T1R3 homomeric sweet taste receptor regulates adipogenesis through Gαs-mediated microtubules disassembly and Rho activation in 3T3-L1 cells

• Published in: PloS one Vol. 12; no. 5; p. e0176841
• Main Authors: Masubuchi, Yosuke, Nakagawa, Yuko, Medina, Johan, Nagasawa, Masahiro, Kojima, Itaru, Rasenick, Mark M., Inagaki, Takeshi, Shibata, Hiroshi
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 04.05.2017; Public Library of Science (PLoS)
• Subjects: 1-Phosphatidylinositol 3-kinase; 3T3-L1 Cells; Actin; Activation; Adipocytes; Adipogenesis; Adipogenesis - physiology; Adipose tissue; AKT protein; AKT1 protein; AKT2 protein; Amino acids; Animals; Antibodies; Atmosphere; Attenuation; Axonogenesis; Biochemistry; Biology; Biology and Life Sciences; Biophysics; Buffers; Cadmium; Calcium; Carbon dioxide; CCAAT/enhancer-binding protein; Cell culture; Cellular biology; Centrifugation; Centrifuging; Chemical industry; Cholera; Chromogranins - physiology; Cloning; Couples; Culture media; Diabetes mellitus; Differentiation; Endocrinology; Fluorescence Resonance Energy Transfer; Glucose; Growth factors; GTP-Binding Protein alpha Subunits, Gs - physiology; Hypertension; Infections; Inhibition; Inhibitors; Insulin; Insulin resistance; Kinases; Membrane potential; Metabolic disorders; Metabolism; Mice; Microtubules; Microtubules - physiology; Phosphatase; Physiology; Potassium; Preadipocytes; Protein kinase; Proteins; Psychiatry; Public health; Receptors, G-Protein-Coupled - physiology; Research and Analysis Methods; rho GTP-Binding Proteins - metabolism; Rocks; Rodents; Sensitivity; Signal transduction; Social Sciences; Stem cells; Stimulation; Taste; Toxins; Waterborne diseases; United States > US; Illinois; Chicago Illinois
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0176841

We previously reported that 3T3-L1 cells express a functional sweet taste receptor possibly as a T1R3 homomer that is coupled to Gs and negatively regulates adipogenesis by a Gαs-mediated but cAMP-independent mechanism. Here, we show that stimulation of this receptor with sucralose or saccharin induced disassembly of the microtubules in 3T3-L1 preadipocytes, which was attenuated by overexpression of the dominant-negative mutant of Gαs (Gαs-G226A). In contrast, overexpression of the constitutively active mutant of Gαs (Gαs-Q227L) as well as treatment with cholera toxin or isoproterenol but not with forskolin caused disassembly of the microtubules. Sweetener-induced microtubule disassembly was accompanied by activation of RhoA and Rho-associated kinase (ROCK). This was attenuated with by knockdown of GEF-H1, a microtubule-localized guanine nucleotide exchange factor for Rho GTPase. Furthermore, overexpression of the dominant-negative mutant of RhoA (RhoA-T19N) blocked sweetener-induced dephosphorylation of Akt and repression of PPARγ and C/EBPα in the early phase of adipogenic differentiation. These results suggest that the T1R3 homomeric sweet taste receptor negatively regulates adipogenesis through Gαs-mediated microtubule disassembly and consequent activation of the Rho/ROCK pathway.