Coordinated regulation of shrinkage-induced Na/H exchange and swelling-induced [K-Cl] cotransport in dog red cells. Further evidence from activation kinetics and phosphatase inhibition.
Hypertonic shrinkage of dog red cells caused rapid activation of Na/H exchange and rapid deactivation of [K-Cl] cotransport. Hypotonic swelling caused delayed deactivation of Na/H exchange and delayed activation of [K-Cl] cotransport. Okadaic acid stimulated shrinkage-induced Na/H exchange and inhibited swelling-induced [K-Cl] cotransport. The data are compatible with the kinetic model of Jennings and Al-Rohil (1990. J. Gen. Physiol. 95:1021-1040) for volume regulation of [K-Cl] cotransport in rabbit red cells and suggest that in dog red cells Na/H exchange and [K-Cl] cotransport are controlled by a common regulatory system. The proposal of Jennings and Schulz (1991. J. Gen. Physiol. 96:799-817) that activation/deactivation of volume-sensitive transport involves phosphorylation/dephosphorylation of a regulatory protein is supported by these observations.
Parker
J C
JC
Department of Medicine, University of North Carolina, Chapel Hill 27599-7035.
Colclasure
G C
GC
McManus
T J
TJ
D000818:Animals; D002352:Carrier Proteins / Q000502:physiology*; D004285:Dogs; D004912:Erythrocytes / Q000187:drug effects / Q000502:physiology*; D004988:Ethers, Cyclic / Q000494:pharmacology; D007038:Hypotonic Solutions; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases / Q000037:antagonists & inhibitors; D010766:Phosphorylation; D017923:Sodium-Hydrogen Exchangers; D027981:Symporters; D014882:Water-Electrolyte Balance / Q000502:physiology; D000096922:K Cl- Cotransporters
D002352:Carrier Proteins; D004988:Ethers, Cyclic; D007038:Hypotonic Solutions; D019319:Okadaic Acid; D010749:Phosphoprotein Phosphatases; D017923:Sodium-Hydrogen Exchangers; D027981:Symporters; D000096922:K Cl- Cotransporters