GTP analogs suppress uptake but not transport ofd-glucose analogs in Glut1 glucose transporter-expressingXenopusoocytes
- 19 July 1993
- journal article
- Published by Wiley in FEBS Letters
- Vol. 327 (1) , 95-98
- https://doi.org/10.1016/0014-5793(93)81047-4
Abstract
A Xenopus oocyte expression-co-injection system was used to study the influence of guanine nucleotides on D-glucose uptake. GTP analogs like GTPγS and GppNHp had no effect on 3-O-methylglucose transport determined by zero-trans uptake or equilibrium exchange, but suppressed 2-deoxyglucose uptake into Glutl glucose transporter-expressing oocytes by up to 86%. Both GTP analogs showed concentration dependence of their effectiveness, with GTPγS being more potent than GppNHp. No statistically significant differences were observed between groups of oocytes co-injected with water or GDPβS (250 and 500 μM intracellular concentration). Glut1 transporter expression in plasma membrane was not different between water or GTPγS-co-injected oocytes. Thus, inhibition of hexokinase catalytic activity is the most likely causative factor for down-regulation of 2-deoxyglucose uptake.Keywords
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