Generation of Alzheimer beta-amyloid protein in the trans-Golgi network in the apparent absence of vesicle formation.
beta-amyloid protein (A beta) formation was reconstituted in permeabilized neuroblastoma cells expressing human Alzheimer beta-amyloid precursor protein (beta APP) harboring the Swedish double mutation associated with familial early-onset Alzheimer disease. Permeabilized cells were prepared following metabolic labeling and incubation at 20 degrees C, a temperature that allows beta APP to accumulate in the trans-Golgi network (TGN) without concomitant A beta formation. Subsequent incubation at 37 degrees C led to the generation of A beta. A beta production in the TGN persisted even under conditions in which formation of nascent post-TGN vesicles was inhibited by addition of guanosine 5'-O-(3-thiotriphosphate), a nonhydrolyzable GTP analogue, or by omission of cytosol. These and other results indicate that vesicle budding and trafficking may not be required for proteolytic metabolism of beta APP to A beta, a process that includes "gamma-secretase" cleavage within the beta APP transmembrane domain.
Xu
H
H
Department of Neurology and Neuroscience, Cornell University Medical College, New York, NY 10021, USA.
Sweeney
D
D
Wang
R
R
Thinakaran
G
G
Lo
A C
AC
Sisodia
S S
SS
Greengard
P
P
Gandy
S
S
D016229:Amyloid beta-Peptides / Q000378:metabolism*; D001692:Biological Transport; D002460:Cell Line; D003594:Cytoplasmic Granules / Q000378:metabolism* / Q000648:ultrastructure; D006056:Golgi Apparatus / Q000378:metabolism* / Q000648:ultrastructure; D006801:Humans
D016229:Amyloid beta-Peptides