0 avis
Glucose-induced ubiquitylation and endocytosis of the yeast JEN1 transporter: Role of K63-linked ubiquitin chains.
Archive ouverte
Edité par CCSD ; American Society for Biochemistry and Molecular Biology -
International audience. Protein ubiquitylation is essential for many events linked to intracellular protein trafficking. Despite the significance of this process, the molecular mechanisms that govern the regulation of ubiquitylation remain largely unknown. Plasma membrane transporters are subjected to tightly regulated endocytosis, and ubiquitylation is a key signal at several stages of the endocytic pathway. The yeast monocarboxylate transporter Jen1 displays glucose-regulated endocytosis. We show here that Casein Kinase 1-dependent phosphorylation, and HECT-ubiquitin ligase Rsp5-dependent ubiquitylation are required for Jen1 endocytosis. Ubiquitylation and endocytosis of Jen1 are induced within minutes in response to glucose addition. Jen1 is modified at the cell surface by oligo-ubiquitylation with ubiquitin-K63 linked chain(s), and Jen1-Lys338 is one of the target residues. Ubiquitin-K63 linked chain(s) are also required directly or indirectly to sort Jen1 into multivesicular bodies (MVBs). Jen1 is one of the few examples for which ubiquitin-K63 linked chain(s) were shown to be required for correct trafficking at two stages of endocytosis: endocytic internalization and sorting at MVBs.