FAM83G/PAWS1 controls cytoskeletal dynamics and cell migration through association with the SH3 adaptor CD2AP

Our previous studies of PAWS1 (Protein Associated With SMAD1) have suggested that this molecule has roles beyond BMP signalling. To investigate these roles, we have used CRISPR/ Cas9to generate PAWS1 knockout U2OS osteosarcoma cells. Here, we show that PAWS1 plays a role in the regulation of the cytoskeletal machinery, including actinand focal adhesiondynamics, and cell migration. Confocal microscopyand live cell imagingof actinin U2OS cells indicate that PAWS1 is also involved in cytoskeletal dynamics and organization. Loss of PAWS1 causes severe defects in F- actinorganization and distribution as well as in lamellipodial organization, resulting in impaired cell migration. PAWS1 interacts in a dynamic fashion with the actin/cytoskeletal regulator CD2AP at lamellae, suggesting that its association with CD2AP controls actinorganization and cellular migration. Genetic ablation of CD2AP from U2OS cells instigates actinand cell migrationdefects reminiscent of those seen in PAWS1 knockout cells.