Faculty, Staff and Student Publications

Language

English

Publication Date

7-7-2025

Journal

Journal of Cell Biology

DOI

10.1083/jcb.202403126

PMID

40314454

PMCID

PMC12047185

PubMedCentral® Posted Date

5-2-2026

PubMedCentral® Full Text Version

Post-print

Abstract

KRAS, a small GTPase involved in cell proliferation and differentiation, frequently gains activating mutations in human cancers. For KRAS to function, it must bind the plasma membrane (PM) via interactions between its membrane anchor and phosphatidylserine (PtdSer). Therefore, depleting PM PtdSer abrogates KRAS PM binding and activity. From a genome-wide siRNA screen to identify genes regulating KRAS PM localization, we identified a set of phosphatidylinositol (PI) 3-phosphatases: myotubularin-related proteins (MTMR) 2, 3, 4, and 7. Here, we show that silencing MTMR 2/3/4/7 disrupts KRAS PM interactions by reducing PM PI 4-phosphate (PI4P) levels, thereby disrupting the localization and operation of ORP5, a lipid transfer protein maintaining PM PtdSer enrichment. Concomitantly, silencing MTMR 2/3/4/7 elevates PM PI3P levels while reducing PM and total PtdSer levels. We also observed MTMR 2/3/4/7 expression is interdependent. We propose that the PI 3-phosphatase activity of MTMR is required for generating PM PI, necessary for PM PI4P synthesis, promoting the PM localization of PtdSer and KRAS.

Keywords

Humans, Proto-Oncogene Proteins p21(ras), Cell Membrane, Phosphatidylinositol Phosphates, Phospholipids, Phosphatidylserines, Phosphoric Monoester Hydrolases, Receptors, Steroid, Cell Line, Tumor

Published Open-Access

yes

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