Axin concentration in early embryos

Value 20 pM
Organism African clawed frog Xenopus laevis
Reference Lee E, Salic A, Krüger R, Heinrich R, Kirschner MW. The roles of APC and Axin derived from experimental and theoretical analysis of the Wnt pathway. PLoS Biol. 2003 Oct1(1):E10 p.120 table 1, p.121 table 2 & p.122 right column bottom paragraphPubMed ID14551908
Method Abstract: "[Investigators] have developed a mathematical model for the canonical Wnt pathway that describes the interactions among the core components: Wnt, Frizzled, Dishevelled, GSK3beta, APC, axin, beta-catenin, and TCF [T-cell factor]. Using a system of differential equations, the model incorporates the kinetics of protein-protein interactions, protein synthesis/degradation, and phosphorylation/dephosphorylation. [They] initially defined a reference state of kinetic, thermodynamic, and flux data from experiments using Xenopus extracts. Predictions based on the analysis of the reference state were used iteratively to develop a more refined model from which [they] analyzed the effects of prolonged and transient Wnt stimulation on beta-catenin and axin turnover. [They] predict several unusual features of the Wnt pathway, some of which [they] tested experimentally."
Comments P.122 right column bottom paragraph: "In establishing quantities for [investigators'] model in Table 1, [they] found that the axin concentration (20 pM) is much lower than the concentration of the other major components (β-catenin, 35 nM, APC [adenomatous polyposis coli], 100 nM, Dsh [Dishevelled], 100 nM, and GSK3β [glycogen synthase kinase 3β], 50 nM). This unusual finding suggests that the function of the Wnt signaling system may actually depend on a low axin concentration." P.125 right column bottom paragraph: "As the axin concentration is several orders of magnitude lower than that of the other components in the degradation pathway (see Table 1), [researchers] decided to test the effect of increasing axin levels (up to, equal to, and greater than the concentrations of other components in the pathway)."
Entered by Paul Jorgensen
ID 101951