The SLC45-family of alternative sugar transporters in animals
Final Report Abstract
In this project, we investigated characteristic properties of the novel SLC45 family of mammalian sugar transporters. We call this family alternative sugar transporters because they, in contrast to the dogma found in any textbook of Physiology, transport not only monosaccharides, but also the disaccharide sucrose and because they are symporters, energized not by the sodium but by the proton motive force. Originally we had verified these properties in the Drosophila SLC45-1 protein and showed in preliminary experiments that mammalian SLC45 protein also are H+/sucrose symporters. Our principal aim of the present project was the analysis of characteristic properties of the mammalian SLC45 proteins. As a first step we verified that mammalian SLC45 proteins indeed are H+/sugar symporters which transport the disaccharide sucrose, but also monosaccharides such as glucose or fructose. Due to the monitored presence of SLC45 mRNA in different mouse tissues, we studied SLC45A3 in the kidney and SLC45A4 in the male reproductive tract. SLC45A3 occurs in the medullary collecting duct, a part of the kidney, which faces a hyperosmotic environment and is responsible for final urine concentration. Our results favor the suggestion that (1) SLC45A3 is an H+ dependent osmolyte transporter in the kidney and that (2) especially sucrose is a novel compatible osmolyte. For SLC45A4 we confirmed that this transporter plays an important role in nutrition of spermatozoa during their maturation in the epididymis. Moreover, experimental approaches regarding the regulation of SLC45 proteins indicated for the first time their interaction with 14-3-3 proteins, leading to a significant decrease in transport rates of the murine SLC45 transporters.
Publications
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(2018) Interaction of mammalian and plant H+/sucrose transporters with 14-3-3 proteins. The Biochemical journal 475 (20) 3239–3254
Vitavska, Olga; Bartölke, Rabea; Tabke, Katharina; Heinisch, Jürgen J.; Wieczorek, Helmut
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(2013) The SLC45 gene family of putative sugar transporters. Molecular Aspects of Medicine 34, 655–660
Vitavska, O. and Wieczorek, H.
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(2014) Proton-associated sucrose transport of mammalian Solute Carrier Family 45: an analysis in Saccharomyces cerevisiae. Biochem. J. 464, 193-201
Bartölke, R., Heinisch, J.J., Helmut Wieczorek, H. and Olga Vitavska, O.
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(2016) Putative role of the H+/sucrose symporter SLC45A3 as an osmolyte transporter in the kidney. Pflügers Archiv - European Journal of Physiology 468, 1353–1362
Vitavska, O., Edemir, B. and Wieczorek, H.
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(2017) Putative role of an SLC45 H+/sugar cotransporter in mammalian spermatozoa. Pflügers Archiv - European Journal of Physiology 469, 1433-1442
Vitavska, O. and Wieczorek, H.
