Description_x000D_ General description_x000D_ CHIR99021 is an aminopyrimidine derivative. CHIR99021 promotes self-renewal potential of embryonic stem cells (ESCs) of mice by inhibiting glycogen synthase kinase-3 (GSK-3) activity and potentiates the upregulation of β-catenin and c-Myc functions. CHIR99021 promotes self-renewal of ESCs by modulating transforming growth factor β (TGF-β), Notch and mitogen-activated protein kinases (MAPK) signaling pathways. CHIR99021 is an agonist of wingless/integrated (wnt) signalling, upregulates cyclinA expression and promotes cell proliferation in non-small-cell lung cancer (NSCLC) cell lines._x000D_ Application_x000D_ CHIR99021 has been used:_x000D_ • in cocktail with small molecules to convert human lung fibroblast cells into neurons_x000D_ • as a culture medium supplement in potassium supplemented simplex optimization medium (KSOM) for the culture of blastocysts_x000D_ • for chronic inhibition of GSK-3 to investigate its role in corticogenesis_x000D_ Packaging_x000D_ 5, 25 mg in glass bottle_x000D_ Biochem/physiol Actions_x000D_ CHIR99021 is a very potent inhibitor of Glycogen synthase kinase 3 (GSK3, IC50 values for GSK3α and GSK3β = 10 and 6.7 nM, respectively). There is no cross-reactivity against CDKs. CHIR99201 potentiates self-renewal of human and mouse embryonic stem cells, and enhances reprogramming of somatic cells into stem cells.