Late endosomal transport and tethering are coupled processes controlled by RILP and the cholesterol sensor ORP1L

• Published in: Journal of cell science Vol. 126; no. Pt 15; pp. 3462 - 3474
• Main Authors: van der Kant, Rik, Fish, Alexander, Janssen, Lennert, Janssen, Hans, Krom, Sabine, Ho, Nataschja, Brummelkamp, Thijn, Carette, Jan, Rocha, Nuno, Neefjes, Jacques
• Format: Journal Article
• Language: English
• Published: England 01.08.2013
• Subjects: Adaptor Proteins, Signal Transducing - genetics; Adaptor Proteins, Signal Transducing - metabolism; Cell Line, Tumor; Cholesterol - metabolism; Dyneins - genetics; Dyneins - metabolism; Endosomes - metabolism; Humans; Melanoma - genetics; Melanoma - metabolism; rab GTP-Binding Proteins - genetics; rab GTP-Binding Proteins - metabolism; Receptors, Steroid - genetics; Receptors, Steroid - metabolism; Transport Vesicles - metabolism; Ebola virus; HOPS complex; RAB7; Dynein; ORP1L; Endosomal fusion; RILP
• ISSN: 0021-9533; 1477-9137
• DOI: 10.1242/jcs.129270

Late endosomes and lysosomes are dynamic organelles that constantly move and fuse to acquire cargo from early endosomes, phagosomes and autophagosome. Defects in lysosomal dynamics cause severe neurodegenerative and developmental diseases, such as Niemann-Pick type C disease and ARC syndrome, yet little is known about the regulation of late endosomal fusion in a mammalian system. Mammalian endosomes destined for fusion need to be transported over very long distances before they tether to initiate contact. Here, we describe that lysosomal tethering and transport are combined processes co-regulated by one multi-protein complex: RAB7-RILP-ORP1L. We show that RILP directly and concomitantly binds the tethering HOPS complex and the p150(Glued) subunit of the dynein motor. ORP1L then functions as a cholesterol-sensing switch controlling RILP-HOPS-p150(Glued) interactions. We show that RILP and ORP1L control Ebola virus infection, a process dependent on late endosomal fusion. By combining recruitment and regulation of both the dynein motor and HOPS complex into a single multiprotein complex, the RAB7-RILP-ORP1L complex efficiently couples and regulates the timing of microtubule minus-end transport and fusion, two major events in endosomal biology.