Toll-like receptors (TLRs) activate innate immunity in response to pathogen-associated molecular patterns (PAMPs). The ectodomain of a TLR directly senses a PAMP and the intracellular TIR domain dimerizes to initiate a signaling cascade. The TIR domains of TLR6 and TLR10, which belong to the TLR1 subfamily, have been structurally characterized in a dimer, whereas those of other subfamilies, including TLR15, have not been explored at the structural or molecular level.
View Article and Find Full Text PDFBiochem Biophys Res Commun
December 2022
Spermidine is a cationic polyamine that plays key roles in diverse biological processes, including biofilm formation and cell viability in bacteria. In some human gastrointestinal bacteria, such as Helicobacter pylori and Campylobacter jejuni, spermidine is biosynthesized using carboxyspermidine dehydrogenase (CASDH) and carboxyspermidine decarboxylase through an alternative pathway rather than the classical pathway found in most bacteria and eukaryotes. CASDH condenses putrescine and aspartate β-semialdehyde into carboxyspermidine in an NADPH-dependent manner.
View Article and Find Full Text PDFLegionella pneumophila infects alveolar macrophages and can cause life-threatening pneumonia in humans. Upon internalization into the host cell, L. pneumophila injects numerous effector proteins into the host cytoplasm as a part of its pathogenesis.
View Article and Find Full Text PDF