信号介导的核蛋白输出对结合鸟苷三磷酸的 Ran 的需求。

Requirement of guanosine triphosphate-bound ran for signal-mediated nuclear protein export.

作者信息

Richards S A, Carey K L, Macara I G

机构信息

Department of Pathology, University of Vermont, Burlington, VT 05405, USA.

出版信息

Science. 1997 Jun 20;276(5320):1842-4. doi: 10.1126/science.276.5320.1842.

DOI:10.1126/science.276.5320.1842

PMID:9188526

Abstract

A leucine-rich nuclear export signal (NES) allows rapid export of proteins from cell nuclei. Microinjection studies revealed a role for the guanosine triphosphatase (GTPase) Ran in NES-mediated export. Nuclear injection of a Ran mutant (Thr24 --> Asn) blocked protein export but not import, whereas depletion of the Ran nucleotide exchange factor RCC1 blocked protein import but not export. However, injection of Ran GTPase-activating protein (RanGAP) into RCC1-depleted cell nuclei inhibited export. Coinjection with Ran mutants insensitive to RanGAP prevented this inhibition. Therefore, NES-mediated protein export appears to require a Ran-GTP complex but does not require Ran-dependent GTP hydrolysis.

摘要

富含亮氨酸的核输出信号（NES）可使蛋白质快速从细胞核输出。显微注射研究揭示了鸟苷三磷酸酶（GTPase）Ran在NES介导的输出过程中发挥作用。对Ran突变体（Thr24→Asn）进行核注射可阻断蛋白质输出，但不影响蛋白质输入，而Ran核苷酸交换因子RCC1的缺失则会阻断蛋白质输入，但不影响蛋白质输出。然而，将Ran GTP酶激活蛋白（RanGAP）注射到RCC1缺失的细胞核中会抑制输出。与对RanGAP不敏感的Ran突变体共同注射可防止这种抑制作用。因此，NES介导的蛋白质输出似乎需要Ran-GTP复合物，但不需要Ran依赖性GTP水解。