1. Division of Human Biology; Fred Hutchinson Cancer Research Center; Seattle WA USA
2. Department of Microbiology; University of Washington School of Medicine; Seattle WA USA
3. BD Biosciences; Seattle WA USA
4. Division of Science and Mathematics; University of Minnesota; Morris MN USA
5. Department of Molecular, Cellular and Developmental Biology; Yale University; New Haven CT USA
6. Centre for Bacterial Cell Biology; Institute for Cell and Molecular Biosciences; Newcastle University; Newcastle upon Tyne UK