‡Center for Neuroscience and Cell Biology, University of Coimbra, 3004-517 Coimbra, Portugal.
Biochem J. 2014 May 1;459(3):441-53. doi: 10.1042/BJ20131014.
PRRXL1 [paired related homeobox-like 1; also known as DRG11 (dorsal root ganglia 11)] is a paired-like homeodomain transcription factor expressed in DRG and dSC (dorsal spinal cord) nociceptive neurons. PRRXL1 is crucial for the establishment and maintenance of nociceptive circuitry, as Prrxl1(-/-) mice present neuronal loss, reduced pain sensitivity and failure to thrive. In the present study, we show that PRRXL1 is highly phosphorylated in vivo, and that its multiple band pattern on electrophoretic analysis is the result of different phosphorylation states. PRRXL1 phosphorylation appears to be differentially regulated along the dSC and DRG development and it is mapped to two functional domains. One region comprises amino acids 107-143, whereas the other one encompasses amino acids 227-263 and displays repressor activity. Using an immunoprecipitation-MS approach, two phosphorylation sites were identified, Ser¹¹⁹ and Ser²³⁸. Phosphorylation at Ser¹¹⁹ is shown to be determinant for PRRXL1 conformation and transcriptional activity. Ser¹¹⁹ phosphorylation is thus proposed as a mechanism for regulating PRRXL1 function and conformation during nociceptive system development.
PRRXL1（配对相关同源盒样 1；也称为 DRG11（背根神经节 11））是一种在背根神经节和背侧脊髓（dorsal spinal cord）伤害感受神经元中表达的配对样同源盒转录因子。PRRXL1 对于伤害感受回路的建立和维持至关重要，因为 Prrxl1（-/-）小鼠存在神经元丢失、疼痛敏感性降低和生长不良。在本研究中，我们表明 PRRXL1 在体内高度磷酸化，其在电泳分析中的多种带型是不同磷酸化状态的结果。PRRXL1 磷酸化似乎沿着 dSC 和 DRG 的发育而差异调节，并映射到两个功能域。一个区域包含氨基酸 107-143，而另一个区域包含氨基酸 227-263 并显示抑制活性。使用免疫沉淀-MS 方法，鉴定出两个磷酸化位点，Ser¹¹⁹ 和 Ser²³⁸。Ser¹¹⁹ 的磷酸化被证明是 PRRXL1 构象和转录活性的决定因素。因此，Ser¹¹⁹ 磷酸化被提议作为调节伤害感受系统发育过程中 PRRXL1 功能和构象的机制。
