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Nutrient sensing is a cell's ability to recognize and respond to fuel substrates such as glucose. Each type of fuel used by the cell requires an alternate pathway of utilization and accessory molecules. In order to conserve resources a cell will only produce molecules that it needs at the time. The level and type of fuel that is available to a cell will determine the type of enzymes it needs to express from its genome for utilization. Receptors on the cell membrane's surface designed to be activated in the presence of specific fuel molecules communicate to the cell nucleus via a means of cascading interactions. In this way the cell is aware of the available nutrients and is able to produce only the molecules specific to that nutrient type. ==Nutrient Sensing in the Cells== Living cells use ATP as the most important direct energy source. Hydrolysis of ATP to ADP and phosphate (or AMP and pyrophosphate) provides energy for most biological processes. The ratio of ATP to ADP and AMP is a barometer of cellular energy status and is therefore tightly monitored by the cell. In eukaryotic cells, AMP-activated protein kinase (AMPK) serves as a key cellular energy energy sensor and a master regulator of metabolism to maintain energy homeostasis. Cell growth is regulated by coordination of both extracellular nutrients and intracellular metabolite concentrations. AMP-activated kinase and mammalian target of rapamycin complex 1 serve as key molecules that sense cellular energy and nutrients levels, respectively. *The interplay among nutrients, metabolites, gene expression, and protein modification are involved in the coordination of cell growth with extracellular and intracellular conditions.〔Molecular Cell, Volume 49, Issue 3, 379-387, 7 February 2013〕 A rapid and efficient response to disturbances in nutrient levels is crucial for the survival of organisms from bacteria to humans. Cells have therefore evolved a host of molecular pathways that can sense nutrient concentrations and quickly regulate gene expression and protein modification to respond to any changes.〔Zagorski, Nick. "Nutrient Sensing, Signaling, & Regulation." Journal of Biological Chemistry. (2010): n. page. Web. 9 Apr. 2013. http://www.jbc.org/site/meeting2010/nutrient〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Nutrient sensing」の詳細全文を読む スポンサード リンク
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