Painfully sunny

In 2009, Spanish researchers reported that the small chemokine protein, CXCL5, helps cause insulin resistance and type 2 diabetes and others expressed a link with cell signaling in cancer. Now it turns out, that this same molecule is involved in making sunburn painful. Writing in the journal Science Translational Medicine, Stephen McMahon of King's College London and colleagues report how this inflammatory molecule activates nerve fibers to cause pain and tenderness after prolonged exposure of the skin to ultraviolet-B rays. "This finding might be indicative of a more general role of CXCL5 in a variety of clinically relevant inflammatory pain states, for instance osteoarthritis or cystitis," says McMahon. The finding could lead to novel analgesic drugs.