title: Photoaffinity labeling of lysosomal membrane proteins with [125I]diiodotyrosine, a system h ligand.
abstract: Percoll-purified rat thyroid FRTL-5 cell lysosomes were photoaffinity-labeled with [125I]diiodotyrosine to identify proteins which bind diiodotyrosine, a ligand for lysosomal transport system h. SDS-PAGE and autoradiography of these membranes showed specific labeling of a 70-kDa protein and weak labeling of three smaller proteins. [125I]Diiodotyrosine photolabeling of the 70-kDa protein was specifically competed against by ligands of lysosomal transport system h ligands. The 70-kDa protein was photolabeled more strongly in lysosomal membranes isolated from thyrotropin-stimulated cells when compared with those grown in the absence of thyrotropin, consistent with previous demonstrations that thyrotropin stimulates system h transport. The 70-kDa protein may represent some portion of the system h carrier protein.
authors.affiliation: Section on Human Biochemical Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: H C
authors.initials: HC
authors.lastname: Andersson
authors.forename: A D
authors.initials: AD
authors.lastname: Kohn
authors.forename: W A
authors.initials: WA
authors.lastname: Gahl
authors.forename: L D
authors.initials: LD
authors.lastname: Kohn
mesh_terms: D000345:Affinity Labels / Q000378:metabolism*; D000594:Amino Acid Oxidoreductases; D000818:Animals; D001693:Biological Transport, Active / Q000187:drug effects; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism; D002460:Cell Line; D004105:Diiodotyrosine / Q000378:metabolism*; D050841:Glycine Dehydrogenase (Decarboxylating); D008024:Ligands; D008247:Lysosomes / Q000187:drug effects / Q000378:metabolism*; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism*; D008970:Molecular Weight; D011485:Protein Binding; D051381:Rats; D013972:Thyrotropin / Q000494:pharmacology
chemical_list: D000345:Affinity Labels; D002352:Carrier Proteins; D008024:Ligands; D008565:Membrane Proteins; D004105:Diiodotyrosine; D013972:Thyrotropin; D000594:Amino Acid Oxidoreductases; D050841:Glycine Dehydrogenase (Decarboxylating)