Drosophila melanogaster contains a single small-conductance Ca²⁺‑activated K⁺ (SK) channel gene most closely related to mammalian SK1, a channel that has proven difficult to characterize using conventional approaches. Similar to rodent SK1, Drosophila SK (dSK) fails to traffic to the cell surface when expressed in heterologous systems. Chimeric channels consisting of the N‑ and C‑terminal domains of rat SK2 fused to the transmembrane regions of dSK showed sensitivity to tetraethylammonium but were insensitive to apamin. Northern blot analysis revealed two distinct transcripts that are developmentally regulated, with highest expression in the adult head. Flies lacking SK function, generated by gamma‑ray deletion, exhibited no overt phenotype.
