Presenilins and gamma-secretase inhibitors affect intracellular trafficking and cell surface localization of the gamma-secretase complex components.
The intramembranous cleavage of Alzheimer beta-amyloid precursor protein and the signaling receptor Notch is mediated by the presenilin (PS, PS1/PS2)-gamma-secretase complex, the components of which also include nicastrin, APH-1, and PEN-2. In addition to its essential role in gamma-secretase activity, we and others have reported that PS1 plays a role in intracellular trafficking of select membrane proteins including nicastrin. Here we examined the fate of PEN-2 in the absence of PS expression or gamma-secretase activity. We found that PEN-2 is retained in the endoplasmic reticulum and has a much shorter half-life in PS-deficient cells than in wild type cells, suggesting that PSs are required for maintaining the stability and proper subcellular trafficking of PEN-2. However, the function of PS in PEN-2 trafficking is distinct from its contribution to gamma-secretase activity because inhibition of gamma-secretase activity by gamma-secretase inhibitors did not affect the PEN-2 level or its egress from the endoplasmic reticulum. Instead, membrane-permeable gamma-secretase inhibitors, but not a membrane-impermeable derivative, markedly increased the cell surface levels of PS1 and PEN-2 without affecting that of nicastrin. In support of its role in PEN-2 trafficking, PS1 was also required for the gamma-secretase inhibitor-induced plasma membrane accumulation of PEN-2. We further showed that gamma-secretase inhibitors specifically accelerated the Golgi to the cell surface transport of PS1 and PEN-2. Taken together, we demonstrate an essential role for PSs in intracellular trafficking of the gamma-secretase components, and that selective gamma-secretase inhibitors differentially affect the trafficking of the gamma-secretase components, which may contribute to an inactivation of gamma-secretase.
Wang
Hong
H
The Fisher Center for Alzheimer's Disease Research and the Laboratory of Molecular and Cellular Neuroscience, The Rockefeller University, New York, New York 10021, USA.
Luo
Wen-Jie
WJ
Zhang
Yun-Wu
YW
Li
Yue-Ming
YM
Thinakaran
Gopal
G
Greengard
Paul
P
Xu
Huaxi
H
D053829:Amyloid Precursor Protein Secretases; D000818:Animals; D016282:Aspartic Acid Endopeptidases; D001692:Biological Transport; D019921:Biotinylation; D015153:Blotting, Western; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000201:enzymology / Q000378:metabolism; D003593:Cytoplasm / Q000378:metabolism; D010450:Endopeptidases / Q000378:metabolism*; D004721:Endoplasmic Reticulum / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006056:Golgi Apparatus / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism; D008565:Membrane Proteins / Q000502:physiology*; D051379:Mice; D011233:Precipitin Tests; D053764:Presenilin-1; D021381:Protein Transport; D013347:Subcellular Fractions / Q000378:metabolism; D013997:Time Factors
D004791:Enzyme Inhibitors; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D053764:Presenilin-1; C413604:nicastrin protein; D053829:Amyloid Precursor Protein Secretases; D010450:Endopeptidases; D016282:Aspartic Acid Endopeptidases; C509282:Bace1 protein, mouse