Roles of Aquaporins in Osmoregulation, Desiccation and Cold Hardiness in InsectsEphraim Cohen*
Department of Entomology, The Hebrew University of Jerusalem, Israel
- *Corresponding Author:
- Ephraim Cohen
The Morris and Helen Mauerberger Chair in Agriculture Entomology
Department of Entomology, The Robert H. Smith Faculty of Agriculture
Food and Environment, The Hebrew University of Jerusalem
Rehovot 76100, Israel
E-mail: [email protected]
Received date: December 20, 2011; Accepted date: January 26, 2012; Published date: March 21, 2012
Citation: Cohen E (2012) Roles of Aquaporins in Osmoregulation, Desiccation and Cold Hardiness in Insects. Entomol Ornithol Herpetol S1:001. doi: 10.4172/2161-0983.S1-001
Copyright: © 2012 Cohen E. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
To maintain water homeostasis and osmoregulation, and to facilitate cryoprotection or overcome desiccation challenges, organisms across all taxa have utilized special and elaborate transmembrane channels that mediate the transport of water molecules (aquaporins, AQPs) as well as uncharged low molecular-weight solutes, such as glycerol (aquaglyceroporins). Nevertheless, some channels like Big Brain (BIB) in Drosophila play different roles that are involved in neural signal transduction, cell migration and cell to cell adhesion. Sanguinivorous insects and ticks, or insects feeding on plant sap are challenged with large volumes of ingested solutes that must be rapidly and effectively voided. AQP genes encoding functional transmembrane channel proteins were cloned from various ticks and mosquitoes species, as well as from xylem- (green leafhoppers) and phloem-sap feeders (whiteflies and aphids). AQPs are largely and abundantly expressed in organs associated with water balance such as the Malpighian tubules and the alimentary canal. In particular, abundance of AQP channels were detected in gut bypasses like the filter chamber in plant-sap feeders. AQPs and mobilization of cryoprotectants or dehydration protectants like glycerol and other polyols were studied in insects that overcome extreme environmental conditions such as sub-zero temperatures or severe desiccation. Hormone-mediated transcriptional regulation of AQP genes was demonstrated in insect and vertebrate systems. Post-translational control, related to trafficking of AQP-containing intracellular membrane vesicles to appropriate location in cell membrane domains, their docking on and fusion with the plasma membrane compartment, recycling and degradation as well as gating their pore entrance, was largely associated with specific kinase-mediated phosphorylation steps. Most of the above research was conducted with mammalian systems, yet several solid lines of evidence show that the same mechanisms apply to insects. As AQPs are tightly linked to human pathophysiological conditions, they have become promising targets for developing pharmaceutical drugs. Likewise, since AQPs are
important for the survival of blood and plant-sap feeding arthropods, they have been suggested as attractive target sites to be tapped for developing effective pest control agents.