MecA dampens transitions to spore, biofilm exopolysaccharide and competence expression by two different mechanisms

Authors

  • Peter Prepiak,

    1. Public Health Research Center at New Jersey Medical School, 225 Warren Street, Newark, NJ 07103, USA
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    • These authors contributed equally to this manuscript.

  • Melissa Defrancesco,

    1. Department of Microbiology and Molecular Genetics, New Jersey Medical School, 225 Warren Street, Newark, NJ 07103, USA
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    • Present addresses: New York University Center for Genomics and Systems Biology, Department of Biology, 1009 Silver Center, 100 Washington Square East, New York, NY 10003-6688, USA;

    • These authors contributed equally to this manuscript.

  • Sophia Spadavecchia,

    1. Public Health Research Center at New Jersey Medical School, 225 Warren Street, Newark, NJ 07103, USA
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  • Nicolas Mirouze,

    1. Public Health Research Center at New Jersey Medical School, 225 Warren Street, Newark, NJ 07103, USA
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  • Mark Albano,

    1. Public Health Research Center at New Jersey Medical School, 225 Warren Street, Newark, NJ 07103, USA
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    • Weill Cornell Medical College, 1300 York Avenue, New York, NY 10065, USA;

  • Marjan Persuh,

    1. Public Health Research Center at New Jersey Medical School, 225 Warren Street, Newark, NJ 07103, USA
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    • Department of Psychology and Program in Cognitive Neuroscience, The City College and Graduate Center of the City, University of New York, New York, NY, USA.

  • Masaya Fujita,

    1. Department of Biology and Biochemistry, University of Houston, Houston, TX 77201-5001, USA
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  • D. Dubnau

    Corresponding author
    1. Public Health Research Center at New Jersey Medical School, 225 Warren Street, Newark, NJ 07103, USA
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E-mail dubnauda@umdnj.edu; Tel. (+1) 973 854 3400; Fax (+1) 973 854 3453.

Summary

The adapter protein MecA targets the transcription factor ComK for degradation by the ClpC/ClpP proteolytic complex, thereby negatively regulating competence in Bacillus subtilis. Here we show that MecA also decreases the frequency of transitions to the sporulation pathway as well as the expression of eps, which encodes synthesis of the biofilm matrix exopolysaccharide. We present genetic and biophysical evidence that MecA downregulates eps expression and spore formation by directly interacting with Spo0A. MecA does not target Spo0A for degradation, and apparently does not prevent the phosphorylation of Spo0A. We propose that it inhibits the transcriptional activity of Spo0A∼P by direct binding. Thus, in its interaction with Spo0A, MecA differs from its role in the regulation of competence where it targets ComK for degradation. MecA acts as a general buffering protein for development, acting by two distinct mechanisms to regulate inappropriate transitions to energy-intensive pathways.

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