PAK1 and craniodiaphyseal dysplasia: To verify the activation status of PAKs in CDD mouse brain and FRAX486 effects thereon, phosphorylation levels at sites which are considered indices of PAKs activation [serine 144 (PAK1 or αPAK), serine 141 (PAK2 or γPAK) and serine 139 (PAK3 or βPAK)] were also assessed.