Department of Bioengineering, Nagaoka University of Technology, 1603-1 Kamitomiokamachi, Nagaoka, Niigata 940-2188, Japan.
Neurosci Lett. 2012 Feb 29;510(2):148-53. doi: 10.1016/j.neulet.2012.01.026. Epub 2012 Jan 21.
NB-2/contactin-5 plays an important role in synapse formation in the developing auditory system of rodents. In this study, to further elucidate the molecular role of NB-2 in synapse formation, we examined the interaction between NB-2 and amyloid precursor-like protein 1 (APLP1), as well as their possible co-localization at the synapse. Pull-down assays and cell surface binding assays demonstrated that NB-2 interacts with APLP1. Furthermore, the protein expression profile of APLP1 in western blots was similar to that of NB-2, and localization of APLP1 mRNA partially overlapped that of NB-2 mRNA. In cultured hippocampal neurons, immunofluorescence signals for both NB-2 and APLP1 overlapped with synapsin, a presynaptic marker. Biochemical analysis showed that both NB-2 and APLP1 were enriched in the presynaptic fraction. These results indicate that NB-2 forms a cis-complex with APLP1 on the presynaptic membrane.
NB-2/contactin-5 在啮齿动物听觉系统发育过程中的突触形成中起着重要作用。在这项研究中，为了进一步阐明 NB-2 在突触形成中的分子作用，我们研究了 NB-2 与淀粉样前体样蛋白 1（APLP1）之间的相互作用，以及它们在突触处可能的共定位。下拉实验和细胞表面结合实验表明 NB-2 与 APLP1 相互作用。此外，APLP1 在 Western blot 中的蛋白表达谱与 NB-2 相似，并且 APLP1 mRNA 的定位与 NB-2 mRNA 的定位部分重叠。在培养的海马神经元中，NB-2 和 APLP1 的免疫荧光信号与突触素（一种突触前标志物）重叠。生化分析表明，NB-2 和 APLP1 均富集在突触前部分。这些结果表明 NB-2 在突触前膜上与 APLP1 形成顺式复合物。
