Furthermore, deletion of PTEN combined with deletion of SOCS3 promotes axon regeneration in adult retinal ganglion cells following crush injury.20,38 Our previous studies also revealed that activation of the mTOR pathway was sufficient to trigger protein translational regulation leading to robust axonal growth as assessed by an increase in β-actin protein levels and that modulation of the PTEN/mTOR pathway also restores the specific pathological effects in motor neurons from a mouse model of SMA.16 Here, MTOR is linked to proximal spinal muscular atrophy.