Dynamics of KRas on endosomes: involvement of acidic phospholipids in its association

Gelabert-Baldrich, Mariona; Soriano-Castell, David; Calvo, Marı́a; Lu, Albert; Viña-Vilaseca, Arnau; Rentero, Carles; Pol, Albert; Grinstein, Sergio; Enrich, Carlos; Tebar, Francesc

doi:10.1096/fj.13-241158

Cited by 18 publications

(15 citation statements)

References 69 publications

(102 reference statements)

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“…In addition to this, we also believe that a potential polybasic region (aa 16 -18) adjacent to transmembrane helices plays a synergistic role in membrane attachment. Polybasic regions (PBR) in small GTPases such as K-Ras4B have been shown to enhance membrane association with negatively charged phospholipids in the plasma membrane (43,44). We speculate that the PBR in PRCD could be contributing similarly along with adjacent hydrophobic transmembrane helices.…”

Section: Discussionmentioning

confidence: 93%

Palmitoylation of Progressive Rod-Cone Degeneration (PRCD) Regulates Protein Stability and Localization

Murphy

Kolandaivelu

2016

Journal of Biological Chemistry

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Progressive rod-cone degeneration (PRCD) is a photoreceptor outer segment (OS) disc-specific protein with unknown function that is associated with retinitis pigmentosa (RP). The most common mutation in PRCD linked with severe RP phenotype is substitution of the only cysteine to tyrosine (C2Y). In this study, we find that PRCD is post-translationally modified by a palmitoyl lipid group at the cysteine residue linked with RP. Disrupting PRCD palmitoylation either chemically or by genetically eliminating the modified cysteine dramatically affects the stability of PRCD. Furthermore, in vivo electroporation of PRCD C2Y mutant in the mouse retina demonstrates that the palmitoylation of PRCD is important for its proper localization in the photoreceptor OS. Mutant PRCD C2Y was found in the inner segment in contrast to normal localization of WT PRCD in the OS. Our results also suggest that zDHHC3, a palmitoyl acyltransferase (PAT), catalyzes the palmitoylation of PRCD in the Golgi compartment. In conclusion, we find that the palmitoylation of PRCD is crucial for its trafficking to the photoreceptor OS and mislocalization of this protein likely leads to RP-related phenotypes.

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Section: Discussionmentioning

confidence: 93%

Palmitoylation of Progressive Rod-Cone Degeneration (PRCD) Regulates Protein Stability and Localization

Murphy

Kolandaivelu

2016

Journal of Biological Chemistry

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“…KRAS4A and KRAS4B have polybasic sequences that facilitate membraneassociation in acidic membrane regions (Gelabert-Baldrich et al, 2014). In addition, KRAS4A and NRAS are covalently modified by a single palmitic acid, whereas HRAS can be palmitoylated at two sites within the HVR.…”

Section: Ras Isoform Differences and Post-translational Modificationsmentioning

confidence: 99%

RAS isoforms and mutations in cancer at a glance

Hobbs

Der

Rossman

2016

Journal of Cell Science

666

709

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RAS proteins (KRAS4A, KRAS4B, NRAS and HRAS) function as GDP-GTP-regulated binary on-off switches, which regulate cytoplasmic signaling networks that control diverse normal cellular processes. Gain-of-function missense mutations in RAS genes are found in ∼25% of human cancers, prompting interest in identifying anti-RAS therapeutic strategies for cancer treatment. However, despite more than three decades of intense effort, no anti-RAS therapies have reached clinical application. Contributing to this failure has been an underestimation of the complexities of RAS. First, there is now appreciation that the four human RAS proteins are not functionally identical. Second, with >130 different missense mutations found in cancer, there is an emerging view that there are mutation-specific consequences on RAS structure, biochemistry and biology, and mutation-selective therapeutic strategies are needed. In this Cell Science at a Glance article and accompanying poster, we provide a snapshot of the differences between RAS isoforms and mutations, as well as the current status of anti-RAS drug-discovery efforts.

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“…A lack of requirement for GTP binding in the release of K-Ras to exosomes is not entirely surprising, because a recent study of K-Ras did not find any statistically significant differences between the percentages of G12V and S17N mutants localized to endosomes (79). By contrast, this prior study revealed an increase in the fluorescence recovery after photobleaching halftime and immobile fractions for the GFP K-Ras S17N mutant as compared with GFP fusions to either active forms of K-Ras (wild-type or G12V).…”

Section: Mvbmentioning

confidence: 99%

Secreted Glioblastoma Nanovesicles Contain Intracellular Signaling Proteins and Active Ras Incorporated in a Farnesylation-dependent Manner

Luhtala

Aslanian

Yates

et al. 2017

Journal of Biological Chemistry

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Edited by Alex TokerGlioblastomas (GBMs) are malignant brain tumors with a median survival of less than 18 months. Redundancy of signaling pathways represented within GBMs contributes to their therapeutic resistance. Exosomes are extracellular nanovesicles released from cells and present in human biofluids that represent a possible biomarker of tumor signaling state that could aid in personalized treatment. Herein, we demonstrate that mouse GBM cell-derived extracellular nanovesicles resembling exosomes from an H-RasV12 myr-Akt mouse model for GBM are enriched for intracellular signaling cascade proteins (GO: 0007242) and Ras protein signal transduction (GO: 0007265), and contain active Ras. Active Ras isolated from human and mouse GBM extracellular nanovesicles lysates using the Rasbinding domain of Raf also coprecipitates with ESCRT (endosomal sorting complex required for transport)-associated exosome proteins Vps4a and Alix. Although we initially hypothesized a role for active Ras protein signaling in exosome biogenesis, we found that GTP binding of K-Ras was dispensable for its packaging within extracellular nanovesicles and for the release of Alix. By contrast, farnesylation of K-Ras was required for its packaging within extracellular nanovesicles, yet expressing a K-Ras farnesylation mutant did not decrease the number of nanovesicles or the amount of Alix protein released per cell. Overall, these results emphasize the primary importance of membrane association in packaging of extracellular nanovesicle factors and indicate that screening nanovesicles within human fluids could provide insight into tissue origin and the wiring of signaling proteins at membranes to predict onset and behavior of cancer and other diseases linked to deregulated membrane signaling states.

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Dynamics of KRas on endosomes: involvement of acidic phospholipids in its association

Cited by 18 publications

References 69 publications

Palmitoylation of Progressive Rod-Cone Degeneration (PRCD) Regulates Protein Stability and Localization

Palmitoylation of Progressive Rod-Cone Degeneration (PRCD) Regulates Protein Stability and Localization

RAS isoforms and mutations in cancer at a glance

Secreted Glioblastoma Nanovesicles Contain Intracellular Signaling Proteins and Active Ras Incorporated in a Farnesylation-dependent Manner

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