Review & comment

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  Mending walls (not)

  Gregory Petsko

  The real topic of Gregory Petsko's Comment in our Metabolism diet and disease series is not, despite its title, mending walls, but patterns of comorbidity that argue for cross-disciplinary research: obesity and cancer are linked, for example, but apparently not if you are also schizophrenic.

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  Visualizing proteins in plants

  Alexander Jones, David Ehrhardt, Wolf Frommer

  Visualizing proteins in plants requires stable expression of fluorescent proteins, with brightness able to overcome the autofluorescence of chlorophyll. Wolf Frommer and colleagues provide a broad overview of what makes an optimal fluorophore and evaluate the virtues of a novel orange fluorescent protein described recently in BMC Biotechnology.

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  From endosymbiont to organelle

  Takuro Nakayama, John Archibald

  The photosynthetic chromatophore of the amoeba Paulinella has a recent origin - at least in evolutionary terms. Nakayama and Archibald discuss how this makes it an ideal model for studying how photosynthetic organelles arise and evolve.

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  The ATPase machine at the heart of the replisome

  Brian Kelch, Debora Makino, Mike O'Donnell, John Kuriyan

  The speed of DNA replication depends on the sliding clamp which encircles the DNA and holds the polymerase in place. Mike O'Donnell, John Kuriyan and colleagues review the growing understanding of the conformational rearrangements whereby the clamp loader opens the clamp and screws it on to the DNA throughout DNA synthesis.

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  Influence of lipids on receptor signaling

  Alan Goddard, Anthony Watts

  The lipid membrane environment influences G-protein coupled receptor signaling. Alan Goddard and Anthony Watts comment on recent data in BMC Cell Biology where a functional, dimerised mu-opioid receptor (OPRM1) complex forms only with palmitate and cholesterol.