Caenorhabditis elegans screen reveals role of PAR-5 in RAB-11-recycling endosome positioning and apicobasal cell polarity

Nat Cell Biol. 2012 May 27;14(7):666-76. doi: 10.1038/ncb2508.

Abstract

Apically enriched Rab11-positive recycling endosomes (Rab11-REs) are important for establishing and maintaining epithelial polarity. Yet, little is known about the molecules controlling trafficking of Rab11-REs in an epithelium in vivo. Here, we report a genome-wide, image-based RNA interference screen for regulators of Rab11-RE positioning and transport of an apical membrane protein (PEPT-1) in C. elegans intestine. Among the 356 screen hits was the 14-3-3 and partitioning defective protein PAR-5, which we found to be specifically required for Rab11-RE positioning and apicobasal polarity maintenance. Depletion of PAR-5 induced abnormal clustering of Rab11-REs to ectopic sites at the basolateral cortex containing F-actin and other apical domain components. This phenotype required key regulators of F-actin dynamics and polarity, such as Rho GTPases (RHO-1 and the Rac1 orthologue CED-10) and apical PAR proteins. Our data suggest that PAR-5 acts as a regulatory hub for a polarity-maintaining network required for apicobasal asymmetry of F-actin and proper Rab11-RE positioning.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Actins / metabolism
  • Animals
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans / metabolism*
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Cell Polarity*
  • Endosomes / metabolism*
  • Fluorescent Antibody Technique
  • Genotype
  • Intestinal Mucosa / metabolism*
  • Microscopy, Confocal
  • Microscopy, Fluorescence
  • Microtubules / metabolism
  • Peptide Transporter 1
  • Phenotype
  • Protein Transport
  • Protein-Serine-Threonine Kinases / metabolism
  • RNA Interference
  • Recombinant Fusion Proteins / metabolism
  • Symporters / metabolism
  • Vesicular Transport Proteins / genetics
  • Vesicular Transport Proteins / metabolism*
  • rac GTP-Binding Proteins / metabolism
  • rho GTP-Binding Proteins / metabolism

Substances

  • Actins
  • CED-10 protein, C elegans
  • Caenorhabditis elegans Proteins
  • Peptide Transporter 1
  • Recombinant Fusion Proteins
  • Symporters
  • Vesicular Transport Proteins
  • par-5 protein, C elegans
  • rab-11.1 protein, C elegans
  • PAR-1 protein, C elegans
  • Protein-Serine-Threonine Kinases
  • RHO-1 protein, C elegans
  • rac GTP-Binding Proteins
  • rho GTP-Binding Proteins