Table 3. Drosophila homologs of mammalian ion/volume homeostasis molecules.

Function	Drosophila	Mammal
Na-K-Cl cotransport	Ncc69, Ncc83	NKCC1
K-Cl cotransport	Kcc	KCC3, KCC4
Ser/Thr kinase	Fray	OSR1 and SPAK/PASK
K channel (inward rectifier)	Ir, Irk2, Irk3	Kir4.1
K channel (voltage-gated)	KCNQ	Kv7.3, Kv7.4
Cl channel	ClC-a	ClC-Ka, ClC-Kb
Gap junction	(Innexin family)	Connexin family
Aquaporin	Drip, CG4019, CG17662, CG17664, CG7777, Bib*	AQP4

Table shows mammalian molecules, described and referenced in the text, that have been shown to function in ion or volume homeostasis in the nervous system or inner ear with corresponding functions. The only Drosophila orthologs with genetic rescue data are Ncc69 and Fray (Leiserson et al. 2010; Leiserson et al. 2000). The candidate orthologous Drosophila molecules were obtained from OrthoDB (Kriventseva et al. 2008); where no putative orthologs were found, related molecules of similar function are shown in parentheses.

^*Evidence suggests that while Bib is homologous to Aquaporins, it may not function as a water channel (Tatsumi et al. 2009).