Related Experiment Video

Updated: Feb 8, 2026

Assays for the Degradation of Misfolded Proteins in Cells
10:56

Assays for the Degradation of Misfolded Proteins in Cells

Published on: August 28, 2016

12.6K

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

Md Golam Mostofa1, Muhammad Arifur Rahman1, Naoki Koike1

  • 1Graduate School of Science and Technology, Shizuoka University, Shizuoka, Japan.

The Journal of Cell Biology
|July 1, 2018
PubMed

Insights

Nutrient starvation triggers nucleophagy in yeast, degrading nucleolar proteins but not DNA. This study reveals that separating ribosomal DNA from proteins is crucial for effective nucleophagy.

Area of Science:

  • Cell Biology
  • Molecular Biology
  • Autophagy Research

Background:

  • Nutrient starvation or TORC1 inactivation induces nucleophagy, a selective autophagy targeting nucleolar components in budding yeast.
  • Ribosomal DNA (rDNA), despite being in the nucleolus, is resistant to nucleophagy.

Purpose of the Study:

  • To investigate the mechanisms behind the selective degradation of nucleolar components during nucleophagy.
  • To understand the fate of rDNA during nutrient starvation-induced nucleophagy.

Main Methods:

  • Yeast genetics and microscopy techniques.
  • Analysis of protein and DNA localization.
  • Investigating the role of CLIP and cohibin in nucleophagy.

Main Results:

  • TORC1 inactivation causes nucleolar proteins and rDNA to relocate to distinct cellular sites.
  • Nucleolar proteins move towards the nuclear-vacuolar junction (NVJ) for potential degradation via micronucleophagy.
  • rDNA dissociates from nucleolar proteins and moves away from NVJs.
  • CLIP and cohibin are essential for the repositioning of nucleolar proteins and rDNA, and for efficient nucleophagic degradation.
  • Micronucleophagy is necessary for the repositioning of rDNA and nucleolar proteins.

Conclusions:

  • Separation of rDNA from nucleolar proteins is a critical step for the selective degradation of nucleolar components during nucleophagy.
  • CLIP and cohibin play key roles in orchestrating this separation and subsequent degradation process.

More Related Videos

Identification of Nucleolar Factors During HIV-1 Replication Through Rev Immunoprecipitation and Mass Spectrometry09:38

Identification of Nucleolar Factors During HIV-1 Replication Through Rev Immunoprecipitation and Mass Spectrometry

Published on: June 26, 2019

8.6K
Cycloheximide Chase Analysis of Protein Degradation in Saccharomyces cerevisiae09:05

Cycloheximide Chase Analysis of Protein Degradation in Saccharomyces cerevisiae

Published on: April 18, 2016

30.0K

Related Concept Videos

Regulated Protein Degradation02:58

Regulated Protein Degradation

It is vital to regulate the activity of enzymatic as well as non-enzymatic proteins inside the cell. This can be achieved either through creating a balance between their rate of synthesis and degradation or regulating the intrinsic activity of the protein. Both these regulation mechanisms play an essential role in the normal functioning of cells.
Protein degradation plays two important roles in the cells. It helps to protect cells from misfolded or damaged proteins before they lead to a...
8.9K
Regulated Protein Degradation02:58

Regulated Protein Degradation

3.2K
Proteins: From Genes to Degradation02:11

Proteins: From Genes to Degradation

Within a biological system, the DNA encodes the RNA, and the nucleotide sequence in the RNA further defines the amino acid sequence in the protein. This is referred to as “The Central Dogma of Molecular Biology” - a term coined by Francis Crick.  Central dogma is a firm principle in biology that defines the flow of genetic information within any life form. The two fundamental steps in central dogma are - transcription and translation.
Transcription is the synthesis of RNA...
14.5K
Proteins: From Genes to Degradation02:11

Proteins: From Genes to Degradation

4.5K
Ribosomal RNA Synthesis02:53

Ribosomal RNA Synthesis

Ribosome synthesis is a highly complex and coordinated process involving more than 200 assembly factors. The synthesis and processing of ribosomal components occurs not only in the nucleolus but also in the nucleoplasm and the cytoplasm of eukaryotic cells.
Ribosome biogenesis begins with the synthesis of 5S and 45S pre-rRNAs by distinct RNA polymerases. The primary transcripts are extensively processed and modified before they are bound and folded by ribosomal proteins and assembly factors,...
14.9K
Separation of Sister Chromatids02:17

Separation of Sister Chromatids

At the transition from prophase to metaphase, there is a reduction in cohesion along the chromosomal arms, resulting in the resolution of sister chromatids. However, residual cohesin connections remain to hold the sister chromatids together until the transition from metaphase to anaphase. The residual connection prevents any premature separation of sister chromatids, blocking the risks of aneuploidy within the daughter cells.
At the onset of anaphase, separase, a proteolytic enzyme, is...
4.5K