Related Experiment Video
Updated: May 28, 2026
09:14
Super-Resolution Microscopy of the Synaptonemal Complex Within the Caenorhabditis elegans Germline
Published on: September 13, 2022
Cohesin: a catenase with separate entry and exit gates?
1University of Oxford, Department of Biochemistry, South Parks Road, Oxford, OX1 3QU, UK. kim.nasmyth@bioch.ox.ac.uk
Nature Cell Biology
|October 5, 2011
Summary
Cohesin forms a ring to hold chromosomes together. DNA enters the ring for loading and exits for release, with acetylation controlling this process until cell division.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Cohesin is a protein complex essential for maintaining sister chromatid cohesion.
- It forms a tripartite ring structure believed to entrap DNA.
- Understanding the cohesin ring cycle is crucial for comprehending chromosome segregation.
Purpose of the Study:
- To discuss the four stages of the cohesin ring cycle.
- To propose a model for cohesin loading and dissociation.
- To elucidate the mechanisms regulating cohesin's role in cell division.
Main Methods:
- Conceptual review and discussion based on the cohesin ring model.
- Postulation of mechanisms for DNA entry and exit from the cohesin ring.
- Analysis of regulatory factors like acetylation and cleavage by separase.
Main Results:
- Cohesin loading involves DNA entry into the ring, facilitated by the kollerin complex.
- Cohesin dissociation involves DNA exit, mediated by Wapl and other subunits (releasin).
- Smc3 acetylation near the exit gate neutralizes releasin, locking the ring until separase cleavage.
Conclusions:
- The cohesin ring cycle can be understood through DNA's entry and exit.
- Distinct gates for entry (Smc1-Smc3) and exit (Smc3-kleisin) are proposed.
- Acetylation and separase-mediated cleavage are key regulators of cohesin function and cell cycle progression.
Related Concept Videos
02:20Cohesins
Cohesin protein complexes are a molecular glue that holds two sister chromatids together. They play an important role both in mitosis and meiosis. In mitosis, all cohesin complexes present on the chromosomes are removed before the start of the anaphase stage.
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
02:20Cohesins
Cohesin protein complexes are a molecular glue that holds two sister chromatids together. They play an important role both in mitosis and meiosis. In mitosis, all cohesin complexes present on the chromosomes are removed before the start of the anaphase stage.
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
Cohesin complexes in Meiotic Division
Meiosis involves two distinct rounds of chromosomal segregation and cell divisions— Meiosis I followed by Meiosis II – producing four daughter cells. Meiosis I includes the separation of homologous...
02:17Separation 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...
At the onset of anaphase, separase, a proteolytic enzyme, is...
02:17Separation 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...
At the onset of anaphase, separase, a proteolytic enzyme, is...
01:23Catenins
Catenins are characterized by multiple binding domains and dynamic structures that allow them to function as linker proteins in cell junction complexes. All catenins, except α-catenin, contain a characteristic protein sequence called the armadillo repeat and are therefore also called armadillo proteins.
Catenins in Cell Junctions
Catenins bind to cell adhesion molecules such as cadherins and link them to different cytoskeletal proteins depending on the type of cell junction. At the adherens...
Catenins in Cell Junctions
Catenins bind to cell adhesion molecules such as cadherins and link them to different cytoskeletal proteins depending on the type of cell junction. At the adherens...
01:24Adherens Junctions
Strong contact points between adjacent cells anchor them to each other, forming tissues. Such anchoring junctions are of two types – adherens junctions and desmosomes. Adherens junctions are abundant in tissues such as epithelium and endothelium, forming a continuous zone of adhesion called the adhesion belt. In other tissues, such as heart muscle, they appear as clusters, linking the cells to produce coordinated heart muscle contraction.
Adherens Junctions are Dynamic
The endothelial cells...
Adherens Junctions are Dynamic
The endothelial cells...