title: Factors affecting transport changes associated with reticulocyte maturation.
abstract: Maturation and aging of the mammalian red blood cell is characterized by the loss in many cytoplasmic and membrane functions including ion and solute transport. We have used long-term in vitro incubation of sheep reticulocytes to examine the nature of several membrane transport changes. Three distinct transport systems have been studied, namely the Na,K-pump measured as specific [3H]ouabain binding sites, Na+/glycine cotransport and the nucleoside transporter measured as specific [3H]nitrobenzylthioinosine binding. As reported previously for the Na,K-pump and Na+/glycine cotransport (Weigensberg, A.M. and Blostein, R., Proc. Nat. Acad. Sci. 80:4978-4982, 1983), the losses of all three functions are diminished markedly by energy (ATP) depletion. Furthermore, for at least one of the transport systems, the Na,K-pump, the maturation-associated loss is modulated by ligand-induced perturbations which are known to effect specific protein conformational changes.
mesh_terms: D000255:Adenosine Triphosphate / Q000097:blood; D000818:Animals; D001693:Biological Transport, Active; D002352:Carrier Proteins / Q000097:blood; D002454:Cell Differentiation; D002462:Cell Membrane / Q000378:metabolism; D066298:In Vitro Techniques; D007473:Ion Channels / Q000378:metabolism; D008565:Membrane Proteins / Q000097:blood; D033703:Nucleoside Transport Proteins; D010042:Ouabain / Q000097:blood; D011188:Potassium / Q000097:blood; D012156:Reticulocytes / Q000166:cytology / Q000378:metabolism*; D012756:Sheep; D012964:Sodium / Q000097:blood
chemical_list: D002352:Carrier Proteins; D007473:Ion Channels; D008565:Membrane Proteins; D033703:Nucleoside Transport Proteins; D010042:Ouabain; D000255:Adenosine Triphosphate; D012964:Sodium; D011188:Potassium