MOE Key Laboratory of Gene Function and Regulation, State Key Laboratory of Biocontrol, Sun Yat-sen University, Guangzhou, China.
School of Life Sciences, Sun Yat-sen University, Guangzhou, China.
Front Immunol. 2019 Feb 28;10:314. doi: 10.3389/fimmu.2019.00314. eCollection 2019.
The SUMO modification system plays an important role in T cell activation, yet how sumoylation regulates TCR-proximal signaling remains largely unknown. We show here that Phospholipase C-γ1 (PLC-γ1) is conjugated by SUMO1 at K54 and K987 upon TCR stimulation and that K54 sumoylation is pivotal for PLC-γ1-mediated T cell activation. We further demonstrate that TCR-induced K54 sumoylation of PLC-γ1 significantly promotes the formation of PLC-γ1 microclusters and the association of PLC-γ1 with the adaptor proteins SLP76 and Gads, but only slightly affects the phosphorylation of PLC-γ1 on Y783, which determines the enzyme catalytic activity. Moreover, upon TCR stimulation, the SUMO E3 ligases PIASxβ and PIAS3 both interact with PLC-γ1 and cooperate to sumoylate PLC-γ1, facilitating the assembly of PLC-γ1 microclusters. Together, our findings reveal a critical role of PLC-γ1 K54 sumoylation in PLC-γ1 microcluster assembly that controls PLC-γ1-mediated T cell activation, suggesting that sumoylation may have an important role in the microcluster assembly of TCR-proximal signaling proteins.
SUMO 修饰系统在 T 细胞激活中发挥着重要作用,但 SUMO 化如何调节 TCR 近端信号仍知之甚少。我们在这里表明,PLC-γ1(PLC-γ1)在 TCR 刺激后被 SUMO1 连接到 K54 和 K987 上,并且 K54 SUMO 化对于 PLC-γ1 介导的 T 细胞激活至关重要。我们进一步证明,TCR 诱导的 PLC-γ1 的 K54 SUMO 化显著促进了 PLC-γ1 微簇的形成和 PLC-γ1 与衔接蛋白 SLP76 和 Gads 的结合,但对决定酶催化活性的 PLC-γ1 上 Y783 的磷酸化影响很小。此外,在 TCR 刺激下,SUMO E3 连接酶 PIASxβ 和 PIAS3 均与 PLC-γ1 相互作用,并协同 SUMO 化 PLC-γ1,促进 PLC-γ1 微簇的组装。总之,我们的发现揭示了 PLC-γ1 K54 SUMO 化在控制 PLC-γ1 介导的 T 细胞激活的 PLC-γ1 微簇组装中的关键作用,表明 SUMO 化可能在 TCR 近端信号蛋白的微簇组装中具有重要作用。