PAK1 inhibition also leads to attenuated mTORC1 but not mTORC2 signaling, suggesting that mTORC2/SGK1 and Rac1/PAK1 pathways are independently responsible for mTORC1 activation in NF2-deficient meningiomas.
Second, we used shRNAs to knockdown Pak1, 2, and 3 in NIH3T3 cells expressing a dominant-negative form of merlin, NF2(BBA) (NIH3T3/NF2(BBA)), and find that simultaneous knockdown of Pak1-3 in these cells significantly reduced their growth rates in vitro and inhibited their ability to form tumors in vivo.