Generation of amyloid-β is reduced by the interaction of calreticulin with amyloid precursor protein, presenilin and nicastrin.

Abstract

Dysregulation of the proteolytic processing of amyloid precursor protein by γ-secretase and the ensuing generation of amyloid-β is associated with the pathogenesis of Alzheimer's disease. Thus, the identification of amyloid precursor protein binding proteins involved in regulating processing of amyloid precursor protein by the γ-secretase complex is essential for understanding the mechanisms underlying the molecular pathology of the disease. We identified calreticulin as novel amyloid precursor protein interaction partner that binds to the γ-secretase cleavage site within amyloid precursor protein and showed that this Ca(2+)- and N-glycan-independent interaction is mediated by amino acids 330-344 in the C-terminal C-domain of calreticulin. Co-immunoprecipitation confirmed that calreticulin is not only associated with amyloid precursor protein but also with the γ-secretase complex members presenilin and nicastrin. Calreticulin was detected at the cell surface by surface biotinylation of cells overexpressing amyloid precursor protein and was co-localized by immunostaining with amyloid precursor protein and presenilin at the cell surface of hippocampal neurons. The P-domain of calreticulin located between the N-terminal N-domain and the C-domain interacts with presenilin, the catalytic subunit of the γ-secretase complex. The P- and C-domains also interact with nicastrin, another functionally important subunit of this complex. Transfection of amyloid precursor protein overexpressing cells with full-length calreticulin leads to a decrease in amyloid-β42 levels in culture supernatants, while transfection with the P-domain increases amyloid-β40 levels. Similarly, application of the recombinant P- or C-domains and of a synthetic calreticulin peptide comprising amino acid 330-344 to amyloid precursor protein overexpressing cells result in elevated amyloid-β40 and amyloid-β42 levels, respectively. These findings indicate that the interaction of calreticulin with amyloid precursor protein and the γ-secretase complex regulates the proteolytic processing of amyloid precursor protein by the γ-secretase complex, pointing to calreticulin as a potential target for therapy in Alzheimer's disease.

• Authors: Nina Stemmer, Elena Strekalova, Nevena Djogo, Frank Plöger, Gabriele Loers, David Lutz, Friedrich Buck, Marek Michalak, Melitta Schachner, Ralf Kleene
• Journal: PloS one (PLoS One) Vol. 8 Issue 4 Pg. e61299 ( 2013) ISSN: 1932-6203 [Electronic] United States
• PMID: 23585889 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Amyloid beta-Peptides
• Amyloid beta-Protein Precursor
• Membrane Glycoproteins
• PSEN1 protein, human
• Peptide Fragments
• Presenilin-1
• Recombinant Proteins
• amyloid beta-protein (1-40)
• amyloid beta-protein (1-42)
• nicastrin protein
• Amyloid Precursor Protein Secretases

Topics

• Amino Acid Sequence
• Amyloid Precursor Protein Secretases (genetics, metabolism)
• Amyloid beta-Peptides (metabolism)
• Amyloid beta-Protein Precursor (metabolism)
• Animals
• Binding Sites
• CHO Cells
• Cricetinae
• Gene Expression Regulation
• Hippocampus (cytology, metabolism)
• Humans
• Membrane Glycoproteins (genetics, metabolism)
• Mice
• Molecular Sequence Data
• Neurons (cytology, metabolism)
• Peptide Fragments (metabolism)
• Presenilin-1 (genetics, metabolism)
• Protein Binding
• Protein Structure, Tertiary
• Proteolysis
• Recombinant Proteins (genetics, metabolism)
• Signal Transduction