Table 2.
Secretion rate, [K+], and potassium flux
| Genotype | Secretion Rate, nl/min | [K+], mM | K+ Flux, pmol/min per Tubule | n | Slope |
|---|---|---|---|---|---|
| Chloride-insensitive WNK expression in adult principal cells, standard bathing medium | |||||
| w; tub-GAL80ts20/+; c42-GAL4/+ | 0.49±0.03 | 143±9.0 | 72±6.2 | 17 | 56.1 |
| w; tub-GAL80ts20/UAS-DmWNKL421F; c42-GAL4/+ | 0.54±0.03 | 137±5.8 | 75±5.6 | 20 | |
| Principal cell Mo25 knockdown | |||||
| w; c42-GAL4/+, standard bathing medium | 0.48±0.05 | 134±6.9 | 68±8.1 | 23 | 56.6 |
| w; c42-GAL4/+, hypotonic | 1.09±0.08 | 108±5.9 | 125±11.9 | 21 | |
| w; UAS-DmMo25RNAi/+; c42-GAL4/+, standard bathing medium | 0.41±0.04 | 138±4.5 | 58±6.5 | 22 | |
| w; UAS-DmMo25RNAi/+; c42-GAL4/+, hypotonic | 0.64±0.07 | 103±3.1 | 65±7.0 | 24 | |
| Principal cell Mo25 rescue, hypotonic | |||||
| w; c42-GAL4/+ | 0.75±0.04 | 137±3.7 | 104±5.8 | 39 | 51.7 |
| w; UAS-DmMo25RNAi/+; c42-GAL4/+ | 0.49±0.03 | 125±4.5 | 64±5.4 | 40 | |
| w; UAS-DmMo25RNAi/+; c42-GAL4/UAS-MmMo25 | 0.93±0.05 | 136±3.8 | 127±8.2 | 31 | |
| Principal cell overexpression of FrayT206E with Mo25, standard bathing medium | |||||
| w; tub-GAL80ts20/+; c42-GAL4/+ | 0.65±0.03 | 150±4 | 99±5.4 | 40 | 52.2 |
| w; tub-GAL80ts20 UAS-DmMo25/+; c42-GAL4/+ | 0.67±0.04 | 153±3 | 103±6.0 | 41 | |
| w; tub-GAL80ts20/UAS-FrayT206E; c42-GAL4/+ | 0.72±0.03 | 152±4 | 112±6.9 | 41 | |
| w; tub-GAL80ts20 UAS-DmMo25/UAS-FrayT206E; c42-GAL4/+ | 0.77±0.04 | 154±3 | 119±7.5 | 41 | |
| Principal cell overexpression of wild-type WNK ± Mo25, standard bathing medium | |||||
| w; tub-GAL80ts20/+; c42-GAL4/+ | 0.64±0.04 | 137±5.4 | 88±6.2 | 29 | 50.7 |
| w; tub-GAL80ts20 UAS-DmWNKWT/+; c42-GAL4/+ | 0.68±0.05 | 131±5.6 | 89±8.0 | 26 | |
| w; tub-GAL80ts20 UAS-DmWNKWT/UAS-DmMo25; c42-GAL4/+ | 0.66±0.05 | 126±8.2 | 83±8.0 | 24 | |
| Principal cell overexpression of chloride-insensitive WNK with Mo25, standard bathing medium | |||||
| w; tub-GAL80ts20/+; c42-GAL4/+ | 0.62±0.04 | 136±3.9 | 84±5.7 | 24 | 58.7 |
| w; tub-GAL80ts20 UAS-DmMo25/+; c42-GAL4/+ | 0.67±0.05 | 138±5.1 | 93±7.4 | 25 | |
| w; tub-GAL80ts20 UAS-DmMo25/UAS-DmWNKL421F; c42-GAL4/+ | 0.84±0.07 | 145±1.9 | 121±9.0 | 24 |
All values shown are mean±SEM. Slope is the mean slope per tenfold difference in [K+] of the electrodes used for each experiment. Note that potassium flux was calculated separately for each tubule analyzed, and therefore, the value of mean secretion rate × mean [K+] may differ slightly from measured potassium flux due to rounding. K+, potassium; DmWNK, D. melanogaster with no lysine kinase; DmMo25, D. melanogaster mouse protein 25; MmMo25, M. musculus mouse protein 25; RNAi, RNA interference; WT, wild type.