生物活性

• 描述GSK-3 (Glycogen synthase kinase 3) is a serine/threonine protein kinase, consisting of GSK-3α andβsubunit, which plays a key role in many different biological processes including tumorigenesis, cell survival, and developmental patterning. GSK-3 is constitutively active in non-stimulated cells and can negatively regulate canonical Wnt/β-catenin signaling. CHIR 99021 （CT99021）is highly selective aminopyrimidine-derivatived inhibitor of GSK-3 with IC50 of 10nM and 6.7nM for GSK-3α and GSK-3β(measured by kinase assays), respectively, and exhibits >500-fold selectivity for GSK-3 over closely related kinases, such as cdc2^[3]Bennett CN, Ross SE, Longo KA, Bajnok L, Hemati N, Johnson KW, Harrison SD, MacDougald OA. Regulation of Wnt signaling during adipogenesis. J Biol Chem. 2002 Aug 23;277(34):30998-1004. doi: 10.1074/jbc.M204527200. Epub 2002 Jun 7. PMID: 12055200. https://pubmed.ncbi.nlm.nih.gov/12055200/. CHIR-99021 can mimic Wnt signaling in preadipocytes. Analysis of cytosolic and membranous fractions show that the free cytosolic -catenin was evaluated in 3T3-L1 preadipocytes treated with 3uM CHIR-99021 for 4 h ^[4]. Chir-99021 can activate glycogen synthase in cells. The concentrations of CHIR-99021 causing half-maximal glycogen synthase stimulation (EC50) were 76 nmol/l for CHO-IR cells. A single oral dose of CHIR 99021 (30mg/kg) rapidly lowered plasma glucose in ZDF rats^[3]. In combination with different small molecules, CHIR-99021 can facilitate cardiomyocyte differentiation from human embryonic stem cells and iPS cells^[5][4], reprogramming, like generation of functional astrocytes from mammalian fibroblasts^[5] and maintaining undifferentiated mouse ES cells in the absence of LIF^[6].