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Repolymerization of actin from actin:thymosin β4 complex induced by diaphanous related formins and gelsolin
Author(s) -
Mannherz Hans Georg,
Mazur Antonina Joanna,
Jockusch Brigitte
Publication year - 2010
Publication title -
annals of the new york academy of sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.712
H-Index - 248
eISSN - 1749-6632
pISSN - 0077-8923
DOI - 10.1111/j.1749-6632.2010.05467.x
Subject(s) - formins , gelsolin , actin , microbiology and biotechnology , cytoplasm , intracellular , mdia1 , microfilament , cytoskeleton , profilin , actin binding protein , biology , chemistry , actin cytoskeleton , actin remodeling , biochemistry , cell
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.