Lu Guangchun, Tang Zhiheng, Wu Mei, Liu Li, Opoku Mitchell, Bian Kaicheng, Ruan Rui, Shang Jinjie, Liu Jia, Feng Gang
Jiangsu Key Laboratory for Pathogens and Ecosystems, College of Life Sciences, Nanjing Normal University, Nanjing, China.
Department of Microbiology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
Genes Cells. 2025 Jan;30(1):e13192. doi: 10.1111/gtc.13192.
Serine-arginine protein kinases (SRPKs) play important roles in diverse biological processes such as alternative splicing and cell cycle. However, the functions of SRPKs in DNA damage response remain unclear. Here we characterized the function of SRPKs homolog Dsk1 in regulating DNA repair in the fission yeast Schizosaccharomyces pombe. We demonstrated that Dsk1 defective mutants of loss of the gene, spacer domain, and kinase activity as well as its overexpression mutant exhibited sensitivities of replication stress. Genetic analysis revealed that the loss of dsk1 compromised the efficiency of homologous recombination (HR) repair, and Dsk1 was probably involved in the Rad52- and Rad51-dependent HR repair pathways. Interestingly, Dsk1 translocated into the nucleus upon replication stress and directly interacted with Rad51-mediator Rad52 and phosphorylated Rad52-Ser365 residue. The Rad52-Ser365 phosphorylation-defective mutant was slightly sensitive to replication stress, and the phosphorylation-mimicking mutants exhibited more sensitivities, which were partially correlated with phenotypes of the loss- and gain-of-function of dsk1. This study uncovers a potential HR repair regulator Dsk1 in response to replication stress and implies that its homolog SRPKs may have the conserved targets and functions in higher eukaryotes.
丝氨酸 - 精氨酸蛋白激酶（SRPKs）在多种生物学过程中发挥重要作用，如可变剪接和细胞周期。然而，SRPKs在DNA损伤应答中的功能仍不清楚。在这里，我们表征了SRPKs同源物Dsk1在裂殖酵母粟酒裂殖酵母中调节DNA修复的功能。我们证明，基因缺失、间隔域缺失、激酶活性缺失的Dsk1缺陷突变体及其过表达突变体均表现出对复制应激的敏感性。遗传分析表明，dsk1的缺失损害了同源重组（HR）修复的效率，并且Dsk1可能参与了Rad52和Rad51依赖性的HR修复途径。有趣的是，Dsk1在复制应激时易位到细胞核中，并直接与Rad51介导物Rad52相互作用，并磷酸化Rad52的Ser365残基。Rad52-Ser365磷酸化缺陷突变体对复制应激略有敏感，而磷酸化模拟突变体表现出更高的敏感性，这与dsk1功能缺失和功能获得的表型部分相关。这项研究揭示了一种潜在的响应复制应激的HR修复调节因子Dsk1，并暗示其同源物SRPKs在高等真核生物中可能具有保守的靶点和功能。
