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Exosomal sorting of the cytoplasmic domain of bovine leukemia virus TM Env protein
Author(s) -
Gassart Aude,
Trentin Bernadette,
Martin Marianne,
Hocquellet Agnès,
BetteBobillo Pascale,
Mamoun Robert,
Vidal Michel
Publication year - 2009
Publication title -
cell biology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.932
H-Index - 77
eISSN - 1095-8355
pISSN - 1065-6995
DOI - 10.1016/j.cellbi.2008.10.001
Subject(s) - microvesicles , endosome , ectodomain , microbiology and biotechnology , secretion , tsg101 , fusion protein , escrt , biology , chimera (genetics) , endocytic cycle , protein targeting , exosome , vesicle , protein subunit , transmembrane protein , chemistry , membrane protein , biochemistry , endocytosis , intracellular , recombinant dna , membrane , cell , microrna , receptor , gene
Exosomes are small membrane vesicles that are released into the extracellular compartment as a consequence of fusion of multivesicular endosomes with the plasma membrane. To unravel the molecular basis of protein sorting into exosomes, we have made a chimeric protein containing the cytosolic domain of the transmembrane subunit of the viral Env protein of BLV and the ectodomain of CD8 (CDTM‐BLV–CD8). When expressed in K562 cells known to constitutively secrete exosomes, the chimera was found to be very efficiently targeted to the released vesicles. Very interestingly, the cytosolic domain of the Env protein contains peptide motifs potentially recognized by components of the ESCRT machinery that could be related to chimera sorting into the vesicles. Then, quantifying the chimera secretion, we investigated the site of exosome biogenesis in K562 cells using a pharmacological approach. We present different arguments indicating that CDTM‐BLV–CD8‐containing exosomes are likely formed from a recycling endosomal/TGN compartment.