摘要Rapamycin was first isolated from a strain of Streptomyces hygroscopicus in the early 1970s from a soil sample taken on Easter Island.1 Because the antiproliferative effects of rapamycin on yeast cell,as well as B and T lymphocytes,it was first identified as an antimicrobial agent with potent immunosuppressive activity and has been used in antirejection therapy.2,3The discovery of rapamycin led to the identification and clone of the mammalian target of rapaymycin (mTOR).mTOR is a highly conserved serine-threonine kinase shown to integrate and coordinate diverse signaling pathway mediated by growth factors,nutrient availability and energy status to play a critical role in cell growth,proliferation,division,migration,and survival.4Structurally,mTOR is a part of two signaling complexes,mTOR complex 1 (mTORC1) and mTORC2.