Motor Deficits and Decreased Striatal Dopamine Receptor 2 Binding Activity in the Striatum-Specific Dyt1 Conditional Knockout Mice

DYT1 early-onset generalized dystonia is a hyperkinetic movement disorder caused by mutations in DYT1 (TOR1A), which codes for torsinA. Recently, significant progress has been made in studying pathophysiology of DYT1 dystonia using targeted mouse models. Dyt1 ΔGAG heterozygous knock-in (KI) and Dyt1 knock-down (KD) mice exhibit motor deficits and alterations of striatal dopamine metabolisms, while Dyt1 knockout (KO) and Dyt1 ΔGAG homozygous KI mice show abnormal nuclear envelopes and neonatal lethality. However, it has not been clear whether motor deficits and striatal abnormality are caused by Dyt1 mutation in the striatum itself or the end results of abnormal signals from other brain regions. To identify the brain region that contributes to these phenotypes, we made a striatum-specific Dyt1 conditional knockout (Dyt1 sKO) mouse. Dyt1 sKO mice exhibited motor deficits and reduced striatal dopamine receptor 2 (D2R) binding activity, whereas they did not exhibit significant alteration of striatal monoamine contents. Furthermore, we also found normal nuclear envelope structure in striatal medium spiny neurons (MSNs) of an adult Dyt1 sKO mouse and cerebral cortical neurons in cerebral cortex-specific Dyt1 conditional knockout (Dyt1 cKO) mice. The results suggest that the loss of striatal torsinA alone is sufficient to produce motor deficits, and that this effect may be mediated, at least in part, through changes in D2R function in the basal ganglia circuit

TorsinA and the TorsinA-Interacting Protein Printor Have No Impact on Endoplasmic Reticulum Stress or Protein Trafficking in Yeast

Early-onset torsion dystonia is a severe, life-long disease that leads to loss of motor control and involuntary muscle contractions. While the molecular etiology of the disease is not fully understood, a mutation in an AAA+ ATPase, torsinA, has been linked to disease onset. Previous work on torsinA has shown that it localizes to the endoplasmic reticulum, where there is evidence that it plays roles in protein trafficking, and potentially also protein folding. Given the high level of evolutionary conservation among proteins involved in these processes, the ability of human such proteins to function effectively in yeast, as well as the previous successes achieved in examining other proteins involved in complex human diseases in yeast, we hypothesized that Saccharomyces cerevisiae might represent a useful model system for studying torsinA function and the effects of its mutants. Since torsinA is proposed to function in protein homeostasis, we tested cells for their ability to respond to various stressors, using a fluorescent reporter to measure the unfolded protein response, as well as their rate of protein secretion. TorsinA did not impact these processes, even after co-expression of its recently identified interacting partner, printor. In light of these findings, we propose that yeast may lack an additional cofactor necessary for torsinA function or proteins required for essential post-translational modifications of torsinA. Alternatively, torsinA may not function in endoplasmic reticulum protein homeostasis. The strains and assays we describe may provide useful tools for identifying and investigating these possibilities and are freely available.Howard Hughes Medical InstituteBachmann-Strauss Dystonia and Parkinson Foundatio

Human TorsinA can function in the yeast cytosol as a molecular chaperone

TorsinA (TorA) is an AAA+ ATPAse linked to dystonia type 1 (DYT1), a neurological disorder that leads to uncontrollable muscular movements. Although DYT1 is linked to a 3bp deletion in the C terminus of TorA, the biological function of TorA remains to be established. Here we use the yeast Saccharomyces cerevisiae as a tractable in vivo model to explore TorA function. We demonstrate that TorA can protect yeast cells against different forms of environmental stress and show that in the absence of the molecular disaggregase Hsp104, TorA can refold heat-denatured luciferase in vivo in an ATP-dependent manner. However, this activity requires TorA to be translocated to the cytoplasm from the ER in order to access and process cytoplasmic protein aggregates. Furthermore, mutational or chemical inactivation of the ATPase activity of TorA blocks this activity. We also find that TorA can inhibit the propagation of certain conformational variants of [ PSI +], the aggregated prion form of the endogenous Sup35 protein. Finally, we show that while cellular localisation remains unchanged in the dystonia-linked TorA mutant ?E302-303, the ability of this mutant form of TorA to protect against cellular stress and to facilitate protein refolding, is impaired, consistent with it being a loss of function mutation

The effectiveness of groupware technology implementation in a multinational company

The effectiveness of groupware technology implementation in a multinational compan

Analisys of information technology investment to improve productivity and effeciency in insurance broker industry. Acase study PT. Duta Sewu Raya Insurance Brokers.

Analisys of information technology investment to improve productivity and effeciency in insurance broker industry. Acase study PT. Duta Sewu Raya Insurance Brokers

Functionalization of large-pore mesoporous silicas with organosilanes by direct synthesis

Functionalization of porous solids plays an important role in many technical aspects such as enzyme immobilization. In this study, functionalized large-pore mesoporous materials with a P6mm symmetry were synthesized by co-condensation of tetraethyl orthosilicate (TEOS) and organosilanes 3-aminopropyltriethoxysilane (APTES), 3-mercaptopropylmethoxysilane (MPTMS), phenyltrimethoxysilane (PTMS), vinyltriethoxysilane (VTES), and 4-(triethoxysilyl)butyronitrile (TSBN) in the presence of nonionic triblock co-polymer Pluronic P 123 under acidic conditions. The effect of the organosilanes present in the initial synthesis mixtures on the mesostructural properties of the resultant materials was systematically studied by varying the molar ratios of organosilane to TEOS. Solid-state nuclear magnetic resonance (NMR), X-ray photoelectron spectroscopy (XPS), thermogravimetric analysis (TGA), and elemental analysis data demonstrated the presence of the functional groups both on the pore surface and inside the solid matrixes. Nitrogen adsorption, small-angle X-ray scattering (SAXS), and transmission electron microscopy (TEM) results showed different levels of disorder of the mesostructures upon incorporation of the functional groups, which are dependent upon the type and amount of the organosilanes present in the initial synthesis mixtures. Among the organosilanes studied, their disruptive effects on the formation of the mesostructure follow VTES < TSBN < PTMS equivalent to MPTMS < APTES. Such different effects are interpreted in terms of their different behaviors under acidic synthetic conditions and steric molecular sizes and shapes, which have direct impact on interactions of P123 with silicate species and on micellation of P123 template. (C) 2004 Elsevier Inc. All rights reserved