In wild-type GFP::HGRS-1 was localized at the apical cortex and on endosomes. Knockdown of vps-33.1
left only the apical pool of HGRS-1 intact, which was somewhat reduced. These data suggest that VPS- 33.1 represents the SM protein of the HOPS complex in C. elegans. It is noteworthy that vps-33.2
(RNAi) caused an accumulation of GFP::HGRS-1 at the apical cortex and distinct bright foci were detected, indicating that HGRS-1 was trapped on endosomes close to endocytosis sites.