To obtain a comprehensive understanding of proteins involved in excitation-contraction coupling, a catalog of proteins from sarcoplasmic reticulum (SR) membrane fractions of New Zealand white rabbit skeletal muscle was analyzed by an optimized shotgun proteomic method. Light and heavy SR membrane fractions were obtained by nonlinear sucrose gradient centrifugation and separated by 1DE followed by a highly reproducible, automated LC-MS/MS on the hybrid linear ion trap (LTQ) Orbitrap mass spectrometer. By integrating as low as 1% false discovery rate as one of the features for quality control method, 483 proteins were identified from both of the two independent SR preparations. Proteins involved in calcium release unit complex, including ryanodine receptor 1, dihydropyridine receptor, calmodulin, triadin, junctin, and calsequestrin, were all detected, which offered validation for this protein identification method. Rigorous bioinformatics analysis was performed. Protein pI value, molecular weight range, hydrophobicity index, and transmembrane region were calculated using bioinformatics softwares. Eighty-three proteins were classified as hydrophobic proteins and 175 proteins were recognized as membrane proteins. Based on the proteomic analysis results, we found as the first time that not only transverse tubule but also mitochondrion physically connected to SR. The complete mapping of these proteomes may help in the elucidation of the process of excitation-contraction coupling and excitation-metabolism coupling.

To obtain a comprehensive understanding of proteins involved in mitochondrion-sarcoplasmic reticulum (SR) linking, a catalog of proteins from mitochondrion-associated membrane (MAM) of New Zealand white rabbit skeletal muscle were analyzed by an optimized shotgun proteomic method. The membrane fractions were prepared by differential centrifugation and separated by 1D electrophoresis followed by a highly reproducible, automated LC-MS/MS on the hybrid linear ion trap (LTQ)-Orbitrap mass spectrometer. By integrating as low as 1% false discovery rate as one of the features for quality control method, 459 proteins were identified from both of the two independent MAM preparations. Protein pI value, molecular weight range, and transmembrane region were calculated using bioinformatics softwares. One hundred one proteins were recognized as membrane proteins. This protein database suggested that the MAM preparations composed of proteins from mitochondrion, SR, and transverse-tubule. This result indicated mitochondria physically linked with SR in rabbit skeletal muscle, voltage-dependent anion channel 1 (VDAC1), VDAC2, and VDAC3 might participate in formation of the tethers between SR and mitochondria.

More and more social Q&A platforms are launching a new business model to monetize online knowledge. This monetizing process introduces a more complicated cost and benefit tradeoff to users, especially for askers' concerns. Much of the previous research was conducted in the context of free‐based Q&A platform, which hardly explains the triggers that motivate askers' pay intention. Based on the theories of social exchange and social capital, this study aims to identify and examine the antecedents of askers' pay intention from the perspective of benefit and cost. We empirically test our predictions based on survey data collected from 322 actual askers in a well‐known trilateral payment‐based social Q&A platform in China. The results by partial least squares (PLS) analysis indicate that besides noneconomic benefits including self‐enhancement, social support, and entertainment, financial factors such as cost and benefit have significant influences on the perceived value of using trilateral payment‐based Q&A platforms. More important, we further identify that the effect of financial benefit is moderated by perceived reciprocity belief, and the effect of perceived value is moderated by perceived trust in answerers. Our findings contribute to the previous literature by proposing a theoretical model that explains askers' behavioral intention, and the practical implications for payment‐based Q&A service providers and participants.

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Our data associated a novel lamin A/C mutation (V445E) with a sudden death form of familial LVNC. The reduced sodium current in mutant LMNA may account for the advent of malignant ventricular arrhythmias. The altered structures of three β sheets and side chains may partially explain the aggregation of lamin A/C protein subjacent to the nuclear envelope.