Tumor cell membranes have multiple components that participate in the process of metastasis. The present study investigates the physical association of β1-integrins and Kv1.3 voltage-gated potassium channels in melanoma cell membranes using resonance energy transfer (RET) techniques. RET between donor-labeled anti–β1-integrin and acceptor-labeled anti-Kv1.3 channels was detected on LOX cells adherent to glass and fibronectin-coated coverslips. However, RET was not observed on LOX cells in suspension, indicating that molecular proximity of these membrane molecules is adherence-related. Several K+ channel blockers, including tetraethylammonium, 4-aminopyridine, and verapamil, inhibited RET between β1-integrins and Kv1.3 channels. However, the irrelevant K+ channel blocker apamin had no effect on RET between β1-integrins and Kv1.3 channels. Based on these findings, we speculate that the lateral association of Kv1.3 channels with β1-integrins contributes to the regulation of integrin function and that channel blockers might affect tumor cell behavior by influencing the assembly of supramolecular structures containing integrins.
Molecular diversity of potassium channels in atrial cell membranes
