Protein lysine acetylation has emerged as a key posttranslational modification in cellular regulation, in particular through the modification of histones and nuclear transcription regulators. We show that lysine acetylation is a prevalent modification in enzymes that catalyze intermediate metabolism. Virtually every enzyme in glycolysis, gluconeogenesis, the tricarboxylic acid (TCA) cycle, the urea cycle, fatty acid metabolism, and glycogen metabolism was found to be acetylated in human liver tissue. The concentration of metabolic fuels, such as glucose, amino acids, and fatty acids, influenced the acetylation status of metabolic enzymes. Acetylation activated enoyl–coenzyme A hydratase/3-hydroxyacyl–coenzyme A dehydrogenase in fatty acid oxidation and malate dehydrogenase in the TCA cycle, inhibited argininosuccinate lyase in the urea cycle, and destabilized phosphoenolpyruvate carboxykinase in gluconeogenesis. Our study reveals that acetylation plays a major role in metabolic regulation.

Sharing of research data in public repositories has become best practice in academia. With the accumulation of massive data, network bandwidth and storage requirements are rapidly increasing. The ProteomeXchange (PX) consortium implements a mode of centralized metadata and distributed raw data management, which promotes effective data sharing. To facilitate open access of proteome data worldwide, we have developed the integrated proteome resource iProX (http://www.iprox.org) as a public platform for collecting and sharing raw data, analysis results and metadata obtained from proteomics experiments. The iProX repository employs a web-based proteome data submission process and open sharing of mass spectrometry-based proteomics datasets. Also, it deploys extensive controlled vocabularies and ontologies to annotate proteomics datasets. Users can use a GUI to provide and access data through a fast Aspera-based transfer tool. iProX is a full member of the PX consortium; all released datasets are freely accessible to the public. iProX is based on a high availability architecture and has been deployed as part of the proteomics infrastructure of China, ensuring long-term and stable resource support. iProX will facilitate worldwide data analysis and sharing of proteomics experiments.

Abscisic acid (ABA) is an important phytohormone that regulates plant stress responses. Proteins from the PYR-PYL-RCAR family were recently identified as ABA receptors. Upon binding to ABA, a PYL protein associates with type 2C protein phosphatases (PP2Cs) such as ABI1 and ABI2, inhibiting their activity; the molecular mechanisms by which PYLs mediate ABA signaling remain unknown, however. Here we report three crystal structures: apo-PYL2, (+)-ABA-bound PYL2 and (+)-ABA-bound PYL1 in complex with phosphatase ABI1. Apo-PYL2 contains a pocket surrounded by four highly conserved surface loops. In response to ABA binding, loop CL2 closes onto the pocket, creating a surface that recognizes ABI1. In the ternary complex, the CL2 loop is located near the active site of ABI1, blocking the entry of substrate proteins. Together, our data reveal the mechanisms by which ABA regulates PYL-mediated inhibition of PP2Cs.

Highlights d Discovery of prognosis-associated proteins and pathways at early stage of LUAD d Proteomics revealed three subtypes related to clinical and molecular features d Identification of subtype-specific kinases and cancerassociated phosphoproteins d Identification of potential prognostic biomarkers and drug targets in LUAD

The nucleobase/ascorbate transporter (NAT) proteins, also known as nucleobase/cation symporter 2 (NCS2) proteins, are responsible for the uptake of nucleobases in all kingdoms of life and for the transport of vitamin C in mammals. Despite functional characterization of the NAT family members in bacteria, fungi and mammals, detailed structural information remains unavailable. Here we report the crystal structure of a representative NAT protein, the Escherichia coli uracil/H(+) symporter UraA, in complex with uracil at a resolution of 2.8 Å. UraA has a novel structural fold, with 14 transmembrane segments (TMs) divided into two inverted repeats. A pair of antiparallel β-strands is located between TM3 and TM10 and has an important role in structural organization and substrate recognition. The structure is spatially arranged into a core domain and a gate domain. Uracil, located at the interface between the two domains, is coordinated mainly by residues from the core domain. Structural analysis suggests that alternating access of the substrate may be achieved through conformational changes of the gate domain.