Komeili A, O'Shea E K
University of California-San Francisco, Department of Biochemistry and Biophysics, 513 Parnassus Avenue, San Francisco, CA 94143-0448, USA.
Science. 1999 May 7;284(5416):977-80. doi: 10.1126/science.284.5416.977.
Transcription factors are often phosphorylated at multiple sites. Here it is shown that multiple phosphorylation sites on the budding yeast transcription factor Pho4 play distinct and separable roles in regulating the factor's activity. Phosphorylation of Pho4 at two sites promotes the factor's nuclear export and phosphorylation at a third site inhibits its nuclear import. Phosphorylation of a fourth site blocks the interaction of Pho4 with the transcription factor Pho2. Multiple phosphorylation sites provide overlapping and partially redundant layers of regulation that function to efficiently control the activity of Pho4.
转录因子常常在多个位点发生磷酸化。本文表明，芽殖酵母转录因子Pho4上的多个磷酸化位点在调节该因子活性方面发挥着不同且可分离的作用。Pho4在两个位点的磷酸化促进该因子的核输出，而在第三个位点的磷酸化则抑制其核输入。第四个位点的磷酸化阻断了Pho4与转录因子Pho2的相互作用。多个磷酸化位点提供了重叠且部分冗余的调控层次，其作用是有效控制Pho4的活性。
