title: A molecular mechanism to regulate lysosome motility for lysosome positioning and tubulation.
abstract: To mediate the degradation of biomacromolecules, lysosomes must traffic towards cargo-carrying vesicles for subsequent membrane fusion or fission. Mutations of the lysosomal Ca(2+) channel TRPML1 cause lysosomal storage disease (LSD) characterized by disordered lysosomal membrane trafficking in cells. Here we show that TRPML1 activity is required to promote Ca(2+)-dependent centripetal movement of lysosomes towards the perinuclear region (where autophagosomes accumulate) following autophagy induction. ALG-2, an EF-hand-containing protein, serves as a lysosomal Ca(2+) sensor that associates physically with the minus-end-directed dynactin-dynein motor, while PtdIns(3,5)P(2), a lysosome-localized phosphoinositide, acts upstream of TRPML1. Furthermore, the PtdIns(3,5)P(2)-TRPML1-ALG-2-dynein signalling is necessary for lysosome tubulation and reformation. In contrast, the TRPML1 pathway is not required for the perinuclear accumulation of lysosomes observed in many LSDs, which is instead likely to be caused by secondary cholesterol accumulation that constitutively activates Rab7-RILP-dependent retrograde transport. Ca(2+) release from lysosomes thus provides an on-demand mechanism regulating lysosome motility, positioning and tubulation.
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA.
authors.forename: Xinran
authors.initials: X
authors.lastname: Li
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA.
authors.forename: Nicholas
authors.initials: N
authors.lastname: Rydzewski
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Hider
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA.
authors.forename: Xiaoli
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Collaborative Innovation Center of Yangtze River Delta Region Green Pharmaceuticals, College of Pharmaceutical Sciences, Zhejiang University of Technology, Hangzhou 310014, China.
authors.forename: Junsheng
authors.initials: J
authors.lastname: Yang
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA.
authors.forename: Wuyang
authors.initials: W
authors.lastname: Wang
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA.
authors.forename: Qiong
authors.initials: Q
authors.lastname: Gao
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA.
authors.forename: Xiping
authors.initials: X
authors.lastname: Cheng
authors.affiliation: Department of Molecular, Cellular, and Developmental Biology, University of Michigan, 3089 Natural Science Building (Kraus), 830 North University, Ann Arbor, Michigan 48109, USA.
authors.forename: Haoxing
authors.initials: H
authors.lastname: Xu
mesh_terms: D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000818:Animals; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D001343:Autophagy; D001483:Base Sequence; D019556:COS Cells; D002118:Calcium / Q000378:metabolism*; D002135:Calcium-Binding Proteins / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D002522:Chlorocebus aethiops; D004398:Dyneins / Q000378:metabolism; D036681:Fluorescence Recovery After Photobleaching; D057809:HEK293 Cells; D006367:HeLa Cells; D006801:Humans; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008247:Lysosomes / Q000378:metabolism*; D018345:Mice, Knockout; D008856:Microscopy, Fluorescence; D008954:Models, Biological; D008969:Molecular Sequence Data; D009154:Mutation; D018129:Phosphatidylinositol Phosphates / Q000378:metabolism; D015398:Signal Transduction; D050051:Transient Receptor Potential Channels / Q000235:genetics / Q000378:metabolism; D020691:rab GTP-Binding Proteins / Q000235:genetics / Q000378:metabolism; D000090802:rab7 GTP-Binding Proteins
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D051017:Apoptosis Regulatory Proteins; D002135:Calcium-Binding Proteins; D008164:Luminescent Proteins; C512321:Mcoln1 protein, mouse; C490815:Pdcd6 protein, mouse; D018129:Phosphatidylinositol Phosphates; C423317:RILP protein, human; D050051:Transient Receptor Potential Channels; C106336:phosphatidylinositol 3,5-diphosphate; D000090802:rab7 GTP-Binding Proteins; C000716463:rab7 GTP-binding proteins, human; C000716465:rab7 GTP-binding proteins, mouse; D004398:Dyneins; D020691:rab GTP-Binding Proteins; D002118:Calcium