PLD (phospholipase D) activity catalyses the generation of the lipid messenger phosphatidic acid, which has been implicated in a number of cellular processes, particularly the regulation of membrane traffic. In the present study, we report that disruption of PLD signalling causes unexpectedly profound effects on the actin-based motility of Dictyostelium. Cells in which PLD activity is inhibited by butan-1-ol show a complete loss of actin-based structures, accompanied by relocalization of F-actin into small clusters, and eventually the nucleus, without a visible fall in levels of F-actin. Addition of exogenous phosphatidic acid reverses the effects of butan-1-ol, confirming that these effects are caused by inhibition of PLD. Loss of motility correlates with complete inhibition of endocytosis and a reduction in phagocytosis. Inhibition of PLD caused a major decrease in the synthesis of PtdIns(4,5)P2, which could again be reversed by exogenously applied phosphatidic acid. Thus the essential role of PLD signalling in both motility and endocytosis appears to be mediated directly via regulation of PtdIns(4)P kinase activity. This implies that localized PLD-regulated synthesis of PtdIns(4,5)P2 is essential for Dictyostelium actin function.
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http://dx.doi.org/10.1042/BJ20050085 | DOI Listing |
Cell Death Dis
January 2025
College of Pharmacy, Dali University, Dali 671003, Yunnan, PR China.
Asparagine endopeptidase (AEP) is ubiquitously expressed in both physiological and pathological contexts, yet its precise role and functional mechanism in breast cancer remain elusive. Here, we identified increased AEP expression in breast cancer tissues, which correlated with poorer survival rates and a propensity for lung metastasis among breast cancer patients. Loss of AEP impaired colony formation by breast cancer cells in vitro and suppressed lung metastasis in mice.
View Article and Find Full Text PDFSci Transl Med
January 2025
Rady Children's Institute for Genomic Medicine, San Diego, CA 92123, USA.
Mutations in lipid regulator genes are a frequent cause of autism spectrum disorder, including those regulating phosphatidylinositol (PI) and phosphoinositide 3-kinase signaling. encodes a key acyltransferase in PI synthesis and is mutated in an autism-related condition with neurodevelopmental delay and epilepsy. Using liquid chromatography-tandem mass spectrometry, we analyzed the PI-associated glycerolipidome in mice and humans during neurodevelopment and found dynamic regulation at times corresponding to neural apoptosis in the brains of knockout mice.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department of Molecular Genetics, University of Texas Southwestern Medical Center, Dallas, TX 75390.
Spns1 mediates the rate-limiting efflux of lysophospholipids from the lysosome to the cytosol. Deficiency of Spns1 is associated with embryonic senescence, as well as liver and skeletal muscle atrophy in animal models. However, the mechanisms by which Spns1 transports lysophospholipid and proton sensing remain unclear.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
January 2025
Department Biochemistry of Neurodegenerative Diseases, Institute of Biochemistry and Pathobiochemistry, Ruhr University Bochum, Bochum 44801, Germany.
Protein misfolding and aggregation are a hallmark of various neurodegenerative disorders. However, the underlying mechanisms driving protein misfolding in the cellular context are incompletely understood. Here, we show that the two-dimensional confinement imposed by a membrane anchor stabilizes the native protein conformation and suppresses liquid-liquid phase separation (LLPS) and protein aggregation.
View Article and Find Full Text PDFBMC Pediatr
December 2024
Department of Intensive Care Unit, Hangzhou Women's Hospital, Hangzhou, 310016, Zhejiang, China.
Background: To compare the impact of two different lipid emulsions, specifically a soybean oil-based emulsion and a multiple oil emulsion (soybean oil, medium-chain triglycerides, olive oil, and fish oil, SMOF), on serum metabolites of very low birth weight (VLBW) infants using untargeted metabolomics analysis.
Methods: A comparative study was conducted on 25 VLBW infants hospitalized in neonatal intensive care units (NICU) of Hangzhou Women's Hospital in 2023. The infants were divided into the SMOF group (13 cases) and the soybean oil group (12 cases) based on the type of lipid emulsion used during parenteral nutrition.
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