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Nat Chem Biol. 2014 May;10(5):350-357. doi: 10.1038/nchembio.1495. Epub 2014 Mar 30.

Golgi sorting regulates organization and activity of GPI proteins at apical membranes.

Author information

1
Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università degli Studi di Napoli Federico II, Napoli, Italy.
2
CEINGE Biotecnologie Avanzate, Napoli, Italy.
3
Unité de Trafic Membranaire et Pathogénèse, Institut Pasteur, Paris, France.
4
Laboratory for Fluorescence Dynamics, University of California, Irvine, California.
5
Institut de génétique et dévelopement de Rennes, UMR 6290.
6
Complexes macromoléculaires en cellules vivantes, Institut Jacques Monod, UMR 7592 CNRS, University Paris-Diderot, France.
#
Contributed equally

Abstract

Here we combined classical biochemistry with new biophysical approaches to study the organization of glycosylphosphatidylinositol (GPI)-anchored proteins (GPI-APs) with high spatial and temporal resolution at the plasma membrane of polarized epithelial cells. We show that in polarized MDCK cells, after sorting in the Golgi, each GPI-AP reaches the apical surface in homoclusters. Golgi-derived homoclusters are required for their subsequent plasma membrane organization into cholesterol-dependent heteroclusters. By contrast, in nonpolarized MDCK cells, GPI-APs are delivered to the surface as monomers in an unpolarized manner and are not able to form heteroclusters. We further demonstrate that this GPI-AP organization is regulated by the content of cholesterol in the Golgi apparatus and is required to maintain the functional state of the protein at the apical membrane. Thus, in contrast to fibroblasts, in polarized epithelial cells, a selective cholesterol-dependent sorting mechanism in the Golgi regulates both the organization and function of GPI-APs at the apical surface.

PMID:
24681536
PMCID:
PMC4027978
DOI:
10.1038/nchembio.1495
[Indexed for MEDLINE]
Free PMC Article

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