Related Experiment Video

Updated: Sep 18, 2025

In Vitro Analysis of E3 Ubiquitin Ligase Function
06:06

In Vitro Analysis of E3 Ubiquitin Ligase Function

Published on: May 14, 2021

5.4K

Structural mechanism for the recognition of E2F1 by the ubiquitin ligase adaptor Cyclin F

Peter Ngoi1, Xianxi Wang2, Sivasankar Putta1

  • 1Department of Chemistry and Biochemistry, University of California, Santa Cruz, CA 95064.

Proceedings of the National Academy of Sciences of the United States of America
|June 23, 2025
PubMed

Insights

Cyclin F, a unique cell cycle regulator, functions differently from other cyclins by targeting proteins for degradation. Structural studies reveal distinct E2F1 binding mechanisms compared to Cyclin A, offering new therapeutic targets.

Area of Science:

  • Molecular Biology
  • Structural Biology
  • Cell Cycle Regulation

Background:

  • Cyclin F is a noncanonical cyclin involved in cell cycle transitions.
  • Unlike canonical cyclins, Cyclin F acts as a substrate receptor in an E3 ubiquitin ligase complex.
  • Its distinct substrate recruitment mechanisms, especially compared to Cyclin A, are not well understood.

Purpose of the Study:

  • To structurally and biochemically characterize Cyclin F's substrate binding.
  • To elucidate the mechanisms of selective substrate recruitment by Cyclin F.
  • To compare Cyclin F's binding interface with that of Cyclin A.

Main Methods:

  • Single-particle cryoelectron microscopy (cryo-EM) of a Cyclin F-Skp1 complex with an E2F1 peptide.
  • Biochemical analysis of substrate binding.

Main Results:

  • Elucidation of the structure of the Cyclin F-Skp1-E2F1 peptide complex.
  • Identification of significant differences in the substrate-binding site of Cyclin F compared to Cyclin A.
  • Discovery of electrostatic interactions at the E2F1 binding interface, extending beyond canonical motifs.

Conclusions:

  • Cyclin F utilizes distinct structural and electrostatic features for E2F1 binding.
  • These findings provide insights into selective substrate recruitment mechanisms.
  • The study may inform therapeutic strategies targeting Cyclin F in cancer and neurodegenerative diseases.
Keywords:
cell cyclecryoelectron microscopyubiquitin ligase

More Related Videos

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay12:26

Identification of Cyclin-dependent Kinase 1 Specific Phosphorylation Sites by an In Vitro Kinase Assay

Published on: May 3, 2018

18.8K
Using In Vitro Fluorescence Resonance Energy Transfer to Study the Dynamics Of Protein Complexes at a Millisecond Time Scale10:50

Using In Vitro Fluorescence Resonance Energy Transfer to Study the Dynamics Of Protein Complexes at a Millisecond Time Scale

Published on: March 14, 2019

8.3K

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...
7.7K
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
Positive Regulator Molecules02:39

Positive Regulator Molecules

Mitotic cell division results in daughter cells that exactly resemble the parent cell. However, errors in the DNA replication or distribution of genetic material may lead to genetic mutations that may be passed down to every new cell formed from the resulting abnormal cell. Propagation of such mutant cells is restricted through checkpoint mechanisms present at different stages of the cell cycle. These checkpoints involve regulator molecules that either promote or demote cell cycle events.
5.7K
MAPK Signaling Cascades01:07

MAPK Signaling Cascades

Mitogen-activated protein kinase, or MAPK pathway, activates three sequential kinases to regulate cellular responses such as proliferation, differentiation, survival, and apoptosis. The canonical MAPK pathway starts with a mitogen or growth factor binding to an RTK. The activated RTKs stimulate Ras, which recruits Raf or MAP3 Kinase (MAPKKK), the first kinase of the MAPK signaling cascade. Raf further phosphorylates and activates MEK or MAP2 Kinases (MAPKK), which in turn phosphorylates MAP...
6.2K
Protein Complexes with Interchangeable Parts01:57

Protein Complexes with Interchangeable Parts

Groups of proteins may form a complex where each protein in this complex has a different role in the overall execution of the complex’s function. Often some of the proteins in the complex can be replaced by a closely related variant to give a complex that contains many of the same components yet is functionally distinct.
The SCF ubiquitin ligase is a protein complex of five individual proteins. This complex attaches ubiquitin to other target proteins to mark them for degradation. In order...
2.6K
Receptor Downregulation in MVBs01:15

Receptor Downregulation in MVBs

Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that  lead to cell proliferation, migration, and differentiation. Overexpression of EGFR  stimulates cells to proliferate. Excessive  EGFR...
2.2K