GTP-related effects and binding by differentiating fetal rabbit type II alveolar cells in vitro.
Type II alveolar cells were isolated from fetal rabbit lungs and used to determine the effect of GTP-binding protein activation on release of surfactant-related material. Cells were prelabelled with [3H]choline for 24 hours. NaF, a G-protein activator and GTP gamma S, a nonhydrolysable analogue of GTP, both loaded by hypoosmotic shock treatment, stimulated release of radioactive disaturated phosphatidylcholine. Localization of the cellular binding of [alpha-32P]GTP in fetal type II cells which were induced to differentiate by exposure to fetal lung fibroblast conditioned medium showed that two proteins of apparent molecular weights of 39.6 kd and 17.9 kd bound [alpha-32P]GTP. These proteins were detected only in the cells exposed to the conditioned medium. These results suggest GTP-binding proteins are involved in DSPC secretion and differentiation of fetal type II cells is accompanied by changes in GTP binding characteristics.
Borys
H L
HL
Department of Oral Biology, Faculty of Dentistry, University of Manitoba, Winnipeg, Canada.
Scott
J E
JE
D000818:Animals; D002454:Cell Differentiation / Q000502:physiology; D002463:Cell Membrane Permeability / Q000187:drug effects; D002478:Cells, Cultured; D002794:Choline / Q000378:metabolism; D004996:Ethidium; D005260:Female; D005333:Fetus; D005452:Fluoresceins; D005453:Fluorescence; D019204:GTP-Binding Proteins / Q000187:drug effects / Q000378:metabolism; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000493:pharmacokinetics; D006160:Guanosine Triphosphate / Q000378:metabolism* / Q000494:pharmacology*; D008168:Lung / Q000166:cytology / Q000196:embryology / Q000378:metabolism; D009994:Osmolar Concentration; D010713:Phosphatidylcholines / Q000378:metabolism; D011247:Pregnancy; D011485:Protein Binding / Q000187:drug effects; D011650:Pulmonary Alveoli / Q000166:cytology / Q000378:metabolism*; D011817:Rabbits; D012969:Sodium Fluoride / Q000494:pharmacology; D013462:Sulfur Radioisotopes; D014316:Tritium
D005452:Fluoresceins; D010713:Phosphatidylcholines; D013462:Sulfur Radioisotopes; D014316:Tritium; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D006160:Guanosine Triphosphate; D012969:Sodium Fluoride; D019204:GTP-Binding Proteins; D004996:Ethidium; D002794:Choline; C018506:diacetylfluorescein