The inflammasome-mediated cleavage of gasdermin D (GSDMD) causes pyroptosis and inflammatory cytokine release to control pathogen infection, but how pathogens evade this immune response remains largely unexplored. Here we identify the known protein phosphatase PtpB from as a phospholipid phosphatase inhibiting the host inflammasome-pyroptosis pathway. Mechanistically, PtpB dephosphorylated phosphatidylinositol-4-monophosphate and phosphatidylinositol-(4,5)-bisphosphate in host cell membrane, thus disrupting the membrane localization of the cleaved GSDMD to inhibit cytokine release and pyroptosis of macrophages. Notably, this phosphatase activity requires PtpB binding to ubiquitin. Disrupting phospholipid phosphatase activity or the ubiquitin-interacting motif of PtpB enhanced host GSDMD-dependent immune responses and reduced intracellular pathogen survival. Thus, pathogens inhibit pyroptosis and counteract host immunity by altering host membrane composition.
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http://dx.doi.org/10.1126/science.abq0132 | DOI Listing |
J Agric Food Chem
January 2025
School of Tropical Agriculture and Forestry & Sanya Institute Breeding and Multiplication, Hainan University, Haikou/Sanya 570228/572025, China.
Stylo () exhibits excellent tolerance to low-phosphate (Pi) availability, but the underlying mechanisms responsible for improving the phosphorus (P) utilization efficiency (PUE) remain unclear. This study employed metabolomics, lipidomics, and gene expression analyses to investigate the differential responses to low-Pi stress between the high-PUE genotype CF047827 and the cultivar Reyan No. 2.
View Article and Find Full Text PDFMethods Mol Biol
January 2025
Estrella Mountain Community College, Phoenix, AZ, USA.
Vacuole fusion is driven by SNARE proteins that require activation-or priming-by the AAA+ protein Sec18 (NSF) before they can bring membranes together and trigger the merger of two bilayers into a continuous membrane. Sec18 resides on vacuoles prior to engaging inactive cis-SNARE complexes through its interaction with the regulatory lipid phosphatidic acid (PA). Binding PA causes Sec18 to undergo large conformational changes that keeps it bound to the membrane, thus precluding its interactions with SNAREs.
View Article and Find Full Text PDFAdv Biol Regul
January 2025
Department of Food Science and the Rutgers Center for Lipid Research, Rutgers University, New Brunswick, NJ, 08901, USA.
Phosphatidic acid phosphatase, a conserved eukaryotic enzyme that catalyzes the Mg-dependent dephosphorylation of phosphatidic acid to produce diacylglycerol, has emerged as a vital regulator of lipid homeostasis. By controlling the balance of phosphatidic acid and diacylglycerol, the enzyme governs the use of the lipids for synthesis of the storage lipid triacylglycerol and the membrane phospholipids needed for cell growth. The mutational, biochemical, and cellular analyses of yeast phosphatidic acid phosphatase have provided insights into the structural determinants of enzyme function with the understanding of its regulation by phosphorylation and dephosphorylation.
View Article and Find Full Text PDFInt J Mol Sci
December 2024
Department of Applied Biological Science, Tokyo University of Agriculture and Technology, Fuchu 183-8509, Japan.
Soluble epoxide hydrolase (sEH) is a bifunctional enzyme with epoxide hydrolase activity in the C-terminal domain (C-EH) and lipid phosphate phosphatase activity in the N-terminal domain (N-phos). The C-EH hydrolyzes bioactive epoxy fatty acids such as epoxyeicosatrienoic acid (EET). The N-phos hydrolyzes lipid phosphomonesters, including the signaling molecules of lysophosphatidic acid (LPA).
View Article and Find Full Text PDFbioRxiv
December 2024
Department of Pharmacology, University of Alberta, Edmonton, AB T6G 2E1, Canada.
Diabetes is associated with the dysfunction of glucagon-producing pancreatic islet α-cells, although the underlying mechanisms regulating glucagon secretion and α-cell dysfunction remain unclear. While insulin secretion from pancreatic β-cells has long been known to be partly controlled by intracellular phospholipid signaling, very little is known about the role of phospholipids in glucagon secretion. Here we show that TMEM55A, a lipid phosphatase that dephosphorylates phosphatidylinositol-4,5-bisphosphate (PIP2) to phosphatidylinositol-5-phosphate (PI5P), regulates α-cell exocytosis and glucagon secretion.
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