| Both Na+/Ca2+ exchanger NCX1 and non-receptor tyrosine kinase Src are widely expressed in many tissues. A recent paper suggested that tyrosine kinase inhibitors activated membrane current generated by NCX in cardiac myocytes. Therefore, we chose to examine the potential influence of Src on NCX1 directly. When co-transfected together into HEK293 cells, Src caused an increase in the mobility of NCX1 when analyzed by SDS gel electrophoresis. The size change was caused by alteration of the structure of the N-linked glycan attached to NCX1. Surface biotinylation experiments suggested that less NCX1 was delivered to the cell surface when co-expressed with Src. Further experiments demonstrated the modification happened during biosynthesis. In summary, we have demonstrated that the co-expression of Src induced a dramatic change in glycosylation and trafficking of the NCX1 protein. These findings may provide a new and intriguing regulation pathway for NCX1. |
