drug effects / Q000378:metabolism*; D005453:Fluorescence; D007527:Isoenzymes; D010725:Phosphocreatine / Q000494:pharmacology; D011817:Rabbits; D027981:Symporters; D000096922:K Cl- Cotransporters
D000255:Adenosine Triphosphate; D002352:Carrier Proteins; D003402:Creatine Kinase; D004139:Dinitrofluorobenzene; D007527:Isoenzymes; D010725:Phosphocreatine; D027981:Symporters; D000096922:K Cl- Cotransporters