Biochemical evidence for localization of AMPA-type glutamate receptor subunits in the dendritic raft.
A low density Triton-insoluble fraction with characteristic lipid composition was prepared from synaptic plasma membrane from the rat forebrain. The fraction was named dendritic raft based on its absence of the presynaptic marker synaptophysin, the presence of postsynaptic Glutamate receptor (GluR) subunits, and its resemblance to raft, caveolae-like structure. We found a differential distribution of NMDA-type and AMPA-type GluR subunits in the dendritic raft and postsynaptic density (PSD) fractions; the latter type GluR subunits were localized to the dendritic raft as well as PSD fraction, whereas the former type was mostly localized to the PSD fraction. We also found the differential distribution of the components of ras/mitogen-activated protein kinase (MAPK) pathway to the dendritic raft and PSD fractions. Dendritic raft and PSD may possibly interact at the postsynaptic sites for efficient signal processing that is required for expression of synaptic plasticity.
Suzuki
T
T
Department of Neuroplasticity, Research Center on Aging and Adaptation, Shinshu University School of Medicine, Matsumoto 390-8621, Japan. suzukit@sch.md.shinshu-u.ac.jp
Ito
J
J
Takagi
H
H
Saitoh
F
F
Nawa
H
H
Shimizu
H
H
D000818:Animals; D000906:Antibodies; D002458:Cell Fractionation; D002462:Cell Membrane / Q000737:chemistry / Q000201:enzymology / Q000648:ultrastructure; D003712:Dendrites / Q000737:chemistry* / Q000201:enzymology / Q000648:ultrastructure; D003902:Detergents; D008854:Microscopy, Electron; D020928:Mitogen-Activated Protein Kinases / Q000032:analysis; D017830:Octoxynol; D016548:Prosencephalon / Q000166:cytology; D011817:Rabbits; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000032:analysis* / Q000276:immunology; D015398:Signal Transduction / Q000502:physiology; D012995:Solubility; D013569:Synapses / Q000737:chemistry* / Q000201:enzymology / Q000648:ultrastructure; D020703:ras GTPase-Activating Proteins / Q000032:analysis
D000906:Antibodies; D003902:Detergents; D018091:Receptors, AMPA; D020703:ras GTPase-Activating Proteins; D017830:Octoxynol; D020928:Mitogen-Activated Protein Kinases