First published online October 13, 2004
Journal of Cell Science 117, 2205e (2004)
© The Company of Biologists Limited
Rafting beyond the cell
Lipid rafts are cholesterol-rich, ordered membrane microdomains. They recruit specific components, including members of the MAL and caveolin protein families, and are thought to function in intracellular signalling and protein sorting. Miguel Alonso and co-workers now describe an extracellular role for rafts – in prostasomes (see p. 5343). Prostasomes are vesicular organelles secreted by prostate epithelial cells into the prostate fluid that probably stimulate/stabilize spermatozoa. Alonso and co-workers show that prostasomes secreted by PC-3 prostate cancer cells possess lipid rafts containing the raft components caveolin 1 (CAV-1), MAL, MAL2 and BENE. They also observe that these are present within PC-3 cells in multivesicular bodies – presumably the source of the prostasomes. The authors then examine the trafficking mechanism underlying prostasome secretion. They find that this is unaffected by brefeldin A (which blocks the classical secretory pathway) but can be inhibited by wortmannin (which blocks late-endosomal trafficking). The authors therefore propose that a non-classical pathway involving endocytic compartments is responsible for prostasome secretion. Since CAV-1 promotes metastasis in prostate cancer, they suggest that CAV-1-containing prostasomes could play a part in this disease.
Related articles in JCS:
- Caveolin-1 and MAL are located on prostasomes secreted by the prostate cancer PC-3 cell line
- Alicia Llorente, María C. de Marco, and Miguel A. Alonso
JCS 2004 117: 5343-5351.
[Abstract]
[Full Text]
