TY - JOUR
T1 - Piecemeal microautophagy of nucleus in Saccharomyces cerevisiae
AU - Roberts, Paul
AU - Moshitch-Moshkovitz, Sharon
AU - Kvam, Erik
AU - O'Toole, Eileen
AU - Winey, Mark
AU - Goldfarb, David S.
PY - 2003/1/1
Y1 - 2003/1/1
N2 - 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.
AB - 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.
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U2 - 10.1091/mbc.E02-08-0483
DO - 10.1091/mbc.E02-08-0483
M3 - Article
C2 - 12529432
AN - SCOPUS:0037243892
VL - 14
SP - 129
EP - 141
JO - Molecular Biology of the Cell
JF - Molecular Biology of the Cell
SN - 1059-1524
IS - 1
ER -