Different GPI-attachment signals affect the oligomerisation of GPI-anchored proteins and their apical sorting.

Simona Paladino (1, 2) , Stephanie Lebreton (3) , Simona Tivodar (1) , Vincenza Campana (3) , Rosaria Tempre (1) , Chiara Zurzolo (1, 3)

1 Dipartimento di Biologia e Patologia Cellulare e Moleculare
2 CEINGE Biotecnologie Avanzate s.c.a.r.l.
3 Trafic membranaire et Pathogénèse

To understand the mechanism involved in the apical sorting of glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) we fused to the C-terminus of GFP the GPI-anchor-attachment signal of the folate receptor (FR) or of the prion protein (PrP), two native GPI-anchored proteins that are sorted apically or basolaterally, respectively, in MDCK cells. We investigated the behaviour of the resulting fusion proteins GFP-FR and GFP-PrP by analysing three parameters: their association with DRMs, their oligomerisation and their apical sorting. Strikingly, we found that different GPI-attachment signals differently modulate the ability of the resulting GFP-fusion protein to oligomerise and to be apically sorted. This is probably owing to differences in the GPI anchor and/or in the surrounding lipid microenvironment. Accordingly, we show that addition of cholesterol to the cells is necessary and sufficient to drive the oligomerisation and consequent apical sorting of GFP-PrP, which under control conditions does not oligomerise and is basolaterally sorted.

Domains: Cellular Biology

Simona Paladino, Stephanie Lebreton, Simona Tivodar, Vincenza Campana, Rosaria Tempre, et al.. Different GPI-attachment signals affect the oligomerisation of GPI-anchored proteins and their apical sorting.. Journal of Cell Science, 2008, 121(Pt 24), pp.4001-7. ⟨10.1242/jcs.036038⟩. ⟨pasteur-00349337⟩