The voltage-gated Na super(+) channel beta 3 subunit does not mediate trans homophilic cell adhesion or associate with the cell adhesion molecule contactin

• Published in: Neuroscience letters 2009-09, Vol.462 (3), p.272-275
• Main Authors: McEwen, Dyke P, Chen, Chunling, Meadows, Laurence S, Lopez-Santiago, Luis, Isom, Lori L
• Format: Article
• Language: English
• ISSN: 0304-3940; 1872-7972
• DOI: 10.1016/j.neulet.2009.07.020

Voltage-gated Na super(+) channel (VGSC) beta 1 and beta 2 subunits are multifunctional, serving as both channel modulators and cell adhesion molecules (CAMs). The purpose of this study was to determine whether VGSC beta 3 subunits function as CAMs. The beta 3 extracellular domain is highly homologous to beta 1, suggesting that beta 3 may also be a functional CAM. We investigated the trans homophilic cell adhesive properties of beta 3, its association with the beta 1-interacting CAM contactin, as well as its ability to interact with the cytoskeletal protein ankyrin. Our results demonstrate that, unlike beta 1, beta 3 does not participate in trans homophilic cell-cell adhesion or associate with contactin. Further, beta 3 does not associate with ankyrin sub(G) in a heterologous system. Previous studies have shown that beta 3 interacts with the CAM neurofascin-186 but not with VGSC beta 1. Taken together, these findings suggest that, although beta 1 and beta 3 exhibit similar channel modulatory properties in heterologous systems, these subunits differ with regard to their homophilic and heterophilic CAM binding profiles.