Publications by authors named "Mengkai Ge"

Loss of phosphatase and tensin homolog (PTEN) has been linked to an immunosuppressive tumor microenvironment, but its underlying mechanisms remain largely enigmatic. Here, we report that PTEN can be secreted by the transmembrane emp24 domain-containing protein 10 (TMED10)-channeled protein secretion pathway. Inhibiting PTEN secretion from tumor cells contributes to immunosuppression and impairs the tumor-suppressive role of PTEN, while intratumoral injection of PTEN protein promotes antitumor immunity and suppresses tumor growth in mice.

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  • Scientists found that when cells lack amino acids, a process happens that causes a protein called mTOR to get a special tag (ubiquitination), which stops it from doing its job.
  • This happens because without enough amino acids, a type of molecule called tRNAs build up, which signals another protein called GCN2 to interact with mTOR.
  • Their research shows a new way that cells can sense whether they have enough amino acids through a specific pathway involving GCN2 and another protein, FBXO22.
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PTENα and PTENβ (PTENα/β), two long translational variants of phosphatase and tensin homolog on chromosome 10 (PTEN), exert distinct roles from canonical PTEN, including promoting carcinogenesis and accelerating immune-resistant cancer progression. However, their roles in carcinogenesis remain greatly unknown. Herein, we report that, after secreting into the extracellular space, PTENα/β proteins are efficiently cleaved into a short N-terminal and a long C-terminal fragment by the proprotein convertase Furin at a polyarginine stretch in their N-terminal extensions.

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Linker histone H1 proteins contain many variants in mammalian and can stabilize the condensed state of chromatin by binding to nucleosomes and promoting a more inaccessible structure of DNA. However, it is poorly understood how the binding of histone H1s to chromatin DNA is regulated. Screened as one of a collection of epithelial cells-enriched long non-coding RNAs (lncRNAs), here we found that small nucleolar RNA host gene 8 (SNHG8) is a chromatin-localized lncRNA and presents strong interaction and phase separation with histone H1 variants.

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  • Scientists found that a protein called ANP32B helps control another important protein called p53, which keeps blood-forming stem cells healthy.
  • When they removed ANP32B from these cells, it made it harder for the stem cells to recover after being hurt.
  • They also discovered that ANP32B is often high in cancer cells from patients with a type of leukemia, and by targeting ANP32B, it could help improve treatments for this cancer.
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Nuclear localization of PTEN is essential for its tumor suppressive role, and loss of nuclear PTEN is more prominent than cytoplasmic PTEN in many kinds of cancers. However, nuclear PTEN-specific regulatory mechanisms were rarely reported. Based on the finding that nuclear PTEN is more unstable than cytoplasmic PTEN, here we identify that F-box only protein 22 (FBXO22) induces ubiquitylation of nuclear but not cytoplasmic PTEN at lysine 221, which is responsible for the degradation of nuclear PTEN.

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An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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PTENα and PTENβ are two longer translational variants of phosphatase and tensin homolog (PTEN) messenger RNA. Their expressional regulations and functions in carcinogenesis remain largely unknown. Here, we demonstrate that, in contrast with the well-established tumour-suppressive role of canonical PTEN, PTENα and PTENβ promote tumourigenesis by directly interacting with the histone H3 lysine 4 (H3K4) presenter WDR5 to promote H3K4 trimethylation and maintain a tumour-promoting signature.

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Dysregulation of pre-mRNA alternative splicing (AS) is closely associated with cancers. However, the relationships between the AS and classic oncogenes/tumor suppressors are largely unknown. Here we show that the deletion of tumor suppressor PTEN alters pre-mRNA splicing in a phosphatase-independent manner, and identify 262 PTEN-regulated AS events in 293T cells by RNA sequencing, which are associated with significant worse outcome of cancer patients.

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Recently, we have reported that apoptosis-inducing factor (AIF) regulates the epithelial-mesenchymal transition (EMT) process of cancers, but the mechanisms underlying the regulation of AIF expression in cancers remain greatly unknown. Here, we report that hypoxia inversely correlates with the expression of AIF in tumor tissues from a cohort of colon cancer patients and inhibits AIF expression in multiple colon cancer cell lines. This inhibition is mediated by hypoxia-inducible factor-1 (HIF-1), which transcriptionally represses AIF through direct binding to the hypoxia-response element in AIF promoter as revealed by luciferase reporter and chromatin immunoprecipitation assays.

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Objective: To investigate the effect and mechanism of Factor Xa on the differentiation of Meg-01 cells into platelet-like particles.

Methods: The Meg-01 cells were used as experimental object, Factor Xa was used as agonist. Cell proliferation was detected by CCK-8 assay.

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Objectives: After development and differentiation, megakaryocytes (MKs) can produce platelets. As is well known, thrombopoietin (TPO) can induce MKs to differentiate. The effect of thrombin on MKs differentiation is not clear.

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Recurrent aphthous ulceration (RAU) is a common oral mucosal disease. The etiological involves in genetics, vitamin deficiencies, trauma, immune dysfunction and stress. This study was to explore the related risk factors of recurrent aphthous ulceration (RAU) among college students, and provide basis for further research.

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