Exosomes are small vesicles that are secreted by cells and act as mediators of cell to cell communication. Because of their potential therapeutic significance, important efforts are being made towards characterizing exosomal contents. However, little is known about the mechanisms that govern exosome biogenesis. We have recently shown that the exosomal protein syntenin supports exosome production. Here we identify the small GTPase ADP ribosylation factor 6 (ARF6) and its effector phospholipase D2 (PLD2) as regulators of syntenin exosomes. ARF6 and PLD2 affect exosomes by controlling the budding of intraluminal vesicles (ILVs) into multivesicular bodies (MVBs). ARF6 also controls epidermal growth factor receptor degradation, suggesting a role in degradative MVBs. Yet ARF6 does not affect HIV-1 budding, excluding general effects on Endosomal Sorting Complexes Required for Transport. Our study highlights a novel pathway controlling ILV budding and exosome biogenesis and identifies an unexpected role for ARF6 in late endosomal trafficking.
- MeSH
- ADP-ribosylační faktory genetika metabolismus MeSH
- buněčné linie MeSH
- endozomální třídící komplexy pro transport genetika metabolismus MeSH
- erbB receptory metabolismus MeSH
- exozómy enzymologie genetika metabolismus MeSH
- fosfolipasa D genetika metabolismus MeSH
- HIV infekce genetika metabolismus virologie MeSH
- HIV-1 fyziologie MeSH
- lidé MeSH
- multivezikulární tělíska enzymologie genetika metabolismus MeSH
- proteiny buněčného cyklu genetika metabolismus MeSH
- proteiny vázající vápník genetika metabolismus MeSH
- synteniny genetika metabolismus MeSH
- transport proteinů MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
Prominin-1 (CD133) is physiologically expressed at the apical membranes of secretory (serous and mucous) and duct cells of major salivary glands. We investigated its expression in various human salivary gland lesions using two distinct anti-prominin-1 monoclonal antibodies (80B258 and AC133) applied on paraffin-embedded sections and characterized its occurrence in saliva. The 80B258 epitope was extensively expressed in adenoid cystic carcinoma, in lesser extent in acinic cell carcinoma and pleomorphic adenoma, and rarely in mucoepidermoid carcinoma. The 80B258 immunoreactivity was predominately detected at the apical membrane of tumor cells showing acinar or intercalated duct cell differentiation, which lined duct- or cyst-like structures, and in luminal secretions. It was observed on the whole cell membrane in non-luminal structures present in the vicinity of thin-walled blood vessels and hemorrhagic areas in adenoid cystic carcinoma. Of note, AC133 labeled only a subset of 80B258-positive structures. In peritumoral salivary gland tissues as well as in obstructive sialadenitis, an up-regulation of prominin-1 (both 80B258 and AC133 immunoreactivities) was observed in intercalated duct cells. In most tissues, prominin-1 was partially co-expressed with two cancer markers: carcinoembryonic antigen (CEA) and mucin-1 (MUC1). Differential centrifugation of saliva followed by immunoblotting indicated that all three markers were released in association with small membrane vesicles. Immuno-isolated prominin-1-positive vesicles contained CEA and MUC1, but also exosome-related proteins CD63, flotillin-1, flotillin-2 and the adaptor protein syntenin-1. The latter protein was shown to interact with prominin-1 as demonstrated by its co-immunoisolation. A fraction of saliva-associated prominin-1 appeared to be ubiquitinated. Collectively, our findings bring new insights into the biochemistry and trafficking of prominin-1 as well as its immunohistochemical profile in certain types of salivary gland tumors and inflammatory diseases.
- MeSH
- buněčná membrána metabolismus MeSH
- CD antigeny metabolismus MeSH
- glykoproteiny metabolismus sekrece MeSH
- karcinoembryonální antigen metabolismus MeSH
- lidé MeSH
- mucin 1 metabolismus MeSH
- nádory slinných žláz metabolismus patologie MeSH
- peptidy metabolismus sekrece MeSH
- regulace genové exprese u nádorů MeSH
- sialoadenitida metabolismus patologie MeSH
- sliny metabolismus MeSH
- stupeň nádoru MeSH
- synteniny metabolismus MeSH
- ubikvitinace * MeSH
- Check Tag
- lidé MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
