Protein Folding in the Eukaryotic Cytosol

描述（由申请人提供）：蛋白质折叠是从基因型到表型信息流动的关键步骤。错误折叠是几种疾病的发病机制的基础，特别是那些涉及神经变性的疾病。我们已经发现了许多促进小管蛋白、肌动蛋白和其他细胞质蛋白折叠的伴侣蛋白。这些伴侣蛋白是前折叠蛋白，II型伴侣蛋白CCT和五种称为辅助因子A-E的微管蛋白特异性伴侣蛋白。这些辅因子a)共同起着微管蛋白二聚体制造机器的作用，b)刺激天然微管蛋白异源二聚体的GTPase活性，将gtp -微管蛋白转化为gdp -微管蛋白。1)我们将通过中和培养细胞中的辅因子功能来验证后一反应调节微管动力学的假设，并分析其对微管细胞骨架的影响。2)我们已经证明，被称为Aris （adp -核糖基化因子样蛋白）的小gtpase家族的成员与微管蛋白和/或微管蛋白特异性伴侣蛋白相互作用。因此，我们建议研究Anl家族成员对辅助因子和微管功能的调节。3)我们将在体外和体外研究两种辅助因子相关的人类蛋白RP2和like的功能。编码RP2基因的突变导致视网膜色素变性；like的功能是未知的。4)我们将分离和表征McKusick-Kaufman综合征（MKKS）蛋白，该蛋白被预测为一种新的与cct相关的II型伴侣蛋白，并研究a)其推测的atp酶和伴侣蛋白活性，以及b)其结合的靶蛋白范围。5)我们将验证CCT的主要功能是打开某些新合成蛋白质的核苷酸结合口袋，使其与核苷酸结合的假设。

DESCRIPTION (provided by applicant): Protein folding is a critical step in the flow of information from genotype to phenotype. Misfolding underlies the pathogenesis of several diseases, particularly those involving neurodegeneration. We have discovered many of the chaperone proteins that facilitate the folding of tubulins, actins and other cytosolic proteins. These chaperones are prefoldin, the Type II chaperonin CCT, and five tubulin-specific chaperone proteins termed cofactors A-E. The cofactors a) function together as a tubulin dimer-making machine, and b) stimulate the GTPase activity of the native tubulin heterodimer, converting GTP-tubulin to GDP-tubulin. 1) We will test the hypothesis that the latter reaction regulates microtubule dynamics by neutralizing cofactor function in cultured cells and assaying the effect on the microtubule cytoskeleton. 2) We have shown that members of a family of small GTPases termed Aris (ADP-ribosylation factor-like proteins) interact with tubulin and/or tubulin-specific chaperones. We therefore propose to examine the regulation of cofactor and microtubute function by members of the Anl family. 3) We will investigate the function of two cofactor-related human proteins, RP2 and E-like, in vitro and in vitro. Mutations in the gene encoding RP2 cause retinitis pigmentosa; the function of E-like is unknown. 4) We will isolate and charactenize the McKusick-Kaufman Syndrome (MKKS) protein, which is pnedicted to be a new CCT-related Type II chaperonin, and study a) its presumptive ATPase and chaperone activities, and b) the range of target proteins to which it binds. 5) We will test the hypothesis that that the main function of CCT is to open up the nucleotidebinding pocket of certain newly synthesized proteins, so as to allow them to bind nucleotide.