Palmitoylation and localisation of RAS isoforms are modulated by the hypervariable linker domain

Laude, Alex; Prior, Ian A.

doi:10.1242/jcs.020107

Cited by 115 publications

(114 citation statements)

References 31 publications

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“…Like N-Ras and H-Ras, the HVR of K-Ras4A contains a cysteine that has been shown to be palmitoylated (8). Indeed, the HVR of K-Ras4A shows sequence homology to that of N-Ras ( Fig.…”

Section: Significancementioning

confidence: 97%

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K-Ras4A splice variant is widely expressed in cancer and uses a hybrid membrane-targeting motif

Tsai

Lopes

Zhou

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

200

256

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The two products of the KRAS locus, K-Ras4A and K-Ras4B, are encoded by alternative fourth exons and therefore, possess distinct membrane-targeting sequences. The common activating mutations occur in exons 1 or 2 and therefore, render both splice variants oncogenic. K-Ras4A has been understudied, because it has been considered a minor splice variant. By priming off of the splice junction, we developed a quantitative RT-PCR assay for K-Ras4A and K-Ras4B message capable of measuring absolute amounts of the two transcripts. We found that K-Ras4A was widely expressed in 30 of 30 human cancer cell lines and amounts equal to K-Ras4B in 17 human colorectal tumors. Using splice variant-specific antibodies, we detected K-Ras4A protein in several tumor cell lines at a level equal to or greater than that of K-Ras4B. In addition to the CAAX motif, the C terminus of K-Ras4A contains a site of palmitoylation as well as a bipartite polybasic region. Although both were required for maximal efficiency, each of these could independently deliver K-Ras4A to the plasma membrane. Thus, among four Ras proteins, K-Ras4A is unique in possessing a dual membrane-targeting motif. We also found that, unlike K-Ras4B, K-Ras4A does not bind to the cytosolic chaperone δ-subunit of cGMP phosphodiesterase type 6 (PDE6δ). We conclude that efforts to develop anti–K-Ras drugs that interfere with membrane trafficking will have to take into account the distinct modes of targeting of the two K-Ras splice variants.

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“…Like N-Ras and H-Ras, the HVR of K-Ras4A contains a cysteine that has been shown to be palmitoylated (8). Indeed, the HVR of K-Ras4A shows sequence homology to that of N-Ras ( Fig.…”

Section: Significancementioning

confidence: 97%

“…The alternative fourth exons encode the HVRs of the proteins that are responsible for membrane targeting. Whereas K-Ras4B lacks a site of palmitoylation, K-Ras4A is palmitoylated (8). K-Ras4A mRNA is expressed early in embryogenesis and differentially expressed in adult tissues (9).…”

mentioning

confidence: 99%

K-Ras4A splice variant is widely expressed in cancer and uses a hybrid membrane-targeting motif

Tsai

Lopes

Zhou

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

200

256

View full text Add to dashboard Cite

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“…KRAS4A also relies on palmitoylation for high-affinity plasma membrane binding (14,16). We find that NADA inhibits plasma membrane translocation of GFP-KRAS4A-G12D as well (Fig.…”

Section: Nada Inhibits Oncogenic Nras Signalingmentioning

confidence: 54%

“…The polybasic region of KRAS4B has been shown to be critical for its plasma membrane targeting and functional activity (15). NRAS, HRAS, and KRAS4A are further palmitoylated on the Golgi, increasing their affinity to bind the plasma membrane (16,17). We have shown previously that interrupting the plasma membrane localization of NRAS and KRAS4A could significantly abrogate their leukemogenic potential (18)(19)(20).…”

Section: Introductionmentioning

confidence: 94%

N-Arachidonoyl Dopamine Inhibits NRAS Neoplastic Transformation by Suppressing Its Plasma Membrane Translocation

Huang

Zhang

et al. 2017

Molecular Cancer Therapeutics

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RAS oncogenic mutations are common in human cancers, but RAS proteins have been difficult to target. We sought to identify pharmacological agents to block RAS oncogenic signaling by a distinct mechanism. Because the biological activity of RAS proteins relies upon lipid modifications and RAS regulates lipid metabolisms in cancer cells, we screened a bioactive lipid library using a RAS-specific cell viability assay. We report the discovery of a new class of inhibitors for RAS transformation. Compounds in the class represented by endocannabinoid N-arachidonoyl dopamine (NADA) can induce cell oncosis, independent of its ability to engage cannabinoid receptors. Further analyses show that NADA is more active in inhibiting the NRAS transformation and signaling than that of KRAS4B. Mechanistically, NADA blocks the plasma membrane translocation of NRAS, but not that of KRAS4B. In addition, NADA inhibits plasma membrane translocation and neoplastic transformation of oncogenic KRAS4A. Interestingly, NADA also redistributes the cytoplasmic NRAS to the Golgi apparatus in a palmitoylation-dependent manner. The results indicate that NADA inhibits NRAS and KRAS4A plasma membrane translocation by targeting a novel molecular process. The new findings would help to develop novel targeted therapies for a broad range of human cancers.

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“…In vitro microscopy techniques have confirmed that signaling-inactive H-RasGDP resides in lipid rafts, but exits these domains when activated by GTP binding to signal from nonordered domains (27,28). With the aid of additional basic residues upstream in its HVR to stabilize the protein-membrane interaction, monopalmitoylated N-Ras can also access raft domains (29). To prevent isoform overlap and maintain unique effector pools, the bound nucleotide of N-Ras produces a membrane localization pattern opposite to that of H-Ras (Fig.…”

Section: Ras Isoform Microlocalization In the Plasma Membranementioning

confidence: 99%

The Ras–Membrane Interface: Isoform-Specific Differences in the Catalytic Domain

Parker

Mattos

2015

Molecular Cancer Research

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The small GTPase Ras is mutated in about 20% of human cancers, primarily at active site amino acid residues G12, G13, and Q61. Thus, structural biology research has focused on the active site, impairment of GTP hydrolysis by oncogenic mutants, and characterization of protein-protein interactions in the effector lobe half of the protein. The C-terminal hypervariable region has increasingly gained attention due to its importance in H-Ras, N-Ras, and K-Ras differences in membrane association. A highresolution molecular view of the Ras-membrane interaction involving the allosteric lobe of the catalytic domain has lagged behind, although evidence suggests that it contributes to isoform specificity. The allosteric lobe has recently gained interest for harboring potential sites for more selective targeting of this elusive "undruggable" protein. The present review reveals critical insight that isoform-specific differences appear prominently at these potentially targetable sites and integrates these differences with knowledge of Ras plasma membrane localization, with the intent to better understand the structure-function relationships needed to design isoform-specific Ras inhibitors. Mol Cancer Res; 13(4); 595-603. Ó2015 AACR.

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Palmitoylation and localisation of RAS isoforms are modulated by the hypervariable linker domain

Cited by 115 publications

References 31 publications

K-Ras4A splice variant is widely expressed in cancer and uses a hybrid membrane-targeting motif

K-Ras4A splice variant is widely expressed in cancer and uses a hybrid membrane-targeting motif

N-Arachidonoyl Dopamine Inhibits NRAS Neoplastic Transformation by Suppressing Its Plasma Membrane Translocation

The Ras–Membrane Interface: Isoform-Specific Differences in the Catalytic Domain

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