ATP-sensitive inward rectifier potassium channels regulate secretion of pro-feeding salivary proteins in the lone star tick (Amblyomma americanum)

Understanding the physiological and molecular regulation of tick feeding is necessary for developing interven-tion strategies to curb disease transmission by ticks. Pharmacological activation of ATP-gated inward rectifier potassium (KATP) channels reduced fluid secretion from isolated salivary gland and blood feeding in the lone star tick, Amblyomma americanum, yet the temporal expression pattern of KATP channel proteins remained unknown. KATP channels were highly expressed in type II and III acini in off-host stage and early feeding phase ticks, yet expression was reduced in later stages of feeding. We next assessed KATP channel regulation of the secreted proteome of tick saliva. LC-MS/MS analysis identified 40 differentially secreted tick saliva proteins after expo-sure to KATP activators or inhibitors. Secretion of previously validated tick saliva proteins that promote tick feeding, AV422, AAS27, and AAS41 were significantly reduced by upwards of 8 log units in ticks exposed to KATP channel activators when compared to untreated ticks. Importantly, activation of KATP channels inhibited tick feeding and vice versa for KATP channel inhibitors. Data indicate KATP channels regulate tick feeding biology by controlling secretion of pro-feeding proteins that are essential during early feeding phases, which provides in-sights into physiological and molecular regulation of tick feeding behavior.

Automated summary

Understanding the regulation of tick feeding is crucial for preventing disease transmission. Activation of KATP channels inhibits fluid secretion and blood feeding in ticks, and the expression of KATP channel proteins varies throughout the feeding stages. KATP channels also control the secretion of pro-feeding proteins in tick saliva.