Kuge S, Jones N, Nomoto A
Institute of Medical Science, University of Tokyo, Minato-ku, Japan.
EMBO J. 1997 Apr 1;16(7):1710-20. doi: 10.1093/emboj/16.7.1710.
The YAP1 gene of Saccharomyces cerevisiae encodes a bZIP-containing transcription factor that is essential for the normal response of cells to oxidative stress. Under stress conditions, the activity of yAP-1 is increased, leading to the induced expression of a number of target genes encoding protective enzymes or molecules. We have examined the mechanism of this activation. Upon imposition of oxidative stress, a small increase in the DNA-binding capacity of yAP-1 occurs. However, the major change is at the level of nuclear localization; upon induction the yAP-1 protein relocalizes from the cytoplasm to the nucleus. This regulated localization is mediated by a cysteine-rich domain (CRD) at the C-terminus, its removal resulting in constitutive nuclear localization and high level activity. Furthermore, the CRD of yAP-1 is sufficient to impose regulated nuclear localization of the GAL4 DNA-binding domain. Amino acid substitutions indicated that three conserved cysteine residues in the CRD are essential for the regulation. We suggest therefore, that these cysteine residues are important in sensing the redox state of the cell and hence regulating yAP-1 activity.
酿酒酵母的YAP1基因编码一种含bZIP的转录因子，该因子对于细胞对氧化应激的正常反应至关重要。在应激条件下，yAP-1的活性增加，导致许多编码保护酶或分子的靶基因的诱导表达。我们研究了这种激活的机制。施加氧化应激后，yAP-1的DNA结合能力略有增加。然而，主要变化发生在核定位水平；诱导后，yAP-1蛋白从细胞质重新定位到细胞核。这种受调控的定位由C末端富含半胱氨酸的结构域（CRD）介导，去除该结构域会导致组成型核定位和高水平活性。此外，yAP-1的CRD足以使GAL4 DNA结合结构域进行受调控的核定位。氨基酸取代表明CRD中的三个保守半胱氨酸残基对于调控至关重要。因此，我们认为这些半胱氨酸残基在感知细胞的氧化还原状态并因此调节yAP-1活性方面很重要。
