Jensen, Camilla Stampe4; Watanabe, Shoji3; Rasmussen, Hanne Borger4; Schmitt, Nicole4; Olesen, Søren-Peter4; Frost, Nicholas A3; Blanpied, Thomas A3; Misonou, Hiroaki3
1 Section of Heart and Circulatory Research, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Københavns Universitet2 Danish Arrhythmia Research Centre, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Københavns Universitet3 unknown4 Section of Heart and Circulatory Research, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, Københavns Universitet
Proper membrane localization of ion channels is essential for the function of neuronal cells. Particularly, the computational ability of dendrites depends on the localization of different ion channels in specific sub-compartments. However, the molecular mechanisms which control ion channel localization in distinct dendritic sub-compartments are largely unknown. Here, we developed a quantitative live-cell imaging method to analyze protein sorting and post-Golgi vesicular trafficking. We focused on two dendritic voltage-gated potassium channels which exhibit distinct localizations; Kv2.1 in proximal dendrites and Kv4.2 in distal dendrites. Our results show that Kv2.1 and Kv4.2 channels are sorted into two distinct populations of vesicles at the Golgi apparatus. The targeting of Kv2.1 and Kv4.2 vesicles occurred by distinct mechanisms evidenced by their requirement for specific peptide motifs, cytoskeletal elements, and motor proteins. By live-cell and super-resolution imaging, we identified a novel trafficking machinery important for the localization of Kv2.1 channels. Particularly, we identified non-muscle myosin II as an important factor in Kv2.1 trafficking. These findings reveal that the sorting of ion channels at the Golgi apparatus and their subsequent trafficking by unique molecular mechanisms, are crucial for their specific localizations within dendrites.
Journal of Biological Chemistry, 2014, Vol 289, p. 10566-10581