Phosphorylation of RS1 (RSC1A1) Steers Inhibition of Different Exocytotic Pathways for Glucose Transporter SGLT1 and Nucleoside Transporter CNT1, and an RS1-Derived Peptide Inhibits Glucose Absorption
| Autor: | Valentin Gorboulev, Jürgen Groll, Hermann Koepsell, Smriti Singh, Helmut Kipp, Rüdiger Pipkorn, Marçal Pastor-Anglada, Chakravarthi Chintalapati, Alexandra Vernaleken, Maike Veyhl-Wichmann, Alexandra Friedrich, Thorsten Keller |
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| Rok vydání: | 2015 |
| Předmět: |
0301 basic medicine
Monosaccharide Transport Proteins Nucleoside transporter Exocytosis Concentrative nucleoside transporter Mice Xenopus laevis 03 medical and health sciences symbols.namesake Sodium-Glucose Transporter 1 Downregulation and upregulation Animals Humans Phosphorylation Mice Knockout Pharmacology biology digestive oral and skin physiology Glucose transporter Membrane Transport Proteins Golgi apparatus Mice Inbred C57BL Glucose 030104 developmental biology Biochemistry biology.protein symbols Molecular Medicine Female Cotransporter Signal Transduction |
| Zdroj: | Molecular Pharmacology. 89:118-132 |
| ISSN: | 1521-0111 0026-895X |
| DOI: | 10.1124/mol.115.101162 |
| Popis: | Cellular uptake adapts rapidly to physiologic demands by changing transporter abundance in the plasma membrane. The human gene RSC1A1 codes for a 67-kDa protein named RS1 that has been shown to induce downregulation of the sodium-D-glucose cotransporter 1 (SGLT1) and of the concentrative nucleoside transporter 1 (CNT1) in the plasma membrane by blocking exocytosis at the Golgi. Injecting RS1 fragments into Xenopus laevis oocytes expressing SGLT1 or CNT1 and measuring the expressed uptake of α-methylglucoside or uridine 1 hour later, we identified a RS1 domain (RS1-Reg) containing multiple predicted phosphorylation sites that is responsible for this post-translational downregulation of SGLT1 and CNT1. Dependent on phosphorylation, RS1-Reg blocks the release of SGLT1-containing vesicles from the Golgi in a glucose-dependent manner or glucose-independent release of CNT1-containing vesicles. We showed that upregulation of SGLT1 in the small intestine after glucose ingestion is promoted by glucose-dependent disinhibition of the RS1-Reg-blocked exocytotic pathway of SGLT1 between meals. Mimicking phosphorylation of RS1-Reg, we obtained a RS1-Reg variant that downregulates SGLT1 in the brush-border membrane at high luminal glucose concentration. Because RS1 mediates short-term regulation of various transporters, we propose that the RS1-Reg-navigated transporter release from Golgi represents a basic regulatory mechanism of general importance, which implies the existence of receptor proteins that recognize different phosphorylated forms of RS1-Reg and of complex transporter-specific sorting in the trans-Golgi. RS1-Reg-derived peptides that downregulate SGLT1 at high intracellular glucose concentrations may be used for downregulation of glucose absorption in small intestine, which has been proposed as strategy for treatment of type 2 diabetes. |
| Databáze: | OpenAIRE |
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