THE ARF FAMILY AS REGULATORS OF PROTEIN SECRETION AND OTHER CELLULAR PROCESSES

本部分主要研究了 调节性GTP结合蛋白超家族成员的作用; 特别是ADP-核糖基化因子（ARF）家族的成员。 ARF蛋白是一个结构和功能相似的亚家族， 保守的21 kDa GTP结合蛋白。 ARF现已被证明具有 在维护完整性和适当性方面的基本职能 高尔基复合体的功能。 目前的工作重点是 根据序列表征该家族的成员， 蜂窝位置和功能。 我们已经发现，在人类中，这个家族不仅包括 5个以前鉴定的基因产物，但超过10个 结构相关基因及其产物。 我们从事克隆 并对这个新扩大的家族进行测序，开始记录其大小， 功能和重要性的细胞生理学和病理生理学。 在 此外，随着序列信息变得可用，我们继续 产生用于诊断目的的更特异的抗血清， 免疫定位 我们继续开发更简单的真核生物， 酵母，以确定ARF蛋白的新功能。 我们将执行 功能筛选，以确定ARF突变的基因外抑制因子， 努力确定ARF途径的其他组成部分和潜在的 ARF活动的监管机构。 ARF被认为是必要的， 在这种生物体中孢子形成，并且在 这个活动。 酵母中许多突变体的表达也 作为目前正在进行的类似研究的背景， 在培养的哺乳动物细胞中的野生型和突变型ARF蛋白。 一个 详尽的筛选现已确定至少有一个温度敏感 ARF 1的等位基因，其将用于帮助定义ARF的功能， ARF无效细胞的结果和基因外的功能筛选 ARF空小区的抑制器。

This section is involved in studies of the functions and mechanisms of action of members of the superfamily of regulatory GTP binding proteins; particularly the members of the ADP-ribosylation factor (ARF) family. The ARF proteins are a subfamily of structurally and functionally conserved 21 kDa GTP binding proteins. ARF has now been shown to have essential functions in the maintenance of the integrity and proper functioning of the Golgi complex. Current work has focused on characterizing the members of this family with regard to sequence, cellular location, and functions. We have discovered that in humans this family consists not only of the five previously identified gene products, but of more than 10 structurally related genes and their products. We are engaged in cloning and sequencing this newly enlarged family to begin to document its size, functions and importance to cell physiology and pathophysiology. In addition, as sequence information becomes available we continue to produce more specific antisera for diagnostic purposes and immunolocalization. We have continued to exploit simpler eukaryotic organisms, particularly yeast, to identify new functions for ARF proteins. We will perform functional screens to identify extragenic suppressors of ARF mutations in efforts to identify other components of the ARF pathway and potential regulators of ARF activities. ARF was found to be required for sporulation in this organism and ARF2 is much more potent than ARF1 in this activity. Expression of a number of mutants in yeast has also served as background for similar studies now underway to express wild-type and mutant ARF proteins in mammalian cells in culture. An exhaustive screen has now identified at least one temperature sensitive allele of ARF1 which will be used to assist in defining functions of ARF, consequences of an arf null cell, and functional screens for extragenic suppressors of the arf null cell.