Document Type
Article
Publication Date
5-5-2025
Abstract
The mitochondrial phosphate carrier (mPiC), encoded by the nuclear gene SLC25A3, is synthesized with an N-terminus mitochondrial targeting sequence (MTS), enabling its import into the mitochondria. mPiC imports inorganic phosphate (Pi) into the mitochondrial matrix for ATP production and other matrix phosphorylation reactions, as well as regulates mitochondrial Ca2+ uptake and buffering of matrix Ca2+. PiC also imports copper (Cu), crucial to COX subunit holoenzyme assembly. Variants in SLC25A3 exist and lead to mPiC deficiency (MPCD), cause a rare autosomal recessive disease with no current cure; patients with MPCD usually die within the first year of life. We have developed a novel therapeutic approach using TAT-mPiC fusion protein for cellular delivery since the TAT peptide enables delivery of proteins across biological membranes. We designed, produced, and purified the TAT-mPiC fusion protein. The fusion protein is delivered into the mitochondria and localizes within the mIM, its natural cellular location, as a processed protein. Treatment of mPiC-knockdown cells with TAT-mPiC fusion protein increased cell growth and improved bioenergetic capabilities, as measured by oxygen consumption rate (OCR), ATP production, and reduction in lactate secretion. Most importantly, TAT-mPiC restored Pi and Cu delivery into the mitochondrial matrix. TAT-mPiC fusion protein also restored the mitochondrial activity of cells harboring various mitochondrial defects. This study presents the first successful delivery of a mitochondrial transmembrane carrier using the TAT-fusion system, offering a potential early treatment strategy for newborns with mPiC deficiency.
Recommended Citation
Zabit, Samar; Melloul, Orly; Lichtenstein, Michal; Seifert, Erin L.; and Lorberboum-Galski, Haya, "Rescue of the First Mitochondrial Membrane Carrier, the mPiC, by TAT-Mediated Protein Replacement Treatment" (2025). Department of Pathology, Anatomy, and Cell Biology Faculty Papers. Paper 445.
https://jdc.jefferson.edu/pacbfp/445
Creative Commons License
This work is licensed under a Creative Commons Attribution 4.0 License.
PubMed ID
40362619
Language
English
Included in
Amino Acids, Peptides, and Proteins Commons, Nutritional and Metabolic Diseases Commons, Pathology Commons
Comments
This article is the author's final published version in International Journal of Molecular Sciences, Volume 26, Issue 9, May 2025, Article number 4379.
The published version is available at https://doi.org/10.3390/ijms26094379.
Copyright © 2025 by the authors