Fig. 3

Cleavage sites in human proteins identified as substrates of HERV-K(HML-2) Protease by TAILS. a. Results of filtering of cleavage sites observed by TAILS. Results for two experiments (rep1, rep2) performed at pH 5.5 and pH 7 are each depicted. Various filters were applied, such as greater than 1.5-fold or 2-fold (fc) enrichment for the observed cleavage event compared to controls and particular amino acids in P1 and P1’ (see the paper text). Resulting numbers after applying the various filters are indicated by bars and by specific numbers when including P1 and P1’. b. Venn diagrams depicting overlap of cleavage sites and protein IDs in replicates (rep1, rep2) performed at pH 5.5 and pH 7. The overlap of protein IDs detected in all four experiments is depicted in the Venn diagram at the bottom. c. Numbers of cleavage sites in proteins identified as substrates of HERV-K(HML-2) Pro. Results are summarized for the replicate (rep1, rep2) TAILS experiments at pH 5.5 and pH 7. A single cleavage event was observed for the vast majority of proteins, fewer proteins were cleaved at more than one position, and a relatively small number of proteins were cleaved at up to 60 different positions within the particular protein. See Additional file 1: Table S2, for selected human proteins with multiple cleavage sites