Trehalose transporter 1, a facilitated and high-capacity trehalose transporter, allows exogenous trehalose uptake into cells

Abstract

Trehalose is potentially a useful cryo-or anhydroprotectant molecule for cells and biomolecules such as proteins and nucleotides. A major obstacle to application is that cellular membranes are impermeable to trehalose. In this study, we isolated and characterized the functions of a facilitated trehalose transporter [trehalose transporter 1 (TRET1)] from an anhydrobiotic insect, Polypedilum vanderplanki. Tret1 cDNA encodes a 504-aa protein with 12 predicted transmembrane structures. Tret1 expression was induced by either desiccation or salinity stress. Expression was predominant in the fat body and occurred concomitantly with the accumulation of trehalose, indicating that TRET1 is involved in transporting trehalose synthesized in the fat body into the hemolymph. Functional expression of TRET1 in Xenopus oocytes showed that transport activity was stereochemically specific for trehalose and independent of extracellular pH (between 4.0 and 9.0) and electrochemical membrane potential. These results indicate that TRET1 is a trehalose-specific facilitated transporter and that the direction of transport is reversible depending on the concentration gradient of trehalose. The extraordinarily high values for apparent K m (>100 mM) and Vmax (>500 pmol/min per oocyte) for trehalose both indicate that TRET1 is a high-capacity transporter of trehalose. Furthermore, TRET1 was found to function in mammalian cells, suggesting that it confers trehalose permeability on cells, including those of vertebrates as well as insects. These characteristic features imply that TRET1 in combination with trehalose has high potential for basic and practical applications in vivo.anhydrobiosis ͉ insect ͉ trehalose transport ͉ Polypedilum vanderplanki dessication-inducible gene

Impact of trehalose transporter knockdown onAnopheles gambiaestress adaptation and susceptibility toPlasmodium falciparuminfection

“…We observed an up-regulation of AgTreT1 transcript and increased hemolymph trehalose concentration when mosquitoes were in low relative humidity or high temperature. Similar mRNA induction of the TreT ortholog in P. vanderplanki was reported during desiccation (9). Thus, multiple lines of research suggest that trehalose transport determines hemolymph trehalose concentration, thereby protecting living organisms in adverse environmental conditions.…”

“…Only one TreT gene is present in the A. gambiae genome, and its trehalosetransport function was characterized by heterologous expression in Xenopus oocytes (22). PvTreT1 was proposed to contribute to the dehydration resistance of P. vanderplanki larvae in vivo (9). Nevertheless, no direct evidence has supported this role of AgTreT1 in the whole vector mosquito A. gambiae.…”

“…Bovine endothelial cell line cultivated with trehalose followed by cryopreservation with trehalose in an optimized solution yielded over 80% viable cells (19). Trehalose levels in anhydrobiotic stage larvae of Polypedilum vanderplanki (sleeping chironomid) accumulate rapidly to ∼20% of the dry body mass, more than five times higher than that of larvae in fresh water (9,20). Furthermore, a recent study has shown that injection of D-(+)-trehalose into the hemocoel of head-intact, starved cockroaches lowers the content of short neuropeptide F in hemolymph, suggesting novel roles of trehalose in regulating brain and midgut interplay in insect digestion and nutrition-associated behavior (21).…”

“…This process involves the specific movement of trehalose across cell membranes facilitated by the trehalose transporter, TreT (9,22). The AgTreT1 cDNA from A. gambiae is an ortholog of PvTreT1 from P. vanderplanki.…”

Late embryogenesis abundant proteins protect human hepatoma cells during acute desiccation

“…Increasing this concentration further would elevate the T g significantly (56) and predictably improve the storage outcomes at room temperature. The high-capacity trehalose transporter used in our studies promotes facilitated diffusion of sugars (32). Higher levels of TRET1 expression at the plasma membrane would promote increased trehalose loading.…”