Enrichment of nuclear proteins in nuclear fractions by comparison to gold standards. (a) Enrichment was defined as the percentage of true nuclear proteins found in each fraction, divided by the number of nuclear proteins expected in a random set of equivalent size. The horizontal line indicates the theoretical enrichment in a random selection of proteins. (b) Nuclear protein content in various protein fractions. The vertical dashed line indicates the PPV for proteins taken at random from the entire parasite proteome. 1-5, fractions 1 to 5; 2-5, all proteins found in any of the four nuclear fractions; 1 excl., proteins found exclusively in fraction 1; 2-5 excl., all proteins found exclusively in any of the four nuclear fractions.