Saccharomyces cerevisiae Golgi Gdt1 protein is a H+ exchanger

Details

Supervisors

Morsomme, Pierre

Faculty

Faculté des bioingénieurs

Degree label

Master [120] : bioingénieur en chimie et bioindustries, à finalité spécialisée

Abstract

Gdt1 is a protein belonging to the uncharacterized protein family 0016 (UPF0016), recently renamed the Gdt1 family. It is localized in the membrane of the cis-medial Golgi apparatus of Saccharomyces cerevisiae and is the yeast ortholog of TMEM165. Two models exist in the literature to explain cation transport mediated by Gdt1p: the Ca2+/Mn2+ antiporter model and the Ca2+-Mn2+/H+ antiporter model. However, recent studies established that Gdt1p is able to transport H+, strengthening the second model. This thesis focuses on investigating the physiological role of Gdt1p for H+ transport at the Golgi level. The main acidification pump of the secretory pathway, and subsequently of the Golgi, is already known; the V-ATPase pump. However, the efflux pathways (H+ leakage channel) or the transport of counterions (Cl-) have not been characterized so far. Through an approach using a pHluorin pH probe to measure pH in the Golgi, we presumably demonstrated that Gdt1p exports H+ from the Golgi to the cytosol, providing further support for the Ca2+-Mn2+/H+ antiporter model. Lastly, this thesis provides indications suggesting that Gdt1p is likely involved in collaborative Golgi pH regulation with other channels/transporters, potentially including Kha1p. However, additional research is necessary to obtain more conclusive findings and ensure confidence.