Ayse Dosemeci19
Jung-Hwa Tao-Cheng15
19Ayse Dosemeci
15Jung-Hwa Tao-Cheng
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Much is known about the composition and function of the postsynaptic density (PSD), but less is known about its molecular organization. We use EM tomography to delineate the organization of PSDs at glutamatergic synapses in rat hippocampal cultures. The core of the PSD is dominated by vertically oriented filaments, and ImmunoGold labeling shows that PSD-95(More)
Postsynaptic densities (PSDs) contain proteins that regulate synaptic transmission. We determined the positions of calcium/calmodulin-dependent protein kinase II (CaMKII) and PSD-95 within the three-dimensional structure of isolated PSDs using immunogold labeling, rotary shadowing, and electron microscopic tomography. The results show that all PSDs contain(More)
Calcium/calmodulin-dependent protein kinase II (CaMKII) is a leading candidate for a synaptic memory molecule because it is persistently activated after long-term potentiation (LTP) induction and because mutations that block this persistent activity prevent LTP and learning. Previous work showed that synaptic stimulation causes a rapidly reversible(More)
The total molecular mass of individual postsynaptic densities (PSDs) isolated from rat forebrain was measured by scanning transmission EM. PSDs had a mean diameter of 360 nm and molecular mass of 1.10 +/- 0.36 GDa. Because the mass represents the sum of the molecular masses of all of the molecules comprising a PSD, it becomes possible to derive the number(More)
PSD-95, a membrane-associated guanylate kinase, is the major scaffolding protein in the excitatory postsynaptic density (PSD) and a potent regulator of synaptic strength. Here we show that PSD-95 is in an extended configuration and positioned into regular arrays of vertical filaments that contact both glutamate receptors and orthogonal horizontal elements(More)
SynGAP, a protein abundant at the postsynaptic density (PSD) of glutamatergic neurons, is known to modulate synaptic strength by regulating the incorporation of AMPA receptors at the synapse. Two isoforms of SynGAP, α1 and α2, which differ in their C-termini, have opposing effects on synaptic strength. In the present study, antibodies specific for SynGAP-α1(More)
We compared the distribution of three scaffolding proteins, all belonging to a family of membrane-associated guanylate kinases, thought to have key roles in the organization of the postsynaptic density (PSD). Isolated PSDs readily adhered to treated glass coverslips where they were labeled with immunogold and rotary shadowed for analysis by EM. The(More)
The number of AMPA receptors at synapses depends on receptor cycling. Because receptors diffuse rapidly in plasma membranes, their exocytosis and endocytosis need not occur near synapses. Here, pre-embedding immunogold electron microscopy is applied to dissociated rat hippocampal cultures to provide sensitive, high-resolution snapshots of the distribution(More)
BACKGROUND Many bacteria swim by rotating helical flagellar filaments. Waterbury et al. discovered an exception, strains of the cyanobacterium Synechococcus that swim without flagella or visible changes in shape. Other species of cyanobacteria glide on surfaces. The hypothesis that Synechococcus might swim using traveling surface waves prompted this(More)