Cell-to-Cell Transfer of Bacterial Lipoproteins

University Of Wyoming, Laramie WY

Investigators

Abstract

Intellectual Merit Myxobacteria rely on cell-cell signaling and gliding motility to live as multicellular organisms that build fruiting body structures in response to starvation. How cell-cell signaling organizes these developmental processes remains a fundamental biological question. To help understand these processes Myxococcus xanthus gliding motility mutants were isolated. A characteristic of the mutants is that they are rescued by extracellular complementation (stimulation) from cells that contain the corresponding wild type gene. Two of these known mutants encode lipoproteins and the mechanism for stimulation involves efficient cell-to-cell transfer of the cognate lipoprotein. Transfer does not involve extracellular secretion, but instead requires physical contact between donor and recipient cells. One of these lipoproteins, Tgl, is polarly localized and when transferred to a recipient cell activates the assembly of the type IV pili gliding motility motor. Specifically, Tgl transfer regulates the assembly of the outer membrane PilQ secretin channel for pilus transport. In general, lipoprotein transfer represents a novel form of cell-cell interactions that may play a role in coordinating cellular movements, forming biofilms and/or the recognition of different cell types. This project will use molecular genetic and fluorescent video microscopy methods to understand the mechanism and broader biological significance of lipoprotein transfer in bacteria. Broader Impacts This project involves the education and training of undergraduate and graduate students in an EPSCoR state. Elements of this project will be incorporated into undergraduate microbial genetic lecture and laboratory classes illustrating current research methods and approaches to students. Graduate students will be trained in scientific thinking and in molecular genetic techniques. An outreach component involves introducing and training Native Americans in microbial genetics. This outreach effort includes trips to a tribal college to recruit Native American students to conduct a summer research internship at the University of Wyoming. Student training in the lab is an interactive process between individuals at all levels. This work will generate high quality research papers and students supported by the project will present at national scientific meetings. Society at large will benefit from the training of young scientists. In addition, the project will provide a broader understanding of how cells interact in communities such as biofilms or in primitive developmental tissues.