title: Intracellular retention of the corticotrophin-releasing hormone (CRH) precursor within COS-7 cells.
abstract: We investigated the intracellular localization of CRH in transiently transfected COS-7 cells expressing the full-length rat corticotropin-releasing hormone (CRH) precursor cDNA. CRH synthesized by transfected COS-7 cells is mainly stored intracellularly. In contrast, CHO-K1 cells expressing the same CRH precursor stored and released equal amounts of immunoreactive (IR)-CRH. Ultrastructural analysis revealed that CRH is stored in electron-dense aggregates in the RER of transiently transfected COS-7 cells and does not migrate into the Golgi apparatus. On the basis of the different intracellular localization, storage, and release of CRH in COS-7 and CHO-K1 cells, we hypothesize that the intracellular trafficking of CRH within the constitutive secretory pathway for protein secretion not only depends on its primary amino acid sequence but might also be influenced by intracellular conditions or factors.
authors.affiliation: Molecular Medicine Unit, Department of Medicine, University of Manchester, Manchester, United Kingdom.
authors.forename: M J
authors.initials: MJ
authors.lastname: Perone
authors.forename: S
authors.initials: S
authors.lastname: Windeatt
authors.forename: E
authors.initials: E
authors.lastname: Morrison
authors.forename: A
authors.initials: A
authors.lastname: Shering
authors.forename: P
authors.initials: P
authors.lastname: Tomasec
authors.forename: E
authors.initials: E
authors.lastname: Linton
authors.forename: P R
authors.initials: PR
authors.lastname: Lowenstein
authors.forename: M G
authors.initials: MG
authors.lastname: Castro
mesh_terms: D000818:Animals; D016466:CHO Cells; D019556:COS Cells / Q000378:metabolism* / Q000648:ultrastructure; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism*; D006224:Cricetinae; D018870:Endoplasmic Reticulum, Rough / Q000378:metabolism; D006056:Golgi Apparatus / Q000378:metabolism; D008854:Microscopy, Electron; D051381:Rats; D014162:Transfection
chemical_list: D003346:Corticotropin-Releasing Hormone