Two functionally different mitochondrial phosphate carriers support Drosophila melanogaster OXPHOS throughout distinct developmental stages

• Published in: Biochimica et biophysica acta. Molecular cell research 2024-01, Vol.1871 (1), p.119615, Article 119615
• Main Authors: Curcio, Rosita, Frattaruolo, Luca, Marra, Federica, Pesole, Graziano, Vozza, Angelo, Cappello, Anna Rita, Fiorillo, Marco, Lauria, Graziantonio, Ahmed, Amer, Fiermonte, Giuseppe, Capobianco, Loredana, Dolce, Vincenza
• Format: Article
• Language: English
• Subjects: Animals; Biological Phenomena; CG4994; CG9090; Drosophila melanogaster; Drosophila melanogaster - genetics; Mitochondria - genetics; Mitochondrial Membrane Transport Proteins; Mitochondrial phosphate carrier; OXPHOS genes; Phosphate Transport Proteins; SLC25 solute carrier
• ISSN: 0167-4889; 1879-2596; 1879-2596
• DOI: 10.1016/j.bbamcr.2023.119615

The mitochondrial oxidative phosphorylation system (OXPHOS) plays a central role in cellular energy metabolism by producing ATP. In this study, an in silico analysis conducted on nuclear somatically expressed Drosophila melanogaster OXPHOS genes, revealed shared features including widespread expression, presence of Nuclear Respiratory Gene (NRG) elements, and coordinated developmental-dependent expression, with two distinct peaks of expression during late embryonic and pupal stages. In contrast, OXPHOS paralog genes showed a unique pupal peak and were primarily expressed in adult testes. Furthermore, we conducted an extensive characterization of D. melanogaster mitochondrial phosphate carrier (Mpcp), a key player of OXPHOS. In Drosophila two genes, CG9090 and CG4994, encode putative Mpcp known as Mpcp1 and Mpcp2. Intriguingly, the expression patterns of Mpcps during development exhibited significant differences from each other and from those of other OXPHOS genes. This suggests that both isoforms contribute to ATP synthesis and are essential for the full organism development, with CG9090 also showing a connection with lifespan and aging processes. Functional complementation assays, swelling experiments carried out in the yeast mir1∆ strain and an extensive kinetic characterization of recombinant mature Mpcp2 confirmed that both isoforms transport phosphate. However, Mpcp1 displays a three folds lower activity compared to Mpcp2. Collectively, these findings suggest that mMpcp1 and mMpcp2 operate similarly to mammalian PiC-A and PiC-B, respectively. This provides a basis for exploring functional differences in mammals and gaining new insights into the mechanisms underlying OXPHOS-related diseases associated to deficiencies in human PiC transporters. [Display omitted] •Somatic OXPHOS Drosophila genes show coordinated developmental expression pattern.•Drosophila phosphate carriers exhibit distinct OXPHOS-linked developmental expression.•Functional characterization of Drosophila mitochondrial phosphate carriers (Mpcps)•Fruit fly mMpcp1 and mMpcp2 overlap mammalian PiC-A and PiC-B functions, respectively.