Consecutive functions of small GTPases guide HOPS-mediated tethering of late endosomes and lysosomes
Ariane Schleinitz,
Lara-Alina Pöttgen,
Tal Keren-Kaplan,
Jing Pu,
Paul Saftig,
Juan S. Bonifacino,
Albert Haas,
Andreas Jeschke
Affiliations
Ariane Schleinitz
Cell Biology Institute, University of Bonn, 53121 Bonn, Germany
Lara-Alina Pöttgen
Cell Biology Institute, University of Bonn, 53121 Bonn, Germany
Tal Keren-Kaplan
Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
Jing Pu
Department of Molecular Genetics and Microbiology, and Autophagy, Inflammation, and Metabolism, Center of Biomedical Research Excellence, University of New Mexico, Albuquerque, NM 87131, USA
Paul Saftig
Biochemical Institute, University of Kiel, 24118 Kiel, Germany
Juan S. Bonifacino
Neurosciences and Cellular and Structural Biology Division, Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
Albert Haas
Cell Biology Institute, University of Bonn, 53121 Bonn, Germany; Corresponding author
Andreas Jeschke
Cell Biology Institute, University of Bonn, 53121 Bonn, Germany; Corresponding author
Summary: The transfer of endocytosed cargoes to lysosomes (LYSs) requires HOPS, a multiprotein complex that tethers late endosomes (LEs) to LYSs before fusion. Many proteins interact with HOPS on LEs/LYSs. However, it is not clear whether these HOPS interactors localize to LEs or LYSs or how they participate in tethering. Here, we biochemically characterized endosomes purified from untreated or experimentally manipulated cells to put HOPS and interacting proteins in order and to establish their functional interdependence. Our results assign Rab2a and Rab7 to LEs and Arl8 and BORC to LYSs and show that HOPS drives LE-LYS fusion by bridging late endosomal Rab2a with lysosomal BORC-anchored Arl8. We further show that Rab7 is absent from sites of HOPS-dependent tethering but promotes fusion by moving LEs toward LYSs via dynein. Thus, our study identifies the topology of the machinery for LE-LYS tethering and elucidates the role of different small GTPases in the process.
