{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\n PTRF (polymerase I and transcript release factor), also known as Cavin‐1, is a cytoplasmic protein that is absolutely essential for the biogenesis and function of caveolae – specialized invaginations of the plasma membrane. PTRF/Cavin‐1 performs a multifaceted role by assembling with caveolins and other cavin family members into a multiprotein coat that not only promotes caveola formation but also stabilizes caveolar structures and regulates the lateral mobility and trafficking of caveolin proteins at the cell surface."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Deficiency or mutation of PTRF/Cavin‐1 disrupts caveola assembly, resulting in reduced numbers or even complete loss of caveolae. Such defects underlie diverse pathologies including congenital generalized lipodystrophy, muscular dystrophy, and cardiac or metabolic dysfunction, as documented by studies that show aberrant caveolin localization, membrane repair defects, and altered signaling cascades when PTRF is absent or mutated."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "3", "end_ref": "5"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Moreover, PTRF/Cavin‐1 has been implicated in dynamic cellular processes beyond caveola formation. For instance, its regulated subcellular targeting – shifting between the nucleus, cytosol, and plasma membrane – appears to influence cellular senescence and mechanotransduction, thereby linking changes in membrane structure to the modulation of intracellular signaling via pathways such as p53/p21."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "6"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n In addition, PTRF/Cavin‐1 plays a critical role in membrane repair by serving as a docking site for repair proteins like MG53, a function that is vital to maintaining cell integrity following injury."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n PTRF/Cavin‐1 is also significant in the context of tumor biology. Its expression modulates exosome secretion and affects the tumor microenvironment, thereby influencing the aggressiveness and metastatic potential of several cancers including glioma and prostate cancer. In prostate cancer models, reintroduction of PTRF/Cavin‐1 not only restores caveola formation but also attenuates anchorage‐independent growth and metastatic behavior, suggesting a tumor‐suppressive role for PTRF/Cavin‐1."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "8", "end_ref": "10"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n Finally, proteomic studies in lung cancer have identified PTRF/Cavin‐1 as a differentially expressed biomarker, while animal models lacking PTRF/Cavin‐1 display marked defects in adipocyte function and energy metabolism, underscoring its broad physiological significance."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "11"}]}, {"type": "t", "text": "\n "}]}, {"type": "t", "text": "\n "}, {"type": "p", "children": [{"type": "t", "text": "\n In summary, PTRF/Cavin‐1 is a central orchestrator of caveola structure and function. By recruiting and stabilizing caveolins at the plasma membrane, it regulates key processes such as membrane repair, signal transduction, and exosome-mediated intercellular communication. Disruption of PTRF/Cavin‐1 not only impairs caveola formation but also contributes to diverse human diseases ranging from metabolic and muscular disorders to cancer.\n "}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Michelle M Hill, Michele Bastiani, Robert Luetterforst, et al. 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