Protein Palmitoylation in Yeast

描述(申请人提供)：棕榈酰化是几种不同的 脂类修饰作用于靶蛋白并将其锚定在细胞膜上 真核细胞。棕榈酰化长期以来一直被认为是在 指导各种信号蛋白的本地化，包括KEY 癌症中的H-和K-Ras、Src、Lck和Rho等角色到质膜 行动地点。尽管有很长的历史，但关于 这种修饰的酶学-负责的酶活性有 没有被确认身份。我们最近在酿酒酵母上的工作， 表明在棕榈酰化过程中需要锚蛋白重复蛋白Akr1p 和随后的I型酪蛋白激酶Yck 2p的膜定位； 在增量细胞中，Yck 2p不是棕榈酰化的，因此是 错误定位弥漫在整个细胞质，而不是胞浆 薄膜。这项提案的主要目标是确定Akr1p的作用 在棕榈酰化过程中。初步工作表明Akr1p是一种 很有可能是棕榈酰转移酶的酶组分。 这将得到测试。此外，还将提纯含有Akr1p的络合物 从酵母中鉴定与Akr1p合作的蛋白质 棕榈酰化。关于Akr1p的另一个重要事实是，它是最接近 人类同源物是一种蛋白质，它可能在亨廷顿氏症中发挥作用 疾病。因此，这些关于Akr1p在酵母中功能的基础研究可能会 将影响我们对癌症和癌症的疾病过程的理解 亨廷顿氏病。

DESCRIPTION (provided by applicant): Palmitoylation is one of several different lipid modifications that serve to target and anchor proteins to membranes in eukaryotic cells. Palmitoylation has been long-recognized for its role in directing the localization of a variety of signaling proteins, including key players in cancer like H- and K-Ras, Src, Lck, and Rho, to plasma membrane sites of action. Despite the long history, little has been learned regarding the enzymology of this modification - the responsible enzymatic activities have not been identified. Our recent work in the yeast Saccharornyces cerevisiae, indicates that the ankyrin-repeat protein Akr1p is required for palmitoylation and consequent membrane localization of the type I casein kinase, Yck2p; in akr1delta cells, Yck2p is not palmitoylated and as a consequence is mislocalized diffusely throughout the cytoplasm, rather than to the plasma membrane. The major goal of this proposal is to characterize the role of Akr1p in the palmitoylation process. Preliminary work indicates that Akr1p is a strong candidate to be an enzymatic component of the palmitoyl transferase. This will be tested. In addition, Akr1p-containing complexes will be purified from yeast to identify the proteins that collaborate with Akr1p for palmitoylation. Another significant fact regarding Akr1p is that is its closest human homolog is a protein identified for its possible role in Huntington's disease. Thus, these fundamental studies on the function of Akr1p in yeast may well impact our understanding of the disease processes in both cancer and in Huntington's disease.