1,449 research outputs found
Phosphorylation of TGB1 by protein kinase CK2 promotes barley stripe mosaic virus movement in monocots and dicots.
The barley stripe mosaic virus (BSMV) triple gene block 1 (TGB1) protein is required for virus cell-to-cell movement. However, little information is available about how these activities are regulated by post-translational modifications. In this study, we showed that the BSMV Xinjiang strain TGB1 (XJTGB1) is phosphorylated in vivo and in vitro by protein kinase CK2 from barley and Nicotiana benthamiana. Liquid chromatography tandem mass spectrometry analysis and in vitro phosphorylation assays demonstrated that Thr-401 is the major phosphorylation site of the XJTGB1 protein, and suggested that a Thr-395 kinase docking site supports Thr-401 phosphorylation. Substitution of Thr-395 with alanine (T395A) only moderately impaired virus cell-to-cell movement and systemic infection. In contrast, the Thr-401 alanine (T401A) virus mutant was unable to systemically infect N. benthamiana but had only minor effects in monocot hosts. Substitution of Thr-395 or Thr-401 with aspartic acid interfered with monocot and dicot cell-to-cell movement and the plants failed to develop systemic infections. However, virus derivatives with single glutamic acid substitutions at Thr-395 and Thr-401 developed nearly normal systemic infections in the monocot hosts but were unable to infect N. benthamiana systemically, and none of the double mutants was able to infect dicot and monocot hosts. The mutant XJTGB1T395A/T401A weakened in vitro interactions between XJTGB1 and XJTGB3 proteins but had little effect on XJTGB1 RNA-binding ability. Taken together, our results support a critical role of CK2 phosphorylation in the movement of BSMV in monocots and dicots, and provide new insights into the roles of phosphorylation in TGB protein functions
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Structural analysis of a trimeric assembly of the mitochondrial dynamin-like GTPase Mgm1.
The fusion of inner mitochondrial membranes requires dynamin-like GTPases, Mgm1 in yeast and OPA1 in mammals, but how they mediate membrane fusion is poorly understood. Here, we determined the crystal structure of Saccharomyces cerevisiae short Mgm1 (s-Mgm1) in complex with GDP. It revealed an N-terminal GTPase (G) domain followed by two helix bundles (HB1 and HB2) and a unique C-terminal lipid-interacting stalk (LIS). Dimers can form through antiparallel HB interactions. Head-to-tail trimers are built by intermolecular interactions between the G domain and HB2-LIS. Biochemical and in vivo analyses support the idea that the assembly interfaces observed here are native and critical for Mgm1 function. We also found that s-Mgm1 interacts with negatively charged lipids via both the G domain and LIS. Based on these observations, we propose that membrane targeting via the G domain and LIS facilitates the in cis assembly of Mgm1, potentially generating a highly curved membrane tip to allow inner membrane fusion
Measuring Star-formation Rate and Far-Infrared Color in High-redshift Galaxies Using the CO (7-6) and [NII] 205 micron Lines
To better characterize the global star formation (SF) activity in a galaxy,
one needs to know not only the star formation rate (SFR) but also the
rest-frame, far-infrared (FIR) color (e.g., the 60-to-100 m color,
] of the dust emission. The latter probes the average intensity of
the dust heating radiation field and scales statistically with the effective
SFR surface density in star-forming galaxies including (ultra-)luminous
infrared galaxies [(U)LIRGs]. To this end, we exploit here a new spectroscopic
approach involving only two emission lines: CO\,(76) at 372 m and [NII]
at 205 m. For local (U)LIRGs, the ratios of the CO (76) luminosity
() to the total infrared luminosity (; 81000
m) are fairly tightly distributed (to within 0.12 dex) and show
little dependence on . This makes a good SFR
tracer, which is less contaminated by active galactic nuclei (AGN) than and may also be much less sensitive to metallicity than . Furthermore, the logarithmic [NII] 205 m to CO (76)
luminosity ratio is fairly steeply (at a slope of ) correlated with
, with a modest scatter (0.23 dex). This makes it a useful
estimator on with an implied uncertainty of 0.15 [or
4 K in the dust temperature () in the case of a
graybody emission with K and a dust emissivity index
]. Our locally calibrated SFR and estimators are shown
to be consistent with the published data of (U)LIRGs of up to 6.5.Comment: 6 pages, 3 figures, 1 table; accepted for publication in the ApJ
Lette
Evaluating the performance of the government venture capital guiding fund using the intuitionistic fuzzy analytic hierarchy process
The Volcker Rule and the hedge fund liquidity circle
The implementation of the Volcker Rule (section 619 of the 2010 Dodd-Frank Act)profoundly impacts the funding liquidity of hedge funds, their liquidity risk exposure and liquidity provision to the market. Analysing a sample of 5,697 hedge funds, we find that following the legislation, capital flows to hedge funds decline, and their flow-performance sensitivity increases. Hedge funds reduce their market liquidity exposure and realign their market-making activities towards the most liquid stocks. These results support the Brunnermeier-Pedersen model of illiquidity spirals
Evaluating the performance of the government venture capital guiding fund using the intuitionistic fuzzy analytic hierarchy process
The performance evaluation of the government venture capital guiding fund (GVCGF) has come into focus in the field of venture capital. Most of the existing studies, such as whether the GVCGF has guided social capital to start-up enterprises and has played its due role in the process of enterprise growth and innovation, are all based on relevant work under the framework of econometric analysis. Unlike in these existing studies, we construct the performance analysis model of the GVCGF from four dimensions, including the standardization development of the guidance fund, the risk control ability, and the leverage and the support effects under the framework of a multi-attribute decision-making analysis. Taking a GVCGF project in Ningbo City, China, as an example, we comprehensively evaluate the development performance of the GVCGF using the intuitionistic fuzzy analytic hierarchy process (IFAHP). The results show that the development performance of the GVCGF is at a “relatively high” level. Compared with the traditional analytic hierarchy process (AHP), the IFAHP effectively avoids the false, enlarged influence caused by data subjectivity and evaluation uncertainty. This study provides a feasible analytical framework for the application of the IFAHP in other project performance evaluations
Capital Inflows and House Prices: Aggregate and Regional Evidence from China
Rising house prices in China have been of concern for investors and policymakers. Prices have risen substantially in the last decade, especially in large urban cities, and some economists have expressed concerns about the affordability of residential housing for young adults. This phenomenon becomes a major concern for policymakers, in terms of managing policies to balance the residential needs of individuals and the transition to a market economy. Theoretically, house prices ought to be linked to economic factors such as disposable income, availability of land to build and credit policy. However, it appears that traditional economic theories fail to appropriately explain house prices in China. We provide an explanation from the perspective of capital inflows into China. In terms of per capita remittances, China receives the highest inflow of foreign capital, and this may have a significant impact on risk adjusted returns in the Chinese market. To investigate this relationship, we use the vector error correction model to assess the impact of capital inflows on house prices. We find that capital inflows have a significant positive effect on house prices. The study makes important contributions to understanding the relationship between house prices and foreign remittances after controlling for other economic factors. China is a large economy. Because the impact of economic development in China has not been consistent across the country, we address the regional differences in the house price changes to capital inflows. Using regional data, we show that capital inflows have an asymmetric effect on the housing market across different provinces and cities of China. This has important implications for the development of economic policies in China that aim to provide fair access to residential housing for everyone. These findings are also relevant to investors in the housing market, whether investing for a personal residential home or as part of their diversified investment portfolio. It will also be informative to see how a reversal of capital inflows associated with tighter financing conditions in advanced countries will affect house prices in China.No Full Tex
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