PPP1CA and meningioma: Proximity-labeling proteomic mass spectrometry coupled with mechanistic and functional approaches demonstrate PKC and PP1A are important for this signaling mechanism in Merlin-intact meningiomas, but (1) other kinases or phosphatases, (2) other Merlin domains, or (3) other Wnt pathway members, including other mediators of β-catenin subcellular localization, such as CK1, GSK3β, JNK, β-TRcP, KDM2A, and TWA142, may also contribute to Wnt signaling in Merlin-intact meningiomas.