@article{FazeliStetterLisacketal.2018,
  author    = {Fazeli, Gholamreza and Stetter, Maurice and Lisack, Jaime N. and Wehman, Ann M.},
  title     = {C. elegans Blastomeres Clear the Corpse of the Second Polar Body by LC3-Associated Phagocytosis},
  series = {Cell Reports},
  volume    = {23},
  journal   = {Cell Reports},
  doi       = {10.1016/j.celrep.2018.04.043},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-227651},
  pages     = {2070-2082},
  year      = {2018},
  abstract  = {To understand how undifferentiated pluripotent cells cope with cell corpses, we examined the clearance of polar bodies born during female meiosis. We found that polar bodies lose membrane integrity and expose phosphatidylserine in Caenorhabditis elegans. Polar body signaling recruits engulfment receptors to the plasma membrane of embryonic blastomeres using the PI3K VPS-34, RAB-5 GTPase and the sorting nexin SNX-6. The second polar body is then phagocytosed using receptor-mediated engulfment pathways dependent on the Rac1 ortholog CED-10 but undergoes non-apoptotic programmed cell death independent of engulfment. RAB-7 GTPase is required for lysosome recruitment to the polar body phagosome, while LC3 lipidation is required for degradation of the corpse membrane after lysosome fusion. The polar body phagolysosome vesiculates in an mTOR- and ARL-8-dependent manner, which assists its timely degradation. Thus, we established a genetic model to study clearance by LC3-associated phagocytosis and reveal insights into the mechanisms of phagosome maturation and degradation.},
  language  = {en}
}
@article{FazeliBeerGeisenhofetal.2020,
  author    = {Fazeli, Gholamreza and Beer, Katharina B. and Geisenhof, Michaela and Tr{\"o}ger, Sarah and K{\"o}nig, Julia and M{\"u}ller-Reichert, Thomas and Wehman, Ann M.},
  title     = {Loss of the Major Phosphatidylserine or Phosphatidylethanolamine Flippases Differentially Affect Phagocytosis},
  series = {Frontiers in Cell and Developmental Biology},
  volume    = {8},
  journal   = {Frontiers in Cell and Developmental Biology},
  issn      = {2296-634X},
  doi       = {10.3389/fcell.2020.00648},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-208771},
  year      = {2020},
  abstract  = {The lipids phosphatidylserine (PtdSer) and phosphatidylethanolamine (PtdEth) are normally asymmetrically localized to the cytosolic face of membrane bilayers, but can both be externalized during diverse biological processes, including cell division, cell fusion, and cell death. Externalized lipids in the plasma membrane are recognized by lipid-binding proteins to regulate the clearance of cell corpses and other cell debris. However, it is unclear whether PtdSer and PtdEth contribute in similar or distinct ways to these processes. We discovered that disruption of the lipid flippases that maintain PtdSer or PtdEth asymmetry in the plasma membrane have opposite effects on phagocytosis in Caenorhabditis elegans embryos. Constitutive PtdSer externalization caused by disruption of the major PtdSer flippase TAT-1 led to increased phagocytosis of cell debris, sometimes leading to two cells engulfing the same debris. In contrast, PtdEth externalization caused by depletion of the major PtdEth flippase TAT-5 or its activator PAD-1 disrupted phagocytosis. These data suggest that PtdSer and PtdEth externalization have opposite effects on phagocytosis. Furthermore, externalizing PtdEth is associated with increased extracellular vesicle release, and we present evidence that the extent of extracellular vesicle accumulation correlates with the extent of phagocytic defects. Thus, a general loss of lipid asymmetry can have opposing impacts through different lipid subtypes simultaneously exerting disparate effects.},
  language  = {en}
}
@article{GoosDejungWehmanetal.2019,
  author    = {Goos, Carina and Dejung, Mario and Wehman, Ann M. and M-Natus, Elisabeth and Schmidt, Johannes and Sunter, Jack and Engstler, Markus and Butter, Falk and Kramer, Susanne},
  title     = {Trypanosomes can initiate nuclear export co-transcriptionally},
  series = {Nucleic Acids Research},
  volume    = {47},
  journal   = {Nucleic Acids Research},
  number    = {1},
  doi       = {10.1093/nar/gky1136},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-177709},
  pages     = {266-282},
  year      = {2019},
  abstract  = {The nuclear envelope serves as important messenger RNA (mRNA) surveillance system. In yeast and human, several control systems act in parallel to prevent nuclear export of unprocessed mRNAs. Trypanosomes lack homologues to most of the involved proteins and their nuclear mRNA metabolism is non-conventional exemplified by polycistronic transcription and mRNA processing by trans-splicing. We here visualized nuclear export in trypanosomes by intra- and intermolecular multi-colour single molecule FISH. We found that, in striking contrast to other eukaryotes, the initiation of nuclear export requires neither the completion of transcription nor splicing. Nevertheless, we show that unspliced mRNAs are mostly prevented from reaching the nucleus-distant cytoplasm and instead accumulate at the nuclear periphery in cytoplasmic nuclear periphery granules (NPGs). Further characterization of NPGs by electron microscopy and proteomics revealed that the granules are located at the cytoplasmic site of the nuclear pores and contain most cytoplasmic RNA-binding proteins but none of the major translation initiation factors, consistent with a function in preventing faulty mRNAs from reaching translation. Our data indicate that trypanosomes regulate the completion of nuclear export, rather than the initiation. Nuclear export control remains poorly understood, in any organism, and the described way of control may not be restricted to trypanosomes.},
  language  = {en}
}