Dual Functional Characteristic of Human Aquaporin 10 for Solute Transport
| Autor: | Megumi Ishii, Katsuhisa Inoue, Hiroaki Yuasa, Takahiro Katano, Kinya Ohta, Aki Miyamoto, Jun Watanabe, Kimihiko Urano |
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| Rok vydání: | 2011 |
| Předmět: |
Glycerol
DNA Complementary Physiology Xenopus Glycerol transport Aquaporin Aquaporins Michaelis–Menten kinetics Xenopus laevis chemistry.chemical_compound Animals Humans DNA Primers Base Sequence biology Chemistry Biological Transport Transporter biology.organism_classification Kinetics Aquaglyceroporins Biochemistry Biophysics Female Efflux |
| Zdroj: | Cellular Physiology and Biochemistry. 27:749-756 |
| ISSN: | 1421-9778 1015-8987 |
| DOI: | 10.1159/000330083 |
| Popis: | Background/Aims: Although aquaglyceroporins have been generally believed to operate in a channel mode, which is of nonsaturable nature, for glycerol as well as for water, we recently found that human aquaporin 9 (hAQP9) operates in a carrier-mediated mode, which is of saturable nature, for glycerol. Based on the finding, we assumed that such a characteristic might be shared by the other aquaglyceroporins and examined the functional characteristics of hAQP10, which is an intestine-specific aquaglyceroporin. Methods: Transport assays were conducted using Xenopus laevis oocytes expressing hAQP10 derived from the microinjected cRNA. Results: The transport of glycerol by hAQP10 was found to be highly saturable with a Michaelis constant of 10.4 µM and specifically inhibited by several glycerol analogs such as monoacetin. Furthermore, when glycerol was preloaded in hAQP10-expressing oocytes, its efflux was trans-stimulated by extracellular glycerol. These results indicate the involvement of a carrier-mediated mechanism in glycerol transport by hAQP10. Interestingly, a channel mechanism was also found to be involved in part in hAQP10-mediated glycerol transport. Conclusion: The present study unveiled the uniquely dual functional characteristic of hAQP10 as a carrier/channel for solute transport, providing a novel insight into its operation mechanism, which would help further elucidate its physiological role. |
| Databáze: | OpenAIRE |
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