Fig. 7. TgSODB2 does not target to the mitochondrion via the ER. Adding an ER retention signal (HDEL) to dense granule and apicoplast targeting constructs to create pTgSODB2^26-84/GFP-HDEL and pTgSODB2^R12A/GFP-HDEL, respectively, caused ER retention of GFP in a cup-shaped pattern. Retention was complete for parasites expressing TgSODB2^26-84/GFP-HDEL, with no vacuolar staining overlapping with GRA4. Some apicoplast staining that colocalized with FNR(l)-dsRED was seen for pTgSODB2^R12A/GFP-HDEL transfected parasites, with extensive smearing and ER involvement. Addition of HDEL had no effect on targeting of cytoplasmic fusion protein TgSODB2^1-25/GFP, indicating that the HDEL signal cannot misdirect proteins not destined for the secretory system. No ER signal was seen for TgSODB2^1-287/GFP-HDEL, which colocalized perfectly with Mitotracker^TM, implying that TgSODB2 does not enter the ER and probably traffics from the cytosol. Scale bar: 5 µm.