Photoaffinity labeling of lysosomal membrane proteins with [125I]diiodotyrosine, a system h ligand.
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.
Andersson
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HC
Section on Human Biochemical Genetics, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA.
Kohn
A D
AD
Gahl
W A
WA
Kohn
L D
LD
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
D000345:Affinity Labels; D002352:Carrier Proteins; D008024:Ligands; D008565:Membrane Proteins; D004105:Diiodotyrosine; D013972:Thyrotropin; D000594:Amino Acid Oxidoreductases; D050841:Glycine Dehydrogenase (Decarboxylating)