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
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Research Support, Non-U.S. Gov't
MeSH terms
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Actins / metabolism
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Animals
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Caenorhabditis elegans / genetics
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Caenorhabditis elegans / metabolism*
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Caenorhabditis elegans Proteins / genetics
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Caenorhabditis elegans Proteins / metabolism*
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Cell Polarity*
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Endosomes / metabolism*
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Fluorescent Antibody Technique
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Genotype
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Intestinal Mucosa / metabolism*
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Microscopy, Confocal
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Microscopy, Fluorescence
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Microtubules / metabolism
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Peptide Transporter 1
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Phenotype
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Protein Serine-Threonine Kinases / metabolism
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Protein Transport
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RNA Interference
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Recombinant Fusion Proteins / metabolism
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Symporters / metabolism
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Vesicular Transport Proteins / genetics
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Vesicular Transport Proteins / metabolism*
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rac GTP-Binding Proteins / metabolism
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rho GTP-Binding Proteins / metabolism
Substances
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Actins
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CED-10 protein, C elegans
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Caenorhabditis elegans Proteins
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Peptide Transporter 1
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Recombinant Fusion Proteins
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Symporters
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Vesicular Transport Proteins
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par-5 protein, C elegans
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rab-11.1 protein, C elegans
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PAR-1 protein, C elegans
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Protein Serine-Threonine Kinases
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RHO-1 protein, C elegans
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rac GTP-Binding Proteins
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rho GTP-Binding Proteins