REGULATION OF THE CHOLINERGIC COTRANSPORTER--MOLECULAR ASPECTS

高亲和力的胆碱转运系统是支持胆碱能传递的重要因素。这种转运体对钠（ChCoT）有强制性要求，并共同运输钠（ChCoT）。这种共转运蛋白的一个重要特征是其转运活性可以调节神经元的活动。乙酰胆碱的调节在生理上是非常重要的。负责ChCoT生理调节的精确分子机制尚不清楚。我们提出了一个由三部分组成的假说来解释ChCoT的这种生理调节。我们提出的假设的第一部分是胆碱能突触中胆碱运输速率的变化反映了质膜中活性chcot数量的平行变化。该假说的第二部分是，端（质）膜的chcot数量由含有chcot的载体囊泡的调控和组成循环决定，端（质）膜的chcot数量由含有chcot的载体囊泡在细胞质和质膜之间的胞质室之间的调控和组成循环决定。为了检验这个三部分假设，我们将完成以下一组具体目标。建立循环ChCoT的囊泡性质，并表征参与这种循环的分子机制。2. 确定蛋白激酶C （PKC）参与ChCoT囊泡循环的分子机制。3. 分离、纯化并开始表征作为可招募的chcot池的细胞质来源的载体囊泡。

A high affinity choline transport system has been characterized as an essential element in supporting of cholinergic transmission. This transporter has a obligatory requirement for, and co-transports sodium (ChCoT). An important feature of this co-transporter is that the transport activity appears to adjust neuronal activity. The adjustment of ACh to be met and thus is physiologically highly significant. The precise molecular mechanisms responsible for this physiological regulation of the ChCoT are not well understood. We propose a three part hypothesis to explain this physiological regulation of the ChCoT. The first part of our proposed hypothesis is that the changes in the transport rates of choline at the cholinergic synapse reflect parallel changes in the number of active ChCoTs in the plasma membrane. The second part of the hypothesis is that the number of ChCoTs is the terminal (plasma) membrane in determined by the regulated and constitutive cycling of carrier vesicles containing ChCoTs is the terminal (plasma) membrane in determined by the regulated and constitutive cycling of carrier vesicles containing ChCoTs between a cytosolic compartment between the cytosol and the plasma membrane is under the influence of intracellular messengers. To test this three part hypothesis we will accomplish the following set of Specific Aims. 1. Establish the vesicular nature of the cycling ChCoT and characterize the molecular mechanisms involved in this cycling. 2. Determine the molecular mechanism of protein kinase C (PKC) involvement in the cycling of ChCoT vesicles. 3. Isolate,, purify and initiate the characterization of the carrier vesicle that serves as the cytoplasmic source of the recruitable pool of ChCoTs.