Repolymerization of actin from actin:thymosin β4 complex induced by diaphanous related formins and gelsolin.

Mannherz, Hans Georg; Mazur, Antonina Joanna; Jockusch, Brigitte

The β-thymosins are peptides of about 5 kDa molecular mass. Thymosin β4 (Tβ4) is the most ubiquitous member of this family and composed of 43 residues. Initially the β-thymosins were supposed to be specifically produced and released by the thymic gland and to possess hormonal activities modulating the immune response. However, it was later noticed that β-thymosins are present in the cytoplasm of almost all eukaryotic cells. Especially high concentrations of Tβ4 were detected in hematopoetic cells, like polymorpho-nuclear leucocytes and in platelets. In these cells the main intracellular function of the β-thymosins is to bind to monomeric actin and to inhibit its polymerization to filamentous actin. Thus Tβ4 allows resting eukaryotic cells to maintain a high concentration of monomeric actin, although the intracellular ionic conditions would favor its almost complete polymerization to F-actin. Thereby monomeric actin is sequestered from the dynamic assembly and disassembly processes of the actin cytoskeleton that constantly occur intracellularly.

THYMOSIN; IMMUNOTHERAPY; POLYMERS; ACTIN; ACTOMYOSIN

Annals of the New York Academy of Sciences, 2010, Vol 1194, Issue 1, p36

0077-8923

Academic Journal

10.1111/j.1749-6632.2010.05467.x