title: The recycling of a secretory granule membrane protein.
abstract: We have used N-hydroxysuccinimido-d-biotin as a reagent for labeling proteins exposed at the surface of cultured bovine adrenal chromaffin cells during Ba2+-stimulated secretion. A specific secretory granule membrane constituent, dopamine-beta-hydroxylase (DBH), has been investigated using immunoprecipitation followed by electrophoresis. Within 30 min of stimulation, exposed DBH had been cleared from the cell surface. Nevertheless, quantitation of labeled DBH using [125I] streptavidin suggested that it remained undegraded over a period of 24 h, a time during which secretory granule stores of catecholamines were being replenished. Subcellular fractionation of the cultured cells suggested that, after 3 or 4 h, the biotinylated DBH, which was still membrane-bound, was located in particulate material that also contained cytochrome b561, another major secretory granule membrane component.
authors.affiliation: Department of Biochemistry, University of Edinburgh Medical School, Scotland, United Kingdom.
authors.forename: A
authors.initials: A
authors.lastname: Hunter
authors.forename: J H
authors.initials: JH
authors.lastname: Phillips
mesh_terms: D000313:Adrenal Medulla / Q000187:drug effects / Q000201:enzymology; D000818:Animals; D001426:Bacterial Proteins / Q000378:metabolism; D001464:Barium / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology; D002395:Catecholamines / Q000378:metabolism; D002417:Cattle; D002458:Cell Fractionation / Q000379:methods; D002478:Cells, Cultured; D002499:Centrifugation, Density Gradient / Q000379:methods; D002837:Chromaffin Granules / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D002838:Chromaffin System / Q000201:enzymology*; D004299:Dopamine beta-Hydroxylase / Q000302:isolation & purification / Q000378:metabolism*; D007425:Intracellular Membranes / Q000201:enzymology*; D008565:Membrane Proteins / Q000302:isolation & purification / Q000378:metabolism*; D008970:Molecular Weight; D019809:Streptavidin
chemical_list: D001426:Bacterial Proteins; D002395:Catecholamines; D008565:Membrane Proteins; D001464:Barium; D019809:Streptavidin; D004299:Dopamine beta-Hydroxylase; D002118:Calcium