The ESCRT-III protein CeVPS-32 is enriched in domains distinct from CeVPS-27 and CeVPS-23 at the endosomal membrane of epithelial cells.
BACKGROUND
Within the endocytic pathway, the ESCRT (endosomal sorting complex required for transport) machinery is essential for the biogenesis of MVBs (multivesicular bodies). In yeast, ESCRTs are recruited at the endosomal membrane and are involved in cargo sorting into intralumenal vesicles of the MVBs.


RESULTS
In the present study, we characterize the ESCRT-III protein CeVPS-32 (Caenorhabditis elegans vacuolar protein sorting 32) and its interactions with CeVPS-27, CeVPS-23 and CeVPS-4. In contrast with other CevpsE (class E vps) genes, depletion of Cevps-32 is embryonic lethal with severe defects in the remodelling of epithelial cell shape during organogenesis. Furthermore, Cevps-32 animals display an accumulation of enlarged early endosomes in epithelial cells and an accumulation of autophagosomes. The CeVPS-32 protein is enriched in epithelial tissues and in residual bodies during spermatid maturation. We show that CeVPS-32 and CeVPS-27/Hrs (hepatocyte-growth-factor-regulated tyrosine kinase substrate) are enriched in distinct subdomains at the endosomal membrane. CeVPS-27-positive subdomains are also enriched for the ESCRT-I protein CeVPS-23/TSG101 (tumour susceptibility gene 101). The formation of CeVPS-27 subdomains is not affected by the depletion of CeVPS-23, CeVPS-32 or the ATPase CeVPS-4.


CONCLUSIONS
Our results suggest that the formation of membrane subdomains is essential for the maturation of endosomes.
Centre de Génétique Moléculaire, CNRS UPR 2167, bâtiment 26, Gif-sur-Yvette Cedex, 91198, France.
Xavier
X
Michelet
Adriana
A
Alberti
Laura
L
Benkemoun
Nathalie
N
Roudier
Christophe
C
Lefebvre
Renaud
R
Legouis
D000818:Animals; D001343:Autophagy / Q000235:genetics; D017173:Caenorhabditis elegans / Q000196:embryology / Q000254:growth & development / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins / Q000737:chemistry / Q000378:metabolism*; D012734:Disorders of Sex Development; D004625:Embryo, Nonmammalian / Q000378:metabolism / Q000648:ultrastructure; D047108:Embryonic Development; D011992:Endosomes / Q000378:metabolism*; D004847:Epithelial Cells / Q000378:metabolism*; D005804:Genes, Lethal; D017930:Genes, Reporter; D005854:Germ Cells / Q000378:metabolism; D007150:Immunohistochemistry; D007814:Larva / Q000254:growth & development / Q000378:metabolism / Q000648:ultrastructure; D008018:Life Cycle Stages; D008297:Male; D008566:Membranes / Q000378:metabolism; D038081:Organogenesis; D034622:RNA Interference; D012727:Sex Characteristics; D014162:Transfection; D033921:Vesicular Transport Proteins / Q000737:chemistry / Q000172:deficiency / Q000378:metabolism*
D029742:Caenorhabditis elegans Proteins; D033921:Vesicular Transport Proteins