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Updated: Apr 4, 2026

Quantitative Localization of a Golgi Protein by Imaging Its Center of Fluorescence Mass
Published on: August 10, 2017
Starvation-Dependent Regulation of Golgi Quality Control Links the TOR Signaling and Vacuolar Protein Sorting
Niv Dobzinski1, Silvia G Chuartzman1, Rachel Kama1
1Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel.
Abstract:
Upon amino acid (AA) starvation and TOR inactivation, plasma-membrane-localized permeases rapidly undergo ubiquitination and internalization via the vacuolar protein sorting/multivesicular body (VPS-MVB) pathway and are degraded in the yeast vacuole. We now show that specific Golgi proteins are also directed to the vacuole under these conditions as part of a Golgi quality-control (GQC) process. The degradation of GQC substrates is dependent upon ubiquitination by the defective-for-SREBP-cleavage (DSC) complex, which was identified via genetic screening and includes the Tul1 E3 ligase. Using a model GQC substrate, GFP-tagged Yif1, we show that vacuolar targeting necessitates upregulation of the VPS pathway via proteasome-mediated degradation of the initial endosomal sorting complex required for transport, ESCRT-0, but not downstream ESCRT components. Thus, early cellular responses to starvation include the targeting of specific Golgi proteins for degradation, a phenomenon reminiscent of the inactivation of BTN1, the yeast Batten disease gene ortholog.
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