Götzke Hansjörg, Palombo Isolde, Muheim Claudio, Perrody Elsa, Genevaux Pierre, Kudva Renuka, Müller Matthias, Daley Daniel O
From the Center for Biomembrane Research, Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.
Laboratoire de Microbiologie et Génétique Moléculaires, CNRS, and Université Paul Sabatier, 31062 Toulouse, France, and.
J Biol Chem. 2014 Jul 4;289(27):19089-97. doi: 10.1074/jbc.M113.541672. Epub 2014 May 22.
Protein secretion in Gram-negative bacteria is essential for both cell viability and pathogenesis. The vast majority of secreted proteins exit the cytoplasm through a transmembrane conduit called the Sec translocon in a process that is facilitated by ancillary modules, such as SecA, SecDF-YajC, YidC, and PpiD. In this study we have characterized YfgM, a protein with no annotated function. We found it to be a novel ancillary subunit of the Sec translocon as it co-purifies with both PpiD and the SecYEG translocon after immunoprecipitation and blue native/SDS-PAGE. Phenotypic analyses of strains lacking yfgM suggest that its physiological role in the cell overlaps with the periplasmic chaperones SurA and Skp. We, therefore, propose a role for YfgM in mediating the trafficking of proteins from the Sec translocon to the periplasmic chaperone network that contains SurA, Skp, DegP, PpiD, and FkpA.
革兰氏阴性菌中的蛋白质分泌对于细胞活力和致病性都至关重要。绝大多数分泌蛋白通过一种名为Sec转运体的跨膜通道离开细胞质，这一过程由辅助模块（如SecA、SecDF-YajC、YidC和PpiD）促进。在本研究中，我们对YfgM进行了表征，它是一种无注释功能的蛋白质。我们发现它是Sec转运体的一个新型辅助亚基，因为在免疫沉淀和蓝色天然/SDS-PAGE后，它与PpiD和SecYEG转运体共纯化。缺乏yfgM的菌株的表型分析表明，其在细胞中的生理作用与周质伴侣蛋白SurA和Skp重叠。因此，我们提出YfgM在介导蛋白质从Sec转运体到包含SurA、Skp、DegP、PpiD和FkpA的周质伴侣蛋白网络的运输中发挥作用。
