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Author:
Date:
2015-01-05
[Abstract] AmTracs are the first example of “activity sensors”, since they report the activity of ammonium transporters by means of fluorescence readout in vivo (De Michele et al., 2013). AmTracs are based on a single fluorescent protein, a circularly permuted GFP (cpGFP), inserted into the cytosolic loop connecting the two pseudosymmetrical halves of the Arabidopsis and yeast plasma membrane ammonium transporters AtAMTs and ScMEP (Figure 1). Recently, FRET-based activity sensors for nitrate and peptide transporters have also been developed (Ho et al., 2014). Since transporter activity directly depends on the availability of substrate, AmTracs measure extracellular ammonium concentrations. Several versions of AmTrac exist, with different fluorescence intensity ...
[摘要] AmTracs是“活性传感器”的第一个例子，因为它们通过体内荧光读数来报告铵转运蛋白的活性（De Michele et al。，2013）。 AmTracs基于单个荧光蛋白，循环置换的GFP（cpGFP），插入连接拟南芥和酵母质膜铵转运蛋白AtAMTs和ScMEP的两个伪对称半部的细胞溶质环（图1）。最近，还开发了基于FRET的硝酸盐和肽转运蛋白活性传感器（Ho et al。，2014）。由于转运蛋白活性直接取决于底物的可用性，因此AmTracs测量细胞外铵浓度。存在几种版本的AmTrac，具有不同的荧光强度（FI）响应和铵的亲和力，并且基于不同的铵转运蛋白（AmTrac：AtAMT1; 3; AmTrac1; 2：At AMT1; 2; MepTrac：ScMEP2）。目前，最有用的AmTrac版本可能是AmTrac-GS（明亮，Km为50μM）和AmTrac-100（高容量版本，Km为100μM）。用于测量荧光计中酵母细胞中铵浓度的方案对于所有版本都是相同的。
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