Incomplete glycosylation and defective intracellular targeting of mutant solute carrier family 11 member 1 (Slc11a1)
- 7 September 2004
- journal article
- Published by Portland Press Ltd. in Biochemical Journal
- Vol. 382 (3) , 811-819
- https://doi.org/10.1042/bj20040808
Abstract
Solute carrier family 11 member 1 (Slc11a1, formerly Nramp1) is a highly glycosylated, 12 transmembrane domain protein expressed in macrophages. It resides in the membrane of late endosomes and lysosomes, where it functions as a bivalent cation transporter. Mice susceptible to infection by various intracellular pathogens including Leishmania donovani and Salmonella typhimurium carry a glycine to aspartic acid substitution at position 169 (G169D, Gly169→Asp), within transmembrane domain 4 of Slc11a1. To investigate the molecular pathogenesis of infectious disease susceptibility, we compared the behaviour of heterologously and endogenously expressed wild-type and mutant Slc11a1 by immunofluorescence, immunoelectron microscopy and Western-blot analysis. We found occasional late endosome/lysosome staining of mutant protein using immunoelectron microscopy, but most of the mutant Slc11a1 was retained within the ER (endoplasmic reticulum). Using glycosylation as a marker for protein maturation in two independent heterologous expression systems, we found that most mutant Slc11a1 existed as an ER-dependent, partially glycosylated intermediate species. Correct endosomal targeting of wild-type Slc11a1 continued despite disruption of N-glycosylation sites, indicating that glycosylation did not influence folding or sorting. We propose that the G169D mutation causes localized misfolding of Slc11a1, resulting in its retention in the ER and manifestation of the loss of function phenotype.Keywords
This publication has 50 references indexed in Scilit:
- Alternative Splicing Regulates the Subcellular Localization of Divalent Metal Transporter 1 IsoformsMolecular Biology of the Cell, 2002
- Defective intracellular transport and processing of OA1 is a major cause of ocular albinism type 1Human Molecular Genetics, 2000
- Natural Resistance to Infection with Intracellular Pathogens: The Nramp1 Protein Is Recruited to the Membrane of the PhagosomeThe Journal of Experimental Medicine, 1997
- The Ity/Lsh/Bcg locus: natural resistance to infection with intracellular parasites is abrogated by disruption of the Nramp1 gene.The Journal of Experimental Medicine, 1995
- Many naturally occurring mutations of myelin proteolipid protein impair its intracellular transportJournal of Neuroscience Research, 1994
- Protein degradation in the endoplasmic reticulumCell, 1990
- The mannose 6-phosphate receptor and the biogenesis of lysosomesCell, 1988
- The endosomal concentration of a mannose 6-phosphate receptor is unchanged in the absence of ligand synthesis.The Journal of cell biology, 1987
- Functional macrophage cell lines transformed by abelson leukemia virusCell, 1978
- A study of positive staining of ultrathin frozen sectionsJournal of Ultrastructure Research, 1978