Rapid cycling of lipid raft markers between the cell surface and Golgi complex

Citation
Bj. Nichols et al., Rapid cycling of lipid raft markers between the cell surface and Golgi complex, J CELL BIOL, 153(3), 2001, pp. 529-541
Citations number
39
Categorie Soggetti
Cell & Developmental Biology
Journal title
JOURNAL OF CELL BIOLOGY
ISSN journal
00219525 → ACNP
Volume
153
Issue
3
Year of publication
2001
Pages
529 - 541
Database
ISI
SICI code
0021-9525(20010430)153:3<529:RCOLRM>2.0.ZU;2-A
Abstract
The endocytic itineraries of lipid raft markers, such as glycosyl phosphati dylinositol (GPI)anchored proteins and glycosphingolipids, are incompletely understood. Here we show that different GPI-anchored proteins have differe nt intracellular distributions; some (such as the folate receptor) accumula te in transferrin-containing compartments, others (such as CD59 and GPI-lin ked green fluorescent protein [GFP]) accumulate in the Golgi apparatus. Sel ective photobleaching shows that the Golgi pool of both GPI-GFP and CD59-GF P constantly and rapidly exchanges with the pool of these proteins found on the plasma membrane (PM). We visualized intermediates carrying GPI-GFP fro m the Golgi apparatus to the PM and separate structures delivering GPI-GFP to the Golgi apparatus. GPI-GFP does not accumulate within endocytic compartments containing transf errin, although it is detected in intracellular structures which are endoso mes by the criteria of accessibility to a fluid phase marker and to cholera and shiga toxin B subunits (CTxB and STxB, which are also found in rafts). GPI-GFP and a proportion of the total CTxB and STxB taken up into cells ar e endocytosed independently of clathrin-associated machinery and are delive red to the Golgi complex via indistinguishable mechanisms, Hence, they ente r the Golgi complex in the same intermediates, get there in dependently of both clathrin and rab5 unction, and are excluded from it at 20 degreesC and under conditions of cholesterol sequestration. The PM-Golgi cycling pathwa y followed by GPI-GFP could serve to regulate lipid raft distribution and f unction within cells.