Inhibition of Acid Sphingomyelinase Depletes Cellular Phosphatidylserine and Mislocalizes K-Ras from the Plasma Membrane

Kwang-jin Cho; Dharini van der Hoeven; Yong Zhou; Masashi Maekawa; Xiaoping Ma; Wei Chen; Gregory D. Fairn; John F. Hancock

doi:10.1128/MCB.00719-15

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Inhibition of Acid Sphingomyelinase Depletes Cellular Phosphatidylserine and Mislocalizes K-Ras from the Plasma Membrane

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Inhibition of Acid Sphingomyelinase Depletes Cellular Phosphatidylserine and Mislocalizes K-Ras from the Plasma Membrane

Kwang-jin Cho, Dharini van der Hoeven, Yong Zhou, Masashi Maekawa, Xiaoping Ma, Wei Chen, Gregory D. Fairn and John F. Hancock

Molecular and cellular biology, Vol.36(2), pp.363-374

01/01/2016

DOI: 10.1128/MCB.00719-15

PMCID: PMC4719297

PMID: 26572827

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Abstract

K-Ras must localize to the plasma membrane for biological activity; thus, preventing plasma membrane interaction blocks K-Ras signal output. Here we show that inhibition of acid sphingomyelinase (ASM) mislocalizes both the K-Ras isoforms K-Ras4A and K-Ras4B from the plasma membrane to the endomembrane and inhibits their nanoclustering. We found that fendiline, a potent ASM inhibitor, reduces the phosphatidylserine (PtdSer) and cholesterol content of the inner plasma membrane. These lipid changes are causative because supplementation of fendiline-treated cells with exogenous PtdSer rapidly restores K-Ras4A and K-Ras4B plasma membrane binding, nanoclustering, and signal output. Conversely, supplementation with exogenous cholesterol restores K-Ras4A but not K-Ras4B nanoclustering. These experiments reveal different operational pools of PtdSer on the plasma membrane. Inhibition of ASM elevates cellular sphingomyelin and reduces cellular ceramide levels. Concordantly, delivery of recombinant ASM or exogenous ceramide to fendiline-treated cells rapidly relocalizes K-Ras4B and PtdSer to the plasma membrane. K-Ras4B mislocalization is also recapitulated in ASM-deficient Neimann-Pick type A and B fibroblasts. This study identifies sphingomyelin metabolism as an indirect regulator of K-Ras4A and K-Ras4B signaling through the control of PtdSer plasma membrane content. It also demonstrates the critical and selective importance of PtdSer to K-Ras4A and K-Ras4B plasma membrane binding and nanoscale spatial organization.

Biochemistry & Molecular Biology

Cell Biology

Life Sciences & Biomedicine

Science & Technology

Details

Title: Subtitle: Inhibition of Acid Sphingomyelinase Depletes Cellular Phosphatidylserine and Mislocalizes K-Ras from the Plasma Membrane
Creators: Kwang-jin Cho - The University of Texas Health Science Center at Houston
Dharini van der Hoeven - The University of Texas Health Science Center at Houston
Yong Zhou - The University of Texas Health Science Center at Houston
Masashi Maekawa - Ehime University
Xiaoping Ma - The University of Texas Health Science Center at Houston
Wei Chen - The University of Texas Health Science Center at Houston
Gregory D. Fairn - St. Michael's Hospital
John F. Hancock - The University of Texas Health Science Center at Houston
Resource Type: Journal article
Publication Details: Molecular and cellular biology, Vol.36(2), pp.363-374
DOI: 10.1128/MCB.00719-15
PMID: 26572827
PMCID: PMC4719297
NLM abbreviation: Mol Cell Biol
ISSN: 0270-7306
eISSN: 1098-5549
Publisher: Amer Soc Microbiology
Number of pages: 12
Grant note: CPRIT: RP130059 / Cancer Research and Prevention Institute of Texas; Cancer Prevention & Research Institute of Texas MOP-133656 / Canadian Institutes of Health Research; Canadian Institutes of Health Research (CIHR) K99-CA188593 / NIH; United States Department of Health & Human Services; National Institutes of Health (NIH) - USA UT School of Dentistry
Language: English
Date published: 01/01/2016
Academic Unit: Oral Pathology, Radiology and Medicine; Dentistry Administration
Record Identifier: 9985157465302771

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