Piecemeal microautophagy of nucleus in Saccharomyces cerevisiae

Paul Roberts, Sharon Moshitch-Moshkovitz, Erik Kvam, Eileen O'Toole, Mark Winey, David S. Goldfarb

Research output: Contribution to journalArticle

281 Scopus citations

Abstract

Nucleus-vacuole (NV) junctions in Saccharomyces cerevisiae are formed through specific interactions between Vac8p on the vacuole membrane and Nvj1p in the nuclear envelope. Herein, we report that NV junctions in yeast promote piecemeal microautophagy of the nucleus (PMN). During PMN, teardrop-like blebs are pinched from the nucleus, released into the vacuole lumen, and degraded by soluble hydrolases. PMN occurs in rapidly dividing cells but is induced to higher levels by carbon and nitrogen starvation and is under the control of the Tor kinase nutrient-sensing pathway. Confocal and biochemical assays demonstrate that Nvj1p is degraded in a PMN-dependent manner. PMN occurs normally in apg7-Δ cells and is, therefore, not dependent on macroautophagy. Transmission electron microscopy reveals that portions of the granular nucleolus are often sequestered into PMN structures. These results introduce a novel mode of selective microautophagy that targets nonessential components of the yeast nucleus for degradation and recycling in the vacuole.

Original languageEnglish (US)
Pages (from-to)129-141
Number of pages13
JournalMolecular Biology of the Cell
Volume14
Issue number1
DOIs
StatePublished - Jan 1 2003
Externally publishedYes

ASJC Scopus subject areas

  • Cell Biology
  • Genetics
  • Molecular Biology

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  • Cite this

    Roberts, P., Moshitch-Moshkovitz, S., Kvam, E., O'Toole, E., Winey, M., & Goldfarb, D. S. (2003). Piecemeal microautophagy of nucleus in Saccharomyces cerevisiae. Molecular Biology of the Cell, 14(1), 129-141. https://doi.org/10.1091/mbc.E02-08-0483