Differential functions of the Apoer2 intracellular domain in selenium uptake and cell signaling
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Irene Masiulis
Abstract
Apolipoprotein E receptor 2 (Apoer2) is a multifunctional transport and signaling receptor that regulates the uptake of selenium into the mouse brain and testis through endocytosis of selenoprotein P (Sepp1). Mice deficient in Apoer2 or Sepp1 are infertile, with kinked and hypomotile spermatozoa. They also develop severe neurological defects on a low selenium diet, due to a profound impairment of selenium uptake. Little is known about the function of Apoer2 in the testis beyond its role as a Sepp1 receptor. By contrast, in the brain, Apoer2 is an essential component of the Reelin signaling pathway, which is required for proper neuronal organization and synapse function. Using knock-in mice, we have functionally dissociated the signaling motifs in the Apoer2 cytoplasmic domain from Sepp1 uptake. Selenium concentration of brain and testis was normal in the knock-in mutants, in contrast to Apoer2 knock-outs. Thus, the neurological defects in the signaling impaired knock-in mice are not caused by a selenium uptake defect, but instead are a direct consequence of a disruption of the Reelin signal. Reduced sperm motility was observed in some of the knock-in mice, indicating a novel signaling role for Apoer2 in sperm development and function that is independent of selenium uptake.
©2009 by Walter de Gruyter Berlin New York
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Articles in the same Issue
- Editor's Note
- Editor's Note
- Protein Structure and Function
- Glyceryl ether monooxygenase resembles aromatic amino acid hydroxylases in metal ion and tetrahydrobiopterin dependence
- Biochemical characterization of the catalytic domains of three different clostridial collagenases
- Impact of detergents on the activity of acetylcholinesterase and on the effectiveness of its inhibitors
- The ADP-ribosylating thermozyme from Sulfolobus solfataricus is a DING protein
- Membranes, Lipids, Glycobiology
- Glycosphingolipids from bovine milk and milk fat globule membranes: a comparative study. Adhesion to enterotoxigenic Escherichia coli strains
- Mannose 6-phosphate receptor-dependent endocytosis of lysosomal enzymes is increased in sulfatide-storing kidney cells
- Cell Biology and Signaling
- Heavy metals induce phosphorylation of the Bcl-2 protein by Jun N-terminal kinase
- Fibroblast growth factor 2 (FGF-2) is a novel substrate for arginine methylation by PRMT5
- Differential functions of the Apoer2 intracellular domain in selenium uptake and cell signaling
- Active immunisation against gastric inhibitory polypeptide (GIP) improves blood glucose control in an animal model of obesity-diabetes
- Novel Techniques
- Applicability of superfolder YFP bimolecular fluorescence complementation in vitro
