Ubiquitin ligase and signalling hub MYCBP2 is required for efficient EPHB2 tyrosine kinase receptor function.
Ubiquitin ligase and signalling hub MYCBP2 is required for efficient EPHB2 tyrosine kinase receptor function.
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泛素连接酶和信号中枢 MYCBP2 是有效 EPHB2 酪氨酸激酶受体功能所必需的。
DOI：
10.1101/2023.06.12.544638
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发表时间：
2023
期刊：
影响因子：
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通讯作者：
Kania,Artur
中科院分区：
文献类型：
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作者：
Chang,Chao;Banerjee,SaraL;Park,SungSoon;Zhang,Xiaolei;Cotnoir-White,David;Opperman,KarlaJ;Desbois,Muriel;Grill,Brock;Kania,Artur
Eph受体酪氨酸激酶参与发育期间和整个成年期的各种正常和致病过程。Eph受体通过不同的细胞信号传导途径传递信号的能力可能促进了这种多功能性：主要通过控制细胞骨架动力学，但也通过调节细胞生长，增殖和存活。尽管许多蛋白质与Eph受体相互作用的这些信号通路相关，但这些联系及其协调背后的具体机制仍有待阐明。在一项针对新型EPHB 2多效应蛋白的蛋白质组学筛选中，我们鉴定了人类MYC结合蛋白2（MYCBP 2或PAM或Phr 1）。MYCBP 2是一个大型信号中枢，参与多种过程，如神经元连接，突触生长，细胞分裂，神经元存活和蛋白质泛素化。我们的生化实验表明，含有EPHB 2和MYCBP 2的复合物的形成是由FBXO 45促进的，FBXO 45是一种已知为MYCBP 2泛素连接酶活性选择底物的蛋白质。MYCBP 2-EPHB 2复合物的形成不需要EPHB 2酪氨酸激酶活性，并且通过肝配蛋白-B配体的结合而不稳定，这表明MYCBP 2-EPHB 2缔合是EPHB 2信号传导的前奏。有趣的是，MYCBP 2的缺失导致EPHB 2的泛素化增加和其蛋白水平的降低，这表明MYCBP 2稳定EPHB 2。与这种效应相对应，我们的细胞实验表明MYCBP 2对于细胞系和原代神经元中有效的EPHB 2信号传导应答是必不可少的。最后，我们对C.线虫提供了肝配蛋白受体VAB-1显示与已知MYCBP 2结合蛋白的遗传相互作用的体内证据。总之，我们的结果与MYCBP 2和EPHB 2功能丧失引起的神经发育表型的相似性一致，并将EPHB 2与控制多种细胞功能的信号效应物偶联。
Eph receptor tyrosine kinases participate in a variety of normal and pathogenic processes during development and throughout adulthood. This versatility is likely facilitated by the ability of Eph receptors to signal through diverse cellular signalling pathways: primarily by controlling cytoskeletal dynamics, but also by regulating cellular growth, proliferation, and survival. Despite many proteins linked to these signalling pathways interacting with Eph receptors, the specific mechanisms behind such links and their coordination remain to be elucidated. In a proteomics screen for novel EPHB2 multi-effector proteins, we identified human MYC binding protein 2 (MYCBP2 or PAM or Phr1). MYCBP2 is a large signalling hub involved in diverse processes such as neuronal connectivity, synaptic growth, cell division, neuronal survival, and protein ubiquitination. Our biochemical experiments demonstrate that the formation of a complex containing EPHB2 and MYCBP2 is facilitated by FBXO45, a protein known to select substrates for MYCBP2 ubiquitin ligase activity. Formation of the MYCBP2-EPHB2 complex does not require EPHB2 tyrosine kinase activity and is destabilised by binding of ephrin-B ligands, suggesting that the MYCBP2-EPHB2 association is a prelude to EPHB2 signalling. Paradoxically, the loss of MYCBP2 results in increased ubiquitination of EPHB2 and a decrease of its protein levels suggesting that MYCBP2 stabilises EPHB2. Commensurate with this effect, our cellular experiments reveal that MYCBP2 is essential for efficient EPHB2 signalling responses in cell lines and primary neurons. Finally, our genetic studies in C. elegans provide in vivo evidence that the ephrin receptor VAB-1 displays genetic interactions with known MYCBP2 binding proteins. Together, our results align with the similarity of neurodevelopmental phenotypes caused by MYCBP2 and EPHB2 loss of function, and couple EPHB2 to a signaling effector that controls diverse cellular functions.