The primary function of the T beta-4 member of the Thymosin-beta family is to maintain the organization of the cell’s cytoskeletal structure. Produced by myoblasts and fibroblasts, TMSB4X acts as a modulator for the production and digestion of actin and to inhibit filamentous actin polymerization. TMSB4X has also been found to induce phenotypic changes in T cell lines during early host defence mechanisms and inhibit the progression of hematopoietic pluripotent stem cells into the s-phase.