{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nMARVELD1 is widely expressed in normal human tissues yet is frequently downregulated in multiple tumor types due to epigenetic modifications such as promoter methylation and, in some cases, genetic deletion. In hepatocellular carcinoma and other cancers, reduced MARVELD1 levels correlate with enhanced tumor cell proliferation and decreased chemosensitivity. Conversely, restoration or overexpression of MARVELD1 suppresses tumor growth by modulating key regulatory proteins (for example, increasing p53 and p16 while decreasing p-ERK1/2 and cyclin D1) and reestablishing normal cell cycle control. Notably, MARVELD1 primarily localizes to the nucleus in normal cells."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nBeyond its tumor-suppressive effects, MARVELD1 plays a critical role in regulating cell adhesion and motility. Its expression influences the balance and distribution of integrin subunits (β1 and β4) on the cell surface, thereby affecting the formation of integrin clusters in microvilli, the organization of actin, and focal adhesion complex signaling (evidenced by decreased vinculin expression and reduced FAK Tyr397 phosphorylation upon overexpression). Moreover, MARVELD1 participates in pre-mRNA processing of integrin β1, thereby modulating cell–extracellular matrix interactions and the epithelial–mesenchymal transition (EMT) in contexts such as non-small cell lung cancer."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "3"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nMARVELD1 is also involved in post‐transcriptional regulation via the modulation of nonsense-mediated mRNA decay (NMD). Through interactions with core NMD components such as SMG1, UPF1, and Y14, MARVELD1 inhibits the pioneer round of translation. It achieves this by promoting the dissociation of SMG1 from UPF1, thereby reducing UPF1 serine phosphorylation and blocking the subsequent recruitment of degradative factors like SMG5. This regulatory mechanism ultimately diminishes the efficiency of NMD, affecting the turnover of mRNAs that contain premature termination codons."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "5"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nUnder conditions of cellular stress, MARVELD1 translocates from its usual nuclear location to the cytoplasm and mitochondria. In these stressed cells, MARVELD1 interacts with the antioxidant enzyme catalase, thereby enhancing its stability and activity. This interaction facilitates more effective scavenging of reactive oxygen species (ROS), leading to reduced intracellular ROS levels, inhibition of tumor cell proliferation, and increased sensitivity to chemotherapeutic agents, particularly in carcinomas of the reproductive system."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "7"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nIn gliomas, the function of MARVELD1 appears to contrast with its tumor‐suppressive role in other cancers. High expression levels of MARVELD1 in glioma tissues correlate with advanced disease grade and poorer patient survival. Functional studies have demonstrated that MARVELD1 promotes malignant behaviors—including increased cell proliferation, migration, and invasion—by activating the JAK/STAT signaling pathway."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "8"}]}, {"type": "t", "text": "\n"}]}, {"type": "t", "text": "\n\n"}, {"type": "p", "children": [{"type": "t", "text": "\nFinally, the intracellular distribution of MARVELD1 is regulated via its interaction with importin‐β1. Importin‐β1 mediates the non‐classical nucleocytoplasmic transport of MARVELD1, and disruption of this interaction shifts MARVELD1 from the nucleus to the cytoplasm while also affecting its overall protein density. This regulatory mechanism underscores the importance of MARVELD1’s subcellular localization in executing its diverse cellular functions."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "9"}]}, {"type": "t", "text": "\n"}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Shan Wang, Yu Li, Fang Han, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Identification and characterization of MARVELD1, a novel nuclear protein that is down-regulated in multiple cancers and silenced by DNA methylation."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Cancer Lett (2009)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1016/j.canlet.2009.03.008"}], "href": "https://doi.org/10.1016/j.canlet.2009.03.008"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "19364627"}], "href": "https://pubmed.ncbi.nlm.nih.gov/19364627"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Youtao Yu, Yubao Zhang, Jianran Hu, et al. "}, {"type": "b", "children": [{"type": "t", "text": "MARVELD1 inhibited cell proliferation and enhance chemosensitivity via increasing expression of p53 and p16 in hepatocellular carcinoma."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Cancer Sci (2012)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1111/j.1349-7006.2012.02220.x"}], "href": "https://doi.org/10.1111/j.1349-7006.2012.02220.x"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "22320884"}], "href": "https://pubmed.ncbi.nlm.nih.gov/22320884"}]}, {"type": "r", "ref": 3, "children": [{"type": "t", "text": "Yuanfei Yao, Ming Shi, Shanshan Liu, et al. 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