Role of chloride/bicarbonate antiport in the control of cytosolic pH. Cell-line differences in activity and regulation of antiport.
Sodium-linked and sodium-independent HCO3-/Cl- antiport was measured under different conditions in a number of cell lines. Transport of HCO3- was estimated from its effect on intracellular pH (pHi) measured with the fluorescent probe 2',7'-bis(carboxyethyl)-5,6-carboxyfluorescein. The associated ion fluxes were estimated from the transport of 36Cl- and 22Na+. Na+-dependent and Na+-independent HCO3-/Cl- antiport were found in many, but not in all cell lines tested. The Na+-independent HCO3-/Cl- antiport was found to be highly pHi-dependent in a number of cell lines, whereas in others this was not the case. Some cell lines were found to have both Na+-dependent and Na+-independent HCO3-/Cl- antiport, whereas in others we could detect only one of these mechanisms. Na+/H+ antiport, which is quantitatively the most important H+-extruding mechanism, was found in all cell lines tested, but the activity varied strongly. Possible reasons for the qualitative and quantitative differences in antiport activity are discussed.
Reinertsen
K V
KV
Institute for Cancer Research, Norwegian Radium Hospital, Oslo.
Tønnessen
T I
TI
Jacobsen
J
J
Sandvig
K
K
Olsnes
S
S
D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D000584:Amiloride / Q000494:pharmacology; D000818:Animals; D001639:Bicarbonates / Q000378:metabolism; D002352:Carrier Proteins / Q000502:physiology*; D002460:Cell Line; D027963:Chloride-Bicarbonate Antiporters; D003600:Cytosol / Q000032:analysis*; D006863:Hydrogen-Ion Concentration; D012964:Sodium / Q000378:metabolism
D001639:Bicarbonates; D002352:Carrier Proteins; D027963:Chloride-Bicarbonate Antiporters; D012856:4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfonic Acid; D000584:Amiloride; D012964:Sodium; D017878:4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid