Endosome maturation. EMBO J

Institute of Biochemistry, ETH Zurich, Switzerland.
The EMBO Journal (Impact Factor: 10.75). 08/2011; 30(17):3481-500. DOI: 10.1038/emboj.2011.286
Source: PubMed

ABSTRACT Being deeply connected to signalling, cell dynamics, growth, regulation, and defence, endocytic processes are linked to almost all aspects of cell life and disease. In this review, we focus on endosomes in the classical endocytic pathway, and on the programme of changes that lead to the formation and maturation of late endosomes/multivesicular bodies. The maturation programme entails a dramatic transformation of these dynamic organelles disconnecting them functionally and spatially from early endosomes and preparing them for their unidirectional role as a feeder pathway to lysosomes.

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Available from: Ari Helenius, Jan 13, 2014
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    • "Direct immunofluorescence studies and co-labeling with Lysotracker Red, a marker for acidic late endosomes and lysosomes, further showed that the internalized antibody was trafficked to acidic organelles in the perinuclear cytoplasm. The known perinuclear localization of lysosomes and late endosomes (Huotari and Helenius, 2011) agreed with the localization of OX42-fluorescence seen here confirming lysosomal trafficking of OX42 antibody in microglia. Lysosomal trafficking is desirable for non-viral vehicles that utilize PEI as DNA condensation agent, because the gradual acidification of endosomes facilitates the endosomal escape of the gene vehicle (Varkouhi et al., 2011). "
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    • "In fact, the core class III PI3K complex containing Vps34, Vps15 and Atg6/Beclin is also found on early endosomes and is required for endocytosis (reviewed in [4] [8]). UVRAG, the accessory protein suspected to have a role in autophagosome maturation, has its primary role in the class III PI3K complex on endosomes, where it is necessary to activate the HOPS complex that mediates membrane tethering to fuse with other endosomes or lysosomes [21] [28]. "
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    • "Furthermore , Maxfield and colleagues suggested early on that endosomal fusion and fission are necessary to sort selected membrane proteins into intraluminal vesicles of late endosomes, while allowing bulk membranes and receptors to be recycled back to the plasma membrane. This process, which was termed " geometric sorting " (Mayor et al. 1993), could explain the existence of recycling endosomes as well as the need of fusion and fission at the level of the early endosome to concentrate cargo proteins for their degradation in the lysosomal lumen (Huotari and Helenius 2011). In the course of the morphological transition of endosomes, which is called endosomal maturation, endosomes also change their membrane surface composition to become competent for fusion with the lysosome . "
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