title: Developmental changes in the association of NMDA receptors with lipid rafts.
abstract: Lipid rafts (LR) are lipid microdomains present in the cell surface membrane that are organizational platforms involved in protein trafficking and formation of cell signaling complexes. In the adult brain, NMDA receptors (NMDAR) and receptor-associated proteins such as membrane-associated guanylate kinases (PSD-95 and SAP102), are distributed between the postsynaptic density (PSD) and lipid rafts. However, the time course of the association of NMDAR with LR during neural development is not known. We therefore investigated the effect of development on the association of NMDAR with LR prepared from rat brains ranging in postnatal age from 1-35 days and compared this with their expression in PSDs. LR and PSD fractions were prepared by extraction of P2 membranes with Tx-100 followed by sucrose density gradient centrifugation. The yield of LR, as reflected by levels of protein, Thy-1, and flotillin-1 increased during postnatal development. NR2A was associated predominantly with the lipid raft fraction at all ages examined whereas NR2B underwent a gradual shift from PSDs to lipid rafts during the first 3 weeks after birth. These changes in the distribution of NR2A and NR2B were paralleled by changes in the distribution of PSD-95 and SAP102 respectively. Tyrosine-phosphorylated proteins, including NR2A and NR2B, were preferentially associated with lipid rafts in older, as compared to younger, animals. These results show that the association of NMDAR with LR is regulated developmentally.
authors.affiliation: Centre for the Neurobiology of Stress, Department of Life Sciences, University of Toronto Scarborough, Toronto, Canada.
authors.forename: Shintaro
authors.initials: S
authors.lastname: Besshoh
authors.forename: Sheng
authors.initials: S
authors.lastname: Chen
authors.forename: Ian R
authors.initials: IR
authors.lastname: Brown
authors.forename: James W
authors.initials: JW
authors.lastname: Gurd
mesh_terms: D000375:Aging / Q000378:metabolism; D000818:Animals; D002784:Cholesterol / Q000378:metabolism; D000076122:Disks Large Homolog 4 Protein; D004591:Electrophoresis, Polyacrylamide Gel; D015151:Immunoblotting; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D021962:Membrane Microdomains / Q000378:metabolism*; D008565:Membrane Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009479:Neuropeptides / Q000378:metabolism; D010766:Phosphorylation; D051381:Rats; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D014443:Tyrosine / Q000378:metabolism
chemical_list: D000076122:Disks Large Homolog 4 Protein; C101195:Dlg3 protein, rat; C501449:Dlg4 protein, rat; D047908:Intracellular Signaling Peptides and Proteins; D008565:Membrane Proteins; C120997:NR2A NMDA receptor; C121001:NR2B NMDA receptor; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D016194:Receptors, N-Methyl-D-Aspartate; D014443:Tyrosine; D002784:Cholesterol