Regulation of Glut 1 Function

描述（由申请人提供）：Glut1葡萄糖转运蛋白是一种完整的质膜蛋白，在许多细胞和组织中表达。我们发现Glut - 1介导的葡萄糖转运的急性（1-2小时）刺激是由质膜中存在的Glut1转运蛋白的“激活”控制的。我们还发现一部分细胞Glut1与stomatin结合，导致Glut1功能的抑制。最近，我们进行了新的观察，发现谷氨酸1的很大一部分，以及几乎所有的口蛋白，都存在于富含胆固醇和鞘脂的抗洗涤剂膜（DRMs）中，并且一部分谷氨酸1（但不是口蛋白）在氧化磷酸化抑制的刺激下，在葡萄糖运输的刺激下，从DRMs中移出。基于我们的研究结果，我们提出定位于质膜的Glut - 1存在两种状态，即非活性状态和活性状态。这一建议将通过以下具体目标进行测试：1)验证stomatin和Glutl关联导致Glut1功能抑制的假说；2)验证Glutl在氧化磷酸化抑制和amp活化蛋白激酶（AMPK）刺激的激活过程中与stomatin分离的假说；3)验证质膜DRMs中Glut - 1被棕榈酰化的假说，以及Glutl从这个微结构域移出反映其去棕榈酰化的假说。4)在基础和刺激条件下鉴定谷氨酸结合蛋白。对导致Glut - 1功能控制的分子事件的理解，将为这种重要转运体潜在的新的生理和药理调节提供新的见解。

DESCRIPTION (provided by applicant): Glut1 glucose transporter is an integral plasma membrane protein that is expressed in many cells and tissues. We have found that the acute (1-2 h) stimulation of Glut 1-mediated glucose transport is controlled by "activation "' of Glut1 transporters pre-existing in the plasma membrane. We have also found that a fraction of cell Glut 1 is bound by stomatin resulting in inhibition of Glut1 function. More recently we have made the novel observation that a significant fraction of Glut1, and virtually all of stomatin, reside in the cholesterol- and sphingolipid-rich detergent-resistant membranes (DRMs), and that a fraction of Glut l (but not stomatin) moves out of the DRMs upon stimulation of glucose transport in response to inhibition of oxidative phosphorylation. Based on our results we propose that Glut 1 localized in the plasma membrane exists in two-states, namely inactive and active. This proposal will be tested by the following Specific Aims: 1) Test the hypothesis that association of stomatin and Glutl leads to inhibition of Glut1 function, 2) Test the hypothesis that Glutl dissociates from stomatin during its activation in response to inhibition of oxidative phosphorylation and following stimulation of AMP-activated protein kinase (AMPK), 3) Test the hypothesis that Glut l present in plasma membrane DRMs are palmitoylated and the movement of Glutl out of this micro-domain reflects its de-palmitoylation, and 4) Identify Glutl-binding proteins under basal and stimulated conditions. An understanding of the molecular events leading to control of Glut l function should provide new insights into potentially novel physiological and pharmacological regulators of this important transporter.