Brambilla R, Schnapp A, Casagranda F, Labrador J P, Bergemann A D, Flanagan J G, Pasquale E B, Klein R
European Molecular Biology Laboratory, Differentiation Programme, Heidelberg, Germany.
EMBO J. 1995 Jul 3;14(13):3116-26. doi: 10.1002/j.1460-2075.1995.tb07314.x.
The Eph-related family of receptor tyrosine kinases consists of at least 13 members, several of which display distinctive expression patterns in the developing and adult nervous system. Recently, a small family of ligands, structurally related to the B61 protein, was identified. Binding of these ligands to Eph-related receptors did not, however, elicit measurable biological signals in cultured cells. In order to study functional interactions between B61-related ligands and Eph-related receptors, we constructed chimeric receptors, containing an Eph-related ectodomain and the cytoplasmic domain of the TrkB neurotrophin receptor. Expression and activation of such chimeric receptors in NIH 3T3 cells induced transformation in focus formation assays. Membrane-bound LERK2 ligand is shown to signal through three different Eph-related receptors, namely Cek5, Cek10 and Elk. LERK2, however, fails to interact functionally with the Cek9 receptor. Quantitative analysis including binding assays indicates that Cek10 is the preferred LERK2 receptor. Preliminary mutagenesis of the LERK2 protein suggests a negative regulatory role for its cytoplasmic domain in LERK2 signaling.
Eph相关的受体酪氨酸激酶家族至少由13个成员组成，其中几个在发育中和成年神经系统中表现出独特的表达模式。最近，鉴定出了一个与B61蛋白结构相关的小分子配体家族。然而，这些配体与Eph相关受体的结合在培养细胞中并未引发可测量的生物学信号。为了研究B61相关配体与Eph相关受体之间的功能相互作用，我们构建了嵌合受体，其包含Eph相关的胞外结构域和TrkB神经营养因子受体的胞质结构域。在NIH 3T3细胞中此类嵌合受体的表达和激活在焦点形成试验中诱导了转化。膜结合的LERK2配体显示可通过三种不同的Eph相关受体发出信号，即Cek5、Cek10和Elk。然而，LERK2未能与Cek9受体发生功能相互作用。包括结合试验在内的定量分析表明Cek10是首选的LERK2受体。LERK2蛋白的初步诱变表明其胞质结构域在LERK2信号传导中起负调节作用。
