GOP-1 promotes apoptotic cell degradation by activating the small GTPase Rab2 in C. elegans

J Cell Biol. 2017 Jun 5;216(6):1775-1794. doi: 10.1083/jcb.201610001. Epub 2017 Apr 19.


Apoptotic cells generated by programmed cell death are engulfed by phagocytes and enclosed within plasma membrane-derived phagosomes. Maturation of phagosomes involves a series of membrane-remodeling events that are governed by the sequential actions of Rab GTPases and lead to formation of phagolysosomes, where cell corpses are degraded. Here we identified gop-1 as a novel regulator of apoptotic cell clearance in Caenorhabditis elegans Loss of gop-1 affects phagosome maturation through the RAB-5-positive stage, causing defects in phagosome acidification and phagolysosome formation, phenotypes identical to and unaffected by loss of unc-108, the C. elegans Rab2 GOP-1 transiently associates with cell corpse-containing phagosomes, and loss of its function abrogates phagosomal association of UNC-108. GOP-1 interacts with GDP-bound and nucleotide-free UNC-108/Rab2, disrupts GDI-UNC-108 complexes, and promotes activation and membrane recruitment of UNC-108/Rab2 in vitro. Loss of gop-1 also abolishes association of UNC-108 with endosomes, causing defects in endosome and dense core vesicle maturation. Thus, GOP-1 is an activator of UNC-108/Rab2 in multiple processes.

Publication types

  • Video-Audio Media

MeSH terms

  • Animals
  • Animals, Genetically Modified
  • Apoptosis
  • Caenorhabditis elegans / enzymology*
  • Caenorhabditis elegans / genetics
  • Caenorhabditis elegans Proteins / genetics
  • Caenorhabditis elegans Proteins / metabolism*
  • Endocytosis
  • Endosomes / enzymology
  • Enzyme Activation
  • Genotype
  • Lectins, C-Type / genetics
  • Lectins, C-Type / metabolism*
  • Microscopy, Fluorescence
  • Microscopy, Video
  • Monosaccharide Transport Proteins / genetics
  • Monosaccharide Transport Proteins / metabolism*
  • Phagosomes / enzymology
  • Phenotype
  • Protein Binding
  • Protein Transport
  • Secretory Vesicles / enzymology
  • Signal Transduction
  • Time Factors
  • Time-Lapse Imaging
  • rab GTP-Binding Proteins / metabolism*
  • rab2 GTP-Binding Protein / metabolism*
  • rab5 GTP-Binding Proteins / genetics
  • rab5 GTP-Binding Proteins / metabolism


  • Caenorhabditis elegans Proteins
  • GOP-1 protein, C elegans
  • Lectins, C-Type
  • Monosaccharide Transport Proteins
  • UNC-108 protein, C elegans
  • rab GTP-Binding Proteins
  • rab2 GTP-Binding Protein
  • rab5 GTP-Binding Proteins