TY - JOUR
T1 - APH1 polar transmembrane residues regulate the assembly and activity of presenilin complexes
AU - Pardossi-Piquard, Raphaëlle
AU - Yang, Seung Pil
AU - Kanemoto, Soshi
AU - Gu, Yongjun
AU - Chen, Fusheng
AU - Böhm, Christopher
AU - Sevalle, Jean
AU - Li, Tong
AU - Wong, Philip C.
AU - Checler, Frédéric
AU - Schmitt-Ulms, Gerold
AU - St. George-Hyslop, Peter
AU - Fraser, Paul E.
PY - 2009/6/12
Y1 - 2009/6/12
N2 - Complexes involved in the γ/ε-secretase-regulated intramembranous proteolysis of substrates such as the amyloid- β precursor protein are composed primarily of presenilin (PS1 or PS2), nicastrin, anterior pharynx defective-1 (APH1), and PEN2. The presenilin aspartyl residues form the catalytic site, and similar potentially functional polar transmembrane residues in APH1 have been identified. Substitution of charged (E84A, R87A) or polar (Q83A) residues in TM3 had no effect on complex assembly or activity. In contrast, changes to either of two highly conserved histidines (H171A, H197A) located in TM5 and TM6 negatively affected PS1 cleavage and altered binding to other secretase components, resulting in decreased amyloid generating activity. Charge replacement with His-to-Lys substitutions rescued nicastrin maturation and PS1 endoproteolysis leading to assembly of the formation of structurally normal but proteolytically inactive γ-secretase complexes. Substitution with a negatively charged side chain (His-to-Asp) or altering the structural location of the histidines also disrupted γ-secretase binding and abolished functionality of APH1. These results suggest that the conserved transmembrane histidine residues contribute to APH1 function and can affect presenilin catalytic activity.
AB - Complexes involved in the γ/ε-secretase-regulated intramembranous proteolysis of substrates such as the amyloid- β precursor protein are composed primarily of presenilin (PS1 or PS2), nicastrin, anterior pharynx defective-1 (APH1), and PEN2. The presenilin aspartyl residues form the catalytic site, and similar potentially functional polar transmembrane residues in APH1 have been identified. Substitution of charged (E84A, R87A) or polar (Q83A) residues in TM3 had no effect on complex assembly or activity. In contrast, changes to either of two highly conserved histidines (H171A, H197A) located in TM5 and TM6 negatively affected PS1 cleavage and altered binding to other secretase components, resulting in decreased amyloid generating activity. Charge replacement with His-to-Lys substitutions rescued nicastrin maturation and PS1 endoproteolysis leading to assembly of the formation of structurally normal but proteolytically inactive γ-secretase complexes. Substitution with a negatively charged side chain (His-to-Asp) or altering the structural location of the histidines also disrupted γ-secretase binding and abolished functionality of APH1. These results suggest that the conserved transmembrane histidine residues contribute to APH1 function and can affect presenilin catalytic activity.
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U2 - 10.1074/jbc.M109.000067
DO - 10.1074/jbc.M109.000067
M3 - Article
C2 - 19369254
AN - SCOPUS:67650245818
SN - 0021-9258
VL - 284
SP - 16298
EP - 16307
JO - Journal of Biological Chemistry
JF - Journal of Biological Chemistry
IS - 24
ER -