One step, two functions: The mechanism of the ABCH class of transporter serving barrier construction and detoxification in insects

Insects occupy a broad range of habitats after terrestrialization and radiation from marine crustaceans 519 million years ago (Schwentner et al., 2017). They found themselves in a new environment, foremost jeopardising them with low humidity i.e. dry or desiccation conditions. In addition, their co-evolution with land plants both as beneficial and maleficial companions exposed them to plant produced xenobiotics (secondary metabolites) that as the plant defence molecules may have potential adverse effects on insects. Insects learned to cope with both situations, among others, through the evolution and activation of H-type ATP-binding cassette (ABC) transporters. Indeed, ABCH transporters are Arthropod-specific ABC transporters that, in all kingdoms of living organisms, using ATP hydrolysis, transport molecules from one side of a membrane to the other, thereby influencing the physiological milieus of both compartments.