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Clinical Cancer Research : An Official... Apr 2015RAS proteins require membrane association for their biologic activity, making this association a logical target for anti-RAS therapeutics. Lipid modification of RAS... (Review)
Review
RAS proteins require membrane association for their biologic activity, making this association a logical target for anti-RAS therapeutics. Lipid modification of RAS proteins by a farnesyl isoprenoid is an obligate step in that association, and is an enzymatic process. Accordingly, farnesyltransferase inhibitors (FTI) were developed as potential anti-RAS drugs. The lack of efficacy of FTIs as anticancer drugs was widely seen as indicating that blocking RAS membrane association was a flawed approach to cancer treatment. However, a deeper understanding of RAS modification and trafficking has revealed that this was an erroneous conclusion. In the presence of FTIs, KRAS and NRAS, which are the RAS isoforms most frequently mutated in cancer, become substrates for alternative modification, can still associate with membranes, and can still function. Thus, FTIs failed not because blocking RAS membrane association is an ineffective approach, but because FTIs failed to accomplish that task. Recent findings regarding RAS isoform trafficking and the regulation of RAS subcellular localization have rekindled interest in efforts to target these processes. In particular, improved understanding of the palmitoylation/depalmitoylation cycle that regulates RAS interaction with the plasma membrane, endomembranes, and cytosol, and of the potential importance of RAS chaperones, have led to new approaches. Efforts to validate and target other enzymatically regulated posttranslational modifications are also ongoing. In this review, we revisit lessons learned, describe the current state of the art, and highlight challenging but promising directions to achieve the goal of disrupting RAS membrane association and subcellular localization for anti-RAS drug development. Clin Cancer Res; 21(8); 1819-27. ©2015 AACR. See all articles in this CCR Focus section, "Targeting RAS-Driven Cancers."
Topics: Acetyltransferases; Acylation; Alkyl and Aryl Transferases; Amino Acid Motifs; Animals; Antineoplastic Agents; Carrier Proteins; Cell Membrane; Drug Discovery; Endopeptidases; Humans; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Molecular Targeted Therapy; Neoplasms; Phosphorylation; Protein Interaction Domains and Motifs; Protein Kinase C; Protein Prenylation; Protein Transport; Proto-Oncogene Proteins p21(ras); Signal Transduction; Thiolester Hydrolases
PubMed: 25878363
DOI: 10.1158/1078-0432.CCR-14-3214 -
Proceedings of the National Academy of... May 2017Cerebral cavernous malformations (CCMs) are common vascular anomalies that develop in the central nervous system and, more rarely, the retina. The lesions can cause...
Cerebral cavernous malformations (CCMs) are common vascular anomalies that develop in the central nervous system and, more rarely, the retina. The lesions can cause headache, seizures, focal neurological deficits, and hemorrhagic stroke. Symptomatic lesions are treated according to their presentation; however, targeted pharmacological therapies that improve the outcome of CCM disease are currently lacking. We performed a high-throughput screen to identify Food and Drug Administration-approved drugs or other bioactive compounds that could effectively suppress hyperproliferation of mouse brain primary astrocytes deficient for CCM3. We demonstrate that fluvastatin, an inhibitor of 3-hydroxy-3-methyl-glutaryl (HMG)-CoA reductase and the -bisphosphonate zoledronic acid monohydrate, an inhibitor of protein prenylation, act synergistically to reverse outcomes of CCM3 loss in cultured mouse primary astrocytes and in glial cells in vivo. Further, the two drugs effectively attenuate neural and vascular deficits in chronic and acute mouse models of CCM3 loss in vivo, significantly reducing lesion burden and extending longevity. Sustained inhibition of the mevalonate pathway represents a potential pharmacological treatment option and suggests advantages of combination therapy for CCM disease.
Topics: Animals; Astrocytes; Diphosphonates; Drosophila; Drug Evaluation, Preclinical; Drug Therapy, Combination; Endothelial Cells; Fatty Acids, Monounsaturated; Female; Fluvastatin; Hemangioma, Cavernous, Central Nervous System; High-Throughput Screening Assays; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Imidazoles; Indoles; MAP Kinase Signaling System; Male; Mice; Pregnancy; Protein Prenylation; Zoledronic Acid
PubMed: 28500274
DOI: 10.1073/pnas.1702942114 -
Cancer Cell Apr 2005Protein farnesylation is a lipid posttranslational modification required for the cancer-causing activity of proteins such as the GTPase Ras. Although farnesyltransferase... (Review)
Review
Protein farnesylation is a lipid posttranslational modification required for the cancer-causing activity of proteins such as the GTPase Ras. Although farnesyltransferase inhibitors (FTIs) are in clinical trials, their mechanism of action and the role of protein farnesylation in normal physiology are ill understood. In this issue of Cancer Cell, two articles shed light on these important issues. Protein farnesylation was found to be essential for early embryogenesis, dispensable for adult homeostasis, and critical for progression but not initiation of tumorigenesis. Furthermore, Rab geranylgeranyltransferase was identified as a target for some FTIs. This minireview discusses the implications of these findings on normal physiology, malignant transformation, and cancer therapy.
Topics: Alkyl and Aryl Transferases; Animals; Caenorhabditis elegans; Cell Proliferation; Cell Transformation, Neoplastic; Embryonic Development; Enzyme Inhibitors; Homeostasis; Humans; Mice; Neoplasms; Protein Prenylation; Protein Processing, Post-Translational; rab GTP-Binding Proteins; ras Proteins; rho GTP-Binding Proteins
PubMed: 15837619
DOI: 10.1016/j.ccr.2005.04.005 -
Current Cancer Drug Targets Sep 2010Polyisoprenylated proteins (PPs) methylation by polyisoprenylated protein methyl transferase (PPMTase) is counteracted by polyisoprenylated methylated protein methyl... (Review)
Review
Polyisoprenylated proteins (PPs) methylation by polyisoprenylated protein methyl transferase (PPMTase) is counteracted by polyisoprenylated methylated protein methyl esterase (PMPMEase). This is the only reversible step of the polyisoprenylation pathway as the relative amounts of the acid and ester forms are determined by the two competing reactions. Since PMPMEase and PPMTase may influence both the structural/functional conformations of PPs, a thorough study of these enzymes is essential to our understanding of the structural/functional features of PPs. PMPMEase has been reported under such pseudonyms as human carboxylesterase 1 (hCE1) because of its apparent broad substrate spectrum. The current study aimed to show the complementarity between its active site and the polyisoprenylated substrates that it metabolizes. Kinetics analysis was conducted with N-, S- and O-substituted substrates using porcine liver PMPMEase and docking analysis using Arguslab. Consistent with the biochemical analysis, the S-ethyl analog yielded an AScore binding energy of -11.32 compared to -13.48, -14.88, -16.15, and -16.81 kcal/mol for S-prenyl (C-5), S-trans-geranyl (C-10), S-trans,trans-farnesyl (C-15) and S-all trans-geranylgeranyl (C-20), respectively. The all trans-geranylgeranyl moiety provides the optimal size for active site interactions. The data reveal that the trans,trans-farnesyl and all trans-geranylgeranyl groups, which are reminiscent of endogenous PPs modifications, have the highest affinity for PMPMEase. Since PPs such as monomeric G-proteins are oncogenic, PMPMEase may be viewed as a viable target for anticancer drug development. The analyses reveal the important structural elements for the design of specific PMPMEase inhibitors to serve in the modulation of oncogenic PPs activities. The results also show that hCE1's repertoire of substrates extends beyond xenobiotics to include PPs as its endogenous substrates.
Topics: Animals; Carboxylic Ester Hydrolases; Humans; Methylation; Protein Conformation; Protein Methyltransferases; Protein Prenylation; Swine
PubMed: 20491620
DOI: 10.2174/156800910791859443 -
Nature Structural & Molecular Biology Jul 2019Protein prenylation is believed to be catalyzed by three heterodimeric enzymes: FTase, GGTase1 and GGTase2. Here we report the identification of a previously unknown...
Protein prenylation is believed to be catalyzed by three heterodimeric enzymes: FTase, GGTase1 and GGTase2. Here we report the identification of a previously unknown human prenyltransferase complex consisting of an orphan prenyltransferase α-subunit, PTAR1, and the catalytic β-subunit of GGTase2, RabGGTB. This enzyme, which we named GGTase3, geranylgeranylates FBXL2 to allow its localization at cell membranes, where this ubiquitin ligase mediates the polyubiquitylation of membrane-anchored proteins. In cells, FBXL2 is specifically recognized by GGTase3 despite having a typical carboxy-terminal CaaX prenylation motif that is predicted to be recognized by GGTase1. Our crystal structure analysis of the full-length GGTase3-FBXL2-SKP1 complex reveals an extensive multivalent interface specifically formed between the leucine-rich repeat domain of FBXL2 and PTAR1, which unmasks the structural basis of the substrate-enzyme specificity. By uncovering a missing prenyltransferase and its unique mode of substrate recognition, our findings call for a revision of the 'prenylation code'.
Topics: Alkyl and Aryl Transferases; Cell Line; Crystallography, X-Ray; Dimethylallyltranstransferase; F-Box Proteins; HeLa Cells; Humans; Models, Molecular; Polyubiquitin; Protein Conformation; Protein Prenylation; Protein Subunits
PubMed: 31209342
DOI: 10.1038/s41594-019-0249-3 -
PloS One 2012The Drosophila mutant loechrig (loe) shows age-dependent degeneration of the nervous system and is caused by the loss of a neuronal isoform of the AMP-activated protein...
The Drosophila mutant loechrig (loe) shows age-dependent degeneration of the nervous system and is caused by the loss of a neuronal isoform of the AMP-activated protein kinase (AMPK) γ-subunit (also known as SNF4Aγ). The trimeric AMPK complex is activated by low energy levels and metabolic insults and regulates multiple important signal pathways that control cell metabolism. A well-known downstream target of AMPK is hydroxyl-methylglutaryl-CoA reductase (HMGR), a key enzyme in isoprenoid synthesis, and we have previously shown that HMGR genetically interacts with loe and affects the severity of the degenerative phenotype. Prenylation of proteins like small G-proteins is an important posttranslational modification providing lipid moieties that allow the association of these proteins with membranes, thereby facilitating their subsequent activation. Rho proteins have been extensively studied in neuronal outgrowth, however, much less is known about their function in neuronal maintenance. Here we show that the loe mutation interferes with isoprenoid synthesis, leading to increased prenylation of the small GTPase Rho1, the fly orthologue of vertebrate RhoA. We also demonstrate that increased prenylation and Rho1 activity causes neurodegeneration and aggravates the behavioral and degenerative phenotypes of loe. Because we cannot detect defects in the development of the central nervous system in loe, this suggests that loe only interferes with the function of the RhoA pathway in maintaining neuronal integrity during adulthood. In addition, our results show that alterations in isoprenoids can result in progressive neurodegeneration, supporting findings in vertebrates that prenylation may play a role in neurodegenerative diseases like Alzheimer's Disease.
Topics: AMP-Activated Protein Kinases; Animals; Drosophila; Hydroxymethylglutaryl CoA Reductases; Mutation; Nervous System; Protein Prenylation; rhoA GTP-Binding Protein
PubMed: 22970217
DOI: 10.1371/journal.pone.0044440 -
The Plant Journal : For Cell and... May 2014Protein prenylation is required for a variety of growth and developmental processes in flowering plants. Here we report the consequences of loss of function of all known...
Protein prenylation is required for a variety of growth and developmental processes in flowering plants. Here we report the consequences of loss of function of all known prenylation subunits in the moss Physcomitrella patens. As in Arabidopsis, protein farnesyltransferase and protein geranylgeranyltransferase type I are not required for viability. However, protein geranylgeranyltransferase type I activity is required for cell adhesion, polar cell elongation, and cell differentiation. Loss of protein geranylgeranyltransferase activity results in colonies of round, single-celled organisms that resemble unicellular algae. The loss of protein farnesylation is not as severe but also results in polar cell elongation and differentiation defects. The complete loss of Rab geranylgeranyltransferase activity appears to be lethal in P. patens. Labeling with antibodies to cell wall components support the lack of polarity establishment and the undifferentiated state of geranylgeranyltransferase type I mutant plants. Our results show that prenylated proteins play key roles in P. patens development and differentiation processes.
Topics: Alkyl and Aryl Transferases; Animals; Arabidopsis; Bryopsida; Cell Adhesion; Cell Differentiation; Cell Polarity; Cell Wall; Gene Knockdown Techniques; Genetic Complementation Test; Light; Mutation; Plant Proteins; Protein Prenylation
PubMed: 24634995
DOI: 10.1111/tpj.12484 -
ACS Chemical Biology Jun 2007The cell has >60 different farnesylated proteins. Many critically important signal transduction proteins are post-translationally modified with attachment of a farnesyl...
The cell has >60 different farnesylated proteins. Many critically important signal transduction proteins are post-translationally modified with attachment of a farnesyl isoprenoid catalyzed by protein farnesyltransferase (FTase). Recently, it has been shown that farnesyl diphosphate (FPP) analogues can alter the peptide substrate specificity of FTase. We have used combinatorial screening of FPP analogues and peptide substrates to identify patterns in FTase substrate selectivity. Each FPP analogue displays a unique pattern of substrate reactivity with the tested peptides; FTase efficiently catalyzes the transfer of an FPP analogue selectively to one peptide and not another. Furthermore, we have demonstrated that these analogues can enter cells and be incorporated into proteins. These FPP analogues could serve as selective tools to examine the role prenylation plays in individual protein function.
Topics: Combinatorial Chemistry Techniques; Humans; Jurkat Cells; Polyisoprenyl Phosphates; Protein Prenylation; Sesquiterpenes
PubMed: 17530735
DOI: 10.1021/cb700062b -
MBio Apr 2024is a widespread intracellular protozoan pathogen infecting virtually all warm-blooded animals. This parasite acquires host-derived resources to support its replication...
is a widespread intracellular protozoan pathogen infecting virtually all warm-blooded animals. This parasite acquires host-derived resources to support its replication inside a membrane-bound parasitophorous vacuole within infected host cells. Previous research has discovered that actively endocytoses host proteins and transports them to a lysosome-equivalent structure for digestion. However, few molecular determinants required for trafficking of host-derived material within the parasite were known. A recent study (Q.-Q. Wang, M. Sun, T. Tang, D.-H. Lai, et al., mBio 14:e01309-23, 2023, https://doi.org/10.1128/mbio.01309-23) identified a critical role for membrane anchoring of proteins via prenylation in the trafficking of endocytosed host proteins by , including an essential ortholog of Rab1B. The authors also found that TgRab1 is crucial for protein trafficking of the rhoptry secretory organelles, indicating a dual role in endocytic and exocytic protein trafficking. This study sets the stage for further dissecting endomembrane trafficking in , along with potentially exploiting protein prenylation as a target for therapeutic development.
Topics: Animals; Toxoplasma; Protein Prenylation; Proteins; Organelles; Protein Transport
PubMed: 38407123
DOI: 10.1128/mbio.00283-24 -
Pharmacological Research May 2021Geranylgeranyl diphosphate synthase (GGDPS), an enzyme in the isoprenoid biosynthetic pathway (IBP), produces the isoprenoid (geranylgeranyl pyrophosphate, GGPP) used in...
Geranylgeranyl diphosphate synthase (GGDPS), an enzyme in the isoprenoid biosynthetic pathway (IBP), produces the isoprenoid (geranylgeranyl pyrophosphate, GGPP) used in protein geranylgeranylation reactions. Our prior studies utilizing triazole bisphosphonate-based GGDPS inhibitors (GGSIs) have revealed that these agents represent a novel strategy by which to induce cancer cell death, including multiple myeloma and pancreatic cancer. Statins inhibit the rate-limiting enzyme in the IBP and potentiate the effects of GGSIs in vitro. The in vivo effects of combination therapy with statins and GGSIs have not been determined. Here we evaluated the effects of combining VSW1198, a novel GGSI, with a statin (lovastatin or pravastatin) in CD-1 mice. Twice-weekly dosing with VSW1198 at the previously established maximally tolerated dose in combination with a statin led to hepatotoxicity, while once-weekly VSW1198-based combinations were feasible. No abnormalities in kidney, spleen, brain or skeletal muscle were observed with combination therapy. Combination therapy disrupted protein geranylgeranylation in vivo. Evaluation of hepatic isoprenoid levels revealed decreased GGPP levels in the single drug groups and undetectable GGPP levels in the combination groups. Additional studies with combinations using 50% dose-reductions of either VSW1198 or lovastatin revealed minimal hepatotoxicity with expected on-target effects of diminished GGPP levels and disruption of protein geranylgeranylation. Combination statin/GGSI therapy significantly slowed tumor growth in a myeloma xenograft model. Collectively, these studies are the first to demonstrate that combination IBP inhibitor therapy alters isoprenoid levels and disrupts protein geranylgeranylation in vivo as well as slows tumor growth in a myeloma xenograft model, thus providing the framework for future clinical exploration.
Topics: Animals; Biosynthetic Pathways; Cell Line, Tumor; Chemical and Drug Induced Liver Injury; Diterpenes; Drug Delivery Systems; Drug Evaluation, Preclinical; Drug Therapy, Combination; Enzyme Inhibitors; Farnesyltranstransferase; Female; Hydroxymethylglutaryl-CoA Reductase Inhibitors; Lovastatin; Mice; Mice, Inbred NOD; Mice, SCID; Pravastatin; Protein Prenylation; Terpenes; Triazoles; Xenograft Model Antitumor Assays
PubMed: 33667685
DOI: 10.1016/j.phrs.2021.105528