Fig. 4: AlphaFold prediction and in vitro phosphorylation of GSK3 sites in βIV spectrin.

A Full sequence of βIV spectrin and predicted phosphosite locations. Predicted GSK3 phosphosites (S45, T352, S2543 and T2541) are shown in yellow. The predicted AKT phosphosite (S119) is shown in orange. B Predicted phosphosite residues within AlphaFold structure of βIV spectrin are depicted at S119 (top), S45 (right), T352 (bottom), S2543 and T2541 (left). C Sequence of peptides used for in vitro phosphorylation. D Real-time luminescence from the Kinase-Glo reaction showing GSK3β activity in presence of control peptide (gray), βIV spectrin peptide containing S45 (teal) and βIV spectrin containing S2543 (green) in the presence of vehicle (darker colors) and CHIR99021 (lighter colors), with corresponding summary bar graphs (n = 3 reactions per tested condition). **p < 0.01 t-test. Each dot represents an independent reaction, each with 6 technical replicates.