Figure 1

Insect transporting epithelia and the V-ATPase hypothesis. (A) Typical insect cross-section, after [16]. (B) Current dogma for insect transporting epithelia (the ‘Wieczorek model’). Transport is energized by an apical protonmotive V-ATPase, which establishes a gradient that drives an Na⁺/H⁺ or K⁺/H⁺ exchanger. These ions enter basally through unspecified mechanisms, likely to be cotransports or channels.