Truncated type IV pilin PilA¹⁰⁸ activates the intramembrane protease AlgW to cleave MucA and PilA¹⁰⁸ itself in vitro

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• 作者：Ronghui Li ; Ryan T. Withers ; Jingcheng Dai ; Jing Ruan ; Wei Li…
• 关键词：Mucoid conversion ; Pseudomonas aeruginosa ; AlgW ; Truncated type IV pilin
• 刊名：Archives of Microbiology
• 出版年：2016
• 出版时间：November 2016
• 年：2016
• 卷：198
• 期：9
• 页码：885-892
• 全文大小：1,222 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Microbiology
  Microbial Ecology
  Biochemistry
  Cell Biology
  Biotechnology
  Ecology
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-072X
• 卷排序：198

文摘

For alginate production in Pseudomonas aeruginosa, the intramembrane protease AlgW must be activated to cleave the periplasmic domain of anti-sigma factor MucA for release of the sequestered ECF sigma factor AlgU. Previously, we reported that three tandem point mutations in the pilA gene, resulting in a truncated type IV pilin termed PilA108 with a C-terminal motif of phenylalanine–threonine–phenylalanine (FTF), induced mucoidy in strain PAO579. In this study, we purified PilA108 protein and synthesized a peptide ‘SGAGDITFTF’ corresponding to C-terminus of PilA108 and found they both caused the degradation of MucA by AlgW. Interestingly, AlgW could also cleave PilA108 between alanine62 and glycine63 residues. Overexpression of the recombinant FTF motif-bearing MucE protein, originally a small periplasmic polypeptide with the C-terminal motif WVF, could induce mucoid conversion in the PAO1 strain. In all, our results provided a model of activation of AlgW by another protein ending with proper motifs. Our data suggest that in addition to MucA cleavage, AlgW may cleave other substrates.