Carrera de Médico Cirujano, FES Iztacala, UNAM, Av. de los Barrios 1, Los Reyes Iztacala, Tlalnepantla, Edo. Mex, Mexico.
Laboratorio de Biofísica Computacional, Doctorado en Biotecnología, SEPI-ENMH Instituto Politécnico Nacional, Av. Guillermo Massieu Helguera 239, Fracc. La Escalera, Ticomán, Gustavo A. Madero, 07320, Mexico City, Mexico.
Sci Rep. 2024 Mar 21;14(1):6761. doi: 10.1038/s41598-024-57117-8.
Voltage-gated sodium channels (Na) are pivotal proteins responsible for initiating and transmitting action potentials. Emerging evidence suggests that proteolytic cleavage of sodium channels by calpains is pivotal in diverse physiological scenarios, including ischemia, brain injury, and neuropathic pain associated with diabetes. Despite this significance, the precise mechanism by which calpains recognize sodium channels, especially given the multiple calpain isoforms expressed in neurons, remains elusive. In this work, we show the interaction of Calpain-10 with Na's C-terminus through a yeast 2-hybrid assay screening of a mouse brain cDNA library and in vitro by GST-pulldown. Later, we also obtained a structural and dynamic hypothesis of this interaction by modeling, docking, and molecular dynamics simulation. These results indicate that Calpain-10 interacts differentially with the C-terminus of Na1.2 and Na1.6. Calpain-10 interacts with Na1.2 through domains III and T in a stable manner. In contrast, its interaction with Na1.6 involves domains II and III, which could promote proteolysis through the Cys-catalytic site and C2 motifs.
电压门控钠离子通道（Na）是启动和传递动作电位的关键蛋白。新出现的证据表明，钙蛋白酶对钠离子通道的蛋白水解切割在多种生理情况下至关重要，包括缺血、脑损伤和与糖尿病相关的神经性疼痛。尽管如此，钙蛋白酶识别钠离子通道的确切机制，特别是考虑到神经元中表达的多种钙蛋白酶同工型，仍然难以捉摸。在这项工作中，我们通过酵母 2 杂交测定筛选小鼠脑 cDNA 文库和体外 GST 下拉实验显示了钙蛋白酶-10 与 Na 的 C 端的相互作用。后来，我们还通过建模、对接和分子动力学模拟获得了这种相互作用的结构和动态假设。这些结果表明，钙蛋白酶-10 与 Na1.2 和 Na1.6 的 C 端以不同的方式相互作用。钙蛋白酶-10 通过稳定的方式与 Na1.2 的 III 结构域和 T 结构域相互作用。相比之下，它与 Na1.6 的相互作用涉及 II 结构域和 III 结构域，这可以通过半胱氨酸催化位点和 C2 基序促进蛋白水解。
