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The targeted endocytic recycling of the T cell receptor (TCR) to the immunological synapse is essential for T cell activation. Despite this, the mechanisms that underlie the sorting of internalised receptors into recycling endosomes remain poorly understood. To build a comprehensive picture of TCR recycling during T cell activation, we developed a suite of new imaging and quantification tools centred on photoactivation of fluorescent proteins. We show that the membrane-organising proteins, flotillin-1 and -2, are required for TCR to reach Rab5-positive endosomes immediately after endocytosis and for transfer from Rab5- to Rab11a-positive compartments. We further observe that after sorting into in Rab11a-positive vesicles, TCR recycles to the plasma membrane independent of flotillin expression. Our data suggest a mechanism whereby flotillins delineate a fast Rab5-Rab11a endocytic recycling axis and functionally contribute to regulate the spatial organisation of these endosomes.
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http://dx.doi.org/10.1038/s41467-019-12352-w | DOI Listing |
J Cell Biol
November 2025
Life Sciences Institute, University of Michigan, Ann Arbor, MI, USA.
Two major protein recycling pathways have emerged as key regulators of enduring forms of synaptic plasticity, such as long-term potentiation (LTP), yet how these pathways are recruited during plasticity is unknown. Phosphatidylinositol-3-phosphate (PI(3)P) is a key regulator of endosomal trafficking and alterations in this lipid have been linked to neurodegeneration. Here, using primary hippocampal neurons, we demonstrate dynamic PI(3)P synthesis during chemical induction of LTP (cLTP), which drives coordinate recruitment of the SNX17-Retriever and SNX27-Retromer pathways to endosomes and synaptic sites.
View Article and Find Full Text PDFPharmacol Res
August 2025
Key Laboratory of Animal Genetics & Breeding and Molecular Design of Jiangsu province, College of Animal Science and Technology, Yangzhou University, Yangzhou, Jiangsu 225009, China. Electronic address:
CD36 is a multifunctional lipid transporter that facilitates long-chain fatty acid uptake and orchestrates metabolic signaling in energy-demanding tissues. Recent studies have uncovered site-specific palmitoylation as a crucial post-translational modification that governs CD36 subcellular trafficking, stabilizing its localization within lipid rafts and regulating its endocytic recycling between the plasma membrane, endosomes, and lipid droplets. This dynamic palmitoylation-depalmitoylation cycle enables CD36 to spatially and temporally couple lipid transport with signal transduction in response to nutritional and hormonal cues.
View Article and Find Full Text PDFJ Fungi (Basel)
August 2025
Departamento de Microbiología, Centro de Investigación Científica y de Educación Superior de Ensenada (CICESE), Ensenada 22860, B.C., Mexico.
Endocytosis in filamentous fungi is spatially restricted to a subapical zone known as the endocytic collar, which plays essential roles in membrane recycling and the maintenance of polarized growth. In this study, we investigated the ontogeny of the endocytic collar in by tracking fimbrin-labeled endocytic patches using confocal microscopy during conidial germination, hyphal branching, and regeneration following mechanical injury. We consistently observed an initial accumulation of endocytic patches at the hyphal tip, forming an apical cap, which later reorganized into a subapical collar.
View Article and Find Full Text PDFPLoS Genet
August 2025
Department of Molecular and Cellular Biosciences, CSIC Centro de Investigaciones Biológicas Margarita Salas, Madrid, Spain.
Using fluorescent protein-tagged F-actin reporters we studied the actin cytoskeleton in Aspergillus nidulans. F-actin probes labeled endocytic patches, contractile actin rings and the Spitzenkörper (SPK), but not exocytic cables generated by the SPK-associated formin, illuminated only by tropomyosin. The SPK actin mesh contains tropomyosin and capping protein, but not fimbrin or Arp2/3, showing that it does not involve branched actin.
View Article and Find Full Text PDFAdv Sci (Weinh)
August 2025
State Key Laboratory of Agricultural and Forestry Biosecurity & Key Lab of Biopesticide and Chemical Biology, Ministry of Education, College of Plant Protection, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
The vacuole degrades and recycles endocytic and autophagic cargos, while the retromer complex sorts cargos from the endosomes to the trans-Golgi network or the plasma membrane, thus preventing unnecessary vacuolar degradation. However, whether the retromer complex regulates vacuolar proteolytic system during autophagic substrate degradation remains unclear. This study demonstrates that the retromer complex regulates both general and selective autophagy by ensuring the delivery of vacuolar protease(s) into the vacuole lumen in the rice blast fungus Magnaporthe oryzae.
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