Type-III protein secretion systems are utilized by gram-negative pathogens to secrete building blocks of the bacterial flagellum, virulence effectors from the cytoplasm into host cells, and structural subunits of the needle complex. The flagellar type-III secretion apparatus utilizes both the energy of the proton motive force and ATP hydrolysis to energize substrate unfolding and translocation. We report formation of functional flagella in the absence of type-III ATPase activity by mutations that increased the proton motive force and flagellar substrate levels. We additionally show that increased proton motive force bypassed the requirement of the Salmonella pathogenicity island 1 virulence-associated type-III ATPase for secretion. Our data support a role for type-III ATPases in enhancing secretion efficiency under limited secretion substrate concentrations and reveal the dispensability of ATPase activity in the type-III protein export process.
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http://dx.doi.org/10.1371/journal.pgen.1004800 | DOI Listing |
Infect Immun
December 2024
Laboratory of Intracellular Bacterial Pathogens, National Centre for Biotechnology (CNB-CSIC), Madrid, Spain.
Type III protein secretion systems (T3SSs) function as multiprotein devices that span the envelope of Gram-negative bacteria using the peptidoglycan (PG) layer as scaffold. This spatial arrangement explains why modifications in PG structure can alter T3SS activity. In incorporation of non-canonical D-amino acids in the PG was shown to decrease the activity of the T3SS encoded by the pathogenicity island-1 (SPI-1) without affecting other T3SS, like the flagellum apparatus.
View Article and Find Full Text PDFCrit Rev Clin Lab Sci
January 2025
Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham, West Midlands, UK.
We present a series of three articles on the genetics and pharmacogenetics of G protein- coupled receptors (GPCR). In the first article, we discuss genetic variants of the G protein subunits and accessory proteins that are associated with human phenotypes; in the second article, we build upon this to discuss "G protein-coupled receptor (GPCR) gene variants and human genetic disease" and in the third article, we survey "G protein-coupled receptor pharmacogenomics". In the present article, we review the processes of ligand binding, GPCR activation, inactivation, and receptor trafficking to the membrane in the context of human genetic disease resulting from pathogenic variants of accessory proteins and G proteins.
View Article and Find Full Text PDFGiven the heightened risk of diabetes-related cardiovascular events associated with inactivity, this study investigates the molecular mechanisms of vascular damage in streptozotocin (STZ)-induced diabetic rats. The aim is to elucidate the impact of different exercises (interval and continuous training) and metformin on biochemical parameters, aortic injury, oxidative stress, and inflammation to provide insights into potential therapeutic interventions for diabetes-associated vascular complications. Male Wistar rats were administered a single dose of STZ (60 mg/kg) to induce diabetes.
View Article and Find Full Text PDFBMC Oral Health
December 2024
Department of Orthodontics, Central Laboratory, Hospital for Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices & Beijing Key Laboratory of Digital Stomatology & Research Center of Engineering and Technology for Computerized Dentistry Ministry of Health & NMPA Key Laboratory for Dental Materials & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Peking University School, 22th Zhongguancun South Ave, Beijing, 100081, China.
Background: Orthodontic tooth movement (OTM) relies on the remodeling of periodontal tissues, including the periodontal ligament (PDL) and alveolar bone. Collagen remodeling plays a crucial role during this process, allowing for the necessary changes in the PDL's structure and function. Endo180, an urokinase plasminogen activator receptor-associated protein, is a transmembrane receptor regulated collagen remodeling.
View Article and Find Full Text PDFSci Rep
December 2024
Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland.
Virulence of many gram-negative bacteria relies upon delivery of type three effectors into host cells. To pass through the conduit of secretion machinery the effectors need to acquire an extended conformation, and in many bacterial species specific chaperones assist in this process. In plant pathogenic bacterium Pseudomonas syringae, secretion of only few effectors requires the function of chaperones.
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