Expression of kcc^HMS01058 under the control of Scer\GAL4^Tsp42Ec leads to reduced acidity in the acidic region of the larval midgut, but no significant effect on larval development or survival under normal conditions, as compared with controls. Mutant larvae exposed to high dietary KCl, but not NaCl, exhibit decreased survival, as compared with controls.

Expression of kcc^HMS01058 under the control of any of the following drivers mushroom body drivers induces bang-sensitive paralytic behavior: Scer\GAL4^Tab2-201Y, Scer\GAL4^Mef2.247, Scer\GAL4^ey-OK107 or Scer\GAL4^c747. Scer\GAL4^ey-OK107>kcc^HMS01058 flies have increased brain volume compared to controls. Giant fiber and lateral pace-making neurons are enlarged compared to controls. The ellipsoid body driver Scer\GAL4^Aph-4-c507 and the motor neuron driver Scer\GAL4^RapGAP1-OK6 cause lethality.

Expression of kcc^HMS01058 in glial cells under the control of Scer\GAL4^repo.PU results in substantial bang-sensitive paralytic behavior. The threshold to evoked seizure-like discharges in these flies is reduced compared to controls and brain volume is increased by approximately 1.3-fold. Whereas in wild type brains mushroom body neuronal cell bodies and calyces are wrapped and interlaced with glial membranes, these associations are largely absent in Scer\GAL4^repo.PU>kcc^HMS01058 flies. Neuropile glia do not envelop the calyx when glia express kcc^HMS01058 during development. Peripheral nerve swelling is also seen; third instar larval abdominal nerves display an increase in the average never cross-sectional area compared to controls. This phenotype is completely penetrant.

Expression of kcc^HMS01058 in subperineurial glia (SPG) cells under the control of Scer\GAL4^Gli-rL82 or Scer\GAL4^moody.PS results in 100% and 65% bang-sensitive paralytic behavior respectively. Additional phenotypes are seen in the kcc^HMS01058>Scer\GAL4^Gli-rL82 flies. Flies often display malformed wings and are especially sensitive to behavioral seizure-like activity. Gentle handling of the vial is sufficient to trigger seizures and the threshold to evoked seizure-like discharges is reduced compared to controls.

Expression of kcc^HMS01058 in cortex glia surrounding neuronal cell bodies under the control of Scer\GAL4^{Akap200-NP2222} results in substantial bang-sensitive paralytic behavior. Bang-sensitive paralytic behavior is also seen when kcc^HMS01058 is expressed using Scer\GAL4^nrv2.PS (cortex and neuropile glia), Scer\GAL4^Mz709 (ensheathing glia) and Scer\GAL4^alrm.PD (astrocyte-like glia).