Post-translational modification of the pyruvate phosphate dikinase from Trypanosoma cruzi |
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| Affiliation: | 1. Laboratorio de Enzimología de Parásitos, Facultad de Ciencias, Universidad de Los Andes, La Hechicera, Mérida 5101, Venezuela;2. Laboratorio de Fisiología de Parásitos, Centro de Biofísica y Bioquímica, Instituto Venezolano de Investigaciones Científicas, Caracas 1020-A, Venezuela;1. Graduate Institute of Biomedical Sciences, College of Medicine, Chang Gung University, Kwei-Shan, Tao-Yuan 333, Taiwan;2. Department of Parasitology, College of Medicine, Chang Gung University, Kwei-Shan, Tao-Yuan 333, Taiwan;3. Bioinformatics Center, Chang Gung University, Kwei-Shan, Tao-Yuan 333, Taiwan;4. Department of Parasitology, Faculty of Medicine, College of Medicine, Kaohsiung Medical University, Kaohsiung 807, Taiwan;5. Department of Microbiology and Immunology, College of Medicine, Chang Gung University, Kwei-Shan, Tao-Yuan 333, Taiwan;1. Unité de Biologie et Génétique du Paludisme, Institut Pasteur, 75724 Paris Cedex 15, Paris, France;2. University of Kentucky College of Medicine, Department of Microbiology, Immunology and Molecular Genetics, 800 Rose Street, Lexington, KY 40536, USA;1. Departamento de Zoología, Instituto de Biología, Universidad Nacional Autónoma de México, Ap. Postal 70-153, C.P. 04510, México D.F., México;2. Posgrado en Ciencias Biológicas, Instituto de Biología, Universidad Nacional Autónoma de México, Ap. Postal 70-153, C.P. 04510, México D.F., México;3. Instituto de Ciencias del Mar y Limnología, Unidad Académica Mazatlán, Universidad Nacional Autónoma de México, Joel Montes Camarena s/n, Mazatlán 82040, Sinaloa, México |
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| Abstract: | In kinetoplastids such as Trypanosoma cruzi, glycolysis is compartmentalized in peroxisome-like organelles called glycosomes. Pyruvate phosphate dikinase (PPDK), an auxiliary enzyme of glycolysis, is also located in the glycosomes. We have detected that this protein is post-translationally modified by phosphorylation and proteolytic cleavage. On western blots of T. cruzi epimastigotes, two PPDK forms were found with apparent MW of 100 kDa and 75 kDa, the latter one being phosphorylated at Thr481, a residue present in a highly conserved region. In subcellular localization assays the 75 kDa PPDK was located peripherally at the glycosomal membrane. Both PPDK forms were found in all life-cycle stages of the parasite. When probing for both PPDK forms during a growth of epimastigotes in batch culture, an increase in the level of the 75 kDa form and a decrease of the 100 kDa one were observed by western blot analysis, signifying that glucose starvation and the concomitant switch of the metabolism to amino acid catabolism may play a role in the post-translational processing of the PPDK. Either one or both of the processes, phosphorylation and proteolytic cleavage of PPDK, result in inactivation of the enzyme. It remains to be established whether the phenomenon exerts a regulatory function. |
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