Thymosins

from Wikipedia, the free encyclopedia

The thymosins are a group of proteins that are characterized by their isoelectric point .

The most important thymosin for humans is thymosin β4 (Tβ4). It was first described in 1966 by Goldstein and White; the complete amino acid sequence and genetic characterization followed in 1981 in the laboratory of Ewald Hannappel in Erlangen and Allan Goldstein in Washington.

Functions

In the body of Tβ4 is almost all cells expressed , with the exception of red blood cells . The leukocytes are rich in the protein consisting of 43 amino acids . a. the macrophages and platelets .

Within the cell, Tβ4 binds to the monomeric G- actin and, as an antagonist of profilin, prevents the polymerisation of this microfilament . These regulatory processes play a major role in the migration processes of cells that are associated with changes in the cytoskeleton ( leukodiapedesis , platelet activation). In the nucleus Tβ4 acts as a transcription factor . In the extracellular space it has an inhibitory effect on the immune reaction and prevents the immigration of macrophages into inflammatory tissue. During blood clotting, fibrin monomers are assembled into fibrin polymers by factor XIIIa ( transglutaminase ) with the help of Tβ4.

It could be shown that administration of Tβ4 significantly increases the survival rate of mice with septic shock . Also NaOH induced burns to the cornea of animals healed at Tβ4 administration with less scarring and therefore less clouding of the lens from. Tβ4 also accelerates wound healing and hair growth. The administration of glucocorticoids ( cortisol ) increases the expression of Tβ4 in monocytes of mice. This could help explain the immunosuppressive effect of the glucocorticoids. The effect of thymosin on human monocytes is currently being researched electrophysiologically at the University of Marburg . In the future, it could prove to be a new drug for inflammatory processes and partially replace the glucocorticoids, which are rich in side effects.

literature

  • Thymosin β4 reduces lethality and down-regulates inflammatorymediators in endotoxin-induced septic shock. Badamchain, Goldstein, Int Immunopharmacology 2003
  • Thymosin β4 is released from human blood platelets and attached by factor XIIIa fo fibrin and collagen, Huff, Hannappel, FASEB 2002
  • Thymosin β4: actin-sequestering protein moonlights to repair injured tissues; Goldstein, Hannappel, Kleiman, TRENDS in Molecular Medicin 2005
  • Thymosin β4 sulfoxide is an anti-inflammatory agent generated by monocytes in the presence of glucocorticoids. Young, Stevenson, Nature 1999