Fig. 3: MEF2B C-terminal missense and frameshift mutations impair S324 phosphorylation.
a The scheme shows the amino acid alignment of MEF2B WT-isoA with MEF2B WT-isoB and the predicted truncated and isoform-switch mutants. The identified phosphorylation sites are marked by triangles (rose red, sites with phosphorylation >95%; gray, phosphorylation <1%). b Schematic representation of the phosphorylation region in MEF2B isoA aa sequence. Phosphorylated aa are labeled in rose red. Amino acid changes found in lymphoma cases are reported on the top using green dots, each representing one patient8,9,10,11,12,16,27. c Phos-tag analysis of MEF2B phosphorylation in SUDHL10 and OCI-Ly7 DLBCL cell lines that were engineered to express Flag-HA MEF2B WT-isoA, lymphoma-associated missense mutants (R307P, I318S, K319M, R322C, P325L and P330L) or phosphorylation-deficient mutants (S310A, S324A and S310A + S324A, labeled as AA). Controls (HA and Vinculin) were resolved on a Tris-Glycine gel. Vinculin was used as loading control; λPP-treated lysate was used as a negative control for phosphorylation detection. d Flag (MEF2B) IP followed by IB with phospho-specific pMEF2BS324 antibody in SUDHL10 and OCI-Ly7 cells that were engineered to express Flag-HA MEF2B WT-isoA or lymphoma-associated missense mutants (R307P, I318S, K319M, R322C, P325L and P330L). Vinculin was used as loading control. Quantifications were normalized to the immunoprecipitated MEF2B (HA). Fold changes were calculated relative to the MEF2B WT sample. The experiments displayed in (c) and (d) were repeated 4 times with similar results. Source data are provided as a Source Data file.
