SLC38A2 and pulmonary hypertension, primary, 1: Furthermore, we found that MTOR silencing decreased the expression of the System L amino acid transporter isoform LAT1 (−68%, P=0.03, n = 5/group,Supplementary Figure S11a,b) and System A amino acid transporter isoform SNAT2 (−54%, P=0.002, n = 5/group, Supplementary Figure S11a, c) in the microvillus plasma membranes (maternal facing plasma membrane) isolated from cultured PHT cells.