TY - JOUR
T1 - Phosphatidylinositol 3,4,5-trisphosphate localization in recycling endosomes is necessary for AP-1B - Dependent sorting in polarized epithelial cells
AU - Fields, Ian C.
AU - King, Shelby M.
AU - Shteyn, Elina
AU - Kang, Richard S.
AU - Fölsch, Heike
PY - 2010/1/1
Y1 - 2010/1/1
N2 - Polarized epithelial cells coexpress two almost identical AP-1 clathrin adaptor complexes: the ubiquitously expressed AP-1A and the epithelial cell - specific AP-1B. The only difference between the two complexes is the incorporation of the respective medium subunits μ1A or μ1B, which are responsible for the different functions of AP-1A and AP-1B in TGN to endosome or endosome to basolateral membrane targeting, respectively. Here we demonstrate that the C-terminus of μ1B is important for AP-1B recruitment onto recycling endosomes. We define a patch of three amino acid residues in μ1B that are necessary for recruitment of AP-1B onto recycling endosomes containing phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3]. We found this lipid enriched in recycling endosomes of epithelial cells only when AP-1B is expressed. Interfering with PI(3,4,5)P3 formation leads to displacement of AP-1B from recycling endosomes and missorting of AP-1B - dependent cargo to the apical plasma membrane. In conclusion, PI(3,4,5)P 3 formation in recycling endosomes is essential for AP-1B function.
AB - Polarized epithelial cells coexpress two almost identical AP-1 clathrin adaptor complexes: the ubiquitously expressed AP-1A and the epithelial cell - specific AP-1B. The only difference between the two complexes is the incorporation of the respective medium subunits μ1A or μ1B, which are responsible for the different functions of AP-1A and AP-1B in TGN to endosome or endosome to basolateral membrane targeting, respectively. Here we demonstrate that the C-terminus of μ1B is important for AP-1B recruitment onto recycling endosomes. We define a patch of three amino acid residues in μ1B that are necessary for recruitment of AP-1B onto recycling endosomes containing phosphatidylinositol 3,4,5-trisphosphate [PI(3,4,5)P3]. We found this lipid enriched in recycling endosomes of epithelial cells only when AP-1B is expressed. Interfering with PI(3,4,5)P3 formation leads to displacement of AP-1B from recycling endosomes and missorting of AP-1B - dependent cargo to the apical plasma membrane. In conclusion, PI(3,4,5)P 3 formation in recycling endosomes is essential for AP-1B function.
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U2 - 10.1091/mbc.E09-01-0036
DO - 10.1091/mbc.E09-01-0036
M3 - Article
C2 - 19864464
AN - SCOPUS:75649096434
SN - 1059-1524
VL - 21
SP - 95
EP - 105
JO - Molecular biology of the cell
JF - Molecular biology of the cell
IS - 1
ER -