Flavobacterium johnsoniae PorV Is Required for Secretion of a Subset of Proteins Targeted to the Type IX Secretion System
Flavobacterium johnsoniae PorV Is Required for Secretion of a Subset of Proteins Targeted to the Type IX Secretion System
复制标题
DOI：
10.1128/jb.02085-14
复制
发表时间：
2015-01-01
影响因子：
3.2
通讯作者：
McBride, Mark J.
中科院分区：
文献类型：
--
作者：
Kharade, Sampada S.;McBride, Mark J.
约氏黄杆菌具有滑动运动性，并能分解许多多糖，包括几丁质。一种新的蛋白质分泌系统，IX型分泌系统（T9SS），需要滑行和几丁质利用。T9SS分泌细胞表面运动粘附素SprB和RemA以及几丁质酶ChiA。参与T9SS分泌的蛋白质包括GldK、GldL、GldM、GldN、SprA、SprE和SprT。牙龈卟啉单胞菌具有其T9SS分泌牙龈菌蛋白酶毒力因子所需的每一种的直向同源物。牙龈卟啉单胞菌porU和porV也与T9SS介导的分泌有关，而F. Johnsoniae具有这些的直系同源物。F.构建约氏菌porU和porV以确定它们是否在分泌中起作用。porV缺失突变体的细胞缺乏几丁质利用，不能分泌ChiA。它们也缺乏运动粘附素RemA的分泌，但保留了分泌SprB的能力。SprB参与滑行运动，并需要在琼脂上形成铺展菌落，而porV突变体表现出滑行运动，并形成铺展菌落。然而，porV突变体部分缺乏附着到玻璃，显然是因为没有RemA和细胞表面上的其他粘附素。porV突变体似乎也缺乏许多其他蛋白质的分泌，这些蛋白质具有与靶向T9SS相关的羧基末端结构域。ChiA、RemA或SprB的分泌不需要PorU，这表明它在F.约翰逊氏菌T9SS.
Flavobacterium johnsoniae exhibits gliding motility and digests many polysaccharides, including chitin. A novel protein secretion system, the type IX secretion system (T9SS), is required for gliding and chitin utilization. The T9SS secretes the cell surface motility adhesins SprB and RemA and the chitinase ChiA. Proteins involved in secretion by the T9SS include GldK, GldL, GldM, GldN, SprA, SprE, and SprT. Porphyromonas gingivalis has orthologs for each of these that are required for secretion of gingipain protease virulence factors by its T9SS. P. gingivalis porU and porV have also been linked to T9SS-mediated secretion, and F. johnsoniae has orthologs of these. Mutations in F. johnsoniae porU and porV were constructed to determine if they function in secretion. Cells of a porV deletion mutant were deficient in chitin utilization and failed to secrete ChiA. They were also deficient in secretion of the motility adhesin RemA but retained the ability to secrete SprB. SprB is involved in gliding motility and is needed for formation of spreading colonies on agar, and the porV mutant exhibited gliding motility and formed spreading colonies. However, the porV mutant was partially deficient in attachment to glass, apparently because of the absence of RemA and other adhesins on the cell surface. The porV mutant also appeared to be deficient in secretion of numerous other proteins that have carboxy-terminal domains associated with targeting to the T9SS. PorU was not required for secretion of ChiA, RemA, or SprB, indicating that it does not play an essential role in the F. johnsoniae T9SS.