| Title: |
ALG-2-interacting Tubby-like protein superfamily member PLSCR3 is secreted by an exosomal pathway and taken up by recipient cultured cells |
| Authors: |
Tatsutoshi Inuzuka; Akira Inokawa; Cen Chen; Kumiko Kizu; Hiroshi Narita; Hideki Shibata; Masatoshi Maki |
| Source: |
Bioscience Reports, Vol 33, Iss 2, p e00026 (2013) |
| Publisher Information: |
Portland Press, Biochemical Society |
| Publication Year: |
2013 |
| Collection: |
Directory of Open Access Journals: DOAJ Articles |
| Subject Terms: |
apoptosis-linked gene 2 (ALG-2); endosome; exosome; palmitoylation; unconventional secretion; vesicle; Life; QH501-531; Microbiology; QR1-502 |
| Description: |
PLSCRs (phospholipid scramblases) are palmitoylated membrane-associating proteins. Regardless of the given names, their physiological functions are not clear and thought to be unrelated to phospholipid scrambling activities observed in vitro. Using a previously established cell line of HEK-293 (human embryonic kidney-293) cells constitutively expressing human Scr3 (PLSCR3) that interacts with ALG-2 (apoptosis-linked gene 2) Ca2+-dependently, we found that Scr3 was secreted into the culture medium. Secretion of Scr3 was suppressed by 2-BP (2-bromopalmitate, a palmitoylation inhibitor) and by GW4869 (an inhibitor of ceramide synthesis). Secreted Scr3 was recovered in exosomal fractions by sucrose density gradient centrifugation. Palmitoylation sites and the N-terminal Pro-rich region were necessary for efficient secretion, but ABSs (ALG-2-binding sites) were dispensable. Overexpression of GFP (green fluorescent protein)-fused VPS4BE235Q, a dominant negative mutant of an AAA (ATPase associated with various cellular activities) ATPase with a defect in disassembling ESCRT (endosomal sorting complex required for transport)-III subunits, significantly reduced secretion of Scr3. Immunofluorescence microscopic analyses showed that Scr3 was largely localized to enlarged endosomes induced by overexpression of a GFP-fused constitutive active mutant of Rab5A (GFP–Rab5AQ79L). Secreted Scr3 was taken up by HeLa cells, suggesting that Scr3 functions as a cell-to-cell transferable modulator carried by exosomes in a paracrine manner. |
| Document Type: |
article in journal/newspaper |
| Language: |
English |
| Relation: |
http://www.bioscirep.org/bsr/033/e026/bsr033e026.htm; https://doaj.org/toc/0144-8463; https://doaj.org/toc/1573-4935; https://doaj.org/article/3a22b9a52d684718a9b2ef800f842885 |
| DOI: |
10.1042/BSR20120123 |
| Availability: |
https://doi.org/10.1042/BSR20120123; https://doaj.org/article/3a22b9a52d684718a9b2ef800f842885 |
| Accession Number: |
edsbas.E3CBDB43 |
| Database: |
BASE |