The ability of regulatory T (T_reg) cells to migrate into inflammatory sites is reduced in autoimmune diseases, including rheumatoid arthritis (RA). The reasons for impaired T_reg cell migration remain largely unknown. We performed multiplex human kinase activity arrays to explore possible differences in the post-translational phosphorylation status of kinase related proteins that could account for altered T_reg cell migration in RA. Results were verified by migration assays and Western blot analysis of CD4⁺ T cells from RA patients and from mice with collagen type II induced arthritis. Kinome profiling of CD4⁺ T cells from RA patients revealed significantly altered post-translational phosphorylation of kinase related proteins, including G-protein-signaling modulator 2 (GPSM2), protein tyrosine kinase 6 (PTK6) and vitronectin precursor (VTNC). These proteins have not been associated with RA until now. We found that GPSM2 expression is reduced in CD4⁺ T cells from RA patients and is significantly downregulated in experimental autoimmune arthritis following immunization of mice with collagen type II. Interestingly, GPSM2 acts as a promoter of T_reg cell migration in healthy individuals. Treatment of RA patients with interleukin-6 receptor (IL-6R) blocking antibodies restores GPSM2 expression, thereby improving T_reg cell migration. Our study highlights the potential of multiplex kinase activity arrays as a tool for the identification of RA-related proteins which could serve as targets for novel treatments.

在包括类风湿性关节炎 (RA) 在内的自身免疫性疾病中，调节性 T (T _{reg ) 细胞迁移到炎症部位的能力降低。T reg}细胞迁移受损的原因仍然很大程度上未知。我们进行了多重人类激酶活性阵列，以探索激酶相关蛋白的翻译后磷酸化状态的可能差异，这可能导致 RA 中 T _reg细胞迁移的改变。结果通过对来自 RA 患者和患有 II 型胶原诱导关节炎的小鼠的 CD4 ⁺ T 细胞的迁移测定和蛋白质印迹分析进行了验证。CD4 ^{+的激酶组分析}来自 RA 患者的 T 细胞显示激酶相关蛋白的翻译后磷酸化显着改变，包括 G 蛋白信号调节剂 2 (GPSM2)、蛋白酪氨酸激酶 6 (PTK6) 和玻连蛋白前体 (VTNC)。直到现在，这些蛋白质还没有与 RA 相关联。我们发现 RA 患者的 CD4 ⁺ T 细胞中 GPSM2 表达降低，并且在用 II 型胶原免疫小鼠后在实验性自身免疫性关节炎中显着下调。有趣的是，GPSM2 在健康个体中充当 T _reg细胞迁移的促进剂。用白细胞介素 6 受体 (IL-6R) 阻断抗体治疗 RA 患者可恢复 GPSM2 表达，从而改善 T _reg细胞迁移。我们的研究强调了多重激酶活性阵列作为识别 RA 相关蛋白的工具的潜力，这些蛋白可以作为新治疗的靶点。