2012年5月
Identification of a tetratricopeptide repeat-like domain in the nicastrin subunit of gamma-secretase using synthetic antibodies
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
- 巻
- 109
- 号
- 22
- 開始ページ
- 8534
- 終了ページ
- 8539
- 記述言語
- 英語
- 掲載種別
- 研究論文(学術雑誌)
- DOI
- 10.1073/pnas.1202691109
- 出版者・発行元
- NATL ACAD SCIENCES
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.
- リンク情報
- ID情報
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- DOI : 10.1073/pnas.1202691109
- ISSN : 0027-8424
- Web of Science ID : WOS:000304881700041