Stephen J. Juris

Identification of otubain 1 as a novel substrate for the Yersinia protein kinase using chemical genetics and mass spectrometry

Yersinia encodes a protein kinase, YpkA, which disrupts the actin cytoskeleton. Using an approach termed chemical genetics, we identified a 36‐kDa substrate for YpkA in both J774 lysates and bovine brain cytosol. Mass spectrometry analysis identified this substrate as FLJ20113, an open reading frame that corresponds to otubain 1, a deubiquitinating enzyme implicated in immune cell clonal anergy. We demonstrate that otubain 1 is phosphorylated by YpkA in vitro and interacts with YpkA and actin in vivo. Identification of otubain 1 as a YpkA substrate suggests that regulation of immune cell anergy may be a survival mechanism for Yersinia.

Cross-linked forms of the isolated N-terminal domain of the lethal factor are potent inhibitors of anthrax toxin.

ABSTRACT The proteins that comprise anthrax toxin self-assemble at the mammalian cell surface into a series of toxic complexes, each containing a heptameric form of protective antigen (PA) plus up to a total of three molecules of the enzymatic moieties of the toxin (lethal factor [LF] and edema factor [EF]). These complexes are trafficked to the endosome, where the PA heptamer forms a pore in the membrane under the influence of low pH, and bound LF and EF unfold and translocate through the pore to the cytosol. To explore the hypothesis that the PA pore can translocate multiple, cross-linked polypeptides simultaneously, we cross-linked LFN, the N-terminal domain of LF, via an introduced cysteine at its N or C terminus and characterized the products. Both dimers and trimers of LFN retained the ability to bind to PA pores and block ion conductance, but they were unable to translocate across the membrane, even at high voltages or with a transmembrane pH gradient. The multimers were remarkably potent inhibitors of toxin action in mammalian cells (20- to 50-fold more potent than monomeric LFN) and in a zebrafish model system. These findings show that the PA pore cannot translocate multimeric, cross-linked polypeptides and demonstrate a new approach to generating potent inhibitors of anthrax toxin.

The Case for Developing Consensus Standards for Research in Microbial Pathogenesis: Bacillus anthracis Toxins as an Example

Communication between research laboratories within a given field is often an important key to rapid successes within that field. We propose that consensus standards may be a useful tool to help facilitate such communication by providing a “common language” for laboratories that utilize similar methodologies within a field. The existence of consensus standards is well known in other fields, and through this commentary we hope to (i) introduce the concept of consensus standards to investigators in the field of microbial pathogenesis/host response who may not be familiar with them and (ii) provoke thought and discussion by others in the field regarding the possible usefulness of additional consensus standards for their own work.

Interdisciplinary undergraduate education: water as life, death, and power and the certificate in global health disparities

Abstract Background Central Michigan Universitys student chapter of Universities Allied for Essential Medicines organised a conference on global health disparities in April, 2011. From this conference came a student-driven initiative to develop interdisciplinary courses on health-related topics, and courses centred on global health and social justice. We describe the preparation and assessment of an interdisciplinary course about water. Methods The course was cotaught by the anthropology, biology, and chemistry faculty to 28 undergraduate students with anthropology, biology, chemistry, and other majors. The course combined waterborne diseases and water treatment with cultural-related and power-related barriers to clean water. The course included a student-mentored seminar stressing activism on water-related issues. The courses theme examined the effect of cholera, a waterborne disease, in a global context. Findings Analysis of pre-class and post-class questions about student attitudes via a written questionnaire showed an increase in social awareness and desire to continue to act towards solutions of global problems. For example, of 29 questions concerning civic engagement issues, all 29 responses showed an increase in agreement, with 11 showing statistically significant increases (28 degrees freedom). Assessment of student interdisciplinary thinking showed trends towards an increased ability to solve complex issues with interdisciplinary logic for seven of eight groups of students (the eighth group kept its high level). Interpretation The student initiative led to the development of an interdisciplinary course that included activism. This course has been expanded to an interdisciplinary undergraduate certificate in global health disparities and might lead to an interdisciplinary major or minor in the future. Funding Central Michigan University (CMU) Faculty Center for Innovative teaching (FaCIT).

Evidence for a Proton–Protein Symport Mechanism in the Anthrax Toxin Channel

1. 1. Basilio, 2. et al. J. Gen. Physiol. 2009 doi:[10.1085/jgp.200810170][1] [1]: /lookup/doi/10.1085/jgp.200810170