●Biodiversity: an index of intactness. Mace, G. M. Nature 3 March (2005)

●High mobility group box 1: nuclear weapon in the immune arsenal. Lotze, M. T. & Tracey, K. J. Nature Reviews Immunology April (2005) This Review discusses recent data that implicate HMGB1 in the delayed immune response. The authors provide an overview of the biological activities of HMGB1 and discuss its role in the pathology of sepsis, arthritis, cancer and other diseases.

●The role of calmodulin as a signal integrator for synaptic plasticity. Xia, Z. & Storm, D. R. Nature Reviews Neuroscience April (2005)

●DUBing down a tumour suppressor. Venkitaraman, A. R. Nature Cell Biology April (2005) This News and Views piece focuses on a recent study that used short-hairpin-RNA-mediated targeting to identify a deubiquitylating enzyme USP1, which removes monoubiquitin from FANCD2. The author speculates on the dynamics of the DUB–FANCD2 interaction, and on how these relate to the DNA repair function of the Fanconi anaemia protein complex.

●Cyclin guides the way. Wittenberg, C. Nature 3 March (2005) This News and Views article discusses a recent study in which the structural basis for the preferential phosphorylation of certain substrates by cyclin–CDK complexes is unveiled.

●Cell entry machines: a common theme in nature? Barocchi, M. A., Masignani, V. & Rappuoli, R. Nature Reviews Microbiology April (2005) In this Opinion article, the authors propose that a family of bacterial cell-entry proteins shares similar structures and common mechanistic principles with the eukaryotic SNAREs and viral fusion proteins. This recurrent structural theme might reflect a convergent evolutionary origin.

●Nuclear receptors — a perspective from Drosophila. King-Jones, K. & Thummel, C. S. Nature Reviews Genetics April (2005) The genome of Drosophila melanogaster has representatives from all of the main nuclear receptor subfamilies and, as outlined in this Review, this organism therefore provides an ideal model for understanding nuclear receptor function and regulation.

●Bacterial toxins and cancer — a case to answer? Lax, A. J. Nature Reviews Microbiology April (2005) Although the molecular mechanisms of oncogenic viruses are well known, the study of bacterial-induced carcinogenesis is in its infancy. The prime suspects in the search for bacterial carcinogens are the bacterial toxins and, in this Opinion article, Alistair Lax lays out the evidence — both epidemiological and molecular — for the oncogenic potential of these bacterial products.