ComX-induced exoproteases degrade ComX in Bacillus subtilis PS-216

Špacapan, Mihael (author), Danevčič, Tjaša (author), Mandić-Mulec, Ines (author)

Gram-positive bacteria use peptides as auto-inducing (AI) signals to regulate the production of extracellular enzymes (e.g., proteases). ComX is an AI peptide, mostly known for its role in the regulation of bacterial competence and surfactant production in Bacillus subtilis. These two traits are regulated accordingly to the bacterial population size, thus classifying ComX as a quorum sensing signal. ComX also indirectly regulates exoprotease production through the intermediate transcriptional regulator DegQ. We here use this peptide-based AI system (the ComQXPA system) as a model to address exoprotease regulation by ComX in biofilms. We also investigate the potential of ComX regulated proteases to degrade the ComX AI peptide. Results indicate that ComX indeed induces the expression of aprE, the gene for the major serine protease subtilisin, and stimulates overall exoprotease production in biofilms of B. subtilis PS-216 and several other B. subtilis soil isolates. We also provide evidence that these exoproteases can degrade ComX. The ComX biological activity decay is reduced in the spent media of floating biofilms with low proteolytic activity found in the comP and degQ mutants. ComX biological activity decay can be restored by the addition of subtilisin to such media. In contrast, inhibition of metalloproteases by EDTA reduces ComX biological activity decay. This suggests that both serine and metalloproteases, which are induced by ComX, are ultimately capable of degrading this signaling peptide. This work brings novel information on regulation of exoproteases in B. subtilis floating biofilms and reveals that these proteolytic enzymes degrade the AI signaling peptide ComX, which is also a major determinant of their expression in biofilms.

• Language: English
• Keywords: cell signaling, protease, quorum quenching, biofilms, degradative enzymes, quorum sensing, auto inducing signal, pellicles
• Work type: Article
• Typology: 1.01 - Original Scientific Article
• Organization: BF - Biotechnical Faculty
• Publication status: Published
• Publication version: Version of Record
• Year: 2018
• Number of pages: 11 str.
• Numbering: Vol. 9, art. 105
• PID: 20.500.12556/RUL-128206
• UDC: 579.2:547.97
• ISSN on article: 1664-302X
• DOI: 10.3389/fmicb.2018.00105
• COBISS.SI-ID: 4876664
• Publication date in RUL: 06.07.2021

Record is a part of a journal

• Title: Frontiers in microbiology
• Shortened title: Front. microbiol.
• Publisher: Frontiers Research Foundation
• ISSN: 1664-302X
• COBISS.SI-ID: 4146296

Licences

• License: CC BY 4.0, Creative Commons Attribution 4.0 International
• Link: http://creativecommons.org/licenses/by/4.0/
• Description: This is the standard Creative Commons license that gives others maximum freedom to do what they want with the work as long as they credit the author.
• Licensing start date: 01.02.2018

Secondary language

• Language: Slovenian
• Keywords: mikrobne združbe, Bacillus subtilis, komunikacija med celicami, zaznavanje celične gostote, zaznavanje kvoruma, biofilmi, peptidi ComX

Projects

• Funder: ARRS - Slovenian Research Agency
• Project number: P4-0116
• Name: Mikrobiologija in biotehnologija živil in okolja

• Funder: ARRS - Slovenian Research Agency
• Funding programme: Young Researcher grant