T1R3 homomeric sweet taste receptor regulates adipogenesis through Gαs-mediated microtubules disassembly and Rho activation in 3T3-L1 cells.
T1R3 homomeric sweet taste receptor regulates adipogenesis through Gαs-mediated microtubules disassembly and Rho activation in 3T3-L1 cells.
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DOI：
10.1371/journal.pone.0176841
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发表时间：
2017
期刊：
影响因子：
3.7
通讯作者：
Shibata H
中科院分区：
文献类型：
--
作者：
Masubuchi Y;Nakagawa Y;Medina J;Nagasawa M;Kojima I;Rasenick MM;Inagaki T;Shibata H
我们以前报道过3 T3-L1细胞表达一种功能性甜味受体，可能是一种T1 R3同聚体，它与Gs偶联，并通过Gα s介导但不依赖cAMP的机制负调控脂肪生成。在这里，我们表明，该受体的刺激与三氯蔗糖或糖精诱导的微管在3 T3-L1前脂肪细胞的解体，这是减弱的Gαs（Gα s-G226 A）的显性负突变过表达。相反，Gαs组成型活性突变体（Gα s-Q227 L）的过表达以及霍乱毒素或异丙肾上腺素处理（而不是毛喉素处理）引起微管解体。甜味剂诱导的微管解体伴随着RhoA和Rho相关激酶（ROCK）的激活。通过敲低GEF-H1（一种Rho GT3的微管定位鸟嘌呤核苷酸交换因子）可减弱这种作用。此外，RhoA显性失活突变体（RhoA-T19 N）的过表达阻断了甜味剂诱导的Akt去磷酸化以及在成脂分化早期对PPARγ和C/EBPα的抑制。这些结果表明，T1 R3同源甜味受体通过Gα s介导的微管分解和随后的Rho/ROCK通路的激活来负性调节脂肪形成。
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.