REGULATION OF ADP-RIBOSYLATION FACTOR

在细胞运动和细胞器之间转移物质的过程中，生物膜经历不断的重塑，同时保持细胞器的特性，并影响通过有丝分裂进行进展所必需的细胞器的组装和重组。本实验室工作的主要目的是阐明膜重塑的调控机制。Arf家族的GTP结合蛋白的作用一直是我们关注的焦点。我们已经发现了一个针对Arf的GTP酶激活蛋白家族，即ASAP/ACAP家族，它含有PH、Arf、GAP和ANK重复结构域。所有被测试的家族成员在体外都可以作为缺口发挥作用。我们发现，这些蛋白在体外和体内都对特定的ARF具有特异性。此外，这些蛋白质的GAP活性依赖于两种磷脂，磷脂酸和磷脂酰肌醇。不同的ASAP/ACAP家族成员也表现出对特定的磷点肌醇异构体的特异性，一些被磷脂酰肌醇4，5二磷酸激活，另一些被磷脂酰肌醇3，4，5三磷酸激活。PH结构域通过一种以前没有为这个基序描述的机制来调节活性。该家族的两个成员甚至被发现与Src和FAK家族蛋白结合，其中一个被证明调节导致细胞迁移的事件的循环。目前的工作旨在确定该家族其他成员的细胞功能，包括一个成员在恶性转化中的可能作用，该成员位于与神经母细胞瘤相关的染色体基因座上。Z01 BC 07365-03 LBC至LCO

Biological membranes undergo continuous remodeling during cell movement and in processes that transfer material between organelles while maintaining organellar identity and affect the assembly and reassembly of organelles necessary for progression through mitosis. The main objective of the work in this laboratory is to elucidate the mechanisms that regulate the membrane remodeling. The role of the Arf family of GTP-binding proteins has been our focus. We have found a family of GTPase-activating proteins (GAPs) for Arf, the ASAP/ACAP family, which contain PH, Arf GAP and ANK repeat domains. All tested members of the family function as GAPs in vitro. We have found that these proteins are specific for particular Arfs both in vitro and in vivo. In addition, the GAP activity of these proteins is dependent on two phospholipids, phosphatidic acid and a phosphoinositide. The different ASAP/ACAP family members also show specificity for the particular phospoinositide isomer, some being activated by phosphatatidylinositol 4,5 bisphosphate and others activated by phosphatidylinositol 3,4,5 trisphosphate. The PH domain regulates activity by a mechanism not previously described for this motif. Two members of the family have een found to bind Src and FAK family proteins, and one of these has been shown to regulate the cycle of events that result in cell migration. Current work is aimed at identifying the cellular functions of other members of the family, including a possible role of one member, which is found on a chromosomal locus linked to neuroblastoma, in malignant transformation. Z01 BC 07365-03 LBC to LCO