Subtopic Deep Dive

mTORC1 Regulation by TSC-Rheb Axis
Research Guide

What is mTORC1 Regulation by TSC-Rheb Axis?

mTORC1 regulation by the TSC-Rheb axis involves the TSC1/2 complex acting as a GTPase-activating protein (GAP) for Rheb, inhibiting Rheb-GTP activation of mTORC1 until growth factors and nutrients relieve this suppression.

TSC2 phosphorylation by AKT and other kinases inactivates the TSC complex, allowing Rheb-GTP to recruit mTORC1 to lysosomes for activation (Laplante and Sabatini, 2009). Loss-of-function TSC mutations cause constitutive mTORC1 signaling in tuberous sclerosis and hamartomas. Over 2000 papers cite core mechanisms since foundational reviews.

Curated Papers

Key Challenges

Why It Matters

Dysregulated TSC-Rheb-mTORC1 signaling drives tuberous sclerosis complex (TSC) hamartomas and informs rapalog therapies like everolimus in renal cell carcinoma (Pópulo et al., 2012). In cancer, TSC2 mutations hyperactivate mTORC1, promoting tumor growth responsive to PI3K/AKT inhibitors (Glaviano et al., 2023). Targeting this axis with rapalogs extends progression-free survival in TSC-associated tumors and subsets of breast cancer (Hua et al., 2019).

Key Research Challenges

TSC2 Phosphorylation Heterogeneity

Multiple kinases including AKT, ERK, and AMPK phosphorylate distinct TSC2 sites, creating context-dependent regulation challenging unified models (Dibble and Cantley, 2015). Cancer mutations disrupt specific sites variably. Over 800 citations highlight unresolved signaling crosstalk.

Rheb Localization Dynamics

Rheb membrane association at lysosomes enables mTORC1 recruitment, but nutrient sensing alters this via TSC relocation (Laplante and Sabatini, 2009). Spatial regulation resists simple biochemical assays. Therapeutic targeting requires lysosomal specificity.

Rapalog Resistance Mechanisms

mTORC1 inhibition by rapalogs induces feedback AKT activation via relieved TSC suppression, limiting efficacy (Kim and Guan, 2015). Dual PI3K/mTOR inhibitors address this partially. Clinical trials show variable responses in TSC-mutant cancers (Zou et al., 2020).

Essential Papers

mTOR signaling at a glance

Mathieu Laplante, David M. Sabatini · 2009 · Journal of Cell Science · 2.1K citations

The mammalian target of rapamycin (mTOR) signaling pathway integrates both intracellular and extracellular signals and serves as a central regulator of cell metabolism, growth, proliferation and su...

mTOR: a pharmacologic target for autophagy regulation

Young Chul Kim, Kun‐Liang Guan · 2015 · Journal of Clinical Investigation · 2.0K citations

mTOR, a serine/threonine kinase, is a master regulator of cellular metabolism. mTOR regulates cell growth and proliferation in response to a wide range of cues, and its signaling pathway is deregul...

PI3K/AKT/mTOR signaling transduction pathway and targeted therapies in cancer

Antonino Glaviano, Aaron Song Chuan Foo, Hiu Yan Lam et al. · 2023 · Molecular Cancer · 1.6K citations

Abstract The PI3K/AKT/mTOR (PAM) signaling pathway is a highly conserved signal transduction network in eukaryotic cells that promotes cell survival, cell growth, and cell cycle progression. Growth...

Targeting PI3K/Akt signal transduction for cancer therapy

Yan He, Miao Sun, Guo Geng Zhang et al. · 2021 · Signal Transduction and Targeted Therapy · 1.6K citations

The kinase mTOR regulates the differentiation of helper T cells through the selective activation of signaling by mTORC1 and mTORC2

Greg M. Delgoffe, Kristen Pollizzi, Adam T. Waickman et al. · 2011 · Nature Immunology · 1.1K citations

Regulation and function of mTOR signalling in T cell fate decisions

Hongbo Chi · 2012 · Nature reviews. Immunology · 969 citations

Targeting mTOR for cancer therapy

Hui Hua, Qingbin Kong, Hongying Zhang et al. · 2019 · Journal of Hematology & Oncology · 905 citations

Reading Guide

Foundational Papers

Start with Laplante and Sabatini (2009, 2102 citations) for TSC-Rheb-mTORC1 overview, then Pópulo et al. (2012, 823 citations) for cancer contexts establishing core axis before phosphorylation details.

Recent Advances

Glaviano et al. (2023, 1583 citations) updates pathway therapies; Zou et al. (2020, 891 citations) analyzes rapalog challenges in TSC dysregulation.

Core Methods

TSC2 immunoprecipitation for kinase assays; Rheb-GTP pulldowns; lysosomal fractionation for mTORC1 localization; phospho-TSC2 mass spectrometry (Dibble and Cantley, 2015).

How PapersFlow Helps You Research mTORC1 Regulation by TSC-Rheb Axis

Discover & Search

Research Agent uses searchPapers('TSC2 Rheb mTORC1 cancer mutations') to retrieve 2102-cited Laplante and Sabatini (2009), then citationGraph to map TSC-Rheb regulators and findSimilarPapers for 2023 Glaviano advances; exaSearch uncovers obscure TSC2 phosphorylation datasets.

Analyze & Verify

Analysis Agent runs readPaperContent on Dibble and Cantley (2015) to extract TSC2 site maps, verifyResponse with CoVe against 825 citing papers for accuracy, and runPythonAnalysis to plot phosphorylation stoichiometries from supplementary tables using pandas; GRADE scores evidence strength for rapalog resistance claims.

Synthesize & Write

Synthesis Agent detects gaps in TSC-Rheb feedback loops across 50 papers via gap detection, flags PI3K/mTOR contradictions; Writing Agent applies latexEditText for signaling pathway revisions, latexSyncCitations for 200+ references, latexCompile figure panels, and exportMermaid for TSC-Rheb-mTORC1 diagrams.

Use Cases

"Extract TSC2 mutation frequencies in renal cancer from recent papers and plot by histology"

Research Agent → searchPapers → Analysis Agent → runPythonAnalysis(pandas groupby + matplotlib barplot) → CSV export of mutation rates by tumor type.

"Draft LaTeX review section on TSC-Rheb axis inhibitors with citations"

Synthesis Agent → gap detection → Writing Agent → latexEditText + latexSyncCitations(Glaviano 2023, Hua 2019) → latexCompile → PDF with pathway figure.

"Find GitHub repos implementing Rheb-GTPase assays from mTOR papers"

Research Agent → paperExtractUrls → Code Discovery → paperFindGithubRepo → githubRepoInspect → runnable Jupyter notebook for TSC knockout simulations.

Automated Workflows

Deep Research workflow scans 50+ TSC-Rheb papers via searchPapers → citationGraph → structured report ranking regulators by citation impact; DeepScan applies 7-step CoVe to verify rapalog resistance in Zou et al. (2020); Theorizer generates hypotheses on TSC2 site-specific inhibitors from Dibble and Cantley (2015) contradictions.

Try Doxa for mTORC1 Regulation by TSC-Rheb Axis Research

Frequently Asked Questions

What defines TSC-Rheb axis regulation of mTORC1?

TSC1/2 acts as Rheb GAP to keep Rheb-GDP inactive; growth factor-induced TSC2 phosphorylation relieves inhibition, enabling Rheb-GTP to activate mTORC1 at lysosomes (Laplante and Sabatini, 2009).

What are key methods studying this axis?

Phospho-specific antibodies map TSC2 sites; Rheb pulldowns quantify GTP loading; CRISPR TSC knockouts assess mTORC1 outputs like S6K phosphorylation (Dibble and Cantley, 2015).

What are seminal papers?

Laplante and Sabatini (2009, 2102 citations) overviews pathway; Dibble and Cantley (2015, 825 citations) details PI3K-TSC2 links; Pópulo et al. (2012, 823 citations) covers cancer implications.

What open problems remain?

Spatial Rheb-TSC dynamics at organelles; combinatorial TSC2 mutation effects; dual PI3K/mTOR inhibitors overcoming feedback resistance (Kim and Guan, 2015; Zou et al., 2020).