Related Experiment Video

Updated: Sep 27, 2025

Development of Inhibitors of Protein-protein Interactions through REPLACE: Application to the Design and Development Non-ATP Competitive CDK Inhibitors
10:33

Development of Inhibitors of Protein-protein Interactions through REPLACE: Application to the Design and Development Non-ATP Competitive CDK Inhibitors

Published on: October 26, 2015

11.4K

Ubiquitin ligase activity inhibits Cdk5 to control axon termination

Muriel Desbois1, Karla J Opperman1, Jonathan Amezquita1,2

  • 1Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington, United States of America.

Plos Genetics
|April 14, 2022
PubMed

Insights

The RPM-1/FSN-1 ubiquitin ligase complex inhibits CDK-5 kinase activity in C. elegans. This discovery reveals a conserved mechanism regulating CDK-5, crucial for nervous system development and function.

Area of Science:

  • Neuroscience
  • Molecular Biology
  • Cell Biology

Background:

  • Cyclin-dependent kinase 5 (CDK5) is vital for nervous system development, plasticity, and disease.
  • Negative regulatory mechanisms controlling CDK5 activity are not fully understood.
  • CDK5 also has non-neuronal roles in cancer, immunity, and insulin secretion.

Purpose of the Study:

  • To investigate the negative regulatory mechanisms of CDK5.
  • To identify substrates and regulators of CDK5 using Caenorhabditis elegans.
  • To elucidate the role of the RPM-1/FSN-1 ubiquitin ligase complex in CDK5 regulation.

Main Methods:

  • Unbiased, in vivo affinity purification proteomics to identify potential CDK5 interactors.
  • CRISPR-based native biochemistry to confirm CDK5 interaction with the RPM-1/FSN-1 complex.
  • CRISPR-engineered substrate 'trap' to analyze binding interactions.
  • Genetic analysis of axon termination in mechanosensory and motor neurons.

Main Results:

  • Proteomics identified CDK5 as a putative substrate of the RPM-1/FSN-1 ubiquitin ligase complex.
  • Biochemical assays confirmed CDK5 directly interacts with RPM-1/FSN-1.
  • FSN-1's substrate recognition module mediates CDK5 binding.
  • RPM-1/FSN-1 ubiquitin ligase activity is essential for proper axon termination, restricting CDK5 function.

Conclusions:

  • The RPM-1/FSN-1 ubiquitin ligase complex acts as a negative regulator of CDK5 in C. elegans.
  • This conserved regulatory mechanism controls CDK5 activity, impacting nervous system development, specifically axon termination.
  • The findings provide insights into the molecular mechanisms restraining CDK5 in the nervous system.

More Related Videos

Detection of Protein Ubiquitination09:00

Detection of Protein Ubiquitination

Published on: August 19, 2009

43.0K
Genetic Manipulation of Cerebellar Granule Neurons In Vitro and In Vivo to Study Neuronal Morphology and Migration09:07

Genetic Manipulation of Cerebellar Granule Neurons In Vitro and In Vivo to Study Neuronal Morphology and Migration

Published on: March 17, 2014

13.9K

Related Concept Videos

Anaphase Promoting Complex00:50

Anaphase Promoting Complex

The stepwise destruction of specific proteins is necessary for the progression and completion of the cell cycle. Such proteins are ubiquitinated by ubiquitin ligases and then subsequently destroyed by the proteasome. The SCF (Skp1/Cullin/F-box) and the anaphase-promoting complex (APC) are two important ubiquitin ligases involved in cell cycle progression. While SCF is active throughout the cell cycle, APC gets activated during metaphase to anaphase transition. Cdc20 or Cdh1 binds to APC and...
3.0K
Inhibition of Cdk Activity02:34

Inhibition of Cdk Activity

The orderly progression of the cell cycle depends on the activation of Cdk protein by binding to its cyclin partner. However, the cell cycle must be restricted when undergoing abnormal changes. Most cancers correlate to the deregulated cell cycle, and since Cdks are a central component of the cell cycle, Cdk inhibitors are extensively studied to develop anticancer agents. For instance, cyclin D associates with several Cdks, such as Cdk 4/6, to form an active complex. The cyclin D-Cdk4/6 complex...
5.0K
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...
3.8K
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...
7.7K
DNA Damage can Stall the Cell Cycle02:37

DNA Damage can Stall the Cell Cycle

In response to DNA damage, cells can pause the cell cycle to assess and repair the breaks. However, the cell must check the DNA at certain critical stages during the cell cycle. If the cell cycle pauses before DNA replication, the cells will contain twice the amount of DNA. On the other hand, if cells arrest after DNA replication but before mitosis, they will contain four times the normal amount of DNA. With a host of specialized proteins at their disposal,cells must use the right protein at...
9.4K
Amplifying Signals via Enzymatic Cascade01:22

Amplifying Signals via Enzymatic Cascade

When a ligand binds to a cell-surface receptor, the receptor's intracellular domain changes shape, which may either activate its enzyme function or allow its binding to other molecules. The initial signal is amplified by most signal transduction pathways. This means that a single ligand molecule can activate multiple molecules of a downstream target. Proteins that relay a signal are most commonly phosphorylated at one or more sites, activating or inactivating the protein. Kinases catalyze...
10.9K