CLIP and cohibin separate rDNA from nucleolar proteins destined for degradation by nucleophagy.

Autor:	Mostofa MG; Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan., Rahman MA; Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan., Koike N; Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan., Yeasmin AM; Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan., Islam N; Course of Biological Science, Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka, Japan., Waliullah TM; Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan., Hosoyamada S; Laboratory of Genome Regeneration, Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo, Japan., Shimobayashi M; Biozentrum, University of Basel, Basel, Switzerland., Kobayashi T; Laboratory of Genome Regeneration, Institute of Molecular and Cellular Biosciences, University of Tokyo, Tokyo, Japan., Hall MN; Biozentrum, University of Basel, Basel, Switzerland., Ushimaru T; Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan takashi.ushimaru@gmail.com.; Course of Biological Science, Department of Science, Graduate School of Integrated Science and Technology, Shizuoka University, Shizuoka, Japan.
Jazyk:	angličtina
Zdroj:	The Journal of cell biology [J Cell Biol] 2018 Aug 06; Vol. 217 (8), pp. 2675-2690. Date of Electronic Publication: 2018 Jun 29.
DOI:	10.1083/jcb.201706164
Abstrakt:	Nutrient starvation or inactivation of target of rapamycin complex 1 (TORC1) in budding yeast induces nucleophagy, a selective autophagy process that preferentially degrades nucleolar components. DNA, including ribosomal DNA (rDNA), is not degraded by nucleophagy, even though rDNA is embedded in the nucleolus. Here, we show that TORC1 inactivation promotes relocalization of nucleolar proteins and rDNA to different sites. Nucleolar proteins move to sites proximal to the nuclear-vacuolar junction (NVJ), where micronucleophagy (or piecemeal microautophagy of the nucleus) occurs, whereas rDNA dissociates from nucleolar proteins and moves to sites distal to NVJs. CLIP and cohibin, which tether rDNA to the inner nuclear membrane, were required for repositioning of nucleolar proteins and rDNA, as well as effective nucleophagic degradation of the nucleolar proteins. Furthermore, micronucleophagy itself was necessary for the repositioning of rDNA and nucleolar proteins. However, rDNA escaped from nucleophagic degradation in CLIP- or cohibin-deficient cells. This study reveals that rDNA-nucleolar protein separation is important for the nucleophagic degradation of nucleolar proteins. (© 2018 Mostofa et al.)
Databáze:	MEDLINE
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