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OEAMV
Homera regulates the activityinduced remodeling of synaptic
structures in cultured hippocampal neurons
1 2 1 1 1
1 1 1 1
1
2
Homer1a LTP seizure
PSD95 Homer1cFactin
1h
4h8hshRNA Homer1a
knock down
Homer1a
OEAMV
PIPKα regulates neuronal microtubule depolymerase KIFA and
suppresses elongation of axon branches
1,2,3 1,2 1 4 4
1
1
2 3
4
Neuronal morphology is regulated by the cytoskeleton. Kinesin superfamily
protein 2A KIF2A depolymerizes microtubules MTs at growth cones and
regulates axon pathfinding. The factors regulating KIF2A in neurite development
remain elusive. Here, using immunoprecipitation with an antibody specific to
KIF2A, we identified phosphatidylinositol 4phosphate 5kinase PIPK as a
candidate membrane protein that regulates the activity of KIF2A. Yeast two
hybrid and biochemical assays demonstrated direct binding between KIF2A and
PIPKα. Partial colocalization of the clusters of punctate signals for these two
molecules was detected by confocal microscopy and photoactivated localization
microscopy. Additionally, the MTdepolymerizing activity of KIF2A was
enhanced in the presence of PIPKα in vitro and in vivo, suggesting a novel PIPK
mediated mechanism controlling MT dynamics in neurite remodeling.
OFAMIII
SNAP
SNARE SNARE
SNAP23 SNAP23 tSNARE
SNAP23 SNAP23
SNAP23
CreloxP
NestinCre
2
SNAP23
OFAMIII
GM130
GBF1
810
GM130 GBF1
GM130 GBF1
OFAMIII
1 1 2
1
2
7 30
15
20
15
δ2
15
δ2 20
δ2
α2 15
20
OFAMIII
Input pathway and target cell typedependent regulation of synaptic
AMPAR subunits in hippocampal CA region
1 2 3 3 3
1
1
Department of Anatomy, Hokkaido University Graduate School of Medicine,
2
Department of Anatomy, Kitasato University School of Medicine, 3 Department of
Cellular Neurobiology, Brain Research Institute, Niigata University
The AMPAtype glutamate receptor AMPAR is a tetramer of GluA subunits
GluA1A4. Subunit combinations and contents of synaptic AMPAR are the
major determinants of physiological properties of glutamatergic synapses. In
the present study, the composition of synaptic AMPAR was investigated using
subunitspecific antibodies and riboprobes in the mouse hippocampal CA1.
Multiplelabeling in situ hybridization revealed that the subunit combination
in pyramidal cells was GluA1, GluA2, and GluA3. Interneurons were high for
GluA1, GluA3, and GluA4, and almost negative for GluA2. Exceptionally,
parvalbumin PVpositive cells expressed all four subunits at high levels.
Quantitative immunogold analyses revealed that labeling densities in Schaffer
collateralCA1 pyramidal cell synapses were much higher than those in perforant
path synapses, showing input pathwaydependent distribution. Synapses on PV
positive cells displayed 23 times higher labeling densities for all four subunits
than those on PVnegative interneurons. These results indicate that the subunit
combinations and content of synaptic AMPAR are differently regulated by input
pathway and target cell typedependent manners.