{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nPPP4R3A, also known as sMEK1, functions as a key regulatory subunit of protein phosphatase 4 that modulates several critical signaling networks. Its activity has been shown to mediate anti-angiogenic and pro-apoptotic effects in tumor cells by interfering with VEGF‐stimulated pathways—attenuating cell proliferation, migration, and capillary‐like network formation—and by directly interacting with tumor suppressors such as BLU to enhance sMEK1 expression and trigger cell death."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n \nDiverse studies further implicate PPP4R3A in the regulation of oncogenic processes. By binding to proteins such as BMI-1, it counteracts oncogene-driven cellular proliferation and survival, modulating the expression of key cell cycle regulators and apoptosis mediators. In leukemic T cells, for instance, overexpression of PPP4R3A diminishes cell growth and colony formation through impacts on multiple signaling axes including MAPK, AKT, JAK/STAT, NFκB, and TGFβ, while forceful downregulation enhances cell survival. Moreover, PPP4R3A has been shown to attenuate the unfolded protein response by inhibiting IRE1 activation and its downstream effectors, hence preserving cellular homeostasis under endoplasmic reticulum stress."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "3", "end_ref": "5"}]}, {"type": "t", "text": "\n \nAlthough not directly examined in the context of PPP4R3A function, genetic studies using declines in glucose metabolism as a proxy for Alzheimer’s disease progression highlight the broader significance of regulatory phosphatases in cellular energy balance and stress responses. These findings, when considered alongside its established roles in apoptosis and angiogenesis, suggest that PPP4R3A may also have potential implications in neurodegenerative conditions, warranting further exploration of its genetic variants and functions."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Seung Myung Dong, Hyun-Jung Byun, Boh-Ram Kim, et al. 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"}, {"type": "b", "children": [{"type": "t", "text": "sMEK1 inhibits endothelial cell proliferation by attenuating VEGFR-2-dependent-Akt/eNOS/HIF-1α signaling pathways."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Oncotarget (2015)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.18632/oncotarget.5570"}], "href": "https://doi.org/10.18632/oncotarget.5570"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "26378810"}], "href": "https://pubmed.ncbi.nlm.nih.gov/26378810"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Boh-Ram Kim, Youngjoo Kwon, Seung Bae Rho "}, {"type": "b", "children": [{"type": "t", "text": "BMI-1 interacts with sMEK1 and inactivates sMEK1-induced apoptotic cell death."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Oncol Rep (2017)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.3892/or.2016.5262"}], "href": "https://doi.org/10.3892/or.2016.5262"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "27878292"}], "href": "https://pubmed.ncbi.nlm.nih.gov/27878292"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Nadieh Kavousi, Daniel P Tonge, Mirna Mourtada-Maarabouni "}, {"type": "b", "children": [{"type": "t", "text": "New insights into the functional role of protein phosphatase 4 regulatory subunit PP4R3A/SMEK1 in the regulation of leukemic cell fate."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Int J Biol Macromol (2023)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.ijbiomac.2023.123467"}], "href": "https://doi.org/10.1016/j.ijbiomac.2023.123467"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "36731689"}], "href": "https://pubmed.ncbi.nlm.nih.gov/36731689"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Ozaira Qadri, Samirul Bashir, Mariam Banday, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Tumour suppressor protein sMEK1 links to IRE1 signalling pathway to modulate its activity during ER stress."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Biochim Biophys Acta Mol Cell Res (2024)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.bbamcr.2024.119774"}], "href": "https://doi.org/10.1016/j.bbamcr.2024.119774"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "38838857"}], "href": "https://pubmed.ncbi.nlm.nih.gov/38838857"}]}, {"type": "r", "ref": 6, "children": [{"type": "t", "text": "Leigh Christopher, Valerio Napolioni, Raiyan R Khan, et al. 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