Cyclin F Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
Cyclin F is a protein encoded by the CCNF gene. It is a member of the F-box protein family and serves as the substrate recognition component of the SCF^CCNF ubiquitin ligase complex. Pathogenic variants in CCNF cause familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). [@lee2016]
Protein Information
Structure
Cyclin F contains:
F-box domain: For SCF complex assembly with Skp1 and Cul1
Cyclin F Protein is an important component in the neurobiology of neurodegenerative diseases. This page provides detailed information about its structure, function, and role in disease processes.
Overview
Cyclin F is a protein encoded by the CCNF gene. It is a member of the F-box protein family and serves as the substrate recognition component of the SCF^CCNF ubiquitin ligase complex. Pathogenic variants in CCNF cause familial amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). [@lee2016]
Protein Information
Structure
Cyclin F contains:
F-box domain: For SCF complex assembly with Skp1 and Cul1
Cyclin F functions as part of the [ubiquitin-proteasome system](/cell-types/ubiquitin-proteasome-system):
Substrate ubiquitination: SCF^CCNF targets specific proteins for proteasomal degradation
Cell cycle regulation: Controls G1/S and G2/M transitions
DNA damage response: Targets proteins involved in DNA repair
Iron homeostasis: Regulates IRP2 stability, controlling cellular iron levels
Ribosomal biogenesis: Controls synthesis of ribosomal proteins
In [neurons](/entities/neurons), cyclin F may regulate:
Synaptic protein turnover
Response to oxidative stress
Axonal transport
Role in Disease
Amyotrophic Lateral Sclerosis (ALS)
Mutations in CCNF cause familial ALS through:
Loss of function: Reduced ubiquitination of substrate proteins
Protein aggregation: Mutant cyclin F forms inclusions
Cellular stress: Impaired protein quality control
Iron dysregulation: Altered IRP2 metabolism
Frontotemporal Dementia (FTD)
CCNF mutations also cause FTD, particularly affecting:
Frontal lobe function
Behavioral regulation
Language (in some variants)
Other Conditions
Cancer: Cyclin F has tumor suppressor functions
Iron metabolism disorders: Altered iron homeostasis
Therapeutic Targeting
Therapeutic approaches include:
Gene therapy: Delivering wild-type CCNF
Small molecules: Enhancing ubiquitination activity
Protein aggregation inhibitors: Preventing inclusion formation
Research Directions
Recent research has focused on understanding how cyclin F dysfunction contributes to neurodegeneration. Key areas of investigation include:
FBXW7 relationship: Studies examining the interaction between cyclin F (CCNF) and FBXW7, another F-box protein in the SCF complex, to understand how these proteins coordinate cell cycle regulation and neuronal survival.
Therapeutic targeting: Research into small molecule inhibitors that can modulate SCF^CCNF activity to prevent aberrant cell cycle re-entry in neurons, which is a hallmark of several neurodegenerative diseases.
Genetic studies: GWAS and exome sequencing studies identifying additional CCNF mutations or variants that modify risk for ALS, FTD, and AD.
Protein aggregation: Investigations into whether cyclin F aggregates form inclusion bodies in affected neurons, similar to other ALS/FTD proteins like [TDP-43](/proteins/tdp-43) and FUS.
Background
The study of Cyclin F Protein has evolved significantly over the past decades. Research in this area has revealed important insights into the underlying mechanisms of neurodegeneration and continues to drive therapeutic development.
Historical context and key discoveries in this field have shaped our current understanding and will continue to guide future research directions.