In contrast, Chen et al. (2015) recently reported that mTOR signaling regulates system A amino acid transport by modulating ubiquitination and plasma membrane trafficking, because inhibition of placental mTORC1 and mTORC2 signaling pathways decreases the expression of SNAT-2 protein in the syncytiotrophoblast microvillous plasma membrane of human IUGR placentas. This evidence concerns the gene MTOR and fetal growth restriction.