Composition and Biophysical Properties of the Sorting Platform Pods in the Shigella Type III Secretion System.
Composition and Biophysical Properties of the Sorting Platform Pods in the Shigella Type III Secretion System.
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DOI：
10.3389/fcimb.2021.682635
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发表时间：
2021
影响因子：
5.7
通讯作者：
Picking WD
中科院分区：
文献类型：
--
作者：
Tachiyama S;Skaar R;Chang Y;Carroll BL;Muthuramalingam M;Whittier SK;Barta ML;Picking WL;Liu J;Picking WD
福氏志贺氏菌是细菌性痢疾(志贺氏病)的病原体，它使用III型分泌系统(T3SS)作为主要毒力因子。T3SS注射剂将效应蛋白输送到宿主细胞中，以促进进入并创造一个重要的细胞内利基。注射体的细胞质分选平台(SP)是有助于底物选择和促进分泌的关键组件。SP由寡聚体Spa33组成，通过MxiK与基底体相连，通过MxiN与Spa47 ATPase相连。豆荚含有Spa33的异源三聚体，其中一个全长拷贝与两个C-末端结构域(Spa33C)拷贝相关联。Spa33C的结构是已知的，但原位豆荚的准确组成和结构仍然难以捉摸。我们在这里证明了重组野生型Spa33可以制备成与MxiK和MxiN形成不同稳定络合物的杂三聚体。在双杂交分析中，Spa33复合体与这些蛋白质的结合是通过全长Spa33组分进行的。此外，这些络合物都具有不同的生物物理性质。基于这些性质、新的高分辨率冷冻电子断层扫描数据以及Spa33和鞭毛薄膜-flin复合体之间的结构相似性，我们提供了SP豆荚中Spa33杂三聚体的初步模型。根据这些发现以及耶尔森氏菌和沙门氏菌T3SS中SP界面和动力学的演变模型，我们提出了一个SP功能模型，在该模型中，两个不同的复合体在SP的背景下聚集在一起，在T3SS分泌底物的募集过程中有助于形成完整的豆荚结构。
Shigella flexneri, causative agent of bacillary dysentery (shigellosis), uses a type III secretion system (T3SS) as its primary virulence factor. The T3SS injectisome delivers effector proteins into host cells to promote entry and create an important intracellular niche. The injectisome’s cytoplasmic sorting platform (SP) is a critical assembly that contributes to substrate selection and energizing secretion. The SP consists of oligomeric Spa33 “pods” that associate with the basal body via MxiK and connect to the Spa47 ATPase via MxiN. The pods contain heterotrimers of Spa33 with one full-length copy associated with two copies of a C-terminal domain (Spa33C). The structure of Spa33C is known, but the precise makeup and structure of the pods in situ remains elusive. We show here that recombinant wild-type Spa33 can be prepared as a heterotrimer that forms distinct stable complexes with MxiK and MxiN. In two-hybrid analyses, association of the Spa33 complex with these proteins occurs via the full-length Spa33 component. Furthermore, these complexes each have distinct biophysical properties. Based on these properties, new high-resolution cryo-electron tomography data and architectural similarities between the Spa33 and flagellar FliM-FliN complexes, we provide a preliminary model of the Spa33 heterotrimers within the SP pods. From these findings and evolving models of SP interfaces and dynamics in the Yersinia and Salmonella T3SS, we suggest a model for SP function in which two distinct complexes come together within the context of the SP to contribute to form the complete pod structures during the recruitment of T3SS secretion substrates.
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影响因子：
7.7
作者：
Carroll BL;Nishikino T;Guo W;Zhu S;Kojima S;Homma M;Liu J
通讯作者：
Liu J
DOI：
10.1083/jcb.147.3.683
发表时间：
1999-11-01
期刊：
The Journal of cell biology
影响因子：
--
作者：
Blocker A;Gounon P;Larquet E;Niebuhr K;Cabiaux V;Parsot C;Sansonetti P
通讯作者：
Sansonetti P
DOI：
10.1073/pnas.1411610112
发表时间：
2015-01-27
影响因子：
11.1
作者：
Hu, Bo;Morado, Dustin R.;Liu, Jun
通讯作者：
Liu, Jun
影响因子：
1.6
作者：
Geisbrecht, BV;Bouyain, S;Pop, M
通讯作者：
Pop, M
影响因子：
3
作者：
Kremer, JR;Mastronarde, DN;McIntosh, JR
通讯作者：
McIntosh, JR