{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nSTYXL1, also known as MK‐STYX, is a catalytically inactive member of the dual‐specificity phosphatase family that has emerged as a multifaceted regulator of cell stress responses and survival. Early RNA interference studies revealed that depletion of STYXL1 impairs mitochondrial apoptosis, as evidenced by a failure to release cytochrome c in response to stressors—a defect reminiscent of the loss of pro‐apoptotic BCL-2 family members."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nFurther investigations uncovered that STYXL1 exerts its prosurvival role through interactions with mitochondrial regulators. In particular, STYXL1 binds to and suppresses the catalytic activity of the mitochondrial phosphatase PTPMT1, thereby facilitating mitochondrial outer membrane permeabilization and governing the sensitivity of cells to chemotherapeutic agents."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nBeyond its impact on apoptosis, STYXL1 has been implicated in neurodevelopmental processes. Genetic studies initially identified a missense mutation in STYXL1 in a consanguineous family with intellectual disability, epilepsy, and behavioral disturbances. However, subsequent analyses have suggested that some variants may be benign, highlighting the genetic heterogeneity underlying cognitive disorders."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn the context of cancer, deregulation of STYXL1 has been observed in glioblastoma. Studies report that STYXL1 is frequently amplified and upregulated in GBM, where it functions as an oncogene by promoting cell growth, colony formation, migration, and transformation, thereby contributing to the aggressive behavior and poor prognosis associated with this malignancy."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nEmerging evidence also supports a role for STYXL1 in intracellular trafficking and lysosomal regulation. Knockdown experiments in cellular models have demonstrated that reduction of STYXL1 enhances the trafficking and lysosomal activity of enzymes such as β-glucocerebrosidase, alters the distribution of endoplasmic reticulum and lysosomal compartments, and promotes the nuclear translocation of stress-responsive transcription factors. These effects point to a novel regulatory function of STYXL1 in maintaining lysosomal homeostasis."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nAt the molecular level, the DUSP domain of STYXL1 directly interacts with the stress granule nucleator G3BP1, modulating its tyrosine phosphorylation and thereby inhibiting stress granule assembly. This interaction ties STYXL1 to the regulation of mRNA metabolism under conditions of cellular stress."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "8"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Natalie M Niemi, Nathan J Lanning, Jeff A Klomp, et al. "}, {"type": "b", "children": [{"type": "t", "text": "MK-STYX, a catalytically inactive phosphatase regulating mitochondrially dependent apoptosis."}]}, {"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.00788-10"}], "href": "https://doi.org/10.1128/MCB.00788-10"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "21262771"}], "href": "https://pubmed.ncbi.nlm.nih.gov/21262771"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Justinn E Barr, Michelle R Munyikwa, Elizabeth A Frazier, et al. "}, {"type": "b", "children": [{"type": "t", "text": "The pseudophosphatase MK-STYX inhibits stress granule assembly independently of Ser149 phosphorylation of G3BP-1."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "FEBS J (2013)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1111/febs.12068"}], "href": "https://doi.org/10.1111/febs.12068"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "23163895"}], "href": "https://pubmed.ncbi.nlm.nih.gov/23163895"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Natalie M Niemi, Juliana L Sacoman, Laura M Westrate, et al. "}, {"type": "b", "children": [{"type": "t", "text": "The pseudophosphatase MK-STYX physically and genetically interacts with the mitochondrial phosphatase PTPMT1."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "PLoS One (2014)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1371/journal.pone.0093896"}], "href": "https://doi.org/10.1371/journal.pone.0093896"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "24709986"}], "href": "https://pubmed.ncbi.nlm.nih.gov/24709986"}]}, {"type": "r", "ref": 4, "children": [{"type": "t", "text": "Mala Isrie, Masoud Zamani Esteki, Hilde Peeters, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Homozygous missense mutation in STYXL1 associated with moderate intellectual disability, epilepsy and behavioural complexities."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Eur J Med Genet (2015)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.ejmg.2015.02.006"}], "href": "https://doi.org/10.1016/j.ejmg.2015.02.006"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "25724587"}], "href": "https://pubmed.ncbi.nlm.nih.gov/25724587"}]}, {"type": "r", "ref": 5, "children": [{"type": "t", "text": "Holger Hengel, Yvonne Schelling, Reinhard Keimer, et al. "}, {"type": "b", "children": [{"type": "t", "text": "A previously identified missense mutation in STYXL1 is likely benign."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Eur J Med Genet (2019)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.ejmg.2018.11.016"}], "href": "https://doi.org/10.1016/j.ejmg.2018.11.016"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "30472486"}], "href": "https://pubmed.ncbi.nlm.nih.gov/30472486"}]}, {"type": "r", "ref": 6, "children": [{"type": "t", "text": "Vivek Singh Tomar, Tapan Kumar Baral, Krishnaveni Nagavelu, et al. 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"}, {"type": "b", "children": [{"type": "t", "text": "The DUSP domain of pseudophosphatase MK-STYX interacts with G3BP1 to decrease stress granules."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Arch Biochem Biophys (2023)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.abb.2023.109702"}], "href": "https://doi.org/10.1016/j.abb.2023.109702"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "37516290"}], "href": "https://pubmed.ncbi.nlm.nih.gov/37516290"}]}]}]}