{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nThe mitochondrial phosphatase PTPMT1 has emerged as a key regulator of cellular energy homeostasis and stem cell function. Studies have demonstrated that loss of PTPMT1 in hematopoietic stem cells leads to dramatic alterations in mitochondrial metabolism, marked changes in the cell cycle, and an unexpected, roughly 40‐fold increase in the stem cell pool accompanied by impaired differentiation. Global deletion of PTPMT1 results in embryonic lethality associated with disrupted cardiolipin biosynthesis—linked to an accumulation of its precursor, phosphatidylglycerolphosphate—as well as deformed mitochondrial morphology. This establishes PTPMT1 as essential for coordinating metabolic signals with proper stem cell maintenance and differentiation."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "1", "end_ref": "3"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nFurther research has revealed that PTPMT1 is indispensable for embryonic stem cell differentiation and neural development. In conditional knockout models, depletion of PTPMT1 in ES cells leads to reduced proliferation, a significant delay in the cell cycle, and a nearly complete block in differentiation—phenomena linked to the upregulation of cyclin-dependent kinase inhibitors. Loss of PTPMT1 in neural precursor populations, for instance, compromises Bergmann glia generation and impairs neural stem cell self-renewal via bioenergetic stress, activating an AMPK-dependent checkpoint. These findings highlight the enzyme’s specific importance in stem and progenitor cell populations, as its ablation in differentiated cells has a much less pronounced impact."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nBeyond its role in stem cell biology, PTPMT1 is critical for maintaining metabolic flexibility in energy-demanding tissues. Deletion of PTPMT1 shifts mitochondrial fuel utilization away from pyruvate oxidation toward enhanced fatty acid metabolism. Although this substrate switch may initially compensate for reduced carbohydrate oxidation, prolonged reliance on lipid metabolism ultimately induces oxidative stress and mitochondrial damage, leading to muscular atrophy and heart failure. These observations underscore the need for balanced utilization of carbohydrates and lipids in preserving the integrity of both skeletal muscle and cardiac tissues."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Wen-Mei Yu, Xia Liu, Jinhua Shen, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Metabolic regulation by the mitochondrial phosphatase PTPMT1 is required for hematopoietic stem cell differentiation."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Cell Stem Cell (2013)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.stem.2012.11.022"}], "href": "https://doi.org/10.1016/j.stem.2012.11.022"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "23290137"}], "href": "https://pubmed.ncbi.nlm.nih.gov/23290137"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Ji Zhang, Ziqiang Guan, Anne N Murphy, et al. 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"}, {"type": "b", "children": [{"type": "t", "text": "Involvement of a mitochondrial phosphatase in the regulation of ATP production and insulin secretion in pancreatic beta cells."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Cell (2005)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.molcel.2005.06.008"}], "href": "https://doi.org/10.1016/j.molcel.2005.06.008"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "16039589"}], "href": "https://pubmed.ncbi.nlm.nih.gov/16039589"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Jinhua Shen, Xia Liu, Wen-Mei Yu, et al. "}, {"type": "b", "children": [{"type": "t", "text": "A critical role of mitochondrial phosphatase Ptpmt1 in embryogenesis reveals a mitochondrial metabolic stress-induced differentiation checkpoint in embryonic stem cells."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Cell Biol (2011)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1128/MCB.05629-11"}], "href": "https://doi.org/10.1128/MCB.05629-11"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "21986498"}], "href": "https://pubmed.ncbi.nlm.nih.gov/21986498"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Hong Zheng, Wen-Mei Yu, Jinhua Shen, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Mitochondrial oxidation of the carbohydrate fuel is required for neural precursor/stem cell function and postnatal cerebellar development."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Sci Adv (2018)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1126/sciadv.aat2681"}], "href": "https://doi.org/10.1126/sciadv.aat2681"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "30338292"}], "href": "https://pubmed.ncbi.nlm.nih.gov/30338292"}]}, {"type": "r", "ref": 6, "children": [{"type": "t", "text": "Hong Zheng, Qianjin Li, Shanhu Li, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Loss of Ptpmt1 limits mitochondrial utilization of carbohydrates and leads to muscle atrophy and heart failure in tissue-specific knockout mice."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Elife (2023)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.7554/eLife.86944"}], "href": "https://doi.org/10.7554/eLife.86944"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "37672386"}], "href": "https://pubmed.ncbi.nlm.nih.gov/37672386"}]}]}]}