Oligomerization is a specific requirement for apical sorting of glycosyl-phosphatidylinositol-anchored proteins but not for non-raft-associated apical proteins.

Simona Paladino (1, 2, 3) , Daniela Sarnataro (1) , Simona Tivodar (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

Protein apical sorting in polarized epithelial cells is mediated by two different mechanisms, raft dependent and raft independent. In Madin-Darby canine kidney (MDCK) cells, an essential step for apical sorting of glycosyl-phosphatidylinositol (GPI)-anchored proteins (GPI-APs) is their coalescence into high-molecular-weight (HMW) oligomers. Here we show that this mechanism is also functional in Fischer rat thyroid cells, which possess a different sorting phenotype compared with MDCK cells. We demonstrate that, as in MDCK cells, both apical and basolateral GPI-APs associate with detergent-resistant microdomains, but that only the apical proteins are able to oligomerize into HMW complexes during their passage through the medial Golgi. We also show that oligomerization is a specific requirement for apical sorting of GPI-APs and is not used by transmembrane, non-raft-associated apical proteins.

Domains: Molecular biology

Simona Paladino, Daniela Sarnataro, Simona Tivodar, Chiara Zurzolo. Oligomerization is a specific requirement for apical sorting of glycosyl-phosphatidylinositol-anchored proteins but not for non-raft-associated apical proteins.. Traffic, 2007, 8 (3), pp.251-8. ⟨10.1111/j.1600-0854.2006.00522.x⟩. ⟨pasteur-00166611⟩