Kv2.1 cell surface clusters are insertion platforms for ion channel delivery to the plasma membrane
| Autor: | Elizabeth J. Akin, Rob J. Loftus, Gentry Hansen, Diego Krapf, Phil Fox, Christopher J. Haberkorn, Emily Deutsch, Aubrey V. Weigel, Michael M. Tamkun |
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| Rok vydání: | 2012 |
| Předmět: |
Surface Properties
Biology Membrane Fusion Exocytosis Membrane Potentials 12. Responsible consumption Cell membrane 03 medical and health sciences Shab Potassium Channels 0302 clinical medicine medicine Humans Molecular Biology Ion channel 030304 developmental biology Neurons Membrane potential 0303 health sciences Microscopy Confocal Voltage-gated ion channel Sodium channel Cell Membrane HEK 293 cells Fluorescence recovery after photobleaching Articles Cell Biology Cell biology HEK293 Cells medicine.anatomical_structure Membrane Trafficking Kv1.4 Potassium Channel SNARE Proteins Ion Channel Gating 030217 neurology & neurosurgery |
| Zdroj: | Molecular Biology of the Cell |
| ISSN: | 1939-4586 1059-1524 |
| DOI: | 10.1091/mbc.e12-01-0047 |
| Popis: | Kv2.1 surface clusters in transfected HEK cells and hippocampal neurons are shown to be trafficking platforms involved in potassium channel movement to and from the cell surface. This work is the first to define stable cell surface sites for ion channel delivery and retrieval at the cell surface. Voltage-gated K+ (Kv) channels regulate membrane potential in many cell types. Although the channel surface density and location must be well controlled, little is known about Kv channel delivery and retrieval on the cell surface. The Kv2.1 channel localizes to micron-sized clusters in neurons and transfected human embryonic kidney (HEK) cells, where it is nonconducting. Because Kv2.1 is postulated to be involved in soluble N-ethylmaleimide–sensitive factor attachment protein receptor–mediated membrane fusion, we examined the hypothesis that these surface clusters are specialized platforms involved in membrane protein trafficking. Total internal reflection–based fluorescence recovery after photobleaching studies and quantum dot imaging of single Kv2.1 channels revealed that Kv2.1-containing vesicles deliver cargo at the Kv2.1 surface clusters in both transfected HEK cells and hippocampal neurons. More than 85% of cytoplasmic and recycling Kv2.1 channels was delivered to the cell surface at the cluster perimeter in both cell types. At least 85% of recycling Kv1.4, which, unlike Kv2.1, has a homogeneous surface distribution, is also delivered here. Actin depolymerization resulted in Kv2.1 exocytosis at cluster-free surface membrane. These results indicate that one nonconducting function of Kv2.1 is to form microdomains involved in membrane protein trafficking. This study is the first to identify stable cell surface platforms involved in ion channel trafficking. |
| Databáze: | OpenAIRE |
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