Uncovering protein-protein interactions of the human sodium channel Nav1.7

Abstract

The voltage-gated sodium channel Nav1.7 plays a crucial role in the initiation and propagation of pain signals. Our previous study has successfully identified the interacting proteins of mouse Nav1.7 (mNav1.7). In this study, we aimed to further elucidate the protein-protein interactions associated with human Nav1.7 (hNav1.7). Stable epitope (TAP)-tagged HEK293 cells expressing hNaV1.7 were utilized for the identification of hNav1.7-interacting proteins. The hNaV1.7-associated complexes were isolated through tandem affinity purification and further characterized by mass spectrometry. Bioinformatics analysis was carried out using the PANTHER classification system. Electrophysiological recording was performed to assess Nav1.7 current. Tap-tagged hNav1.7 was expressed effectively in HEK293 cells, exhibiting normal functional Nav1.7 currents. A total of 261 proteins were identified as interactors of hNav1.7, mainly located across the cell membrane and cytoplasm, and primarily involved in biological processes related to protein translation and expression. Comparison between human and mouse Nav1.7-interacting proteins revealed shared proteins (such as Eef1a1, Eef2, Tcp1, Cct2, Cct3, Cct5, Cct6a, and Cct7) as well as protein families (such as kinesin and Rab GTPases family). Knockdown of two of the shared interacting proteins, CCT5 and TMED10, resulted in reduced Nav1.7 current density. In conclusion, the protein interactions of hNaV1.7 were successfully mapped in the current work. These novel findings offer essential insights into the regulatory mechanisms that govern Nav1.7 function. Significance statementChronic pain affects approximately 20% of the worlds population and is a global major public health problem. Nav1.7 has been recognized as a promising target for novel analgesics. However, the drug development process for Nav1.7 is challenging. A thorough understanding of the regulatory mechanism of Nav1.7 would greatly assist in the development of its analgesic drugs. Our previous work successfully mapped the mNav1.7 protein interactions. In the current study, the interacting proteins of hNav1.7 were further defined. Our findings provide important implications for the development of Nav1.7-based analgesics for human use.