Sebastien Leon

..Therefore, Ear1p/Ssh4p recruit Rsp5p and assist it in its function at MVBs by directing the ubiquitylation of specific cargoes...

..In addition, expression of this mutant protein in wild-type cells confers a dominant-negative, oleate-specific growth defect, which is a useful tool for a better understanding of peroxisomal receptor recycling...

..Finally, because these adaptors represent an additional layer of specificity in the ubiquitylation cascade, and can themselves be subject to a complex regulation, they are essential actors in the fine-tuning of endocytosis...

..Our data are consistent with a model in which Pex20p enters peroxisomes and recycles back to the cytosol in an ubiquitin-dependent manner...

..A failure to generate K63Ub chains in yeast leads to an MVB ultrastructure alteration. Our work thus unravels a double function of K63Ub chains in cargo sorting and MVB biogenesis...

..In the present review, we discuss recent examples illustrating the role of Rsp5p in membrane protein trafficking and providing new insights into the regulation of this E3 by adaptor proteins...

..The defect appears at the level of ATP9 mRNA translation, while its maturation remained unchanged in the mutants. This study describes a new role of the ubiquitin system in mitochondrial biogenesis...

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..This chapter discusses methods that have been used for the study of such interactions among both soluble and membrane-associated proteins in peroxisome biogenesis. The procedures are equally applicable to other cellular processes...

..These data suggest a direct interaction between PpPex8p and Pex20p. Our studies shed light on the mechanism and evolution of the dual import pathways for PpPex8p...

..In this paper, we discuss recent data on the intricate connections between arrestins and the ubiquitin pathway in the control of endocytosis...

..Our data support the idea that PpPex8p is a special cargo whose translocation into peroxisomes depends only on the PTS receptors and Pex14p and not on intraperoxisomal Pex8p, the RING subcomplex, or the receptor-recycling machinery...

..Moreover, yeast Acb1 and several proteins required for its secretion are necessary for sporulation in P. pastoris. Our findings implicate currently unknown, evolutionarily conserved pathways in unconventional secretion...

..Therefore, PpAtg30 is a key player in the selection of peroxisomes as cargo and in their delivery to the autophagy machinery for pexophagy...

..The growth environment-specific role of these peroxins, their dual localization, and the function of their dysferlin domains provide novel insights into peroxisome morphogenesis...

..We discuss roles for Pex3p in the assembly of specific peroxisomal membrane protein subcomplexes whose formation is necessary for matrix protein import...

..Therefore, we speculate that SG might facilitate elongation of any double membrane from the PAS and this enhancer function of SG becomes essential when extremely large double membranes are formed...

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..The discovery of a Cvt pathway in P. pastoris makes it an excellent model system for the dissection of autophagy-related pathways in a single organism and for the discovery of new Cvt pathway components...

..As a rule, the larger the cargo, the more cargo-specific Atg proteins become essential for its sequestration...

..We provide below a brief historical perspective regarding the importomer and its role in peroxisome biogenesis. We also identify areas in which further work is needed to uncover the physiological role of the importomer...

..Also included are protocols for the labeling of different subcellular organelles with vital stains...

..Rather, the defects in all autophagic pathways observed when PpUvrag was overexpressed support its presence in a complex that competes with the PI3K complex required for autophagy...

..A paper in this issue addresses, in a very thorough fashion, the assembly, cofactor binding, and import of an oligomeric protein, acyl-CoA oxidase (Aox), into the peroxisome matrix (Titorenko et al., 2002, this issue)...

..In this manuscript we review the recent progress made in our understanding of the mechanisms by which matrix and membrane proteins are sorted to and assembled into peroxisomes...

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..2007) show that Atg8 conjugated to PE mediates tethering between adjacent membranes and stimulates membrane hemifusion, an event that may mimic expansion of the autophagosomal membrane during autophagy...

..Related DRPs also function in the division of mitochondria and chloroplasts. Many other proteins and signals regulate peroxisome division and proliferation, but their modes of action are still being studied...

..We propose that pexophagy requires the simultaneous activation of this MAPK pathway and a hexose-sensing mechanism acting through protein kinase A and cyclic adenosine monophosphate...

..These insights and additional observations in the literature provide a framework for an understanding of the physiological role(s) of pexophagy...

..We discuss the potential role of this vesicle population in the context of pathways for the exchange of metabolites and/or macromolecules between these compartments...

..We propose that MXR1 is the P. pastoris homologue of S. cerevisiae ADR1 but that it has gained new functions and lost others through evolution as a result of changes in the spectrum of genes that it controls...

..The identification of ATG28 suggests that pexophagy may involve species-specific components, since this gene appears to have only weak homologues in other yeasts...