Analysis of post-lysosomal compartments

Hirota, Yuko; Masuyama, Naoko; Kuronita, Toshio; Fujita, Hideaki; Himeno, Masaru; Tanaka, Yoshitaka

doi:10.1016/j.bbrc.2003.12.092

Cited by 21 publications

(17 citation statements)

References 29 publications

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“…Degradation occurs in the early acidic lysosomes, and late lysosomes are sites of membrane and protein retrieval. The latter may be nonacidic, a prerequisite for further fusion with other compartments, sustaining the idea that lysosomes are not a dead-end but part of a membrane trafficking cycle in cells (Hirota et al, 2004).…”

Section: Discussionmentioning

confidence: 99%

The Phosphoinositide Kinase PIKfyve/Fab1p Regulates Terminal Lysosome Maturation inCaenorhabditis elegans

Nicot

Fares

Payrastre

et al. 2006

MBoC

122

154

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Membrane dynamics is necessary for cell homeostasis and signal transduction and is in part regulated by phosphoinositides. Pikfyve/Fab1p is a phosphoinositide kinase that phosphorylates phosphatidylinositol 3-monophosphate into phosphatidylinositol-3,5-bisphosphate [PtdIns(3,5)P 2 ] and is implicated in membrane homeostasis in yeast and in mammalian cells. These two phosphoinositides are substrates of myotubularin phosphatases found mutated in neuromuscular diseases. We studied the roles of phosphatidylinositol phosphate kinase 3 (PPK-3), the orthologue of PIKfyve/Fab1p, in a multicellular organism, Caenorhabditis elegans. Complete loss of ppk-3 function induces developmental defects characterized by embryonic lethality, whereas partial loss of function leads to growth retardation. At the cellular level, ppk-3 mutants display a striking enlargement of vacuoles positive for lysosome-associated membrane protein 1 in different tissues. In the intestine, RAB-7-positive late endosomes are also enlarged. Membranes of the enlarged lysosomes originate at least in part from smaller lysosomes, and functional and genetic analyses show that the terminal maturation of lysosomes is defective. Protein degradation is not affected in the hypomorphic ppk-3 mutant and is thus uncoupled from membrane retrieval. We measured the level of PtdIns(3,5)P 2 and showed that its production is impaired in this mutant. This work strongly suggests that the main function of PPK-3 is to mediate membrane retrieval from matured lysosomes through regulation of PtdIns(3,5)P 2 . INTRODUCTIONIn eukaryotic cells, spatiotemporal regulation of cellular organization and cell communication requires tightly regulated second messengers and microdomains. Phosphoinositides (PIs) are second messengers implicated in transduction pathways and membrane trafficking. Seven distinct PIs can be produced by phosphorylation of phosphatidylinositol at different positions. They recruit specific protein effectors leading to their localization to their site of action (Wenk and De Camilli, 2004). Several lipid-binding protein domains have been described (Simonsen et al., 2001). For example, phosphatidylinositol-3,4,5-triphosphate recruits Akt/protein kinase B through its pleckstrin homology domain at the plasma membrane, leading to phosphorylation of effectors and activation of downstream pathways, whereas phosphatidylinositol 3-monophosphate [PtdIns(3)P] binds to the FYVE domains of early endosomal antigen EEA1 and Hrs, proteins implicated respectively in early endosome fusion and in receptor sorting in multivesicular bodies (MVBs) (Gruenberg and Stenmark, 2004). PtdIns(3)P is found mainly on early endosomes and internal membranes of MVBs, whereas phosphatidylinositol-3,5-bisphosphate [PtdIns(3,5)P 2 ] is on the external membrane of MVBs. These PIs regulate endocytosis and thus protein transport and degradation. For example, growth factors receptors are internalized after stimulation and their signals are downregulated by their degradation in lysosomes (Miaczynska et al., 2...

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Section: Discussionmentioning

confidence: 99%

The Phosphoinositide Kinase PIKfyve/Fab1p Regulates Terminal Lysosome Maturation inCaenorhabditis elegans

Nicot

Fares

Payrastre

et al. 2006

MBoC

122

154

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“…Immunocytochemistry Cells were immunostained as described previously (Hirota et al, 2004). The following antibodies were used in this study: anti-AP-1 (clone 100/3, Sigma), anti-EEA1 (clone 14, BD Transduction Laboratories), anti-LAMP-1 (clone H4A3, Santa Cruz), anti-LC3 (MBL, #PM036), anti-p62 (MBL, #PM045), antiubiquitin (Dako, Z045801), and Alexa Fluor 589-labeled secondary antibodies (Molecular Probes).…”

Section: Transmission Electron Microscopymentioning

confidence: 99%

A Diffraction-Quality Protein Crystal Processed as an Autophagic Cargo

et al. 2015

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Crystallization of proteins may occur in the cytosol of a living cell, but how a cell responds to intracellular protein crystallization remains unknown. We developed a variant of coral fluorescent protein that forms diffraction-quality crystals within mammalian cells. This expression system allowed the direct determination of its crystal structure at 2.9 Å, as well as observation of the crystallization process and cellular responses. The micron-sized crystal, which emerged rapidly, was a pure assembly of properly folded β-barrels and was recognized as an autophagic cargo that was transferred to lysosomes via a process involving p62 and LC3. Several lines of evidence indicated that autophagy was not required for crystal nucleation or growth. These findings demonstrate that in vivo protein crystals can provide an experimental model to study chemical catalysis. This knowledge may be beneficial for structural biology studies on normal and disease-related protein aggregation.

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“…Survival and proliferation of cortical astrocytes (Sibilia et al 1998;Wagner et al 2006); Astrocyte development and neuronal survival (Kornblum et al 1998 Regulation of neural tube development (Deng et al 1997;Hasegawa et al 2004); OL differentiation (Zhou et al 2006) p75NTR Negative regulation of hippocampal pyramidal neuron dendritic morphology and neurite outgrowth (Zagrebelsky et al 2005); Schwann cell migration, remyelination (Bentley and Lee 2000;Song et al 2006;Tomita et al 2007) TrkA Development of sensory sympathetic and cholinergic neurons Fagan et al 1996) TrkB Development of motor and/or sensory neurons (Ernfors et al 1994;Klein 1994;Pinon et al 1996); Interneuron migration (Polleux et al 2002) TrkC Development of sensory neurons Liebl et al 1997) 1998; Hirota et al 2004), in which cytoplasmic domains of the receptor are no longer accessible to signaling proteins, rendering the receptor signaling incompetent. Moreover, the increasingly acidic lysosomal environment ( pH 4.0) promotes protein degradation.…”

Section: Endocytosis and Endosomal Targetingmentioning

confidence: 99%

Directing traffic in neural cells: determinants of receptor tyrosine kinase localization and cellular responses

Romanelli

Wood²

2008

Journal of Neurochemistry

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The trafficking of receptor tyrosine kinases (RTKs) to distinct subcellular locations is essential for the specificity and fidelity of signal transduction and biological responses. This is particularly important in the PNS and CNS in which RTKs mediate key events in the development and maintenance of neurons and glia through a wide range of neural processes, including survival, proliferation, differentiation, neurite outgrowth, and synaptogenesis. The mechanisms that regulate the targeting of RTKs to their subcellular destinations for appropriate signal transduction, however, are still elusive. In this review, we discuss evidence for the spatial organization of signaling machinery into distinct subcellular compartments, as well as the role for ligand specificity, receptor sorting signals, and lipid raft microdomains in RTK targeting and the resultant cellular responses in neural cells.

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Analysis of post-lysosomal compartments

Cited by 21 publications

References 29 publications

The Phosphoinositide Kinase PIKfyve/Fab1p Regulates Terminal Lysosome Maturation inCaenorhabditis elegans

The Phosphoinositide Kinase PIKfyve/Fab1p Regulates Terminal Lysosome Maturation inCaenorhabditis elegans

A Diffraction-Quality Protein Crystal Processed as an Autophagic Cargo

Directing traffic in neural cells: determinants of receptor tyrosine kinase localization and cellular responses

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