Thymosin beta-4
Category: Proteins · Last updated
Thymosin beta-4 (Tβ4) is a 43-amino-acid protein and the dominant G-actin-sequestering molecule in eukaryotic cells. It was first isolated from calf thymus in 1981 by Allan Goldstein at George Washington University. The protein is widely distributed across tissues, including thymus, spleen, peripheral leukocytes, and most epithelia.
Function
Tβ4 binds monomeric G-actin in a 1:1 stoichiometry, sequestering it from the F-actin polymerization pool. The net cellular consequence is regulation of the actin-cytoskeleton turnover rate.
Several short fragments of Tβ4 retain biological activity at fractional cost:
- Ac-SDKP (residues 1–4) · anti-inflammatory and anti-fibrotic activity
- LKKTETQ + 1 aa (residues 17–23, the TB-500 fragment) · the actin-binding domain plus one downstream residue; promotes cell migration, angiogenesis, and wound healing
Relevance to research peptides
- TB-500 · the synthetic LKKTETQ fragment, supplied as research-grade material
See also
References
- Goldstein AL, Hannappel E, Kleinman HK. "Thymosin beta-4: actin-sequestering protein moonlights to repair injured tissues." Trends Mol Med. 2005;11(9):421-9. PMID 16099219.
- Sosne G, Qiu P, Goldstein AL, Wheater M. "Biological activities of thymosin beta4 defined by active sites in short peptide sequences." FASEB J. 2010;24(7):2144-51. PMID 20179146.