Abstract
Many unicellular tubes such as capillaries form lumens intracellularly, a process that is not well understood. Here we show that the cortical membrane organizer ERM-1 is required to expand the intracellular apical/lumenal membrane and its actin undercoat during single-cell Caenorhabditis elegans excretory canal morphogenesis. We characterize AQP-8, identified in an ERM-1-overexpression (ERM-1[++]) suppressor screen, as a canalicular aquaporin that interacts with ERM-1 in lumen extension in a mercury-sensitive manner, implicating water-channel activity. AQP-8 is transiently recruited to the lumen by ERM-1, co-localizing in peri-lumenal cuffs interspaced along expanding canals. An ERM-1[++]-mediated increase in the number of lumen-associated canaliculi is reversed by AQP-8 depletion. We propose that the ERM-1/AQP-8 interaction propels lumen extension by translumenal flux, suggesting a direct morphogenetic effect of water-channel-regulated fluid pressure.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, Non-U.S. Gov't
MeSH terms
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Actin Cytoskeleton / metabolism
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Animals
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Animals, Genetically Modified
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Aquaporins / genetics
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Aquaporins / metabolism*
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Caenorhabditis elegans / drug effects
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Caenorhabditis elegans / embryology
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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 Membrane / drug effects
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Cell Membrane / metabolism*
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Cell Membrane Permeability
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Cytoskeletal Proteins / genetics
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Cytoskeletal Proteins / metabolism*
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Gene Expression Regulation, Developmental
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Genotype
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Mercuric Chloride / pharmacology
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Morphogenesis
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Mutation
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Osmotic Pressure
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Phenotype
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Protein Binding
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Protein Transport
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RNA Interference
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Time Factors
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Water / metabolism
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Water-Electrolyte Balance
Substances
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Aquaporins
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Caenorhabditis elegans Proteins
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Cytoskeletal Proteins
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ERM-1 protein, C elegans
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aquaporin 8
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Water
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Mercuric Chloride