Alzheimer's A beta(1-42) is generated in the endoplasmic reticulum/intermediate compartment of NT2N cells.
Alzheimer's disease (AD) is a neurodegenerative disorder involving the florid deposition of vascular and cerebral plaques composed chiefly of amyloid beta-peptide (A beta) derived from cleavage of the amyloid precursor protein (APP). Varying in length from 39 to 43 amino acids, A beta, particularly the longer A beta(42), is thought to play a significant role in AD pathogenesis. To better understand AD it is important to identify the subcellular organelles generating A beta. Studies using agents that disrupt endosomal/lysosomal function suggest that A beta is generated late in the secretory and endocytic pathways. However, much of what is known about A beta biosynthesis has been inferred by monitoring extracellular A beta levels since intracellular A beta is undetectable in most cell types. Consequently, the precise site or sites that generate A beta, or whether A beta(1-40) and A beta(1-42) are generated at the same point in the biosynthetic pathway, is not known. Using human NT2N neurons, we found that retention of APP in the endoplasmic reticulum/intermediate compartment (ER/IC) by three independent approaches eliminated production of intracellular A beta(1-40), but did not alter intracellular A beta(1-42) synthesis. These findings suggest that the ER/IC may be an important site for generating this highly amyloidogenic species of A beta.
Cook
D G
DG
Department of Pathology & Laboratory Medicine, University of Pennsylvania, Abramson Research Center, Philadelphia 19104, USA.
Forman
M S
MS
Sung
J C
JC
Leight
S
S
Kolson
D L
DL
Iwatsubo
T
T
Lee
V M
VM
Doms
R W
RW
D000544:Alzheimer Disease / Q000209:etiology / Q000378:metabolism* / Q000473:pathology; D000595:Amino Acid Sequence; D016229:Amyloid beta-Peptides / Q000096:biosynthesis* / Q000235:genetics; D001483:Base Sequence; D020126:Brefeldin A; D002451:Cell Compartmentation; D002460:Cell Line; D003517:Cyclopentanes / Q000494:pharmacology; D017931:DNA Primers / Q000235:genetics; D004721:Endoplasmic Reticulum / Q000378:metabolism*; D006801:Humans; D008856:Microscopy, Fluorescence; D016297:Mutagenesis, Site-Directed; D009474:Neurons / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D010446:Peptide Fragments / Q000096:biosynthesis* / Q000235:genetics; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology
D016229:Amyloid beta-Peptides; D003517:Cyclopentanes; D017931:DNA Primers; D010446:Peptide Fragments; D011500:Protein Synthesis Inhibitors; C075222:amyloid beta-protein (1-42); D020126:Brefeldin A