Rapid internalization of the oncogenic K+ channel K(V)10.1.
K(V)10.1 is a mammalian brain voltage-gated potassium channel whose ectopic expression outside of the brain has been proven relevant for tumor biology. Promotion of cancer cell proliferation by K(V)10.1 depends largely on ion flow, but some oncogenic properties remain in the absence of ion permeation. Additionally, K(V)10.1 surface populations are small compared to large intracellular pools. Control of protein turnover within cells is key to both cellular plasticity and homeostasis, and therefore we set out to analyze how endocytic trafficking participates in controlling K(V)10.1 intracellular distribution and life cycle. To follow plasma membrane K(V)10.1 selectively, we generated a modified channel of displaying an extracellular affinity tag for surface labeling by α-bungarotoxin. This modification only minimally affected K(V)10.1 electrophysiological properties. Using a combination of microscopy and biochemistry techniques, we show that K(V)10.1 is constitutively internalized involving at least two distinct pathways of endocytosis and mainly sorted to lysosomes. This occurs at a relatively fast rate. Simultaneously, recycling seems to contribute to maintain basal K(V)10.1 surface levels. Brief K(V)10.1 surface half-life and rapid lysosomal targeting is a relevant factor to be taken into account for potential drug delivery and targeting strategies directed against K(V)10.1 on tumor cells.
Max-Planck-Institute of Experimental Medicine, Department of Molecular Biology of Neuronal Signals, Göttingen, Germany.
Tobias
T
Kohl
Eva
E
Lörinczi
Luis A
LA
Pardo
Walter
W
Stühmer
D001665:Binding Sites; D002038:Bungarotoxins / Q000378:metabolism; D002462:Cell Membrane / Q000378:metabolism; D002966:Clathrin / Q000378:metabolism; D004705:Endocytosis; D011992:Endosomes / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D057809:HEK293 Cells; D006801:Humans; D015640:Ion Channel Gating; D008247:Lysosomes / Q000378:metabolism; D016254:Mutagenesis, Insertional / Q000235:genetics; D009857:Oncogenes; D024642:Potassium Channels, Voltage-Gated / Q000737:chemistry / Q000378:metabolism*; D017433:Protein Structure, Secondary; D059748:Proteolysis; D013194:Staining and Labeling; D013499:Surface Properties
D002038:Bungarotoxins; D002966:Clathrin; D005456:Fluorescent Dyes; D024642:Potassium Channels, Voltage-Gated