Coincidence in dendritic clustering and synaptic targeting of homer proteins and NMDA receptor complex proteins NR2B and PSD95 during development of cultured hippocampal neurons.
Homer is a scaffold protein that binds glutamate receptor complexes and actin cytoskeleton in postsynapses. The present study analyzed developmental changes in subcellular localization of Homer proteins in cultured hippocampal neurons. All three Homer family proteins, Homer 1b/c, Cupidin/Homer 2, and Homer 3, not only form heteromeric coclusters, but also localize close to the NMDA receptor complex including the NR2B subunit and PSD95 throughout dendritic and synaptic differentiation. Synaptic clustering of Homer proteins is enhanced by simultaneous blockade of NMDA receptor and cAMP phosphodiesterase activities, as is clustering of NMDA receptors. Homer proteins colocalize with actin-cytoskeletal proteins F-actin and Drebrin partially during the middle stage and to a greater extent in the late stage, and with the GluR1 subunit of AMPA receptors only in the late stage. Clustering sites of Homer are not synaptic in early-middle stages, but become synaptic in the late stage, as deduced from synaptic targeting of Bassoon, Synaptophysin, and N-cadherin. Our results indicate a coincidence in dendritic clustering in addition to developmental and activity-regulated synaptic targeting between Homer and the NMDA receptor complex.
Shiraishi
Yoko
Y
Laboratory for Molecular Neurogenesis, RIKEN Brain Science Institute, Wako, Japan.
Mizutani
Akihiro
A
Mikoshiba
Katsuhiko
K
Furuichi
Teiichi
T
D015105:3',5'-Cyclic-AMP Phosphodiesterases / Q000037:antagonists & inhibitors / Q000378:metabolism; D000199:Actins / Q000378:metabolism; D000818:Animals; D000906:Antibodies; D015820:Cadherins / Q000378:metabolism; D002352:Carrier Proteins / Q000378:metabolism*; D002454:Cell Differentiation / Q000502:physiology*; D002478:Cells, Cultured; D003712:Dendrites / Q000378:metabolism* / Q000648:ultrastructure; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D005333:Fetus; D006624:Hippocampus / Q000196:embryology* / Q000378:metabolism / Q000648:ultrastructure; D000072233:Homer Scaffolding Proteins; D007150:Immunohistochemistry; D009419:Nerve Tissue Proteins / Q000378:metabolism*; D009434:Neural Pathways / Q000196:embryology / Q000378:metabolism / Q000648:ultrastructure; D009479:Neuropeptides / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism*; D013570:Synaptic Membranes / Q000378:metabolism* / Q000648:ultrastructure; D016708:Synaptophysin / Q000378:metabolism
D015105:3',5'-Cyclic-AMP Phosphodiesterases; D000199:Actins; D000906:Antibodies; D015820:Cadherins; D002352:Carrier Proteins; D018691:Excitatory Amino Acid Antagonists; D000072233:Homer Scaffolding Proteins; D009419:Nerve Tissue Proteins; D009479:Neuropeptides; D018091:Receptors, AMPA; D016194:Receptors, N-Methyl-D-Aspartate; D016708:Synaptophysin; C113688:Bsn protein, rat; C121001:NR2B NMDA receptor; C053386:drebrins; C033652:postsynaptic density proteins