Introducing Professor Wolfgang Schumann, Microbial Stress Responses Section Editor

Abstract

Dear Colleagues It is a pleasure to announce the opening of a new dedicated section in Cell Stress & Chaperones, “Microbial Stress Responses,” and to introduce our founding section editor, Wolfgang Schumann. Since 1993, Wolfgang has been Professor of Genetics at the Institute of Genetics of the University of Bayreuth, Germany. He studied biology at the Johannes-Gutenberg University in Mainz. His PhD thesis was an immunogenetic analysis of different strains of the mosquito Culex pipiens related to cytoplasmic incompatibility. Thereafter, he started to work on two different bacteriophages: first the Salmonella typhimurium phage P22 at the Institute of Microbiology, University of Goettingen, and then the Escherichia coli phage Mu at the Department of Biology, University of Konstanz. Wolfgang has worked on bacterial stress responses since 1989, searching for inducible promoters in the genome of Bacillus subtilis. While studying the regulation of the dnaK and groE operons of B. subtilis, he discovered a new regulation mechanism which turned out to be the most widespread heat shock regulation mechanism currently known in the eubacterial world (Schmidt et al 1992; Wetzstein et al 1992). It consists of the repressor protein HrcA, which binds to an operator sequence called the CIRCE element (Schulz et al 1995; Schulz et al 1996; Zuber and Schumann 1994). How is the activity of the HrcA repressor protein modulated during heat shock? Several lines of experimental data suggest that the GroE chaperonin system exerts an important role in this process. This leads to the working model that the GroE team participates in the conversion of inactive HRCA into its active form (Mogk et al 1997; Reischl et al 2002). According to this model, inactive HrcA is present immediately after de novo synthesis and after dissociation from its operator. Recently, Wolfgang started working with Thomas Wiegert to study the alkaline stress in B. subtilis (Wiegert et al 2001). To start the new section, Wolfgang has contributed a timely review article on the B. subtilis heat shock stimulon that includes a discussion of possible thermosensors (Schumann 2003). His review is joined in this issue by a second review article featuring the E. coli stress protein GrpE that functions as a nucleotide exchange factor for the molecular chaperone DnaK (Harrison 2003). This review, which emphasizes the structural and kinetic aspects of GrpE and also discusses the thermosensor hypothesis, is an excellent companion article arranged by our Reviews Editor, Avrom Caplan. Also, although not strictly a microbial stress response article, the paper by Morales et al (2003), also in this issue, speaks to the types of interactions between microbial cells, gram negative bacteria in this example, and cells of vertebrate immune systems that no doubt influenced the evolution of both. I would like to give our readers a taste of the articles that have appeared in recent issues of Cell Stress & Chaperones involving microbes and microbial stress responses. In a study of how yeast survive oxidative stress during dessication, Periera and colleagues (2003) showed that both cytosolic and mitochondrial forms of superoxide dismutase contribute to survival, as does the disaccharide trehalose. How do yeast survive cold stress? Somer et al (2002) showed that chaperonin CCT (cytoplasmic cpn60) is a cold shock protein that appears to be needed during recovery from low temperatures and growth transition at higher temperatures. Properties and functions of microbial stress proteins were described in a second group of articles. From a comparison of four evolutionarily diverse Hsp70s including E. coli DnaK, Kumaraguru et al (2003) showed that only human Hsp70 can stimulate protective immunity in mice against HSV1. In a similar vein, Lewthwaite et al (2002) showed that the Rhizobium chaperonin 60.3 induces cytokine production by human monocytes, but the very closely related Rhizobium chaperonin 60.1 does not. Maguire et al (2002) have contributed a very useful review comparing Cpn60 proteins to expand upon the point that these proteins can have quite distinct biological properties and discussing the evidence of their activities in cell signaling pathways. Using a set of monoclonal antibodies raised against E. coli DnaJ, Krzewski et al (2003) demonstrated significant immunological similarity between DnaJ and its human homolog HDJ-1, suggesting that HDJ-1 may be targeted in vivo by immune responses stimulated by a bacterial stress protein. A third area in which we hope this new section will stimulate activity is the study of interactions between microbial cells and animal or plant cells that stimulate stress responses. An example is a study by Malago et al (2003) in which stress proteins were induced by S. enteritidis 857, a human intestinal pathogen, in the human enterocyte cell line Caco-2. Manuscripts for the new Microbial Stress Response Section or any other section of Cell Stress & Chaperones can now be submitted electronically at our new website http://cellstress.allentrack.net.