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Updated: Jul 19, 2026

Density Gradient Ultracentrifugation for Investigating Endocytic Recycling in Mammalian Cells
Published on: June 30, 2021
EFA6 regulates endosomal trafficking and affects early endosomes in polarized MDCK cells
Tamar Shultz1, Nadav Nash-Livni, Miriam Shmuel
1Department of Pharmacology, School of Pharmacy, Faculty of Medicine, The Hebrew University of Jerusalem, Jerusalem 91120, Israel.
Abstract:
The small-GTPase family of ADP ribosylation factors (ARFs) recruit coat proteins to promote vesicle budding. ARFs are activated by an association with sec7-containing exchange factors which load them with GTP. In epithelial cells, the small GTPase ARF6 operates within the endocytic system and has been shown to associate with ARNO to promote apical endocytosis and early to late endosomal trafficking. EFA6 has been shown to stimulate tight-junction formation and maintenance. Here, we show that in polarized epithelial MDCK cells, EFA6 is localized to early endosomes, causes their dramatic enlargement, and promotes basolateral targeting of IgA, which is normally targeted to the apical PM. These results suggest that the physiological function of ARF6 within the endocytic system is regulated by the exchange factor it associates with.
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