Thymosin beta4 and its posttranslational modifications.
Hannappel. E E
Key Findings
- Thymosin beta‑4 is made without its starting methionine and its N‑terminus gets acetylated.
- Several lysine residues can be acetylated and two threonines can be phosphorylated, but the functional impact is unknown.
- The peptide can be cross‑linked by transglutaminase and cut by prolyl oligopeptidase to produce a small fragment (ac‑SDKP).
- Levels of C‑terminal fragments of thymosin beta‑4 are increased in the blood of rheumatoid arthritis patients.
Practical Outcomes
- For biohackers, this study mainly highlights that thymosin beta‑4 exists in many modified forms, but we lack data on their concentrations or effects. Until more research clarifies whether any of these modifications change health outcomes, there’s no actionable dosing or protocol change to recommend.
Summary
The paper explains how the protein thymosin beta‑4 is chemically modified inside the body (acetylation, phosphorylation, cross‑linking, and cutting into smaller pieces). It points out that we still don’t know how much of these modified forms exist in cells or what they actually do, and that a fragment of the protein is higher in people with rheumatoid arthritis.
Abstract
Thymosin beta(4) as well as the other members of the beta-thymosin family are important G-actin sequestering peptides. The chemical properties, the biosynthesis, and posttranslational modifications (PTMs) of these peptides are discussed. During biosynthesis of thymosin beta(4) the initiator methionine is removed and the N-terminus is acetylated. Research on proteomics revealed several acetylated lysine residues and two phosphorylated threonine residues. The enormous number of phosphorylable and acetylable sites in the human proteome raises the question about the biological significance of these PTMs in the context of beta-thymosins. Presently, this question cannot be answered because neither the concentration of these modified beta-thymosins in cells is known nor the consequences of the modifications on the biological function(s) of beta-thymosins have been studied yet. Thymosin beta(4) is also posttranslationally modified by transglutaminase forming covalent bonds with other molecules. Prolyl oligopeptidase generates ac-SDKP from thymosin beta(4). The concentration of C-terminal peptide fragments of thymosin beta(4) is elevated in the blood of patients with rheumatoid arthritis.
Study Information
pubmed
2010
2010-05-01T00:00:00.000Z
10.1111/j.1749-6632.2010.05485.x
39
63