title: 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.
abstract: 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.
authors.affiliation: Institute of Anatomy and Cell Biology, University Würzburg, Germany (M.V., A.V., H.Ki, V.G., C.C., H.Ko.); Department of Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Germany (S.S., J.G.); Leibnitz Institute for Interactive Materials, Rheinisch-Westfälische Technische Hochschule, University Aachen, Germany (S.S.); German Cancer Research Center, Heidelberg, Germany (R.P.); Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University Barcelona & CIBER EHD, Barcelona, Spain (M.P.); and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Würzburg, Germany (A.F., T.K., H.Ko).
authors.forename: Maike
authors.initials: M
authors.lastname: Veyhl-Wichmann
authors.affiliation: Institute of Anatomy and Cell Biology, University Würzburg, Germany (M.V., A.V., H.Ki, V.G., C.C., H.Ko.); Department of Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Germany (S.S., J.G.); Leibnitz Institute for Interactive Materials, Rheinisch-Westfälische Technische Hochschule, University Aachen, Germany (S.S.); German Cancer Research Center, Heidelberg, Germany (R.P.); Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University Barcelona & CIBER EHD, Barcelona, Spain (M.P.); and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Würzburg, Germany (A.F., T.K., H.Ko).
authors.forename: Alexandra
authors.initials: A
authors.lastname: Friedrich
authors.affiliation: Institute of Anatomy and Cell Biology, University Würzburg, Germany (M.V., A.V., H.Ki, V.G., C.C., H.Ko.); Department of Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Germany (S.S., J.G.); Leibnitz Institute for Interactive Materials, Rheinisch-Westfälische Technische Hochschule, University Aachen, Germany (S.S.); German Cancer Research Center, Heidelberg, Germany (R.P.); Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University Barcelona & CIBER EHD, Barcelona, Spain (M.P.); and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Würzburg, Germany (A.F., T.K., H.Ko).
authors.forename: Alexandra
authors.initials: A
authors.lastname: Vernaleken
authors.affiliation: Institute of Anatomy and Cell Biology, University Würzburg, Germany (M.V., A.V., H.Ki, V.G., C.C., H.Ko.); Department of Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Germany (S.S., J.G.); Leibnitz Institute for Interactive Materials, Rheinisch-Westfälische Technische Hochschule, University Aachen, Germany (S.S.); German Cancer Research Center, Heidelberg, Germany (R.P.); Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University Barcelona & CIBER EHD, Barcelona, Spain (M.P.); and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Würzburg, Germany (A.F., T.K., H.Ko).
authors.forename: Smriti
authors.initials: S
authors.lastname: Singh
authors.affiliation: Institute of Anatomy and Cell Biology, University Würzburg, Germany (M.V., A.V., H.Ki, V.G., C.C., H.Ko.); Department of Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Germany (S.S., J.G.); Leibnitz Institute for Interactive Materials, Rheinisch-Westfälische Technische Hochschule, University Aachen, Germany (S.S.); German Cancer Research Center, Heidelberg, Germany (R.P.); Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University Barcelona & CIBER EHD, Barcelona, Spain (M.P.); and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Würzburg, Germany (A.F., T.K., H.Ko).
authors.forename: Helmut
authors.initials: H
authors.lastname: Kipp
authors.affiliation: Institute of Anatomy and Cell Biology, University Würzburg, Germany (M.V., A.V., H.Ki, V.G., C.C., H.Ko.); Department of Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Germany (S.S., J.G.); Leibnitz Institute for Interactive Materials, Rheinisch-Westfälische Technische Hochschule, University Aachen, Germany (S.S.); German Cancer Research Center, Heidelberg, Germany (R.P.); Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University Barcelona & CIBER EHD, Barcelona, Spain (M.P.); and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Würzburg, Germany (A.F., T.K., H.Ko).
authors.forename: Valentin
authors.initials: V
authors.lastname: Gorboulev
authors.affiliation: Institute of Anatomy and Cell Biology, University Würzburg, Germany (M.V., A.V., H.Ki, V.G., C.C., H.Ko.); Department of Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Germany (S.S., J.G.); Leibnitz Institute for Interactive Materials, Rheinisch-Westfälische Technische Hochschule, University Aachen, Germany (S.S.); German Cancer Research Center, Heidelberg, Germany (R.P.); Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University Barcelona & CIBER EHD, Barcelona, Spain (M.P.); and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Würzburg, Germany (A.F., T.K., H.Ko).
authors.forename: Thorsten
authors.initials: T
authors.lastname: Keller
authors.affiliation: Institute of Anatomy and Cell Biology, University Würzburg, Germany (M.V., A.V., H.Ki, V.G., C.C., H.Ko.); Department of Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Germany (S.S., J.G.); Leibnitz Institute for Interactive Materials, Rheinisch-Westfälische Technische Hochschule, University Aachen, Germany (S.S.); German Cancer Research Center, Heidelberg, Germany (R.P.); Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University Barcelona & CIBER EHD, Barcelona, Spain (M.P.); and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Würzburg, Germany (A.F., T.K., H.Ko).
authors.forename: Chakravarthi
authors.initials: C
authors.lastname: Chintalapati
authors.affiliation: Institute of Anatomy and Cell Biology, University Würzburg, Germany (M.V., A.V., H.Ki, V.G., C.C., H.Ko.); Department of Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Germany (S.S., J.G.); Leibnitz Institute for Interactive Materials, Rheinisch-Westfälische Technische Hochschule, University Aachen, Germany (S.S.); German Cancer Research Center, Heidelberg, Germany (R.P.); Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University Barcelona & CIBER EHD, Barcelona, Spain (M.P.); and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Würzburg, Germany (A.F., T.K., H.Ko).
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Pipkorn
authors.affiliation: Institute of Anatomy and Cell Biology, University Würzburg, Germany (M.V., A.V., H.Ki, V.G., C.C., H.Ko.); Department of Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Germany (S.S., J.G.); Leibnitz Institute for Interactive Materials, Rheinisch-Westfälische Technische Hochschule, University Aachen, Germany (S.S.); German Cancer Research Center, Heidelberg, Germany (R.P.); Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University Barcelona & CIBER EHD, Barcelona, Spain (M.P.); and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Würzburg, Germany (A.F., T.K., H.Ko).
authors.forename: Marçal
authors.initials: M
authors.lastname: Pastor-Anglada
authors.affiliation: Institute of Anatomy and Cell Biology, University Würzburg, Germany (M.V., A.V., H.Ki, V.G., C.C., H.Ko.); Department of Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Germany (S.S., J.G.); Leibnitz Institute for Interactive Materials, Rheinisch-Westfälische Technische Hochschule, University Aachen, Germany (S.S.); German Cancer Research Center, Heidelberg, Germany (R.P.); Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University Barcelona & CIBER EHD, Barcelona, Spain (M.P.); and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Würzburg, Germany (A.F., T.K., H.Ko).
authors.forename: Jürgen
authors.initials: J
authors.lastname: Groll
authors.affiliation: Institute of Anatomy and Cell Biology, University Würzburg, Germany (M.V., A.V., H.Ki, V.G., C.C., H.Ko.); Department of Functional Materials in Medicine and Dentistry, University Hospital Würzburg, Germany (S.S., J.G.); Leibnitz Institute for Interactive Materials, Rheinisch-Westfälische Technische Hochschule, University Aachen, Germany (S.S.); German Cancer Research Center, Heidelberg, Germany (R.P.); Department of Biochemistry and Molecular Biology, Institute of Biomedicine, University Barcelona & CIBER EHD, Barcelona, Spain (M.P.); and Department of Molecular Plant Physiology and Biophysics, Julius-von-Sachs-Institute, University Würzburg, Germany (A.F., T.K., H.Ko) Hermann@koepsell.de.
authors.forename: Hermann
authors.initials: H
authors.lastname: Koepsell
mesh_terms: D000818:Animals; D005089:Exocytosis / Q000502:physiology*; D005260:Female; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D026901:Membrane Transport Proteins / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D010766:Phosphorylation / Q000502:physiology; D015398:Signal Transduction / Q000502:physiology*; D051269:Sodium-Glucose Transporter 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014982:Xenopus laevis
chemical_list: D026901:Membrane Transport Proteins; D009004:Monosaccharide Transport Proteins; C101014:RSC1A1 protein, human; C495674:SLC5A1 protein, human; D051269:Sodium-Glucose Transporter 1; C065171:cif nucleoside transporter; D005947:Glucose