To examine the role of mTOR (which is required for the function of both mTORC1 and mTORC2) in PASMC proliferation and the development of hypoxia-induced pulmonary hypertension (HPH), we first generated the SM-specific mTOR conditional and inducible KO mice (mTORSM−/−) (Figure 1Aa) through crossing the floxed mTOR mice with a transgenic mouse line expressing a fusion protein of the Cre recombinase with the modified estrogen receptor binding domain (CreERT2) under the control of the SM myosin heavy chain promoter. Here, MTOR is linked to pulmonary hypertension.