{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nPLEKHF2, also known as Phafin2, is a dual lipid‐binding protein that plays a critical role in the regulation of autophagy. Upon autophagy induction, Phafin2 interacts with the serine/threonine kinase Akt and accumulates in lysosomes through a PtdIns(3)P‐dependent mechanism, facilitating the digestion of intracellular components and even pathogens in macrophages."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn addition to its involvement in autophagy, Phafin2 regulates early endosome dynamics and receptor trafficking. Loss or overexpression of Phafin2 alters endosome size and morphology, affecting the degradation of the epidermal growth factor receptor (EGFR) and fluid‐phase uptake. Moreover, Phafin2 directly engages the endosomal tether EEA1 and activates Rab5, thereby promoting endosome biogenesis and downstream signaling such as insulin receptor recycling."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nPhafin2 further contributes to the regulation of programmed cell death. Overexpression of Phafin2 enhances the sensitivity of cells to TNF‑α–induced apoptosis by mediating a rapid calcium influx, activating ER‐associated caspase‑12 and downstream caspase‑3, and promoting mitochondrial membrane permeabilization. This ER–mitochondrial apoptotic pathway underlines the protein’s potential impact on cellular responses to stress and chemotherapy."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nMoreover, Phafin2 is transiently recruited to nascent macropinosomes where it orchestrates actin reorganization. By binding to both PtdIns(3)P and PtdIns(4)P, Phafin2 facilitates the delamination of the actin coat from newly formed macropinosomes, ensuring their proper internalization and maturation—a process essential for effective nutrient uptake, particularly in KRAS‐transformed cancer cells."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "5"}]}, {"type": "t", "text": ""}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nBiophysical characterization of Phafin2 reveals that it is a moderately elongated monomer whose activity relies on two phosphoinositide‐binding domains. While the FYVE domain binds PtdIns(3)P constitutively, the PH domain is regulated via autoinhibition by a conserved C‑terminal acidic motif, delineating a highly controlled mechanism for membrane localization. In parallel, amplification of the PLEKHF2 gene has been linked to decreased survival in prostate cancer, suggesting an involvement in metastatic progression and highlighting its potential as a diagnostic biomarker."}, {"type": "fg", "children": [{"type": "fg_fs", "start_ref": "6", "end_ref": "8"}]}, {"type": "t", "text": ""}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Mami Matsuda-Lennikov, Futoshi Suizu, Noriyuki Hirata, et al. 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