Regulation of nutrient transport into the cells by endocytosis
Dr Sébastien LÉON
Institut Jacques Monod, France
Wednesday, October 9th 2019 - 11 a.m.
- Auditorium, IGBMC
Hosted by Manuel MENDOZA, Izabela SUMARA
Cells have evolved complex mechanisms to optimize nutrient transport when facing variations in nutrient availability. Part of this regulation involves a regulated degradation of nutrient transporters by endocytosis when they are no longer required. The ubiquitylation of transporters by ubiquitin ligases of the Rsp5/Nedd4 family can act as a molecular trigger for their internalization. Our goal is to understand how transporter ubiquitylation and endocytosis are coordinated with the cellular physiology and metabolism. Using yeast as a model system, we discovered the involvement of a family of proteins that are distant relatives of visual/beta-arrestins (named ARTs, arrestin-related proteins) in this process. ARTs act as effectors of nutrient signalling pathways in the control of endocytosis. Their post-translational modifications (phosphorylation, ubiquitylation) are regulated by nutrient availability through nutrient signalling and, in turn, control their activity in endocytosis. I will provide examples of this regulation by describing the mechanisms regulating endocytosis with respect to glucose availability in the medium through AMPK signaling. I will also mention the redundancy within this family of proteins and the multiple places where ART proteins can control membrane protein trafficking in the cell to highlight the robustness and the integrated nature of endocytic decisions.