Cell-Cycle-Dependent Regulation of Ca²⁺-Activated K⁺ Channel in Jurkat T-Lymphocyte

Abstract

Small-conductance Ca²⁺-activated K⁺ (SK2) channel plays an important role in the activation of Jurkat T-lymphocytes by maintaining electrical gradients for the sustained Ca²⁺ influx. Apamin-sensitive K⁺ current was significantly decreased with cell-cycle progression from G₀/G₁ into G₂/M phases, and protein expression of SK2 channels showed parallel down-regulation, with its highest expression at early G₀/G₁ phase. In the G₀/G₁ phase, the apamin-sensitive component of thapsigargin-induced Ca²⁺ influx was significantly larger than that in the G₂/M phase. These observations suggest that SK2-channel activation may largely contribute to the sustained Ca²⁺ influx in the G₀/G₁ phase in comparison of that in the G₂/M phase in Jurkat T-lymphocytes.