Guanine nucleotide exchange factors (GEFs) are proteins or protein domains that activate monomeric GTPases by stimulating the release of guanosine diphosphate (GDP) to allow binding of guanosine triphosphate (GTP). [1] . A variety of unrelated structural domains have been shown to exhibit guanine nucleotide exchange activity.

GEF（GMP exchange factor）是鸟苷酸交换因子，在受体酪氨酸激酶信号转导途径中的Ras蛋白GTP-GDP转换机制中与Ras蛋白结合促使与Ras蛋白结合的GDP释放。 另外，sar1和G蛋白偶联受体也是鸟苷酸交换因子。

The Ras-related GTPase Ran was first isolated as a complex with the chromatin-associated protein RCC1 (Bischoff and Ponstingl, 1991a), which turned out to be its guanine nucleotide exchange factor (GEF; Bischoff and Ponstingl, 1991b). Ran was mainly found in the nucleus and hence was designated the Ras-related nuclear protein. Most other Ras ...

鸟苷酸核苷酸交换因子（GEFs）是一类蛋白或蛋白结构域，能够刺激鸟苷二磷酸（GDP）的释放，并促进与 鸟苷三磷酸 （GTP）的结合，从而激活单体的GTP酶。 鸟苷酸核苷酸交换因子是参与激活一些小GTP酶的蛋白质或蛋白质结构域。 这些小GTP酶在细胞内信号转导中起着分子开关的作用，并有许多下游靶点。 最著名的GTP酶包括 Ras超家族，参与细胞分化和增殖、细胞骨架组织、囊泡运输和核传递等重要细胞过程。 GTP酶在结合GTP时活跃，在结合GDP时不活跃，其活 …

2007年6月1日 · GEFs and GAPs are multidomain proteins that are regulated by extracellular signals and localized cues that control cellular events in time and space. Recent evidence suggests that these proteins may be potential therapeutic targets for developing drugs to treat various diseases, including cancer.

Thus, our work reveals a new route of Ran activation independent of guanine nucleotide exchange factor (GEF), which may account for the hyper-proliferation induced by Ran cancer mutations. Keywords: Small GTPases, Nuclear transport, GTP bias, Activation, Cancer mutations

They found that Ran-bound RCC1 had a stronger chromosome association. Locking RCC1 to Ran, using a mutant version of Ran, immobilized RCC1 on chromosomes. Ran also enhanced RCC1 binding to chromatin in vitro. Only nucleotide exchange, which displaces RCC1 from Ran, released the GEF and RanGTP from chromosomes.

2020年12月30日 · Thus, our work reveals a new route of Ran activation independent of guanine nucleotide exchange factor (GEF), which may account for the hyper-proliferation induced by Ran cancer mutations.

RCC1 is a chromosomal protein that functions as a GEF of the nuclear G protein Ran, which GTPase activity is enhanced by RNA1 located in the cytoplasm. RCC1 has no preference for GTP or GDP-bound Ran, so that GTP-Ran formation in vivo is regulated by relative concentrations of GTP/GDP and regulatory …

RAN is a small GTPase involved in the assembly of microtubules to form mitotic spindles. The protein encoded by this gene is a cytoplasmic guanine nucleotide exchange factor (GEF) that binds beta-tubulin and has GEF activity toward RAN. The encoded protein plays a role in the formation of noncentrosomal microtubules.