Review & comment

• 

  Neuroprotective role for microglia

  Mariko Howe, Ben Barres

  Ramified microglia, previously branded as 'resting', protect hippocampal neurons against excitotoxicity according to research published in Journal of Neuroinflammation. Mariko Howe and Ben Barres discuss how these findings add to a growing recognition of active roles for microglia in health and disease.

• 

  Signaling by shape shifts

  Ruth Nussinov, Buyong Ma

  Sixteen new conformations of the ligand-binding domain of the cell:cell signaling receptor EphrinA4 are identified in research published in BMC Biophysics. Nussinov and Ma discuss how such conformational diversity allows binding of different ligands to propagate distinct signals through secondary conformational change.

• 

  Untangling messy evolutionary histories

  Hervé Philippe, Béatrice Roure

  Niels Bohr said that 'Prediction is very difficult, especially about the future,' but phylogeneticists would just be happy with the past. Philippe and Roure discuss some methods for dealing with particularly difficult evolutionary problems, and how corroboration is the key to success.

• 

  Morphogenesis and ways to turn inside out

  Ray Keller, David Shook

  Keller and Shook explore how cell shape changes, junctional interactions and epithelial morphogenetic processes drive early development, including data from a recent analysis by Hoehn and Hallmann of a relatively unexplored inversion process in the multicellular alga Volvox globator.

• 

  Tracing the hemangioblast to its origin

  Sabrina Gordon-Keylock, Alexander Medvinsky

  Both blood cells and vascular cells can differentiate from a single precursor cell, the hemangioblast. But what is the origin of the hemangioblast? Gordon-Keylock and Medvinsky discuss a new method of labeling these cells, reported by Ana T Tavares and colleagues, that may provide an answer.