Targeting of proteins of the striatin family to dendritic spines: role of the coiled-coil domain.
Striatin, SG2NA and zinedin, the three mammalian members of the striatin family are multimodular WD-repeat, calmodulin and calveolin-binding proteins. These scaffolding proteins, involved in both signaling and trafficking, are highly expressed in neurons. Using ultrastructural immunolabeling, we showed that, in Purkinje cells and hippocampal neurons, SG2NA is confined to the somatodendritic compartment with the highest density in dendritic spines. In cultured hippocampal neurons, SG2NA is also highly concentrated in dendritic spines. By expressing truncated forms of HA-tagged SG2NAbeta, we demonstrated that the coiled-coil domain plays an essential role in the targeting of SG2NA within spines. Furthermore, co-immunoprecipitation experiments indicate that this coiled-coil domain is also crucial for the homo- and hetero-oligomerization of these proteins. Thus, oligomerization of the striatin family proteins is probably an obligatory step for their routing to the dendritic spines, and hetero-oligomerization explains why all these proteins are often co-expressed in the neurons of the rat brain and spinal cord.
Gaillard
Stéphane
S
INSERM-UMR 641, Institut Jean Roche, Université de la Méditerranée, Faculté de Médecine Secteur-Nord, Marseille, France.
Bailly
Yannick
Y
Benoist
Marion
M
Rakitina
Tatiana
T
Kessler
Jean-Pierre
JP
Fronzaroli-Molinières
Laure
L
Dargent
Bénédicte
B
Castets
Francis
F
D000818:Animals; D001324:Autoantigens / Q000096:biosynthesis*; D019556:COS Cells; D002148:Calmodulin-Binding Proteins / Q000096:biosynthesis*; D002478:Cells, Cultured; D002522:Chlorocebus aethiops; D049229:Dendritic Spines / Q000737:chemistry / Q000378:metabolism*; D018014:Gene Transfer Techniques; D008565:Membrane Proteins / Q000096:biosynthesis*; D051379:Mice; D008810:Mice, Inbred C57BL; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000096:biosynthesis*; D017434:Protein Structure, Tertiary / Q000502:physiology; D051381:Rats; D015398:Signal Transduction
D001324:Autoantigens; D002148:Calmodulin-Binding Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C114095:Strn protein, rat; C485774:Strn3 protein, rat; C411649:zinedin