Nat. Cell Biol. 13, 423–433 (2011); published online 20 March 2011; corrected after print 8 December 2014 In the version of this Article originally published online, incorrect values appearing in Supplementary Table S4 were used to generate Fig. 3a and to calculate the P and R values. The annotationbetween Exosome and HDL should have read 'R = 0.