RESUMO
The mechanistic target of rapamycin (mTOR) is a central regulator of cellular metabolic processes. Dysregulation of this kinase complex can result in a variety of human diseases. Rapamycin and its analogs target mTORC1 directly; however, chronic treatment in certain cell types and in vivo results in the inhibition of both mTORC1 and mTORC2. We have developed a high-throughput cell-based screen for the detection of phosphorylated forms of the mTORC1 (4E-BP1, S6K1) and mTORC2 (Akt) substrates and have identified and characterized a chemical scaffold that demonstrates a profile consistent with the selective inhibition of mTORC1. Stable isotope labeling of amino acids in cell culture-based proteomic target identification revealed that class I glucose transporters were the primary target for these compounds yielding potent inhibition of glucose uptake and, as a result, selective inhibition of mTORC1. The link between the glucose uptake and selective mTORC1 inhibition are discussed in the context of a yet-to-be discovered glucose sensor.
Assuntos
Proteínas Facilitadoras de Transporte de Glucose/efeitos dos fármacos , Alvo Mecanístico do Complexo 1 de Rapamicina/antagonistas & inibidores , Alvo Mecanístico do Complexo 1 de Rapamicina/metabolismo , Sirolimo/farmacologia , Animais , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos/métodos , Glucose/metabolismo , Ensaios de Triagem em Larga Escala/métodos , Humanos , Alvo Mecanístico do Complexo 2 de Rapamicina/efeitos dos fármacos , Alvo Mecanístico do Complexo 2 de Rapamicina/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Complexos Multiproteicos/metabolismo , Fosforilação , Proteômica/métodos , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais/efeitos dos fármacos , Sirolimo/análogos & derivados , Sirolimo/metabolismo , Fatores de Transcrição/metabolismoRESUMO
The mammalian target of rapamycin complex 1 (mTORC1) has the ability to sense a variety of essential nutrients and respond by altering cellular metabolic processes. Hence, this protein kinase complex is poised to influence adaptive changes to nutrient fluctuations toward the maintenance of whole-body metabolic homeostasis. Defects in mTORC1 regulation, arising from either physiological or genetic conditions, are believed to contribute to the metabolic dysfunction underlying a variety of human diseases, including type 2 diabetes. We are just now beginning to gain insights into the complex tissue-specific functions of mTORC1. In this review, we detail the current knowledge of the physiological functions of mTORC1 in controlling systemic metabolism, with a focus on advances obtained through genetic mouse models.