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）刺激是由质膜中预先存在的 Glut1 转运蛋白的“激活”控制的。我们还发现细胞 Glut 1 的一部分与造口素结合，导致 Glut1 功能受到抑制。最近，我们进行了一项新的观察，即很大一部分 Glut1 以及几乎所有的stomatin 都驻留在富含胆固醇和鞘脂的耐去垢剂膜 (DRM) 中，并且一小部分 Glut1（但不是stomatin）在响应氧化磷酸化抑制而刺激葡萄糖转运时从 DRM 中移出。根据我们的结果，我们提出定位于质膜中的 Glut 1 以两种状态存在，即非活性和活性。该提案将通过以下具体目标进行测试：1) 测试 Stomatin 和 Glutl 的结合导致 Glut1 功能受到抑制的假设，2) 测试 Glutl 在响应氧化磷酸化抑制和 AMP 激活蛋白激酶 (AMPK) 刺激后激活期间从 Stomatin 解离的假设，3) 测试质膜 DRM 中存在的 Glut l 被棕榈酰化以及 Glutl 移出 Stomatin 的假设。该微结构域反映了其去棕榈酰化，并且 4) 在基础和刺激条件下识别 Glutl 结合蛋白。 对导致 Glut l 功能控制的分子事件的理解应该为这种重要转运蛋白的潜在新型生理和药理学调节剂提供新的见解。

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.