Abstract
The mammalian target of rapamycin (mTOR) signaling pathway has been studied in the context of an impressive number of biological processes and disease states, including major diseases of the lung such as idiopathic pulmonary fibrosis and chronic obstructive pulmonary disease, as well as the rare condition lymphangioleiomyomatosis. The involvement of mTOR in so many disease states (in and out of the lung) raises the question how one signaling pathway can have overlapping but diverse roles seemingly everywhere. Findings in the last decade have placed the mTOR pathway in a new context as an important, conserved mediator of the aging process. This offers one explanation for the pleiotropic effects of mTOR: -that many chronic diseases are also diseases of aging and that pathways modulating aging will have widespread effects on associated disease. However, this may not be the entire story, because mTOR is also implicated in a large number of diseases not linked to aging. In this article, we discuss the current state of knowledge regarding mTOR, especially in the context of lung pathologies, and offer a potential explanation for its widespread involvement in human disease.