Primer name / gene ID Primer Sequence (5’-3’) Restriction enzyme pδ1-amastin (F) Tc00.1047053511071.40 TTGTTCTAGAGTAGGAAGCAATG XbaI pδ1-amastin (R) Tc00.1047053511071.40 CGCTGGATCCGAACCACGTGCA BamHI β1-amastin (F) Tc00.1047053509965.390 CCTAGGAGGATGTCGAAGAAGAAG AvrII β1-amastin (R) Tc00.1047053509965.390 AGATCTCGAGCACAATGAGGCCCAG BglII β2-amastin (F) Tc00.1047053509965.394 TCTAGATGGGCTTCGAAACGCTTGC XbaI β2-amastin (R) Tc00.1047053509965.394 GGATCCCCAGTGCCAGCAAGAAGACTG

BamHI The underlined sequences correspond to the restriction sites click here recognized by the restriction enzyme. Plasmid constructions To express different amastin genes in fusion with GFP we initially constructed a plasmid named pTREXAmastinGFP. The coding sequence of the TcA21 cDNA clone [3] (accession number U04339) was PCR-amplified using a forward primer (5’-CATCTAGAAAGCAATGAGCAAAC-3’) and a reverse primer (5’-CTGGATCCCTAGCATACGCAGAAGCAC-3’) containing the XbaI and BamHI restriction sites (underlined in the primers), respectively. After digesting the PCR product with XbaI and BamHI, the fragment was ligated with the vector fragment of pTREX-GFP [24] that was previously cleaved with BamHI and XhoI. To generate the GFP constructions Blasticidin S cell line with other amastin

genes, their corresponding ORFs were PCR-amplified using the primers listed in Table 1 and total genomic DNA that was purified from epimastigote cultures of T. cruzi CL Brener according to previously described protocols [3]. The PCR products were cloned initially into pTZ (Qiagen) and the amastin sequences, digested with the indicated enzymes, were purified from agarose gels with Illustra GFX PCR DNA and Gel Band Purification Kit (GE Healthcare). The fragment corresponding to the TcA21 Glutamate dehydrogenase amastin cDNA was removed from pTREXAmastinGFP after digestion with XbaI/BamHI and the fragments corresponding to the other amastin sequences were ligated in the same vector, generating pTREXAma40GFP, pTREXAma390GFPand pTREXAma394GFP. All plasmids

were purified using QIAGEN plasmid purification kits and sequenced to confirm that the amastin sequences were properly inserted, in frame with the GFP sequence. Parasite transfections and fluorescence microscopy analyses Epimastigotes of T. cruzi CL Brener, growing to a density of 1 to 2 × 107 parasites/mL, were transfected as described by DaRocha et al., 2004 [24]. After electroporation, cells were recovered in 5 ml LIT plus 10% FCS 28°C for 24 h and analysed by confocal microscopy using the ConfocalRadiance2100 (BioRad) system with a 63/100x NA 1.4 oil immersion objective. To perform co-localization analyses, transfected parasites expressing amastin-GFP fusions were prepared for immunofluorescence assays by fixing the cells for 20 minutes in 4% PFA-PBS at room temperature. Parasites adhered to poly-L-lysine coverslips (Sigma) were permeabilized with 0.