{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nPLAAT1 belongs to the HRAS-like suppressor (HRASLS) subfamily of enzymes, a group known for its ability to remodel membrane glycerophospholipids. These enzymes, including PLAAT1, exhibit phospholipase A₁/A₂ and acyltransferase activities that catalyze the hydrolysis of phospholipid acyl chains and the subsequent transfer of acyl groups, thereby modulating the composition and properties of cellular membranes. Such catalytic functions highlight the role of PLAAT1 in phospholipid metabolism and lipid remodeling, processes that are fundamental to normal cellular physiology and may also influence disease states."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": ""}, {"type": "p", "children": [{"type": "t", "text": "\nStudies on a member of this enzyme family, known as A‑C1 protein, reinforce the notion that PLAAT1 and its relatives operate as Ca²⁺‑independent phospholipases. In experiments where recombinant A‑C1 from human, mouse, and rat was overexpressed, a marked phospholipase A activity was observed—predominantly PLA₁ activity—with acyltransferase functions that further modify key membrane lipids. This dual enzymatic capability underscores the multifaceted role of PLAAT1 in lipid turnover and membrane remodeling in tissues including brain, testis, skeletal muscle, and heart."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": ""}, {"type": "p", "children": [{"type": "t", "text": "\nStructural investigations have provided additional insights into the catalytic mechanism of HRASLS enzymes. For instance, analysis of the N‑terminal domain of H‑REV107—a close homolog in this family—revealed a conserved Cys‑His‑His catalytic triad reminiscent of NlpC/P60 peptidases. Such structural similarities suggest that PLAAT1 likely employs a comparable catalytic strategy in its phospholipase and acyltransferase activities, offering a molecular basis for its role in phospholipid substrate processing."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": ""}, {"type": "p", "children": [{"type": "t", "text": "\nBeyond their enzymatic function, members of the HRASLS subfamily, including PLAAT1, have been implicated in the regulation of oncogenic Ras signaling. Biochemical and structural studies have demonstrated that these proteins can interact with activated Ras, thereby modulating its activity. Such interactions are thought to contribute to the tumor suppressor properties of the HRASLS proteins, linking PLAAT1 function to the inhibition of processes involved in uncontrolled cell proliferation."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "4"}]}, {"type": "t", "text": ""}, {"type": "p", "children": [{"type": "t", "text": "\nFinally, emerging integrative analyses in diverse disease contexts, such as Alzheimer’s disease and lung squamous cell carcinoma, underscore the broader significance of lipid metabolism reprogramming—the process in which PLAAT1 may play a contributory role. Although these studies primarily identified other lipid metabolism‑related genes, the observed associations highlight how perturbations in phospholipid remodeling and signaling, potentially mediated by enzymes like PLAAT1, can impact disease pathogenesis."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "5"}]}, {"type": "t", "text": ""}]}]}]}]}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Emily B Mardian, Ryan M Bradley, Robin E Duncan "}, {"type": "b", "children": [{"type": "t", "text": "The HRASLS (PLA/AT) subfamily of enzymes."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "J Biomed Sci (2015)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1186/s12929-015-0210-7"}], "href": "https://doi.org/10.1186/s12929-015-0210-7"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "26503625"}], "href": "https://pubmed.ncbi.nlm.nih.gov/26503625"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Naoki Shinohara, Toru Uyama, Xing-Hua Jin, et al. 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