title: Tetrameric hub structure of postsynaptic scaffolding protein homer.
abstract: Homer is a crucial postsynaptic scaffolding protein involved in both maintenance and activity-induced plasticity of the synapse. However, its quaternary structure has yet to be determined. We conducted a series of biophysical experiments that provide the first evidence that Homer forms a tetramer via its coiled-coil domain, in which all subunits are aligned in parallel orientation. To test the importance of the tetrameric structure for functionality, we engineered dimeric and tetrameric Homer by deleting a part of coiled-coil domain or replacing it with artificially engineered dimeric or tetrameric coiled-coil domain from a yeast protein. The structure-activity relationship was determined by assaying cocluster formation with its ligand in heterologous cells, distribution in dendritic spines, and turnover rate of protein exist in dendritic spines. Our results provide the first insight into the structure of native Homer protein as a tetramer and the functional significance conferred by that structure.
authors.affiliation: RIKEN-MIT Neuroscience Research Center, The Picower Institute for Learning and Memory, Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
authors.forename: Mariko Kato
authors.initials: MK
authors.lastname: Hayashi
authors.forename: Heather M
authors.initials: HM
authors.lastname: Ames
authors.forename: Yasunori
authors.initials: Y
authors.lastname: Hayashi
mesh_terms: D000818:Animals; D055592:Biophysical Phenomena; D001703:Biophysics; D019556:COS Cells; D002352:Carrier Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism / Q000502:physiology; D002522:Chlorocebus aethiops; D049229:Dendritic Spines / Q000378:metabolism; D031541:Fluorescence Resonance Energy Transfer; D000072233:Homer Scaffolding Proteins; D006801:Humans; D008024:Ligands; D011487:Protein Conformation; D015202:Protein Engineering; D020033:Protein Isoforms / Q000378:metabolism; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary / Q000502:physiology; D051381:Rats; D018094:Receptors, Metabotropic Glutamate / Q000378:metabolism; D013329:Structure-Activity Relationship; D013569:Synapses / Q000378:metabolism; D013997:Time Factors
chemical_list: D002352:Carrier Proteins; D000072233:Homer Scaffolding Proteins; D008024:Ligands; D020033:Protein Isoforms; D018094:Receptors, Metabotropic Glutamate; C104077:metabotropic glutamate receptor type 1