KITLG and prostate cancer: mTOR inhibitors should reactivate DEPTOR, particularly in prostate cancer with low DEPTOR expression; Second, DEPTOR is subjected to ubiquitylation by SCFβTrCP E3 ubiquitin ligase for proteasome degradation [45–47], thus inhibition of SCF E3 by MLN4924 should cause DEPTOR accumulation [48].