Differential involvement of synaptic vesicle and presynaptic plasma membrane proteins in Alzheimer's disease.
Alzheimer's disease (AD) is characterized by progressive cognitive decline. Recent studies have shown that synaptic loss in the cortex is the major correlate of cognitive decline in AD. In the present study we assessed synaptic proteins such as synaptobrevin, synaptophysin, synaptotagmin, synaptosomal-associated protein 25 (SNAP-25), and syntaxin1/HPC-1 in control and AD brains to determine whether synaptic proteins are equally or differentially affected in AD. Western analysis showed that in AD levels of synaptobrevin and synaptophysin were decreased by some 30% from amounts in controls, while those of synaptotagmin, SNAP-25, and syntaxin 1/HPC-1 were decreased by only about 10%. As synaptobrevin and synaptophysin are localized mainly in transmitter-containing synaptic vesicles while SNAP-25 and syntaxin 1/HPC-1 are found in presynaptic plasma membranes, these results suggest differential involvement of synaptic components in AD.
Shimohama
S
S
Department of Neurology, Faculty of Medicine, Kyoto University, Sakyoku, Japan. i53367@sakura.kudpc.kyoto-u.ac.jp
Kamiya
S
S
Taniguchi
T
T
Akagawa
K
K
Kimura
J
J
D000544:Alzheimer Disease / Q000378:metabolism*; D000818:Animals; D015153:Blotting, Western; D002135:Calcium-Binding Proteins; D008562:Membrane Glycoproteins / Q000378:metabolism; D008565:Membrane Proteins / Q000378:metabolism*; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D050683:R-SNARE Proteins; D051381:Rats; D013570:Synaptic Membranes / Q000378:metabolism*; D013572:Synaptic Vesicles / Q000378:metabolism*; D016708:Synaptophysin / Q000378:metabolism; D050825:Synaptosomal-Associated Protein 25; D050857:Synaptotagmins; D013702:Temporal Lobe / Q000378:metabolism
D002135:Calcium-Binding Proteins; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; D050683:R-SNARE Proteins; C494210:Snap25 protein, rat; D016708:Synaptophysin; D050825:Synaptosomal-Associated Protein 25; D050857:Synaptotagmins