Sugar sensing in the unicellular red alga Galdieria sulphuraria

最近，人们发现了一种新的酵母糖传感途径。它通过G蛋白偶联受体系统(GPCR)和糖的磷酸化激活腺苷环化酶，从而在葡萄糖刺激下产生cAMP信号。这一信号级联可能代表了一种确定可发酵糖胞外浓度的方法。本项目的主要目的是分析GPCR系统激活腺苷环化酶所需的异常葡萄糖磷酸化。这将通过两种方式完成。首先，我们将研究一种已知作用于酵母中cAMP途径和哺乳动物中葡萄糖磷酸化的蛋白磷酸酶的可能参与。其次，我们将尝试分离GPCR系统激活cAMP合成不依赖于葡萄糖磷酸化的突变体。由于在真核细胞中，葡萄糖磷酸化对葡萄糖传感的要求几乎是普遍的，所以该结果可能具有普遍的适用性。

Recently, a new pathway for sugar sensing in yeast has been found. It is involved in the generation of a cAMP signal in response to a glucose stimulus due to activation of the adenylate cyclase by a G-protein coupled receptor system (GPCR) and sugar phosphorylation. This signalling cascade may represent a way to determine the extracellular concentration of fermentable sugars. The main object of this project is to analyse the unusual glucose phosphorylation requirement for activation of adenylate cyclase by the GPCR system. This will be done in two ways. First we will investigate the possible involvement of a protein phosphatase known to act on the cAMP pathway in yeast and on glucose phosphorylation in mammals. Second we will try to isolate mutants in which the activation of cAMP synthesis by the GPCR system is independent of glucose phosphyorylation. Because of the near universal requirement of glucose phosphorylation for glucose sensing in eukaryotic cells the results might have general applicability.