PPP1CA and meningioma: Sequence analysis of the Merlin NTD showed a phosphorylation site on serine 13 (S13) within consensus motifs for a kinase (PKC) and a phosphatase (PP1A), both of which are core components of the Wnt pathway that were also identified in proximity to MerlinFLAG-APEX2 constructs in meningioma cells (Supplementary Table 2).