Identification and validation of Trypanosoma cruzi’s glycosomal adenylate kinase containing a peroxisomal targeting signal

Abstract

Adenylate kinases are key enzymes involved in cell energy management. Trypanosomatid organisms have the largest number of isoforms found in a single cell, constituting a major difference with the mammalian hosts. In this work we study an adenylate kinase, TcADK3, the only Trypanosoma cruzi protein harboring the putative peroxisomal, glycosomal, targeting signal, CKl. Parasites expressing GFP fused to TcADK3 showed a strong fluorescence in the glycosomes. The same result was obtained when the tripeptide CKL was added at the C-terminus of the GFP, demonstrating that this signal is necessary and sufficient for targeting proteins to glycosomes. When this tripeptide was removed from the GFP-TcADK3 fusion protein, the fluorescence was re-localized in the cytoplasm. The CKL signal could be used for targeting foreign proteins to the glycosomes. This model also provides a useful tool to study glycosomes dynamics, morphology or number in living parasites in any stage of the life cycle.