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| Open AccessNPC1 regulates ER contacts with endocytic organelles to mediate cholesterol egress
Though endocytosed dietary cholesterol is transferred to the endoplasmic reticulum (ER), how this is regulated is unclear. Here, the authors report a role for Niemann-Pick Type C Protein 1 (NPC1) in tethering endocytic organelles to the ER, which may contribute to interorganelle cholesterol transport.
- D. Höglinger
- , T. Burgoyne
- & E. R Eden
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Article
| Open AccessWHAMM initiates autolysosome tubulation by promoting actin polymerization on autolysosomes
After autophagic cargo degradation, autolysosomes undergo a reformation process to recycle lysosomal membrane components. Here, Dai et al. demonstrate that the actin nucleation promoting factor WHAMM is required for autolysosome reformation by providing an actin scaffold to drive tubulation.
- Anbang Dai
- , Li Yu
- & Hong-Wei Wang
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Article
| Open AccessLysosomal integral membrane protein-2 (LIMP-2/SCARB2) is involved in lysosomal cholesterol export
Cholesterol transport is tightly regulated in the cell and in lysosomes is regulated by NPC1/2. Here, Heybrock et al. use molecular modeling, knockout mice and cell based studies to show that LIMP-2 also mediates lysosomal cholesterol transport.
- Saskia Heybrock
- , Kristiina Kanerva
- & Dante Neculai
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| Open AccessLysosomal degradation of newly formed insulin granules contributes to β cell failure in diabetes
Impaired beta-cell insulin secretion is a key pathological feature of type 2 diabetes. Here, the authors describe metabolic stress induced lysosomal degradation of newly formed insulin granules, independent of macroautophagy, as a potential mechanism for beta-cell dysfunction.
- Adrien Pasquier
- , Kevin Vivot
- & Romeo Ricci
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| Open AccessApoptotic signalling targets the post-endocytic sorting machinery of the death receptor Fas/CD95
Fas is a death receptor that regulates apoptosis in many cell types and is downregulated on the cell surface in many cancers. Here, Sharma et al. show that endosome associated trafficking regulator ENTR1 regulates delivery of Fas to lysosomes, thereby controlling its degradation and signalling.
- Shruti Sharma
- , Antonio Carmona
- & Kai S. Erdmann
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Article
| Open AccessAdult stem cell deficits drive Slc29a3 disorders in mice
Mutations in equilibrative nucleoside transporter 3 (ENT3), encoded by SLC29A3, cause a spectrum of human genetic disorders. Here, the authors show altered haematopoietic stem cell and mesenchymal stem cell fates in ENT3-deficient mice, due to misregulation of the AMPK-mTOR-ULK axis.
- Sreenath Nair
- , Anne M. Strohecker
- & Rajgopal Govindarajan
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Article
| Open AccessThe intralumenal fragment pathway mediates ESCRT-independent surface transporter down-regulation
Cell surface receptors are thought to be internalized via the multivesicular bodies (MVBs) in an ESCRT-dependent pathway. Here, the authors report that in yeast, a hexose transporter is internalized via an ESCRT-independent pathway into intralumenal fragments (ILF).
- Erin Kate McNally
- & Christopher Leonard Brett
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Article
| Open AccessLysosomal protease deficiency or substrate overload induces an oxidative-stress mediated STAT3-dependent pathway of lysosomal homeostasis
How cells regulate their lysosomal proteolytic capacity is only partly understood. Here, the authors show that lysosomal protease deficiency or substrate overload induces lysosomal stress leading to activation of a STAT3-dependent, TFEB-independent pathway of lysosomal hydrolase expression.
- Jonathan Martínez-Fábregas
- , Alan Prescott
- & Colin Watts
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Article
| Open AccessAutophagy differentially regulates TNF receptor Fn14 by distinct mammalian Atg8 proteins
The TNF receptor Fn14 is a short-lived protein. Here the authors show that Fn14 turnover is regulated by selective autophagy, with different ATG8 proteins having distinct roles during the process.
- Hila Winer
- , Milana Fraiberg
- & Zvulun Elazar
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Article
| Open AccessNeuronal lysosomal dysfunction releases exosomes harboring APP C-terminal fragments and unique lipid signatures
Neurodegeneration is increasingly associated with endolysosomal and autophagy dysfunction. Here, Miranda and colleagues show that disruption of neuronal PI3P/Vps34 signaling leads to endolysosomal membrane damage and aberrant release of undigested material in APP-CTF- and BMP-positive exosomes.
- André M. Miranda
- , Zofia M. Lasiecka
- & Gilbert Di Paolo
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| Open AccessImpaired autophagy bridges lysosomal storage disease and epithelial dysfunction in the kidney
Nephropathic cystinosis is a lysosomal storage disease characterized by proximal tubular cell dysfunction. Here Festa and colleagues show that these lysosomal alterations lead to defective autophagic clearance of mitochondria and increased oxidative stress that, in turn, activates the transcription factor ZONAB leading to impaired cell differentiation.
- Beatrice Paola Festa
- , Zhiyong Chen
- & Alessandro Luciani
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| Open AccessPhosphorylation of LAMP2A by p38 MAPK couples ER stress to chaperone-mediated autophagy
The endoplasmic reticulum (ER) and lysosome are central to cellular stress responses, but it is unclear how ER stress is signaled to lysosomes. Here the authors show that ER stress activates chaperone-mediated autophagy (CMA) via direct phosphorylation of the CMA receptor LAMP2A by the lysosomal p38 MAPK.
- Wenming Li
- , Jinqiu Zhu
- & Zixu Mao
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Article
| Open AccessTFEB regulates lysosomal positioning by modulating TMEM55B expression and JIP4 recruitment to lysosomes
Lysosomal distribution is linked to the role of lysosomes in many cellular functions. Here the authors show that the lysosomal protein TMEM55B is regulated by TFEB and recruits JIP4 to the lysosomal surface inducing dynein-dependent transport of lysosomes toward the cell center in response to stress conditions.
- Rose Willett
- , José A. Martina
- & Rosa Puertollano
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| Open AccessSpermine synthase deficiency causes lysosomal dysfunction and oxidative stress in models of Snyder-Robinson syndrome
Mutations in spermine synthase lead to Snyder-Robinson syndrome, a form of intellectual disability syndrome. Here the authors develop a Drosophila model of this disease, and show that lysosomal dysfunction and oxidative stress contribute to the morphological phenotype in these flies, as well as to cellular deficits in cells derived from patients.
- Chong Li
- , Jennifer M. Brazill
- & R. Grace Zhai
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| Open AccessImpaired prosaposin lysosomal trafficking in frontotemporal lobar degeneration due to progranulin mutations
Mutations in the granulin gene are associated with frontotemporal lobe dementia (FTLD) and a lysosomal storage disease. The authors show that reduced progranulin levels leads to impaired neuronal uptake and lysosomal delivery of prosaposin, and that decreased prosaposin expression in mice leads to FTLD-like behaviour.
- Xiaolai Zhou
- , Lirong Sun
- & Fenghua Hu
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Article
| Open AccessBimodal antagonism of PKA signalling by ARHGAP36
Protein kinase A (PKA) is a key mediator of cyclic AMP signalling. Here, Eccles et al. show that ARHGAP36 antagonizes PKA by acting as a kinase inhibitor and targeting the catalytic subunit for endolysosomal degradation, thus reducing sensitivity of cells to cAMP and promoting Hedgehog signalling.
- Rebecca L. Eccles
- , Maciej T. Czajkowski
- & Oliver Rocks
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| Open AccessMCOLN1 is a ROS sensor in lysosomes that regulates autophagy
Reactive oxygen species (ROS) damage cell components, necessitating their clearance through autophagy. Here, the authors show that ROS can induce autophagy by triggering TRPML1 to release Ca2+from the lysosomal lumen, in turn activating the autophagy and lysosomal biogenesis regulator TFEB.
- Xiaoli Zhang
- , Xiping Cheng
- & Haoxing Xu
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Article
| Open AccessLysosomal recruitment of TSC2 is a universal response to cellular stress
In response to amino acid and growth factor removal the TSC1/2 complex translocates to the lysosome to inactivate mTOR and inhibit cell growth. Here, the authors have shown that other cellular stresses also trigger this translocation to the lysosome suggesting that this is a universal mechanism in the stress response.
- Constantinos Demetriades
- , Monika Plescher
- & Aurelio A. Teleman
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| Open AccessCoupling of lysosomal and mitochondrial membrane permeabilization in trypanolysis by APOL1
The human serum protein apolipoprotein L1 (APOL1) is taken up by trypanosomes where it triggers cell death, forming pores in endolysosomal membranes. Vanwalleghem et al.show that APOL1 triggers both lysosomal and mitochondrial membrane permeabilization, and that the latter is responsible for trypanolysis.
- Gilles Vanwalleghem
- , Frédéric Fontaine
- & Etienne Pays
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| Open AccessLAPTM4b recruits the LAT1-4F2hc Leu transporter to lysosomes and promotes mTORC1 activation
Essential amino acids such as leucine activate mTORC1 signalling after entering the lysosome, but the molecular basis for lysosomal amino-acid uptake is unclear. Here Milkereit et al. show that LAPTM4b, a lysosomal membrane protein, recruits a leucine transporter to the lysosome and promotes amino-acid influx and mTORC1 signalling.
- Ruth Milkereit
- , Avinash Persaud
- & Daniela Rotin
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| Open AccessAutophagosome–lysosome fusion is independent of V-ATPase-mediated acidification
BafilomycinA1 is an autophagy inhibitor, presumably owing to its blocking effect on the lysosomal proton pump V-ATPase. Here the authors show that V-ATPase-deficient lysosomes can still fuse with autophagosomes, showing that lysosomal acidification and fusion are two separable, independent events.
- Caroline Mauvezin
- , Péter Nagy
- & Thomas P. Neufeld
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Article |
A non-conserved miRNA regulates lysosomal function and impacts on a human lysosomal storage disorder
Multiple sulfatase deficiency is a lysosomal storage disorder arising from mutations in the sulfatase modifying factor 1 (SUMF1) gene. Here Frankel et al. show that targeting a microRNA, miR-95, can increase residual SUMF1 expression and restore sulfatase activity in patient cells.
- Lisa B. Frankel
- , Chiara Di Malta
- & Anders H. Lund
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| Open AccessLysosome sorting of β-glucocerebrosidase by LIMP-2 is targeted by the mannose 6-phosphate receptor
LIMP-2 is a membrane protein involved in β-glucocerebrosidase lysosomal targeting. Here Zhao et al. report structural and biochemical results showing how LIMP-2 interacts with β-glucocerebrosidase and the mannose 6-phosphate receptor, and propose a mechanism for LIMP-2-associated lysosomal targeting.
- Yuguang Zhao
- , Jingshan Ren
- & David I. Stuart
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Rag GTPases are cardioprotective by regulating lysosomal function
Rag family proteins control activation of the mTORC1 complex at the lysosome. Here the authors show that loss of RagA/B causes cardiac hypertrophy in mice, revealing an mTORC-independent function of Rag GTPAses as regulators of lysosome function and autophagic flux in cardiomyocytes.
- Young Chul Kim
- , Hyun Woo Park
- & Kun-Liang Guan
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Spatiotemporally controlled induction of autophagy-mediated lysosome turnover
Lysosomes are the major degradative compartments within cells, but little is known about cellular mechanisms that control lysosome quality. Here Hung et al.show that lysosomes damaged by light-induced activation of a photosensitizer are selectively ubiquitinated and subsequently eliminated by autophagy.
- Yu-Hsien Hung
- , Lily Man-Wen Chen
- & Wei Yuan Yang
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hVps41 and VAMP7 function in direct TGN to late endosome transport of lysosomal membrane proteins
Delivery of lysosome-associated membrane proteins (LAMPs), is important for lysosome stability and function. Here, Pols et al. identify a previously uncharacterized pathway for transport of lysosome-associated membrane proteins LAMPs directly from the trans-golgi network to late endosomes.
- Maaike S. Pols
- , Eline van Meel
- & Judith Klumperman
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Delivery of endosomes to lysosomes via microautophagy in the visceral endoderm of mouse embryos
Nutrients and growth factors initiate endocytotic processes in the embryonic endoderm that control embryonic patterning. Here, Kawamuraet al.show that the small GTP-binding protein rab7 controls a unique microautophagy-like process that is involved in endocytosis in the endoderm of mouse embryos.
- Nobuyuki Kawamura
- , Ge-Hong Sun-Wada
- & Yoh Wada
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p47 negatively regulates IKK activation by inducing the lysosomal degradation of polyubiquitinated NEMO
The IKK complex activates the NF-κB pathway and can culminate in inflammation, which needs to be tightly controlled. NEMO is part of the IKK complex and, in this study, is shown to associate with the golgi-reassembly protein p47, resulting in the lysosomal degradation of NEMO and inhibition of NF-κB activation.
- Yuri Shibata
- , Masaaki Oyama
- & Jun-ichiro Inoue
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Lipid storage disorders block lysosomal trafficking by inhibiting a TRP channel and lysosomal calcium release
Accumulation of lysosomal lipids is a feature of Niemann'-Picks (NP) disease, but how these lipids contribute to the disease is unclear. In this study, calcium released via the lysosomal TRPML1 channel is shown to be reduced in NP-type C cells, and sphingomyelins are found to inhibit the channel's activity.
- Dongbiao Shen
- , Xiang Wang
- & Haoxing Xu
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PI(3,5)P2 controls membrane trafficking by direct activation of mucolipin Ca2+ release channels in the endolysosome
Phosphoinositides activate intracellular ion channels to release Ca2+ from membrane-bound stores. This study demonstrates that Ca2+-permeable mucolipin TRP channels, TRPMLs, are activated by the phospholipid PI(3,5)P2in murine endolysosomes and yeast vacuoles.
- Xian-ping Dong
- , Dongbiao Shen
- & Haoxing Xu