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Thymosin β 4 is released from human blood platelets and attached by factor XIIIa (transglutaminase) to fibrin and collagen
Author(s) -
Huff Thomas,
Otto Angela M.,
Müller Christian S. G.,
Meier Markus,
Hannappel Ewald
Publication year - 2002
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.01-0713com
Subject(s) - tissue transglutaminase , factor xiiia , thymosin , chemistry , fibrin , umbilical vein , platelet , thrombin , microbiology and biotechnology , extracellular matrix , wound healing , extracellular , biochemistry , immunology , biology , fibrinogen , enzyme , in vitro
The β‐thymosins constitute a family of highly conserved and extremely water‐soluble 5 kDa polypeptides. Thymosin β 4 is the most abundant member; it is expressed in most cell types and is regarded as the main intracellular G‐actin sequestering peptide. There is increasing evidence for extracellular functions of thymosin β 4 . For example, thymosin β 4 increases the rate of attachment and spreading of endothelial cells on matrix components and stimulates the migration of human umbilical vein endothelial cells. Here we show that thymosin β 4 can be cross‐linked to proteins such as fibrin and collagen by tissue transglutaminase. Thymosin β 4 is not cross‐linked to many other proteins and its cross‐linking to fibrin is competed by another family member, thymosin β 10 . After activation of human platelets with thrombin, thymosin β 4 is released and crosslinked to fibrin in a time‐ and calcium‐dependent manner. We suggest that thymosin β 4 cross‐linking is mediated by factor XIIIa, a transglutaminase that is coreleased from stimulated platelets. This provides a mechanism to increase the local concentration of thymosin β 4 near sites of clots and tissue damage, where it may contribute to wound healing, angiogenesis and inflammatory responses.