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Updated: Jul 4, 2025

Fully Processed Recombinant KRAS4b: Isolating and Characterizing the Farnesylated and Methylated Protein
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Fully Processed Recombinant KRAS4b: Isolating and Characterizing the Farnesylated and Methylated Protein

Published on: January 16, 2020

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MTMR regulates KRAS function by controlling plasma membrane levels of phospholipids

Taylor E Lange, Ali Naji, Ransome van der Hoeven

    Biorxiv : the Preprint Server for Biology
    |February 8, 2024
    PubMed

    Insights

    Myotubularin-related proteins (MTMR) regulate KRAS protein localization by maintaining plasma membrane phosphatidylserine (PtdSer) levels. Silencing MTMR disrupts this process, impacting cancer cell proliferation and differentiation.

    Area of Science:

    • Cell Biology
    • Molecular Oncology

    Background:

    • KRAS, a GTPase crucial for cell signaling, requires plasma membrane (PM) binding for its function.
    • KRAS localization to the PM depends on interactions with phosphatidylserine (PtdSer).

    Purpose of the Study:

    • To identify genes regulating KRAS PM localization.
    • To elucidate the role of phosphatidylinositol (PI) 3-phosphatases in KRAS membrane binding.

    Main Methods:

    • Genome-wide siRNA screen to identify regulators of KRAS PM localization.
    • Analysis of PI 4-phosphate (PI4P) and PI 3-phosphate (PI3P) levels in response to MTMR silencing.
    • Assessment of PtdSer and ORP5 localization.

    Main Results:

    • Silencing myotubularin-related proteins (MTMR) 2, 3, 4, and 7 disrupts KRAS PM interactions.
    • MTMR depletion reduces PM PI4P, impairing ORP5 function and PtdSer enrichment at the PM.
    • MTMR silencing elevates PM PI3P and reduces PM and total PtdSer levels.

    Conclusions:

    • MTMR proteins are essential for maintaining PM PtdSer levels necessary for KRAS localization.
    • MTMR PI 3-phosphatase activity is required for generating PM PI, supporting PI4P synthesis and PtdSer enrichment.
    • Dysregulation of MTMR impacts KRAS signaling, potentially affecting cancer progression.

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