Antibody to AP1B adaptor blocks biosynthetic and recycling routes of basolateral proteins at recycling endosomes

Jorge Cancino, Carolina Torrealba, Andrea Soza, María Isabel Yuseff, Diego Gravotta, Peter Henklein, Enrique Rodriguez-Boulan, Alfonso González*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

78 Scopus citations

Abstract

The epithelial-specific adaptor AP1B sorts basolateral plasma membrane (PM) proteins in both biosynthetic and recycling routes, but the site where it carries out this function remains incompletely defined. Here, we have investigated this topic in Fischer rat thyroid (FRT) epithelial cells using an antibody against the medium subunit μ1B. This antibody was suitable for immunofluorescence and blocked the function of AP1B in these cells. The antibody blocked the basolateral recycling of two basolateral PM markers, Transferrin receptor (TfR) and LDL receptor (LDLR), in a perinuclear compartment with marker and functional characteristics of recycling endosomes (RE). Live imaging experiments demonstrated that in the presence of the antibody two newly synthesized GFP-tagged basolateral proteins (vesicular stomatitis virus G [VSVG] protein and TfR) exited the trans-Golgi network (TGN) normally but became blocked at the RE within 3-5 min. By contrast, the antibody did not block trafficking of green fluorescent protein (GFP)-LDLR from the TGN to the PM but stopped its recycling after internalization into RE in ∼45 min. Our experiments conclusively demonstrate that 1) AP1B functions exclusively at RE; 2) TGN-to-RE transport is very fast and selective and is mediated by adaptors different from AP1B; and 3) the TGN and AP1B-containing RE cooperate in biosynthetic basolateral sorting.

Original languageEnglish
Pages (from-to)4872-4884
Number of pages13
JournalMolecular Biology of the Cell
Volume18
Issue number12
DOIs
StatePublished - 2007
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

Fingerprint

Dive into the research topics of 'Antibody to AP1B adaptor blocks biosynthetic and recycling routes of basolateral proteins at recycling endosomes'. Together they form a unique fingerprint.

Cite this