The Biogenesis of Lysosomes
TL;DR: Article de synthese sur les lysosomes: biogenese, definition, role biologique, Les enzymes lysOSomales sont decrites ainsi that leur role dans l'exo et l'endocytose.
Abstract: Article de synthese sur les lysosomes: biogenese, definition, role biologique. Les enzymes lysosomales sont decrites ainsi que leur role dans l'exo et l'endocytose. La structure et le biogenese de la membrane lysosomale sont etudiees
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TL;DR: The molecular mechanism of autophagosome formation is described with particular focus on the function of Atg proteins and the long-standing discussion regarding the origin of the autophagous membrane membrane.
Abstract: Macroautophagy is mediated by a unique organelle, the autophagosome, which encloses a portion of cytoplasm for delivery to the lysosome. Autophagosome formation is dynamically regulated by starvation and other stresses and involves complicated membrane reorganization. Since the discovery of yeast Atg-related proteins, autophagosome formation has been dissected at the molecular level. In this review we describe the molecular mechanism of autophagosome formation with particular focus on the function of Atg proteins and the long-standing discussion regarding the origin of the autophagosome membrane.
2,522 citations
TL;DR: It is demonstrated that IGF-II is indispensable for normal embryonic growth and that the IGF- II gene is subject to tissue-specific parental imprinting.
1,738 citations
TL;DR: A photoactivatable variant of the Aequorea victoria green fluorescent protein is reported that, after intense irradiation with 413-nanometer light, increases fluorescence 100 times when excited by 488-nanometers light and remains stable for days under aerobic conditions.
Abstract: We report a photoactivatable variant of the Aequorea victoria green fluorescent protein (GFP) that, after intense irradiation with 413-nanometer light, increases fluorescence 100 times when excited by 488-nanometer light and remains stable for days under aerobic conditions. These characteristics offer a new tool for exploring intracellular protein dynamics by tracking photoactivated molecules that are the only visible GFPs in the cell. Here, we use the photoactivatable GFP both as a free protein to measure protein diffusion across the nuclear envelope and as a chimera with a lysosomal membrane protein to demonstrate rapid interlysosomal membrane exchange.
1,605 citations
TL;DR: This review attempts to integrate emerging concepts concerning the protein-based signals responsible for molecular sorting and the cytosolic complexes responsible for the decoding of these signals to present a more coherent picture of how the endocytic pathway is organized and how the intracellular transport of internalized membrane components is controlled.
Abstract: Endocytosis in eukaryotic cells is characterized by the continuous and regulated formation of prolific numbers of membrane vesicles at the plasma membrane. These vesicles come in several different varieties, ranging from the actin-dependent formation of phagosomes involved in particle uptake, to smaller clathrin-coated vesicles responsible for the internalization of extracellular fluid and receptor-bound ligands. In general, each of these vesicle types results in the delivery of their contents to lysosomes for degradation. The membrane components of endocytic vesicles, on the other hand, are subject to a series of highly complex and iterative molecular sorting events resulting in their targeting to specific destinations. In recent years, much has been learned about the function of the endocytic pathway and the mechanisms responsible for the molecular sorting of proteins and lipids. This review attempts to integrate these new concepts with long-established views of endocytosis to present a more coherent picture of how the endocytic pathway is organized and how the intracellular transport of internalized membrane components is controlled. Of particular importance are emerging concepts concerning the protein-based signals responsible for molecular sorting and the cytosolic complexes responsible for the decoding of these signals.
1,584 citations
Cites background from "The Biogenesis of Lysosomes"
...Moreover, this pH range is sufficient to result in the dissociation of ligands such as low density lipoprotein (LDL) (Kornfeld & Mellman 1989)....
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...They often have abundant internal membranes and are enriched in lgp/lamps, rab7, rab9, and the cation-independent MPR (Griffiths et al 1988, Geuze et al 1989, Kornfeld & Mellman 1989, Chavrier et al 1991, Lombardi et al 1993, Simons & Zerial 1993, Feng et al 1995)....
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...In many cells, lgp/lamps reach their destination by transport directly from the TGN to the endocytic pathway, possibly via CCVs (Kornfeld & Mellman 1989)....
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...In addition, although recycling plasma membrane receptors are restricted to EEs and recycling vesicles, LEs contain MPR (which recycles predominantly to the TGN) (Kornfeld & Mellman 1989)....
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...A well-characterized example of such signals is provided by the LDL receptor, which contains two distinct tyrosine-dependent determinants (Figure 7)....
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TL;DR: An expert system is reported for predicting localization sites of proteins only from the information on the amino acid sequence and the source origin, which is powerful and flexible enough to be used in genome analyses.
1,545 citations