Both the Sequence and Length of the C Terminus of PEN-2 Are Critical for Intermolecular Interactions and Function of Presenilin Complexes

Hiroshi Hasegawa,Nobuo Sanjo,Fusheng Chen,Yong-Jun Gu,Cortney Shier,Agnes Petit,Toshitaka Kawarai,Taiichi Katayama,Stephen D Schmidt,Paul M Mathews,Gerold Schmitt-Ulms,Paul E Fraser,Peter St George-Hyslop

doi:10.1074/jbc.m406289200

Hiroshi Hasegawa, Nobuo Sanjo + Show 11 more

Open Access

https://doi.org/10.1074/jbc.m406289200

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Abstract

Presenilin 1 or presenilin 2, nicastrin, APH-1, and PEN-2 form high molecular weight complexes that play a pivotal role in the cleavage of various Type I transmembrane proteins, including the beta-amyloid precursor protein. The specific function of PEN-2 is unclear. To explore its function and intermolecular interactions, we conducted deletion and mutagenesis studies on a series of conserved residues at the C terminus of PEN-2. These studies suggest that: 1) both the presence and amino acid sequence of the conserved DYLSF domain at the C terminus of PEN-2 (residues 90-94) is critical for binding PEN-2 to other components in the presenilin complex and 2) the overall length of the exposed C terminus is critical for functional gamma-secretase activity.

Highlights

The presenilin proteins (PS1 and PS2) are evolutionarily conserved polytopic transmembrane proteins that are required for the regulated intramembranous proteolysis of several Type 1 transmembrane proteins including the ␤-amyloid precursor protein (APP),1 Notch receptor, and p75 [1,2,3,4]
Note that the interference with the anti-PEN-2 antibody recognition sequence has no functional effect because transient transfection of N-terminal V5-tagged wild-type PEN-2 constructs into cells in which endogenous PEN-2 expression had been suppressed by RNAi fully complemented the loss of endogenous PEN-2, resulting in restoration of PS1 endoproteolysis, nicastrin maturation, and A␤ production.) In contrast, mutant PEN-2 with a deletion after residue 96 moderately reduced the binding of the exogenous PEN-2 to PS1, nicastrin, and APH-1 and was able to partially displace endogenous PEN-2
The del84 –101 and del90 –101 did not co-precipitate with either APH-1 or nicastrin (Fig. 2B, panels 4 and 5). These observations suggest that the C terminus, and in particular residues 90 –96, which contain the highly conserved DYLSF motif, may either: 1) be essential for the stability of PEN-2; 2) be essential for the proper trafficking of PEN-2; or 3) be involved in binding of PEN-2 to other components of the presenilin complex

Summary

Introduction

The presenilin proteins (PS1 and PS2) are evolutionarily conserved polytopic transmembrane proteins that are required for the regulated intramembranous proteolysis of several Type 1 transmembrane proteins including the ␤-amyloid precursor protein (APP),1 Notch receptor, and p75 [1,2,3,4]. These studies suggest that: 1) both the presence and amino acid sequence of the conserved DYLSF domain at the C terminus of PEN-2 (residues 90 –94) is critical for binding PEN-2 to other components in the presenilin complex and 2) the overall length of the exposed C terminus is critical for functional ␥-secretase activity.

Results

Conclusion