PRF1 and Miyoshi myopathy: In addition, MLN4924 restored the reduced level of perforin polarization at the IS in the presence of TGFβ, as observed in confocal microscopy (Supplementary Fig. 14C), and the expression level of NKG2D, a critical NK cell activating receptor for MM recognition and killing [17, 23], the expression of which is severely inhibited by TGFβ [10, 12] (Fig. 8 and Supplementary Fig. 14).