Arf6 regulates AP-1B-dependent sorting in polarized epithelial cells

J Cell Biol. 2011 Sep 19;194(6):873-87. doi: 10.1083/jcb.201106010. Epub 2011 Sep 12.

Abstract

The epithelial cell-specific clathrin adaptor complex AP-1B facilitates the sorting of various transmembrane proteins from recycling endosomes (REs) to the basolateral plasma membrane. Despite AP-1B's clear importance in polarized epithelial cells, we still do not fully understand how AP-1B orchestrates basolateral targeting. Here we identify the ADP-ribosylation factor 6 (Arf6) as an important regulator of AP-1B. We show that activated Arf6 pulled down AP-1B in vitro. Furthermore, interfering with Arf6 function through overexpression of dominant-active Arf6Q67L or dominant-negative Arf6D125N, as well as depletion of Arf6 with short hairpin RNA (shRNA), led to apical missorting of AP-1B-dependent cargos. In agreement with these data, we found that Arf6 colocalized with AP-1B and transferrin receptor (TfnR) in REs. In addition, we observed specific recruitment of AP-1B into Arf6-induced membrane ruffles in nonpolarized cells. We conclude that activated Arf6 directs membrane recruitment of AP-1B, thus regulating AP-1B's functions in polarized epithelial cells.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • ADP-Ribosylation Factor 6
  • ADP-Ribosylation Factors / genetics*
  • ADP-Ribosylation Factors / metabolism
  • Adaptor Protein Complex 1 / genetics
  • Adaptor Protein Complex 1 / metabolism*
  • Animals
  • Cell Polarity / physiology*
  • Cells, Cultured
  • Dogs
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism*
  • Fluorescent Antibody Technique
  • HEK293 Cells
  • Humans
  • Mice
  • RNA, Small Interfering / genetics
  • RNA, Small Interfering / metabolism
  • Rats
  • Receptors, Transferrin / genetics
  • Receptors, Transferrin / metabolism
  • Swine

Substances

  • ADP-Ribosylation Factor 6
  • Adaptor Protein Complex 1
  • RNA, Small Interfering
  • Receptors, Transferrin
  • ADP-Ribosylation Factors
  • ARF6 protein, human
  • Arf6 protein, mouse
  • Arf6 protein, rat