Protocadherin-19 belongs to the cadherin family of cell surface receptors and has been shown to play essential roles in the development of the vertebrate nervous system. Mutations in human Protocadherin-19 (PCDH19) lead to PCDH19 Female-limited epilepsy (PCDH19 FLE) in humans, characterized by the early onset of epileptic seizures in children and a range of cognitive and behavioral problems in adults. Despite being considered the second most prevalent gene in epilepsy, very little is known about the intercellular pathways in which it participates. In order to characterize the protein complexes within which Pcdh19 functions, we generated Pcdh19-BioID fusion proteins and utilized proximity-dependent biotinylation to identify neighboring proteins. Proteomic identification and analysis revealed that the Pcdh19 interactome is enriched in proteins that regulate Rho family GTPases, microtubule binding proteins and proteins that regulate cell divisions. We cloned the centrosomal protein Nedd1 and the RacGEF Dock7 and verified their interactions with Pcdh19 in vitro. Our findings provide the first comprehensive insights into the interactome of Pcdh19, and provide a platform for future investigations into the cellular and molecular biology of this protein critical to the proper development of the nervous system.

Protocadherin-19 属于细胞表面受体的钙粘蛋白家族，已被证明在脊椎动物神经系统的发育中发挥重要作用。人类 Protocadherin-19 ( PCDH19 ) 的突变导致PCDH19女性局限性癫痫 ( PCDH19)FLE）在人类中，其特征是儿童早期癫痫发作和成人的一系列认知和行为问题。尽管被认为是癫痫中第二大流行基因，但对其参与的细胞间通路知之甚少。为了表征 Pcdh19 在其中发挥作用的蛋白质复合物，我们生成了 Pcdh19-BioID 融合蛋白，并利用接近依赖性生物素化来识别相邻蛋白质。蛋白质组学鉴定和分析表明，Pcdh19 相互作用组富含调节 Rho 家族 GTP 酶、微管结合蛋白和调节细胞分裂的蛋白质。我们克隆了中心体蛋白 Nedd1 和 RacGEF Dock7 并在体外验证了它们与 Pcdh19 的相互作用. 我们的发现提供了对 Pcdh19 相互作用组的第一个全面见解，并为未来研究该蛋白质的细胞和分子生物学提供了一个平台，该蛋白质对神经系统的正常发育至关重要。