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带有GTP及稳定类似物的COPII衣被的动力学

Dynamics of the COPII coat with GTP and stable analogues.

作者信息

Antonny B, Madden D, Hamamoto S, Orci L, Schekman R

机构信息

Department of Molecular and Cell Biology, Howard Hugues Medical Institute, Stanley Hall, University of California, Berkeley, California 94720, USA.

出版信息

Nat Cell Biol. 2001 Jun;3(6):531-7. doi: 10.1038/35078500.

DOI:10.1038/35078500

PMID:11389436

Abstract

We have developed an assay to monitor the assembly of the COPII coat onto liposomes in real time. We show that with Sar1pGTP bound to liposomes, a single round of assembly and disassembly of the COPII coat lasts a few seconds. The two large COPII complexes Sec23/24p and Sec13/31p bind almost instantaneously (in less than 1 s) to Sar1pGTP-doped liposomes. This binding is followed by a fast (less than 10 s) disassembly due to a 10-fold acceleration of the GTPase-activating protein activity of Sec23/24p by the Sec13/31p complex. Experiments with the phosphate analogue BeFx suggest that Sec23/24p provides residues directly involved in GTP hydrolysis on Sar1p.

摘要

我们开发了一种检测方法，可实时监测COPII衣被在脂质体上的组装过程。我们发现，当Sar1pGTP与脂质体结合时，COPII衣被的一轮组装和拆卸过程持续几秒。两种大型COPII复合物Sec23/24p和Sec13/31p几乎瞬间（不到1秒）结合到掺有Sar1pGTP的脂质体上。随后，由于Sec13/31p复合物使Sec23/24p的GTPase激活蛋白活性加速10倍，导致快速（不到10秒）拆卸。使用磷酸盐类似物BeFx进行的实验表明，Sec23/24p提供了直接参与Sar1p上GTP水解的残基。