Thymosin β4 interactions

Thymosin β4 is a small, 5-kDa protein with a diverse range of activities, including its function as an actin monomer sequestering protein, an antiinflammatory agent, and an inhibitor of bone marrow stem cell proliferation. Only the effects of thymosin β4 on the actin cytoskeleton have an explanation based on identified molecular interactions. Thymosin β4 is largely unfolded or perhaps completely unfolded in solution. Based on the paradigm introduced by Wright and Dyson (1999) that unfolded proteins may have multiple functions based on their ability to recognize numerous ligands, the flexible structure of thymosin β4 may facilitate the recognition of a variety of molecular targets, thus explaining the plethora of functions attributed to thymosin β4. Furthermore, if multiple ligands bind to thymosin β4, then it is possible that thymosin β4 has a unique integrative function that links the actin cytoskeleton to important immune and cell growth-signaling cascades.© 2003, Elsevier Science (USA). © 2003 Elsevier Science (USA). All rights reserved.