What is Follistatin-344?
Follistatin-344 is a glycoprotein that acts as an inhibitor of myostatin, the primary negative regulator of muscle growth. By binding and neutralizing myostatin, follistatin removes the "brake" on muscle development, allowing for enhanced muscle hypertrophy.
The "344" refers to this isoform consisting of 344 amino acids, which is the most common circulating form. Other isoforms exist (FS-288, FS-315) with different tissue distributions and properties.
Myostatin Inhibition
What is Myostatin?
- Also called GDF-8
- Negative regulator of muscle growth
- "Limits" how much muscle can develop
- Myostatin-null animals are hypermuscular
Follistatin's Role
- Binds and sequesters myostatin
- Prevents myostatin receptor binding
- Removes growth limitation
- Allows muscle hypertrophy
Molecular Profile
Structure
| Property | Value |
|---|---|
| Type | Glycoprotein |
| Amino Acids | 344 |
| Molecular Weight | ~38-40 kDa |
| Mechanism | Myostatin binding |
Isoforms
| Form | Location | Notes |
|---|---|---|
| FS-344 | Circulating | Most common research form |
| FS-315 | Serum | Circulating form |
| FS-288 | Tissue-bound | Localized effects |
Research Applications
Muscle Growth
Primary research interest:
- Enhanced muscle hypertrophy
- Strength increases
- Muscle wasting diseases
- Sarcopenia research
Medical Research
Studied for:
- Duchenne muscular dystrophy
- Cancer cachexia
- Age-related muscle loss
- Other myopathies
Gene Therapy Approaches
Research includes:
- AAV-follistatin delivery
- Localized expression
- Long-term effects
- Clinical trials (DMD)
Comparison with Other Myostatin Approaches
| Approach | Mechanism | Stage |
|---|---|---|
| Follistatin | Binds myostatin | Research |
| Anti-myostatin antibodies | Block myostatin | Clinical trials |
| Myostatin receptor blockers | Block receptor | Development |
| ACE-031 | ActRIIB trap | Discontinued |
Challenges
Research Limitations:
- Large protein size
- Production complexity
- Delivery challenges
- Specificity considerations
Summary
Follistatin-344 offers a mechanism for muscle growth by neutralizing myostatin, with research applications ranging from muscular dystrophy to age-related muscle loss.
Key Points:
- Classification: Myostatin inhibitor glycoprotein
- Mechanism: Binds and neutralizes myostatin
- Effect: Removes muscle growth limitation
- Research Focus: Muscle disorders, sarcopenia