title: A chemically unmasked, chloride dependent K+ transport in low K+ sheep red cells: genetic and evolutionary aspects.
abstract: Recent evidence for a chemically unmasked, Cl- dependent K+ transport system present in LK sheep red cells has been reviewed. Exposure of LK cells to millimolar concentrations of N-ethylmaleimide (NEM) caused an up to 10 fold increase of a Cl- dependent K+ permeability with saturation kinetics and a low K+ affinity. Genetically associated with the expression of the LK gene, the chemically uncovered, Cl- activated K+ flux resembles evolutionary ancient cation transport systems found in nucleated red cells and non-erythrocytic mammalian cells. Perhaps the K+ transport system here described may play a significant role in volume reduction when sheep reticulocytes "mature" to adult red cells.
mesh_terms: D000818:Animals; D000954:Antigens, Surface / Q000032:analysis; D001692:Biological Transport / Q000187:drug effects; D002463:Cell Membrane Permeability / Q000187:drug effects; D002712:Chlorides / Q000097:blood; D004910:Erythrocyte Membrane / Q000276:immunology / Q000378:metabolism*; D004912:Erythrocytes / Q000378:metabolism*; D004920:Erythropoiesis; D005033:Ethylmaleimide / Q000494:pharmacology; D009566:Nitrates / Q000097:blood; D011188:Potassium / Q000097:blood*; D012756:Sheep; D012964:Sodium / Q000097:blood
chemical_list: D000954:Antigens, Surface; D002712:Chlorides; D009566:Nitrates; D012964:Sodium; D005033:Ethylmaleimide; D011188:Potassium