PTK2 and Miyoshi myopathy: Moreover, merlin has been identified as a negative regulator of the FAK-SRC signaling in MM: restoration of merlin expression in NF2-null MM cells was found to decrease significantly cell invasiveness promoted by FAK overexpression and reduce the phosphorylation of FAK at Tyr397, thus impairing its interaction with SRC and p85 (the regulatory subunit of PI3K) [95].