Protein interactions and regulation of EscA in enterohemorrhagic E. coli.
Infections caused by enterohemorrhagic Escherichia coli (EHEC) can lead to diarrhea with abdominal cramps and sometimes are complicated by severe hemolytic uremic syndrome. EHEC secretes effector proteins into host cells through a type III secretion system that is composed of proteins encoded by a chromosomal island, locus for the enterocyte effacement (LEE). EspA is the major component of the filamentous structure connecting the bacteria and the host's cells. Synthesis and secretion of EspA must be carefully controlled since the protein is prone to polymerize. CesAB, CesA2, and EscL have been identified as being able to interact with EspA. Furthermore, the intracellular level of EspA declines when cesAB, cesA2, and escL are individually deleted. Here, we report a LEE gene named l0033, which also affects the intracellular level of EspA. We renamed l0033 as escA since its counterpart in enteropathogenic E. coli has been recently described. Similar to CesAB, EscL, and CesA2, EscA interacts with EspA and enhances the protein stability of EspA. However, EscA is also able to interact with inner membrane-associated EscL, CesA2, and EscN, but not with cytoplasmic CesAB. In terms of gene organizations, escA locates in LEE3. Expression of EscA is faithfully regulated via Mpc, the first gene product of LEE3. Since Mpc is tightly regulated to low level, we suggest that EscA is highly synchronized and critical to the process of escorting EspA to its final destination.
Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China.
Ching-Nan
CN
Lin
Institute of Biochemistry and Molecular Biology, National Yang-Ming University, Taipei, Taiwan, Republic of China ; Taiwan International Graduate Program in Molecular Medicine, Academia Sinica, Taipei, Taiwan, Republic of China.
Wei-Sheng W
WS
Sun
Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China.
Hui-Yin
HY
Lu
Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China.
Swee-Chuan
SC
Ng
Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China.
Ying-Shu
YS
Liao
Institute of Microbiology and Immunology, National Yang-Ming University, Taipei, Taiwan, Republic of China ; Taiwan International Graduate Program in Molecular Medicine, Academia Sinica, Taipei, Taiwan, Republic of China.
Wan-Jr
WJ
Syu
D058947:Bacterial Secretion Systems; D002846:Chromatography, Affinity; D019453:Escherichia coli O157 / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000378:metabolism*; D017353:Gene Deletion; D008954:Models, Biological; D011485:Protein Binding; D060066:Protein Interaction Maps; D055550:Protein Stability
D058947:Bacterial Secretion Systems; D029968:Escherichia coli Proteins