File(s) under permanent embargo
Endosomal trafficking of the Menkes copper ATPase ATP7A is mediated by vesicles containing the Rab7 and Rab5 GTPase proteins
journal contributionposted on 2003-12-10, 00:00 authored by M Pascale, S Franceschelli, O Moltedo, F Belleudi, M Torrisi, C Bucci, Sharon La FontaineSharon La Fontaine, Julian MercerJulian Mercer, A Leone
The Cu-ATPase ATP7A (MNK) is localized in the trans-Golgi network (TGN) and relocalizes in the plasma membrane via vesicle-mediated traffic following exposure of the cells to high concentrations of copper. Rab proteins are organelle-specific GTPases, markers of different endosomal compartments; their role has been recently reviewed (Trends Cell Biol. 11(2001) 487). In this article we analyze the endosomal pathway of trafficking of the MNK protein in stably transfected clones of CHO cells, expressing chimeric Rab5-myc or Rab7-myc proteins, markers of early or late endosome compartments, respectively. We demonstrate by immunofluorescence and confocal and electron microscopy techniques that the increase in the concentration of copper in the medium (189 μM) rapidly induces a redistribution of the MNK protein from early sorting endosomes, positive for Rab5-myc protein, to late endosomes, containing the Rab7-myc protein. Cell fractionation experiments confirm these results; i.e., the MNK protein is recruited to the endosomal fraction on copper stimulation and colocalizes with Rab5 and Rab7 proteins. These findings allow the first characterization of the vesicles involved in the intracellular routing of the MNK protein from the TGN to the plasma membrane, a key mechanism allowing appropriate efflux of copper in cells grown in high concentrations of the metal.
JournalExperimental cell research
Pagination377 - 385
LocationSan Diego, Calif
Publication classificationC1 Refereed article in a scholarly journal
Copyright notice2003, Elsevier Inc.
Read the peer-reviewed publication
MNK proteinrab proteinsvesicular traffickingcopper transportChinese hamster ovary cellstrans-Golgi networkScience & TechnologyLife Sciences & BiomedicineOncologyCell BiologyPLASMA-MEMBRANECANDIDATE GENEINTRACELLULAR-LOCALIZATIONGOLGI LOCALIZATIONDISEASEENDOCYTOSISTRANSPORTFUSIONIDENTIFICATIONMUTATIONS