The microtubule-associated protein Tau is a major component of the neurofibrillary tangles that serve as a neuropathological hallmark of Alzheimer's disease. Tau is a substrate for protein phosphorylation at multiple sites and occurs in tangles in a hyperphosphorylated state. However, the physiological functions of Tau phosphorylation or how it may contribute mechanistically to Alzheimer's pathophysiology are not completely understood. Here, we examined the function of human Tau phosphorylation at three sites, Ser199, Ser202, and Thr205, which together comprise the AT8 sites that mark abnormal phosphorylation in Alzheimer's disease. Overexpression of wild-type Tau or mutated forms in which these sites had been changed to either unphosphorylatable alanines or phosphomimetic aspartates inhibited mitochondrial movement in the neurite processes of PC12 cells as well as the axons of mouse brain cortical neurons. However, the greatest effects on mitochondrial translocation were induced by phosphomimetic mutations. These mutations also caused expansion of the space between microtubules in cultured cells when membrane tension was reduced by disrupting actin filaments. Thus, Tau phosphorylation at the AT8 sites may have meaningful effects on mitochondrial movement, likely by controlling microtubule spacing. Hyperphosphorylation of the AT8 sites may contribute to axonal degeneration by disrupting mitochondrial transport in Alzheimer's disease.

The Drosophila melanogaster sex-peptide (melSP) is a seminal fluid component that induces postmating responses (PMR) of females via the sex-peptide receptor (SPR) . Although SP orthologs are found in many Drosophila species, their functions remain poorly characterized. It is unknown whether SP functions are conserved across species or rather specific to each species. Here, we developed a GFP-tagged melSP (G-SP) and used it to visualize cross-species binding activity to the female reproductive system of various species. First we demonstrated that ectopically expressed G-SP induced PMR in D. melanogaster females and bound to the female reproductive system, most notably to the common oviduct. No binding occurred in the females lacking SPR, indicating that G-SP binding was dependent on SPR. Next we tested whether G-SP binds to the common oviducts from 11 Drosophila species using dissected reproductive tracts. The binding was observed in six species belonging to the D. melanogaster species group, but not to those outside the group. Injection of melSP reduced the receptivity of females belonging to the D. melanogaster species group, but not of those outside the group, being consistent with the ability to bind G-SP. Thus the SP-mediated PMR appears to be limited to this species group. SPR was expressed in the oviducts at high levels in this group; therefore, we speculate that an enhanced expression of SPR in the oviduct was critical to establish the SP-mediated PMR during evolution.KEYWORDS sex-peptide; SP receptor; GFP-tag; postmating response T HE mating behavior and physiology of Drosophila melanogaster females are dramatically modified after copulation: they reject courting males by extruding their ovipositor, a behavior not seen in virgin females and start to lay many eggs (Kubli 1992). Sex-peptide (SP), a seminal fluid peptide, has been shown to play a major role in eliciting postmating response (PMR). Injection of SP into the abdominal cavity of virgin females reduces receptivity and stimulates oviposition (Chen et al. 1988) and these phenotypes can be induced by ectopic expression of SP in virgin females (Aigaki et al. 1991). Furthermore, experiments involving an SP null mutant generated by gene targeting and dsRNAi-mediated gene knockdown unambiguously demonstrated that SP is a major component in inducing changes in receptivity, ovulation, and oviposition in mated females (Liu and Kubli 2003;Chapman et al. 2003). In addition, SP stimulates food intake (Hanin et al. 2011) and activates immune response genes (Peng et al. 2005b).An extensive transgenic RNAi screen identified a receptor for sex-peptide (SPR), a G-protein-coupled receptor broadly expressed in the female reproductive tracts and in some neural tissues (Yapici et al. 2008). Mutant females deleted for SPR do not respond to mating, accept repeated mating, and maintain a low level of oviposition (Yapici et al. 2008). It has been demonstrated that SPR expression in a limited number of pickpocket-expressing neurons in the female common oviduct was...

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To realize a trivalent ion conduction in solids, the Sc 2 (WO 4 ) 3 -type structure was chosen on the basis of the mobile trivalent ions and the structure which reduces the electrostatic interaction between the framework and the mobile trivalent ionic species as much as possible. The typical conductivity of the rare earth tungstates R 2 (WO 4 ) 3 (R ) Sc, Y, and Er-Lu) with the Sc 2 (WO 4 ) 3 -type structure was found to be on the order of 10 -5 S cm -1 at 600 °C. Among the rare earth tungstates, Sc 2 (WO 4 ) 3 (σ 600°C ) 6.5 × 10 -5 S cm -1 , E a ) 44.1 kJ mol -1 ) was found to be the most suitable size for the ionic conduction with regard to the relation between the mobile ion radius and the lattice size. The rare earth ion conducting characteristics were investigated by means of the rare earth concentration cell measurements and dc electrolyses. The electromotive force measurements with the Sc-Y binary alloy and the yttrium tungsten bronze as the electrodes strongly suggest the possibility of the trivalent ion conduction of rare earths such as Sc 3+ and Y 3+ . Furthermore, by the dc electrolysis, the mobile species was clarified to be the rare earth ions Sc 3+ and Y 3+ in the rare earth tungstates with the Sc 2 (WO 4 ) 3 -type structure.

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