title: Important role for the V-type H(+)-ATPase and the Golgi apparatus in the recycling of PTH/PTHrP receptor.
abstract: Our previous studies demonstrated that a green fluorescent protein-tagged parathyroid hormone (PTH)/PTH-related peptide (PTHrP) receptor stably expressed in LLCPK-1 cells undergoes agonist-dependent internalization into clathrin-coated pits. The subcellular localization of the internalized PTH/PTHrP receptor is not known. In the present study, we explored the intracellular pathways of the internalized PTH/PTHrP receptor. Using immunofluorescence and confocal microscopy, we show that the internalized receptors localize at a juxtanuclear compartment identified as the Golgi apparatus. The receptors do not colocalize with lysosomes. Furthermore, whereas the internalized receptors exhibit rapid recycling, treatment with proton pump inhibitors (bafilomycin-A1 and concanamycin A) or brefeldin A, Golgi disrupting agents, reduces PTH/PTHrP receptor recycling. Together, these data indicate an important role for the vacuolar-type hydrogen-ATPase and the Golgi apparatus in postendocytic PTH/PTHrP receptor recovery.
authors.affiliation: Endocrine Unit, Massachusetts General Hospital, Harvard Medical School, Bulfinch 327, 55 Fruit St., Boston, MA 02114, USA. tawfeek@helix.mgh.harvard.edu
authors.forename: Hesham A W
authors.initials: HA
authors.lastname: Tawfeek
authors.forename: Abdul B
authors.initials: AB
authors.lastname: Abou-Samra
mesh_terms: D000818:Animals; D020126:Brefeldin A / Q000494:pharmacology; D004705:Endocytosis / Q000187:drug effects / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D006056:Golgi Apparatus / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D018374:LLC-PK1 Cells; D018942:Macrolides / Q000494:pharmacology; D018613:Microscopy, Confocal; D021381:Protein Transport / Q000187:drug effects / Q000502:physiology; D044168:Receptor, Parathyroid Hormone, Type 1 / Q000378:metabolism*; D018016:Receptors, Parathyroid Hormone / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D013347:Subcellular Fractions / Q000187:drug effects / Q000201:enzymology / Q000648:ultrastructure; D013552:Swine; D025262:Vacuolar Proton-Translocating ATPases / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D018942:Macrolides; D044168:Receptor, Parathyroid Hormone, Type 1; D018016:Receptors, Parathyroid Hormone; D020126:Brefeldin A; C040929:bafilomycin A1; D025262:Vacuolar Proton-Translocating ATPases