{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nNote that while the query refers to OPA1‐AS1, none of the provided abstracts mention this RNA. Instead, they consistently focus on protein 4.1N and its diverse biological functions. In the neural context, one study demonstrates that 4.1N is essential for the activity‐dependent insertion of AMPA receptor subunits into the plasma membrane—a process crucial for synaptic plasticity. Phosphorylation by protein kinase C at key serine residues enhances 4.1N binding to GluR1, while palmitoylation of GluR1 further fine‐tunes this molecular interaction, collectively ensuring proper receptor trafficking during synaptic modulation."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn the oncological setting, another study reveals that loss of 4.1N in epithelial ovarian cancer is strongly associated with advanced disease and poor patient survival. The deficiency of 4.1N leads to constitutive activation of the epithelial–mesenchymal transition, resistance to anoikis, and enhanced cell entosis. Mechanistically, 4.1N normally binds to and accelerates the degradation of 14-3-3 proteins, an interaction that when disrupted contributes to tumor spread. This work not only clarifies the tumor-suppressing role of 4.1N but also suggests potential therapeutic avenues aimed at restoring its function or targeting downstream pathways."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nA third study, utilizing 4.1N knockout mice, establishes a critical role for 4.1N in reproductive system development. Mice lacking 4.1N exhibit impaired growth and notable atrophy of reproductive organs. The study further indicates that 4.1N is pivotal for proper neuroendocrine function: its absence disrupts the axonal transport of gonadotropin-releasing hormone (GnRH) from the hypothalamus and adversely affects secretory activity in the pituitary gland. These findings underscore the importance of 4.1N in the hypothalamus–pituitary–gonadal axis, linking it directly to reproductive competence."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": ""}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Da-Ting Lin, Yuichi Makino, Kamal Sharma, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Regulation of AMPA receptor extrasynaptic insertion by 4.1N, phosphorylation and palmitoylation."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Nat Neurosci (2009)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/nn.2351"}], "href": "https://doi.org/10.1038/nn.2351"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "19503082"}], "href": "https://pubmed.ncbi.nlm.nih.gov/19503082"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Dandan Wang, Letian Zhang, Ajin Hu, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Loss of 4.1N in epithelial ovarian cancer results in EMT and matrix-detached cell death resistance."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Protein Cell (2021)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1007/s13238-020-00723-9"}], "href": "https://doi.org/10.1007/s13238-020-00723-9"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "32448967"}], "href": "https://pubmed.ncbi.nlm.nih.gov/32448967"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Hua Wang, Marilyn Parra, John G Conboy, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Selective effects of protein 4.1N deficiency on neuroendocrine and reproductive systems."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Sci Rep (2020)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1038/s41598-020-73795-6"}], "href": "https://doi.org/10.1038/s41598-020-73795-6"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "33046791"}], "href": "https://pubmed.ncbi.nlm.nih.gov/33046791"}]}]}]}