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Margenat M, Betancour G, Irving V, Costábile A, García-Cedrés T, Portela MM, Carrión F, Herrera FE, Villarino A. Characteristics of Mycobacterium tuberculosis PtpA interaction and activity on the alpha subunit of human mitochondrial trifunctional protein, a key enzyme of lipid metabolism. Front Cell Infect Microbiol 2023; 13:1095060. [PMID: 37424790 PMCID: PMC10325834 DOI: 10.3389/fcimb.2023.1095060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 05/29/2023] [Indexed: 07/11/2023] Open
Abstract
During Mycobacterium tuberculosis (Mtb) infection, the virulence factor PtpA belonging to the protein tyrosine phosphatase family is delivered into the cytosol of the macrophage. PtpA interacts with numerous eukaryotic proteins modulating phagosome maturation, innate immune response, apoptosis, and potentially host-lipid metabolism, as previously reported by our group. In vitro, the human trifunctional protein enzyme (hTFP) is a bona fide PtpA substrate, a key enzyme of mitochondrial β-oxidation of long-chain fatty acids, containing two alpha and two beta subunits arranged in a tetramer structure. Interestingly, it has been described that the alpha subunit of hTFP (ECHA, hTFPα) is no longer detected in mitochondria during macrophage infection with the virulent Mtb H37Rv. To better understand if PtpA could be the bacterial factor responsible for this effect, in the present work, we studied in-depth the PtpA activity and interaction with hTFPα. With this aim, we performed docking and in vitro dephosphorylation assays defining the P-Tyr-271 as the potential target of mycobacterial PtpA, a residue located in the helix-10 of hTFPα, previously described as relevant for its mitochondrial membrane localization and activity. Phylogenetic analysis showed that Tyr-271 is absent in TFPα of bacteria and is present in more complex eukaryotic organisms. These results suggest that this residue is a specific PtpA target, and its phosphorylation state is a way of regulating its subcellular localization. We also showed that phosphorylation of Tyr-271 can be catalyzed by Jak kinase. In addition, we found by molecular dynamics that PtpA and hTFPα form a stable protein complex through the PtpA active site, and we determined the dissociation equilibrium constant. Finally, a detailed study of PtpA interaction with ubiquitin, a reported PtpA activator, showed that additional factors are required to explain a ubiquitin-mediated activation of PtpA. Altogether, our results provide further evidence supporting that PtpA could be the bacterial factor that dephosphorylates hTFPα during infection, potentially affecting its mitochondrial localization or β-oxidation activity.
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Affiliation(s)
- Mariana Margenat
- Instituto de Biología, Sección Bioquímica, Facultad de Ciencias-Universidad de la República, Montevideo, Uruguay
| | - Gabriela Betancour
- Instituto de Biología, Sección Bioquímica, Facultad de Ciencias-Universidad de la República, Montevideo, Uruguay
| | - Vivian Irving
- Instituto de Biología, Sección Bioquímica, Facultad de Ciencias-Universidad de la República, Montevideo, Uruguay
| | - Alicia Costábile
- Instituto de Biología, Sección Bioquímica, Facultad de Ciencias-Universidad de la República, Montevideo, Uruguay
| | - Tania García-Cedrés
- Instituto de Biología, Sección Bioquímica, Facultad de Ciencias-Universidad de la República, Montevideo, Uruguay
| | - María Magdalena Portela
- Instituto de Biología, Facultad de Ciencias-Universidad de la República, Montevideo, Uruguay
- Unidad de Bioquímica y Proteómica Analíticas, Institut Pasteur de Montevideo and Instituto de Investigaciones Biológicas Clemente Estable, Montevideo, Uruguay
| | - Federico Carrión
- Laboratorio de Inmunovirología, Institut Pasteur de Montevideo, Montevideo, Uruguay
| | - Fernando E. Herrera
- Departamento de Física, Facultad de Bioquímica y Ciencias Biológicas-Universidad Nacional del Litoral – CONICET, Santa Fe, Argentina
| | - Andrea Villarino
- Instituto de Biología, Sección Bioquímica, Facultad de Ciencias-Universidad de la República, Montevideo, Uruguay
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