DUSP3 is a phosphatase expressed and active in several tissues that dephosphorylates tyrosine residues in many regulatory proteins of cellular activities such as proliferation, survival, and cell death. Recently, two new independent functions were assigned to this enzyme: dephosphorylation of focal adhesion kinase (FAK) and regulation of nucleotide-excision repair (NER) pathway. Genotoxic stress by UV radiation is known to affect cell morphology, adhesion, and migration for affecting, for example, the Rho GTPases that regulate actin cytoskeleton. This work investigated the intersection of DUSP3 function, XPA protein activity, and UV toxicity by examining cell migration, FAK, and SRC kinase phosphorylation status, in addition to cell morphology, in fibroblast cells proficient (MRC-5) or deficient (XPA) of the NER pathway. DUSP3 loss reduced cell migration of normal cells, which was stimulated by the genotoxic stress, effects evidenced in presence of serum mitogenic stimulus. However, NER-deficient cells migration response was the opposite since DUSP3 loss increased migration, especially after cells being exposed to UV stress. The levels of pFAK(Y397) peaked 15 min and 1 h after UV radiation in normal cells, but only slightly increased in repair-deficient cells. However, the DUSP3 knockdown strongly raised pFAK(Y397) levels in both cells, but especially in XPA cells as supported by the higher SRC activity. These effects impacted on the dynamics of actin-based structures formation, such as stress fibres, apparently dependent on DUSP3 and DNA-repair (NER) proficiency of the cells. Altogether our findings suggest this dual-phosphatase is bridging gaps between the complex regulation of cell morphology, motility, and genomic stability.

DUSP3 是一种在多种组织中表达并具有活性的磷酸酶，可将许多细胞活动（例如增殖、存活和细胞死亡）调节蛋白中的酪氨酸残基去磷酸化。最近，该酶被赋予了两个新的独立功能：粘着斑激酶（FAK）的去磷酸化和核苷酸切除修复（NER）途径的调节。众所周知，紫外线辐射造成的基因毒性应激会影响细胞形态、粘附和迁移，从而影响调节肌动蛋白细胞骨架的 Rho GTP 酶等。这项工作通过检查细胞迁移、FAK 和 SRC 激酶磷酸化状态以及细胞形态，在富含 (MRC-5) 或缺乏 (XPA) 的成纤维细胞中研究了 DUSP3 功能、XPA 蛋白活性和紫外线毒性。 NER途径。 DUSP3 缺失减少了正常细胞的细胞迁移，这是由基因毒性应激刺激的，在血清促有丝分裂刺激物的存在下证实了这种效应。然而，NER 缺陷细胞的迁移反应却相反，因为 DUSP3 缺失增加了迁移，尤其是在细胞暴露于紫外线应激后。在正常细胞中，pFAK(Y397) 水平在紫外线辐射后 15 分钟和 1 小时达到峰值，但在修复缺陷细胞中仅略有增加。然而，DUSP3 敲低显着提高了两种细胞中的 pFAK(Y397) 水平，尤其是在 XPA 细胞中，这得到了较高 SRC 活性的支持。这些效应影响了基于肌动蛋白的结构形成的动力学，例如应力纤维，显然依赖于细胞的 DUSP3 和 DNA 修复 (NER) 能力。总而言之，我们的研究结果表明，这种双磷酸酶正在弥合细胞形态、运动性和基因组稳定性的复杂调节之间的差距。