VPS41 recruits biosynthetic LAMP-positive vesicles through interaction with Arl8b

J Cell Biol. 2025 Apr 3;224(4):e202405002. doi: 10.1083/jcb.202405002. Epub 2025 Feb 5.

Abstract

Vacuolar protein sorting 41 (VPS41), a component of the homotypic fusion and protein sorting (HOPS) complex for lysosomal fusion, is essential for the trafficking of lysosomal membrane proteins via lysosome-associated membrane protein (LAMP) carriers from the trans-Golgi network (TGN) to endo/lysosomes. However, the molecular mechanisms underlying this pathway and VPS41's role herein remain poorly understood. Here, we investigated the effects of ectopically localizing VPS41 to mitochondria on LAMP distribution. Using electron microscopy, we identified that mitochondrial-localized VPS41 recruited LAMP1- and LAMP2A-positive vesicles resembling LAMP carriers. The retention using selective hooks (RUSH) system further revealed that newly synthesized LAMPs were specifically recruited by mitochondrial VPS41, a function not shared by other HOPS subunits. Notably, we identified the small GTPase Arl8b as a critical factor for LAMP carrier trafficking. Arl8b was present on LAMP carriers and bound to the WD40 domain of VPS41, enabling their recruitment. These findings reveal a unique role of VPS41 in recruiting TGN-derived LAMP carriers and expand our understanding of VPS41-Arl8b interactions beyond endosome-lysosome fusion, providing new insights into lysosomal trafficking mechanisms.

MeSH terms

  • ADP-Ribosylation Factors* / genetics
  • ADP-Ribosylation Factors* / metabolism
  • Endosomes / metabolism
  • HEK293 Cells
  • HeLa Cells
  • Humans
  • Lysosomal Membrane Proteins* / genetics
  • Lysosomal Membrane Proteins* / metabolism
  • Lysosomal-Associated Membrane Protein 1
  • Lysosomal-Associated Membrane Protein 2* / genetics
  • Lysosomal-Associated Membrane Protein 2* / metabolism
  • Lysosomes / metabolism
  • Mitochondria / metabolism
  • Protein Binding
  • Protein Transport
  • Vesicular Transport Proteins* / genetics
  • Vesicular Transport Proteins* / metabolism
  • trans-Golgi Network / metabolism

Substances

  • Vesicular Transport Proteins
  • ADP-Ribosylation Factors
  • Lysosomal Membrane Proteins
  • ARL8B protein, human
  • VPS41 protein, human
  • Lysosomal-Associated Membrane Protein 2
  • LAMP1 protein, human
  • LAMP2 protein, human
  • Lysosomal-Associated Membrane Protein 1