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Proteomic Insights into Mechanisms of Microbial Dormancy


EMSL Project ID
49543

Abstract

Ecologically important processes such as carbon and nutrient cycling largely depend on the active fraction of microbial communities, and only a small portion of the total soil microbiome is active under typical conditions. Inactivity is the more common physiological state of environmental populations. Although it is thought that most, perhaps all, microorganisms can enter low activity states when nutrient limited, there is very little understanding of mechanism - those adaptive changes that permit organisms to enter states of low or suspended metabolic activity, but also rapidly respond to transient growth-permissive conditions. Thus, a mechanistic understanding of dormancy is of general relevance to all systems having a major microbial component, and essential to develop predictive local and global ecosystem models that must incorporate the increasing environmental variability associated with climate change. As one of the most energy-intensive cellular processes (as much as 50% of total energy expenditures), protein synthesis is highly down regulated in response to nutrient limitations. An important unanswered question is what mechanisms are responsible for rapid and robust regulation of ribosomal activity (i.e. protein synthesis) upon entrance and emergence from states of dormancy? Recent findings imply that there is likely a multifaceted system of regulation of ribosomal activation/inactivation involving both protein posttranslational modifications (PTMs) and rRNA cleavage/ligation reactions that occur on the ribosome. Emergence from dormancy may also depend on preselected association of ribosomes with mRNAs essential for rapid recovery. To address this challenge, we propose to develop a novel ribosome characterization capability based on rapid isolation and enrichment of intact ribosomes, top-down proteomic analysis of ribosomal and ribosome associated proteins, and ribosome bound mRNA/rRNA analysis. A capability of this type coupled with microbial growth conditions that induce entrance and exit from dormancy will enable precise characterization of the regulatory mechanisms controlling the translation machinery.

Project Details

Start Date
2017-02-23
End Date
2018-09-30
Status
Closed

Team

Principal Investigator

Jared Shaw
Institution
Environmental Molecular Sciences Laboratory

Team Members

Carter Bracken
Institution
Environmental Molecular Sciences Laboratory

Neha Malhan
Institution
Environmental Molecular Sciences Laboratory

Jonathan Dworkin
Institution
Columbia University

Stephen Callister
Institution
Pacific Northwest National Laboratory

David Stahl
Institution
University of Washington