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Updated: Sep 4, 2025

A Mass Spectrometry-Based Approach to Identify Phosphoprotein Phosphatases and their Interactors
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A Mass Spectrometry-Based Approach to Identify Phosphoprotein Phosphatases and their Interactors

Published on: April 29, 2022

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Phosphoproteomic Analysis of FLCN Inactivation Highlights Differential Kinase Pathways and Regulatory TFEB

Iris E Glykofridis1, Alex A Henneman2, Jesper A Balk1

  • 1Amsterdam UMC, location VUmc, Vrije Universiteit Amsterdam, Human Genetics, Cancer Center Amsterdam, Amsterdam, The Netherlands.

Molecular & Cellular Proteomics : MCP
|July 21, 2022
PubMed

Insights

Loss of the Folliculin (FLCN) gene in Birt-Hogg-Dubé syndrome alters renal cell kinase signaling, impacting pathways like MAPK and PIK3CD. This reveals potential new therapeutic targets for BHD-associated renal cancer.

Area of Science:

  • Molecular Biology
  • Oncology
  • Genetics

Background:

  • Birt-Hogg-Dubé (BHD) syndrome is linked to Folliculin (FLCN) gene mutations, increasing renal cancer risk.
  • Understanding how FLCN inactivation affects cellular signaling is crucial for BHD pathogenesis research.

Purpose of the Study:

  • To investigate the impact of FLCN inactivation on kinase signaling pathways in human renal tubular epithelial cells.
  • To identify specific kinases and downstream targets affected by FLCN loss for potential therapeutic strategies.

Main Methods:

  • Comprehensive phosphoproteomic profiling of FLCN-positive (FLCNPOS) and FLCN-negative (FLCNNEG) renal cells.
  • INKA analysis to identify altered kinase activities and downstream signaling.
  • Validation experiments in BHD renal tumor cell lines and assessment of drug sensitivity.

Main Results:

  • FLCN loss significantly altered the phosphorylation status of numerous kinases, including EGFR, MET, EPHA2, EPHB1, and MAPK1/3.
  • Enhanced MAPK1/3 and RPS6K1/3 signaling was confirmed in FLCN-negative cells, with increased sensitivity to MAPK inhibitor Ulixertinib.
  • FLCN inactivation led to PIK3CD phosphorylation and TFEB dephosphorylation, potentially linked to oxidative stress.

Conclusions:

  • FLCN inactivation drives differential phosphorylation of specific kinases and substrates in renal cells, contributing to BHD-associated renal tumorigenesis.
  • The study identifies novel signaling alterations and potential therapeutic targets, such as MAPK pathway inhibitors, for BHD-related renal cancers.

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