Clustering based on clinicophysiologic parameters yielded 4 stable and reproducible clusters that associate with different pathobiological pathways.

SUMMARY Integral membrane proteins are found in all cellular membranes and carry out many of the functions that are essential to life. The membrane-embedded domains of integral membrane proteins are structurally quite simple, allowing the use of various prediction methods and biochemical methods to obtain structural information about membrane proteins. A critical step in the biosynthetic pathway leading to the folded protein in the membrane is its insertion into the lipid bilayer. Understanding of the fundamentals of the insertion and folding processes will significantly improve the methods used to predict the three-dimensional membrane protein structure from the amino acid sequence. In the first part of this review, biochemical approaches to elucidate membrane protein topology are reviewed and evaluated, and in the second part, the use of similar techniques to study membrane protein insertion is discussed. The latter studies search for signals in the polypeptide chain that direct the insertion process. Knowledge of the topogenic signals in the nascent chain of a membrane protein is essential for the evaluation of membrane topology studies.

Local lung epithelial IL-6TS activation in the absence of type 2 airway inflammation defines a novel subset of asthmatic patients and might drive airway inflammation and epithelial dysfunction in these patients.

U-BIOPRED cohort n=91 epithelial brushings or biopsies IL-17 High Clinical phenotype Nasal polyps Smoking Antibiotic use Epithelial Gene Expression Profile Clinical phenotype FeNO Exacerbations Gene expression shared with psoriasis IDO1 IL1B DEFB4B S100A8, S100A9 PI3 CXCL3, CXCL8 CXCL10, CCL20 Gene signature SERPINB2 POSTN CLCA1 IL-13 High T cell infiltration Neutrophilia Eosinophilia IL-17-high asthma with features of a psoriasis immunophenotype From a the Respiratory,

The predicted secondary structure model of the sodium ion-dependent citrate carrier of Klebsiella pneumoniae (CitS) presents the 12-transmembrane helix motif observed for many secondary transporters. Biochemical evidence presented in this paper is not consistent with this model. N-terminal and C-terminal fusions of CitS with the biotin acceptor domain of the oxaloacetate decarboxylase of K. pneumoniae catalyze citrate transport, showing the correct folding of the CitS part of the fusion proteins in the membrane. Proteolysis experiments with these fusion proteins revealed that the N terminus of CitS is located in the cytoplasm, while the C terminus faces the periplasm. The membrane topology was studied further by constructing a set of 20 different fusions of N-terminal fragments of the citrate transporter with the reporter enzyme alkaline phosphatase (CitS-PhoA fusions). Most fusion points were selected in hydrophilic areas flanking the putative transmembrane-spanning domains in CitS that are predicted from the hydropathy profile of the primary sequence. The alkaline phosphatase activities of cells expressing the CitS-PhoA fusions suggest that the polypeptide traverses the membrane nine times and that the C-terminal half of the protein is characterized by two large hydrophobic periplasmic loops and two large hydrophilic cytoplasmic loops.CitS belongs to the family of the 2-hydroxycarboxylate transporters in which also the citrate carriers, CitPs, of lactic acid bacteria and the malate transporter, MleP, of Lactococcus lactis are found. Since the hydrophobicity profile of CitS is very similar to the hydrophobicity profiles of CitP and MleP, it is most likely that the new structural motif of nine transmembrane segments is shared within this new transporter family.Bacterial secondary solute transporters use the free energy stored in electrochemical gradients of H ϩ and/or Na ϩ to drive the uptake of solutes by coupling the translocation of solute and cation(s) across the membrane. In Klebsiella pneumoniae a unique Na ϩ -dependent citrate carrier (CitS) is induced upon anaerobic growth on citrate (1). The gene coding for the transporter has been cloned and sequenced (2, 3), and the enzyme has been characterized and purified to homogeneity after expression in Escherichia coli. Studies with whole cells of E. coli expressing CitS and with membrane vesicles prepared from these cells have demonstrated that CitS obligatorily couples the translocation of the divalent citrate anion (Hcit 2Ϫ ) to the translocation of two sodium ions and one proton (4, 5). More recent studies with purified CitS (6) reconstituted in proteoliposomes have raised some doubt about the electrogenic nature of the translocation catalyzed by the transporter, and it was concluded that one of the two Na ϩ ions recycle during the translocation of citrate (7).The citS gene encodes a highly hydrophobic protein with a predicted molecular mass of 47,531 Da. The gene is homologous to the genes coding for the citrate carriers of lactic acid bacteria, CitPs (8, ...