Identification of V-ATPase as a major component in the raft fraction prepared from the synaptic plasma membrane and the synaptic vesicle of rat brain.

Cholesterol is important in the maintenance and remodeling of the synapse. Since membrane cholesterol participates in the formation of the membrane microdomain (raft), the characterization of raft components within membrane structures in the synaptic region could be a good approach to understand the role of cholesterol in the synaptic function. In this study, protein complexes in the raft prepared from synaptic plasma membrane and the synaptic vesicle were analyzed with blue-native polyacrylamide gel electrophoresis and vacuolar H(+)-pump (V-ATPase) was identified as a major raft component using mass spectrometry. The ATPase activity was reduced through cholesterol deprivation with methyl-beta-cyclodextrin. Since the H(+) -gradient is used to transport synaptic transmitters or their precursors into the vesicle, this result suggests the essential role of cholesterol and raft in the synaptic function.