Identification of a tetratricopeptide repeat-like domain in the nicastrin subunit of γ-secretase using synthetic antibodies Journal Article
| Authors: | Zhang, X. L.; Hoey, R. J.; Lin, G. Q.; Koide, A.; Leung, B.; Ahn, K.; Dolios, G.; Paduch, M.; Ikeuchi, T.; Wang, R.; Li, Y. M.; Koide, S.; Sisodia, S. S. |
| Article Title: | Identification of a tetratricopeptide repeat-like domain in the nicastrin subunit of γ-secretase using synthetic antibodies |
| Abstract: | The gamma-secretase complex, composed of presenilin, anterior-pharynx-defective 1, nicastrin, and presenilin enhancer 2, catalyzes the intramembranous processing of a wide variety of type I membrane proteins, including amyloid precursor protein (APP) and Notch. Earlier studies have revealed that nicastrin, a type I membrane-anchored glycoprotein, plays a role in gamma-secretase assembly and trafficking and has been proposed to bind substrates. To gain more insights regarding nicastrin structure and function, we generated a conformation-specific synthetic antibody and used it as a molecular probe to map functional domains within nicastrin ectodomain. The antibody bound to a conformational epitope within a nicastrin segment encompassing residues 245-630 and inhibited the processing of APP and Notch substrates in in vitro gamma-secretase activity assays, suggesting that a functional domain pertinent to gamma-secretase activity resides within this region. Epitope mapping and database searches revealed the presence of a structured segment, located downstream of the previously identified DAP domain (DYIGS and peptidase; residues 261-502), that is homologous to a tetratricopeptide repeat (TPR) domain commonly involved in peptide recognition. Mutagenesis analyses within the predicted TPR-like domain showed that disruption of the signature helical structure resulted in the loss of gamma-secretase activity but not the assembly of the gamma-secretase and that Leu571 within the TPR-like domain plays an important role in mediating substrate binding. Taken together, these studies offer provocative insights pertaining to the structural basis for nicastrin function as a "substrate receptor" within the gamma-secretase complex. |
| Keywords: | glycosylation; amyloid precursor protein; presenilin; pathway; complex; alzheimers-disease; stability; trafficking; requires; golgi-apparatus |
| Journal Title: | Proceedings of the National Academy of Sciences of the United States of America |
| Volume: | 109 |
| Issue: | 22 |
| ISSN: | 0027-8424 |
| Publisher: | National Academy of Sciences |
| Date Published: | 2012-05-01 |
| Start Page: | 8534 |
| End Page: | 8539 |
| Language: | English |
| ACCESSION: | WOS:000304881700041 |
| DOI: | 10.1073/pnas.1202691109 |
| PROVIDER: | wos |
| PMCID: | PMC3365189 |
| PUBMED: | 22586122 |
| Notes: | --- - Article - "Source: Wos" |
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