Monitoring Editor: Benjamin Glick Protein glycosylation modulates a wide variety of intracellular events and dysfunction of the glycosylation pathway has been reported in a variety of human pathologies. Endo-apyrases have been suggested to have critical roles in protein glycosylation and sugar metabolism. However, deciphering the physiological relevance of Endo-apyrases activity has actually proved difficult, owing to their complexity and the functional redundancy within the family. We report here that an UDP/GDPase, homologous to the human apyrase Scan-1, is present in the membranes of Caenorhabditis elegans, encoded by the ORF F08C6.6 and hereinafter-named APY-1. We showed that ER stress induced by tunicamycin or high temperature resulted in increased transcription of
apy-1. This increase was not observed in C.elegans mutants defective in
ire-1 or
atf-6, demonstrating the requirement of both ER stress sensors for up-regulation of
apy-1. Depletion of APY-1 resulted in constitutively activated UPR. Defects in the pharynx, and impaired organization of thin fibers in muscle cells, were observed in adult worms depleted of APY-1. Some of the
apy-1(RNAi) phenotypes are suggestive of premature aging, since these animals also showed accumulation of lipofuscin and reduced lifespan that was not dependent on the functioning of DAF-2, the receptor of the insulin/IGF-1 signaling pathway.