category
bioRxiv
date
Mar 12, 2026
slug
status
Published
summary
首次揭示TSC2的核内转录调控功能,发现其作为miR-514b-3p的转录因子通过NLS依赖机制调控MIR514B启动子活性,建立TSC2-miR-514b-3p-TSPAN9调控轴,并阐明该轴与PI3K-AKT-MTOR通路的串扰机制,同时发现AKT通过调控TSC2核定位影响该轴的上游调控。
tags
测序技术
type
Post

📄 原文题目

TSC2 acting as a transcription factor for miR-514b-3p and regulating PI3K-AKT-MTOR pathway via nucleus

🔗 原文链接

💡 AI 核心解读

首次揭示TSC2的核内转录调控功能,发现其作为miR-514b-3p的转录因子通过NLS依赖机制调控MIR514B启动子活性,建立TSC2-miR-514b-3p-TSPAN9调控轴,并阐明该轴与PI3K-AKT-MTOR通路的串扰机制,同时发现AKT通过调控TSC2核定位影响该轴的上游调控。

📝 英文原版摘要

The PI3K-AKT-MTOR signalling axis is pivotal in regulating cell survival, proliferation, and growth. TSC2 (tuberous sclerosis complex subunit 2) is a well-established negative regulator of this pathway, which primarily acts by suppressing the MTORC1 activity. While the cytoplasmic role of TSC2 is well characterized, emerging evidence suggests its additional nuclear functions. Previous work from our laboratory identified TSC2 as a transcriptional repressor of the EREG (Epiregulin) gene. Building on this foundation, the present study investigates the transcriptional role of TSC2 in miRNA (microRNA) gene regulation. A genome-wide miRNA microarray profiling of TSC2-depleted cells from an oral squamous cell carcinoma (OSCC) cell line, SCC131, identified 19 upregulated and 24 downregulated miRNAs. Of them, miR-514b-3p emerged as one of the most significantly upregulated miRNAs. TSC2 knockdown resulted in robust miR-514b-3p upregulation, whereas TSC2 overexpression suppressed its expression. Moreover, TSC2 negatively regulates MIR514B promoter activity in an NLS-dependent manner. The chromatin immunoprecipitation analysis showed direct binding between TSC2 and MIR514B promoter, establishing miR-514b-3p as a transcriptional target of TSC2. We further identified TSPAN9 (Tetraspanin 9) as a direct downstream target of miR-514b-3p. The dual-luciferase reporter assay and Western blot analysis confirmed direct interaction between miR-514b-3p and TSPAN9 3'UTR. Furthermore, TSC2 positively regulates TSPAN9 levels by repressing miR-514b-3p, thereby establishing a novel TSC2-miR-514b-3p-TSPAN9 regulatory axis. Additionally, we uncovered crosstalk between TSC2-miR-514b-3p-TSPAN9 axis and the canonical PI3K-AKT-MTOR signalling, where miR-514b-3p positively, and TSPAN9 negatively regulates
the PI3K-AKT-MTOR pathway. Interestingly, AKT functions as an upstream regulator of this axis by modulating TSC2 nuclear localization. Collectively, this study provides new insights into the non-canonical, nucleus-dependent transcriptional functions of TSC2, thus expanding its role beyond cytoplasmic signalling regulation and underscoring its significance in the cellular signalling networks.
在α1β2γ2 GABAA受体的α1亚基M2-M3连接区引入脯氨酸可解除通道激活的分子刹车基线细胞状态决定KRAS突变体在胰腺癌细胞中的分子影响
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