The N-terminus of the human copper transporter 1 (hCTR1) is localized extracellularly, and interacts with itself
- 15 March 2003
- journal article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 370 (3), 881-889
- https://doi.org/10.1042/bj20021128
Abstract
We have used indirect immunofluorescense studies and glycosylation-site insertion and deletion mapping to characterize the topology of human copper transporter 1 (hCTR1), the putative human high-affinity copper-import protein. Both approaches indicated that hCTR1 contains three transmembrane domains and that the N-terminus of hCTR1, which contains several putative copper-binding sites, is localized extracellularly, whereas the C-terminus is exposed to the cytosol. Based on previous observations that CTR1 proteins form high-molecular-mass complexes, we investigated directly whether CTR1 proteins interact with themselves. Yeast two-hybrid studies showed that interaction of yeast, mouse, rat and human CTR1 occurs at the sites of their N-terminal domains, and is not dependent on the copper concentration in the growth media. Analysis of deletion constructs indicated that multiple regions in the N-terminus are essential for this self-interaction. In contrast, the N-terminal tail of the presumed low-affinity copper transporter, hCTR2, does not interact with itself. Taken together, these results suggest that CTR1 spans the membrane at least six times, permitting formation of a channel, which is consistent with its proposed role as a copper transporter.Keywords
This publication has 38 references indexed in Scilit:
- Characterization of the hCTR1 gene: Genomic organization, functional expression, and identification of a highly homologous processed geneGene, 2000
- Characterization of the Saccharomyces cerevisiae High Affinity Copper Transporter Ctr3Published by Elsevier BV ,2000
- Isolation of a murine copper transporter gene, tissue specific expression and functional complementation of a yeast copper transport mutantGene, 2000
- Functional Expression of the Human hZIP2 Zinc TransporterPublished by Elsevier BV ,2000
- Delivering copper within plant cellsCurrent Opinion in Plant Biology, 2000
- Characterization of the Interaction between the Wilson and Menkes Disease Proteins and the Cytoplasmic Copper Chaperone, HAH1pJournal of Biological Chemistry, 1999
- Undetectable Intracellular Free Copper: The Requirement of a Copper Chaperone for Superoxide DismutaseScience, 1999
- N-glycosylation requirements for the AT1a angiotensin II receptor delivery to the plasma membrane.1999
- h CTR1 : A human gene for copper uptake identified by complementation in yeastProceedings of the National Academy of Sciences of the United States of America, 1997
- Glycosylation of Asn397 or Asn418 is Required for Normal Insulin Receptor Biosynthesis and ProcessingDiabetes, 1993