Skip to Main content Skip to Navigation
Theses

Identification et caractérisation de nouveaux acteurs de deux voies de trafic intracellulaire : le recyclage et l'autophagie dans la levure Saccharomyces cerevisiae

Abstract : During endocytosis, plasma membrane (PM) cargoes are internalized and targeted to the early endosomes (EE) and the multivesicular bodies (MVBs) before reaching the lysosome/vacuole where they are degraded. Sorting of proteins to invaginated regions of the MVBs is a process conserved from yeast to mammals and dependent on the ESCRTs complexes. Deficiencies in the ESCRT machinery lead to the formation of an abnormal endosomal compartment (Cl E) and to the accumulation of various cargoes at the PM. We show that in S. cerevisiae the stabilization of the uracil permease (Fur4p) at the PM in ESCRTs mutants is due to an enhanced recycling of the endocytosed protein. Fur4p does not pass through the Golgi apparatus on its road from the Cl E compartment to the PM. We thus show a new recycling pathway, different from the one described for the v-SNARE Snc1p. Fur4p can also recycle from the EE and, in this case, follows the same road as Snc1p, suggesting a previously non-expected complexity of recycling pathways in yeast.
We also studied 2 EH domain proteins Irs4p and Tax4p, a domain typically found in proteins involved in endocytosis and recycling. Irs4p and Tax4p are not necessary for those processes but display a redundant function in autophagy, a catabolic transport of fractions of cytoplasm or organelles to the lysosome/vacuole. Irs4p and Tax4p interact physically with the autophagic machinery and are partially localized to the Pre-Autophagosomal Structure, the yeast perivacuolar site where autophagosomes are formed. These results show the involvement of a new class of proteins in autophagy and extend the known functions of the EH domain proteins to a new trafficking pathway.
Document type :
Theses
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00276753
Contributor : Amandine Bugnicourt <>
Submitted on : Friday, May 2, 2008 - 1:49:59 AM
Last modification on : Monday, October 19, 2020 - 11:08:47 AM
Long-term archiving on: : Friday, May 28, 2010 - 6:10:30 PM

Identifiers

  • HAL Id : tel-00276753, version 1

Collections

Citation

Amandine Bugnicourt. Identification et caractérisation de nouveaux acteurs de deux voies de trafic intracellulaire : le recyclage et l'autophagie dans la levure Saccharomyces cerevisiae. Biologie cellulaire. Université Paris-Diderot - Paris VII, 2007. Français. ⟨tel-00276753⟩

Share

Metrics

Record views

503

Files downloads

1688