Requirement of essential Pbp2x and GpsB for septal ring closure in Streptococcus pneumoniae D39.
Requirement of essential Pbp2x and GpsB for septal ring closure in Streptococcus pneumoniae D39.
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DOI：
10.1111/mmi.12408
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发表时间：
2013-12
影响因子：
3.6
通讯作者：
Winkler ME
中科院分区：
文献类型：
--
作者：
Land AD;Tsui HC;Kocaoglu O;Vella SA;Shaw SL;Keen SK;Sham LT;Carlson EE;Winkler ME
Bacterial cell shapes are manifestations of programs carried out by multi-protein machines that synthesize and remodel the peptidoglycan (PG) mesh and other polymers surrounding cells. GpsB protein is conserved in low-GC Gram-positive bacteria and is not essential in rod-shaped Bacillus subtilis, where it plays a role in shuttling penicillin binding proteins (PBPs) between septal side-wall sites of PG synthesis. In contrast, we report here that GpsB is essential in ellipsoid-shaped, ovococcal Streptococcus pneumoniae (pneumococcus), and depletion of GpsB leads to formation of elongated, enlarged cells containing unsegregated nucleoids and multiple, unconstricted rings of fluorescent-vancomycin staining, and eventual lysis. These phenotypes are similar to those caused by selective inhibition of Pbp2x by methicillin that prevents septal PG synthesis. Dual-protein 2D and 3D-SIM (structured illumination) immunofluorescence microscopy (IFM) showed that GpsB and FtsZ have overlapping, but not identical, patterns of localization during cell division and that multiple, unconstricted rings of division proteins FtsZ, Pbp2x, Pbp1a, and MreC are in elongated cells depleted of GpsB. These patterns suggest that GpsB, like Pbp2x, mediates septal ring closure. This first dual-protein 3D-SIM IFM analysis also revealed separate positioning of Pbp2x and Pbp1a in constricting septa, consistent with two separable PG synthesis machines.
