title: Arl8 and SKIP act together to link lysosomes to kinesin-1.
abstract: Lysosomes move bidirectionally on microtubules, and this motility can be stimulated by overexpression of the small GTPase Arl8. By using affinity chromatography, we find that Arl8-GTP binds to the soluble protein SKIP (SifA and kinesin-interacting protein, aka PLEKHM2). SKIP was originally identified as a target of the Salmonella effector protein SifA and found to bind the light chain of kinesin-1 to activate the motor on the bacteria's replicative vacuole. We show that in uninfected cells both Arl8 and SKIP are required for lysosomes to distribute away from the microtubule-organizing center. We identify two kinesin light chain binding motifs in SKIP that are required for lysosomes to accumulate kinesin-1 and redistribute to the cell periphery. Thus, Arl8 binding to SKIP provides a link from lysosomal membranes to plus-end-directed motility. A splice variant of SKIP that lacks a light chain binding motif does not stimulate movement, suggesting fine-tuning by alternative splicing.
authors.affiliation: MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 0QH, UK.
authors.forename: Cláudia
authors.initials: C
authors.lastname: Rosa-Ferreira
authors.forename: Sean
authors.initials: S
authors.lastname: Munro
mesh_terms: D020727:ADP-Ribosylation Factors / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D048868:Adaptor Proteins, Signal Transducing / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D017398:Alternative Splicing; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D019556:COS Cells; D002522:Chlorocebus aethiops; D003593:Cytoplasm / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D006863:Hydrogen-Ion Concentration; D016547:Kinesins / Q000378:metabolism*; D008247:Lysosomes / Q000378:metabolism* / Q000502:physiology; D008969:Molecular Sequence Data; D009068:Movement; D054730:Protein Interaction Domains and Motifs; D034741:RNA, Small Interfering / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D017386:Sequence Homology, Amino Acid; D020798:Two-Hybrid System Techniques
chemical_list: D048868:Adaptor Proteins, Signal Transducing; C488101:KIF5B protein, human; D034741:RNA, Small Interfering; D011993:Recombinant Fusion Proteins; C466999:SPHKAP protein, human; C477339:ARL5B protein, human; D016547:Kinesins; D020727:ADP-Ribosylation Factors