Zhang Gu, Brady John, Liang Wei-Ching, Wu Yan, Henkemeyer Mark, Yan Minhong
Department of Molecular Oncology, Division of Research, Genentech Inc., 1 DNA Way, South San Francisco, CA 94080, USA.
Department of Antibody Engineering, Division of Research, Genentech Inc., 1 DNA Way, South San Francisco, California 94080, USA.
Nat Commun. 2015 Apr 13;6:6625. doi: 10.1038/ncomms7625.
Bidirectional signalling is regarded as a notable hallmark of the Eph-ephrin signalling system: Eph-dependent forward signalling in Eph-expressing cells and ephrin-dependent reverse signalling in Ephrin-expressing cells. The notion of ephrin-dependent reverse signalling derives from genetic experiments utilizing mice carrying mutations in the intracellular region of ephrinBs. Here we show that EphB4-dependent forward signalling regulates lymphatic valve development, a process previously thought to be regulated by ephrinB2-dependent reverse signalling. We develop antibodies that selectively target EphB4 and ephrinB2. We find that mice bearing genetically altered cytoplasmic region of ephrinB2 have significantly altered EphB4-dependent forward signalling. Selective inhibition of EphB4 using a functional blocking antibody results in defective lymphatic valve development. Furthermore, a chemical genetic approach is used to unequivocally show that the kinase activity of EphB4 is essential for lymphatic valve development.
双向信号传导被视为Eph-ephrin信号系统的一个显著标志：在表达Eph的细胞中存在Eph依赖性正向信号传导，而在表达Ephrin的细胞中存在ephrin依赖性反向信号传导。ephrin依赖性反向信号传导的概念源于利用在ephrinB的细胞内区域携带突变的小鼠进行的遗传学实验。在此，我们表明EphB4依赖性正向信号传导调节淋巴管瓣膜发育，这一过程此前被认为是由ephrinB2依赖性反向信号传导所调节的。我们研发了选择性靶向EphB4和ephrinB2的抗体。我们发现，携带基因改变的ephrinB2细胞质区域的小鼠，其EphB4依赖性正向信号传导发生了显著改变。使用功能性阻断抗体对EphB4进行选择性抑制会导致淋巴管瓣膜发育缺陷。此外，采用化学遗传学方法明确证明EphB4的激酶活性对于淋巴管瓣膜发育至关重要。
