Arf6-independent GPI-anchored protein-enriched early endosomal compartments fuse with sorting endosomes via a Rab5/phosphatidylinositol-3 '-kinase-dependent machinery

Kalia, Manjula, Kumari, Sudha, Chadda, Rahul, Hill, Michelle M., Parton, Robert G. and Mayor, Satyajit (2006) Arf6-independent GPI-anchored protein-enriched early endosomal compartments fuse with sorting endosomes via a Rab5/phosphatidylinositol-3 '-kinase-dependent machinery. Molecular Biology of The Cell, 17 8: 3689-3704.


Author Kalia, Manjula
Kumari, Sudha
Chadda, Rahul
Hill, Michelle M.
Parton, Robert G.
Mayor, Satyajit
Title Arf6-independent GPI-anchored protein-enriched early endosomal compartments fuse with sorting endosomes via a Rab5/phosphatidylinositol-3 '-kinase-dependent machinery
Journal name Molecular Biology of The Cell   Check publisher's open access policy
ISSN 1059-1524
Publication date 2006-08
Year available 2006-06-07
Sub-type Article (original research)
DOI 10.1091/mbc.E05-10-0980
Volume 17
Issue 8
Start page 3689
End page 3704
Total pages 16
Editor Sandra L. Schmid
Place of publication Bethesda
Publisher American Society of Cell Biology
Collection year 2006
Language eng
Subject C1
270104 Membrane Biology
730105 Endocrine organs and diseases (incl. diabetes)
Abstract In the process of internalization of molecules from the extracellular milieu, a cell uses multiple endocytic pathways, consequently generating different endocytic vesicles. These primary endocytic vesicles are targeted to specific destinations inside the cell. Here, we show that GPI-anchored proteins are internalized by an Arf6-independent mechanism into GPI-anchored protein-enriched early endosomal compartments (GEECs). Internalized GPI-anchored proteins and the fluid phase are first visualized in GEECs that are acidic, primary endocytic structures, negative for early endosomal markers, Rab4, Rab5, and early endosome antigen (EEA)1. They subsequently acquire Rab5 and EEA1 before homotypic fusion with other GEECs, and heterotypic fusion with endosomes containing cargo from the clathrin-dependent endocytic pathway. Although, the formation of GEECs is unaffected by inhibition of Rab5 GTPase and phosphatidylinositol-3'-kinase (PI3K) activity, their fusion with sorting endosomes is dependent on both activities. Overexpression of Rab5 reverts PI3K inhibition of fusion, providing evidence that Rab5 effectors play important roles in heterotypic fusion between the dynamin-independent GEECs and clathrin- and dynamin-dependent sorting endosomes.
Keyword -early Endosomal Antigen
Geec
Gpi-anchored Protein-enriched Early Endosomal Compartment
Pi3p
Phosphatidylinositol 3'-phosphate
Pkc
Protein Kinase C
Wt
Wortmannin
Cell Biology
Clathrin-independent Endocytosis
Plasma-membrane
Mediated Endocytosis
Dependent Retention
Urokinase Receptor
Prion Protein
Rab Proteins
Coated Pits
Lipid Rafts
Pathway
Q-Index Code C1
Additional Notes DOI: 10.1091/mbc.E05-10-0980

 
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