title: Thyrotropin-induced plasma membrane protein modifications in porcine thyroid cells.
abstract: Highly purified plasma membranes were obtained from isolated porcine thyroid cells maintained in conditions of culture in the presence of thyrotropin (stimulated cells) or in their absence (non-stimulated cells). Analyses of both types of membranes by high-resolution sodium dodecylsulfate-polyacrylamide slab gel electrophoresis showed reproducible quantitative differences in protein bands of apparent molecular weight 38,000, 36,000 and inconstantly 96,000. Phosphorylation of membranes by [gamma-32P]ATP was 2-3 times higher in membranes from thyrotropin-stimulated than in membranes from non-stimulated cells. About 20 32P-labeled bands were detected by slab gel electrophoresis in denaturing conditions, among which the catalytic subunit of Na+, K+ ATPase was characterized. In addition, plasma membranes from thyrotropin-stimulated cells contained a firmly bound [14C]glucosamine-containing glycoprotein probably related to an aggregation-promoting factor. 125I-labeled thyroglobulin and components of unknown nature were associated with plasma membranes from thyrotropin-stimulated cells. Whether they participate in the structure and function(s) of the plasma membrane or represent contaminants of the preparation is not clear at the present time.
mesh_terms: D000818:Animals; D002462:Cell Membrane / Q000187:drug effects / Q000378:metabolism; D004589:Electrophoresis, Disc; D005944:Glucosamine / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D011494:Protein Kinases / Q000378:metabolism; D013552:Swine; D013961:Thyroid Gland / Q000187:drug effects / Q000378:metabolism*; D013972:Thyrotropin / Q000494:pharmacology*
chemical_list: D008565:Membrane Proteins; D013972:Thyrotropin; D011494:Protein Kinases; D007930:Leucine; D005944:Glucosamine