CDK4 and glioblastoma: Phosphorylation of FLNA required for GBM migration and invasion can be initiated by several protein kinases, including cyclic AMP (cAMP)-dependent protein kinase, p90 ribosomal kinase, PAK1, cyclin D1/Cdk4, PKCα and mediated by mTORC2, the last one induces actin changes in the cytoskeleton and further influences cell motility and invasiveness [48].