Thesis Title

Vps1's Implication on Late Endosome-to-Vacuole Traffic

Date of Graduation

Spring 2012


Master of Science in Biology



Committee Chair

Kyoungtae Kim


Vps1, endosome, vacuole, trafficking, FM4-64

Subject Categories



Previous studies have shown Vps1 to be necessary for both sorting of soluble vacuolar proteins from the Golgi and retention of Golgi membrane proteins. I have recently found that Vps1 is implicated in membrane trafficking from the plasma membrane through the endosomal system to the vacuole. Loss of Vps1 resulted in accumulation of FM4-64 puncta that colocalize with a late endosomal marker (GFP-Pep12), indicating a slower late endosome-to-vacuole traffic. In addition, Vps1 was found to genetically interact with Vps36 and Ypt7, which are involved in the late endosome-to-vacuole traffic. Protein's functional role is generally correlated with its localization, so I investigated the subcellular localization of Vps1-GFP in relation to endocytic sites and endosomal compartments. In a FM4-64 pulse-chase experiment, I found that the extent of colocalization of FM4-64 with Vps1-GFP drastically increased after 20 min chase, indicating Vps1-carrying vesicles are among the population of late endosomal compartments. Consistently, I observed that Vps1-GFP coincides with PI3P (endosomal marker), but not with the plasma membrane endocytic markers such as Abp1 and Ede1, suggesting that Vps1 is a component of endosomal compartments. Taken together, I postulate that Vps1 is required for an efficient traffic toward the vacuole from late endosomal compartments.


© Jacob Robert Hayden


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