泛素化在蛋白质稳定性、亚细胞定位和相互作用中发挥着重要作用。不同类型的泛素化之间的串扰会导致蛋白质产生不同的生物学结果。然而，泛素化相关串扰在淋巴结（LN）转移中的作用以及控制该过程的关键调控因素尚未确定。通过高通量测序，我们发现泛素结合酶 E2 C (UBE2C) 在膀胱癌 (BCa) 中过度表达，并且与不良预后密切相关。 UBE2C 的过表达增加了 BCa 淋巴管生成，并在体外和体内促进了 LN 转移。从机制上讲，UBE2C 介导钠偶联中性氨基酸转运蛋白 2 (SNAT2) 在赖氨酸 59 处的单泛素化，从而抑制 SNAT2 在赖氨酸 33 处的 K63 连接的多泛素化。单泛素化和 K63 连接的多泛素化之间的串扰通过抑制 Epsin 1 介导的（EPN1 介导的）内吞作用来增加 SNAT2 膜蛋白水平。 SNAT2促进谷氨酰胺的摄取和代谢，从而促进VEGFC分泌，最终导致BCa患者的淋巴管生成和淋巴结转移。重要的是，在患者来源的异种移植模型中，抑制 UBE2C 显着减弱 BCa 淋巴管生成。我们的结果揭示了UBE2C介导SNAT2的单泛素化和K63连接的多泛素化之间的串扰以促进BCa转移的机制，并将UBE2C确定为治疗LN转移性BCa的有希望的靶点。

Ubiquitination plays an essential role in protein stability, subcellular localization, and interactions. Crosstalk between different types of ubiquitination results in distinct biological outcomes for proteins. However, the role of ubiquitination-related crosstalk in lymph node (LN) metastasis and the key regulatory factors controlling this process have not been determined. Using high-throughput sequencing, we found that ubiquitin-conjugating enzyme E2 C (UBE2C) was overexpressed in bladder cancer (BCa) and was strongly associated with an unfavorable prognosis. Overexpression of UBE2C increased BCa lymphangiogenesis and promoted LN metastasis both in vitro and in vivo. Mechanistically, UBE2C mediated sodium-coupled neutral amino acid transporter 2 (SNAT2) monoubiquitination at lysine 59 to inhibit K63-linked polyubiquitination at lysine 33 of SNAT2. Crosstalk between monoubiquitination and K63-linked polyubiquitination increased SNAT2 membrane protein levels by suppressing epsin 1-mediated (EPN1-mediated) endocytosis. SNAT2 facilitated glutamine uptake and metabolism to promote VEGFC secretion, ultimately leading to lymphangiogenesis and LN metastasis in patients with BCa. Importantly, inhibition of UBE2C significantly attenuated BCa lymphangiogenesis in a patient-derived xenograft model. Our results reveal the mechanism by which UBE2C mediates crosstalk between the monoubiquitination and K63-linked polyubiquitination of SNAT2 to promote BCa metastasis and identify UBE2C as a promising target for treating LN-metastatic BCa.