Herzog Britta, Popova Blagovesta, Jakobshagen Antonia, Shahpasandzadeh Hedieh, Braus Gerhard H
Institute of Microbiology and Genetics, Georg-August-Universität Göttingen, Göttingen, Germany.
Eukaryot Cell. 2013 Aug;12(8):1142-54. doi: 10.1128/EC.00123-13. Epub 2013 Jun 21.
Hac1 is the activator of the cellular response to the accumulation of unfolded proteins in the endoplasmic reticulum. Hac1 function requires the activity of Gcn4, which mainly acts as a regulator of the general amino acid control network providing Saccharomyces cerevisiae cells with amino acids. Here, we demonstrate novel functions of Hac1 and describe a mutual connection between Hac1 and Gcn4. Hac1 is required for induction of Gcn4-responsive promoter elements in haploid as well as diploid cells and therefore participates in the cellular amino acid supply. Furthermore, Hac1 and Gcn4 mutually influence their mRNA expression levels. Hac1 is also involved in FLO11 expression and adhesion upon amino acid starvation. Hac1 and Gcn4 act through the same promoter regions of the FLO11 flocculin. The results indicate an indirect effect of both transcription factors on FLO11 expression. Our data suggest a complex mutual cross talk between the Hac1- and Gcn4-controlled networks.
Hac1是细胞对内质网中未折叠蛋白积累作出反应的激活因子。Hac1的功能需要Gcn4的活性，Gcn4主要作为一般氨基酸控制网络的调节因子，为酿酒酵母细胞提供氨基酸。在此，我们展示了Hac1的新功能，并描述了Hac1与Gcn4之间的相互联系。单倍体细胞和二倍体细胞中诱导Gcn4反应性启动子元件都需要Hac1，因此Hac1参与细胞氨基酸供应。此外，Hac1和Gcn4相互影响它们的mRNA表达水平。Hac1还参与氨基酸饥饿时FLO11的表达和黏附。Hac1和Gcn4通过絮凝蛋白FLO11的相同启动子区域发挥作用。结果表明这两种转录因子对FLO11表达有间接影响。我们的数据表明Hac1控制的网络和Gcn4控制的网络之间存在复杂的相互串扰。
