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Kattan WE, Hancock JF. RAS Function in cancer cells: translating membrane biology and biochemistry into new therapeutics. Biochem J 2020; 477:2893-2919. [PMID: 32797215 PMCID: PMC7891675 DOI: 10.1042/bcj20190839] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 07/20/2020] [Accepted: 07/22/2020] [Indexed: 02/07/2023]
Abstract
The three human RAS proteins are mutated and constitutively activated in ∼20% of cancers leading to cell growth and proliferation. For the past three decades, many attempts have been made to inhibit these proteins with little success. Recently; however, multiple methods have emerged to inhibit KRAS, the most prevalently mutated isoform. These methods and the underlying biology will be discussed in this review with a special focus on KRAS-plasma membrane interactions.
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Affiliation(s)
- Walaa E. Kattan
- Department of Integrative Biology and Pharmacology, McGovern Medical School University of Texas Health Science Center at Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, TX 77030, USA
| | - John F. Hancock
- Department of Integrative Biology and Pharmacology, McGovern Medical School University of Texas Health Science Center at Houston, TX 77030, USA
- The University of Texas MD Anderson Cancer Center UTHealth Graduate School of Biomedical Sciences, TX 77030, USA
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2
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Ahearn I, Zhou M, Philips MR. Posttranslational Modifications of RAS Proteins. Cold Spring Harb Perspect Med 2018; 8:cshperspect.a031484. [PMID: 29311131 DOI: 10.1101/cshperspect.a031484] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The three human RAS genes encode four proteins that play central roles in oncogenesis by acting as binary molecular switches that regulate signaling pathways for growth and differentiation. Each is subject to a set of posttranslational modifications (PTMs) that modify their activity or are required for membrane targeting. The enzymes that catalyze the various PTMs are potential targets for anti-RAS drug discovery. The PTMs of RAS proteins are the focus of this review.
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Affiliation(s)
- Ian Ahearn
- Department of Medicine, Perlmutter Cancer Center, New York University School of Medicine, New York, New York 10016
| | - Mo Zhou
- Department of Medicine, Perlmutter Cancer Center, New York University School of Medicine, New York, New York 10016
| | - Mark R Philips
- Department of Medicine, Perlmutter Cancer Center, New York University School of Medicine, New York, New York 10016
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3
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Inversion of the Side-Chain Stereochemistry of Indvidual Thr or Ile Residues in a Protein Molecule: Impact on the Folding, Stability, and Structure of the ShK Toxin. Angew Chem Int Ed Engl 2017. [DOI: 10.1002/ange.201612398] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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4
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Dang B, Shen R, Kubota T, Mandal K, Bezanilla F, Roux B, Kent SBH. Inversion of the Side-Chain Stereochemistry of Indvidual Thr or Ile Residues in a Protein Molecule: Impact on the Folding, Stability, and Structure of the ShK Toxin. Angew Chem Int Ed Engl 2017; 56:3324-3328. [PMID: 28194851 DOI: 10.1002/anie.201612398] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Indexed: 11/05/2022]
Abstract
ShK toxin is a cysteine-rich 35-residue protein ion-channel ligand isolated from the sea anemone Stichodactyla helianthus. In this work, we studied the effect of inverting the side chain stereochemistry of individual Thr or Ile residues on the properties of the ShK protein. Molecular dynamics simulations were used to calculate the free energy cost of inverting the side-chain stereochemistry of individual Thr or Ile residues. Guided by the computational results, we used chemical protein synthesis to prepare three ShK polypeptide chain analogues, each containing either an allo-Thr or an allo-Ile residue. The three allo-Thr or allo-Ile-containing ShK polypeptides were able to fold into defined protein products, but with different folding propensities. Their relative thermal stabilities were measured and were consistent with the MD simulation data. Structures of the three ShK analogue proteins were determined by quasi-racemic X-ray crystallography and were similar to wild-type ShK. All three ShK analogues retained ion-channel blocking activity.
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Affiliation(s)
- Bobo Dang
- Department of Chemistry, Department of Biochemistry & Molecular Biology, Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, 60637, USA
| | - Rong Shen
- Department of Biochemistry & Molecular Biology, Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, 60637, USA
| | - Tomoya Kubota
- Department of Biochemistry & Molecular Biology, Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, 60637, USA
| | - Kalyaneswar Mandal
- Department of Chemistry, Department of Biochemistry & Molecular Biology, Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, 60637, USA
| | - Francisco Bezanilla
- Department of Biochemistry & Molecular Biology, Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, 60637, USA
| | - Benoit Roux
- Department of Biochemistry & Molecular Biology, Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, 60637, USA
| | - Stephen B H Kent
- Department of Chemistry, Department of Biochemistry & Molecular Biology, Institute for Biophysical Dynamics, University of Chicago, Chicago, IL, 60637, USA
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5
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Lu S, Jang H, Muratcioglu S, Gursoy A, Keskin O, Nussinov R, Zhang J. Ras Conformational Ensembles, Allostery, and Signaling. Chem Rev 2016; 116:6607-65. [PMID: 26815308 DOI: 10.1021/acs.chemrev.5b00542] [Citation(s) in RCA: 262] [Impact Index Per Article: 32.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ras proteins are classical members of small GTPases that function as molecular switches by alternating between inactive GDP-bound and active GTP-bound states. Ras activation is regulated by guanine nucleotide exchange factors that catalyze the exchange of GDP by GTP, and inactivation is terminated by GTPase-activating proteins that accelerate the intrinsic GTP hydrolysis rate by orders of magnitude. In this review, we focus on data that have accumulated over the past few years pertaining to the conformational ensembles and the allosteric regulation of Ras proteins and their interpretation from our conformational landscape standpoint. The Ras ensemble embodies all states, including the ligand-bound conformations, the activated (or inactivated) allosteric modulated states, post-translationally modified states, mutational states, transition states, and nonfunctional states serving as a reservoir for emerging functions. The ensemble is shifted by distinct mutational events, cofactors, post-translational modifications, and different membrane compositions. A better understanding of Ras biology can contribute to therapeutic strategies.
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Affiliation(s)
- Shaoyong Lu
- Department of Pathophysiology, Shanghai Universities E-Institute for Chemical Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine , Shanghai, 200025, China.,Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, National Cancer Institute , Frederick, Maryland 21702, United States
| | - Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, National Cancer Institute , Frederick, Maryland 21702, United States
| | | | | | | | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory, National Cancer Institute , Frederick, Maryland 21702, United States.,Department of Human Genetics and Molecular Medicine, Sackler School of Medicine, Sackler Institute of Molecular Medicine, Tel Aviv University , Tel Aviv 69978, Israel
| | - Jian Zhang
- Department of Pathophysiology, Shanghai Universities E-Institute for Chemical Biology, Key Laboratory of Cell Differentiation and Apoptosis of Chinese Ministry of Education, Shanghai Jiao Tong University, School of Medicine , Shanghai, 200025, China
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6
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Andrographolide derivatives inhibit guanine nucleotide exchange and abrogate oncogenic Ras function. Proc Natl Acad Sci U S A 2013; 110:10201-6. [PMID: 23737504 DOI: 10.1073/pnas.1300016110] [Citation(s) in RCA: 117] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Aberrant signaling by oncogenic mutant rat sarcoma (Ras) proteins occurs in ∼15% of all human tumors, yet direct inhibition of Ras by small molecules has remained elusive. Recently, several small-molecule ligands have been discovered that directly bind Ras and inhibit its function by interfering with exchange factor binding. However, it is unclear whether, or how, these ligands could lead to drugs that act against constitutively active oncogenic mutant Ras. Using a dynamics-based pocket identification scheme, ensemble docking, and innovative cell-based assays, here we show that andrographolide (AGP)--a bicyclic diterpenoid lactone isolated from Andrographis paniculata--and its benzylidene derivatives bind to transient pockets on Kirsten-Ras (K-Ras) and inhibit GDP-GTP exchange. As expected for inhibitors of exchange factor binding, AGP derivatives reduced GTP loading of wild-type K-Ras in response to acute EGF stimulation with a concomitant reduction in MAPK activation. Remarkably, however, prolonged treatment with AGP derivatives also reduced GTP loading of, and signal transmission by, oncogenic mutant K-RasG12V. In sum, the combined analysis of our computational and cell biology results show that AGP derivatives directly bind Ras, block GDP-GTP exchange, and inhibit both wild-type and oncogenic K-Ras signaling. Importantly, our findings not only show that nucleotide exchange factors are required for oncogenic Ras signaling but also demonstrate that inhibiting nucleotide exchange is a valid approach to abrogating the function of oncogenic mutant Ras.
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Abstract
Phosphoryl transfer plays key roles in signaling, energy transduction, protein synthesis, and maintaining the integrity of the genetic material. On the surface, it would appear to be a simple nucleophile displacement reaction. However, this simplicity is deceptive, as, even in aqueous solution, the low-lying d-orbitals on the phosphorus atom allow for eight distinct mechanistic possibilities, before even introducing the complexities of the enzyme catalyzed reactions. To further complicate matters, while powerful, traditional experimental techniques such as the use of linear free-energy relationships (LFER) or measuring isotope effects cannot make unique distinctions between different potential mechanisms. A quarter of a century has passed since Westheimer wrote his seminal review, 'Why Nature Chose Phosphate' (Science 235 (1987), 1173), and a lot has changed in the field since then. The present review revisits this biologically crucial issue, exploring both relevant enzymatic systems as well as the corresponding chemistry in aqueous solution, and demonstrating that the only way key questions in this field are likely to be resolved is through careful theoretical studies (which of course should be able to reproduce all relevant experimental data). Finally, we demonstrate that the reason that nature really chose phosphate is due to interplay between two counteracting effects: on the one hand, phosphates are negatively charged and the resulting charge-charge repulsion with the attacking nucleophile contributes to the very high barrier for hydrolysis, making phosphate esters among the most inert compounds known. However, biology is not only about reducing the barrier to unfavorable chemical reactions. That is, the same charge-charge repulsion that makes phosphate ester hydrolysis so unfavorable also makes it possible to regulate, by exploiting the electrostatics. This means that phosphate ester hydrolysis can not only be turned on, but also be turned off, by fine tuning the electrostatic environment and the present review demonstrates numerous examples where this is the case. Without this capacity for regulation, it would be impossible to have for instance a signaling or metabolic cascade, where the action of each participant is determined by the fine-tuned activity of the previous piece in the production line. This makes phosphate esters the ideal compounds to facilitate life as we know it.
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Ahearn IM, Haigis K, Bar-Sagi D, Philips MR. Regulating the regulator: post-translational modification of RAS. Nat Rev Mol Cell Biol 2011; 13:39-51. [PMID: 22189424 PMCID: PMC3879958 DOI: 10.1038/nrm3255] [Citation(s) in RCA: 402] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
RAS proteins are monomeric GTPases that act as binary molecular switches to regulate a wide range of cellular processes. The exchange of GTP for GDP on RAS is regulated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs), which regulate the activation state of RAS without covalently modifying it. By contrast, post-translational modifications (PTMs) of RAS proteins direct them to various cellular membranes and, in some cases, modulate GTP-GDP exchange. Important RAS PTMs include the constitutive and irreversible remodelling of its carboxy-terminal CAAX motif by farnesylation, proteolysis and methylation, reversible palmitoylation, and conditional modifications, including phosphorylation, peptidyl-prolyl isomerisation, monoubiquitylation, diubiquitylation, nitrosylation, ADP ribosylation and glucosylation.
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Affiliation(s)
- Ian M Ahearn
- NYU School of Medicine, 550 First Avenue, New York, NY 10016, USA
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Fonvielle M, Chemama M, Villet R, Lecerf M, Bouhss A, Valéry JM, Ethève-Quelquejeu M, Arthur M. Aminoacyl-tRNA recognition by the FemXWv transferase for bacterial cell wall synthesis. Nucleic Acids Res 2009; 37:1589-601. [PMID: 19151092 PMCID: PMC2655667 DOI: 10.1093/nar/gkn1039] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Transferases of the Fem family catalyse peptide-bond formation by using aminoacyl-tRNAs and peptidoglycan precursors as donor and acceptor substrates, respectively. The specificity of Fem transferases is essential since mis-incorporated amino acids could act as chain terminators thereby preventing formation of a functional stress-bearing peptidoglycan network. Here we have developed chemical acylation of RNA helices with natural and non-proteinogenic amino acids to gain insight into the specificity of the model transferase FemX(Wv). Combining modifications in the RNA and aminoacyl moieties of the donor substrate revealed that unfavourable interactions of FemX(Wv) with the acceptor arm of tRNA(Gly) and with L-Ser or larger residues quantitatively accounts for the preferential transfer of L-Ala observed with complete aminoacyl-tRNAs. The main FemX(Wv) identity determinant was identified as the penultimate base pair (G(2)-C(71)) of the acceptor arm instead of G(3)*U(70) for the alanyl-tRNA synthetase. FemX(Wv) tolerated a configuration inversion of the Calpha of L-Ala but not the introduction of a second methyl on this atom. These results indicate that aminoacyl-tRNA recognition by FemX(Wv) is distinct from other components of the translation machinery and relies on the exclusion of bulky amino acids and of the sequence of tRNA(Gly) from the active site.
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Affiliation(s)
- Matthieu Fonvielle
- Centre de Recherche des Cordeliers, LRMA, Equipe 12, INSERM, Université Pierre et Marie Curie - Paris 6, France
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Duca M, Chen S, Hecht SM. Aminoacylation of transfer RNAs with one and two amino acids. Methods 2008; 44:87-99. [PMID: 18241791 DOI: 10.1016/j.ymeth.2007.10.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2007] [Revised: 10/20/2007] [Accepted: 10/22/2007] [Indexed: 11/18/2022] Open
Abstract
The detailed synthesis of (bis)aminoacyl-pdCpAs and the corresponding singly and tandemly activated tRNAs is reported. The synthetic pathway leading to these compounds has been validated for simple amino acid residues as well as for amino acids bearing more complex side chains. Protection/deprotection strategies are described. For the bisaminoacylated tRNAs, both the synthesis of tRNAs bearing the same amino acid residue at the 2' and 3' positions and tRNAs bearing two different aminoacyl moieties are reported. Further, it is shown that the tandemly activated tRNAs are able to participate in protein synthesis.
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Affiliation(s)
- Maria Duca
- Departments of Chemistry and Biology, University of Virginia, Charlottesville, VA 22904, USA.
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11
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Duca M, Maloney DJ, Lodder M, Wang B, Hecht SM. Synthesis of bisaminoacylated pdCpAs and tandemly activated transfer RNAs. Bioorg Med Chem 2007; 15:4629-42. [PMID: 17490885 DOI: 10.1016/j.bmc.2007.03.088] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2007] [Revised: 03/28/2007] [Accepted: 03/29/2007] [Indexed: 10/23/2022]
Abstract
Described herein is the preparation of new bisacylated tRNAs and their participation in protein synthesis. It has been reported that Thermus thermophilus phenylalanyl-tRNA synthetase can introduce two phenylalanine moieties onto the 3'-terminal adenosine of its cognate tRNA. It is also possible to prepare bisactivated tRNAs in vitro; these participate in protein synthesis [Wang, B.; Zhou, J.; Lodder, M.; Anderson, R. D.; Hecht, S. M. J. Biol. Chem.2006, 281, 13865]. Presently, the chemical strategy used for the synthesis of the key intermediate bisacylated pdCpAs is described. Bis-S-alanyl- and bis-S-methionyl-pdCpAs were prepared initially. Further, S-threonine, S-allo-threonine, S-homoserine, and (S)-(+)-2-amino-3-hydroxy-3-methylbutyric acid were coupled with the dinucleotide to define preparative methods applicable to more complex amino acids bearing additional functionality in the form of an OH group.
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Affiliation(s)
- Maria Duca
- Department of Chemistry and Biology, University of Virginia, Charlottesville, VA 22904, USA
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12
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Zenker M, Lehmann K, Schulz AL, Barth H, Hansmann D, Koenig R, Korinthenberg R, Kreiss-Nachtsheim M, Meinecke P, Morlot S, Mundlos S, Quante AS, Raskin S, Schnabel D, Wehner LE, Kratz CP, Horn D, Kutsche K. Expansion of the genotypic and phenotypic spectrum in patients with KRAS germline mutations. J Med Genet 2006; 44:131-5. [PMID: 17056636 PMCID: PMC2598066 DOI: 10.1136/jmg.2006.046300] [Citation(s) in RCA: 136] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
BACKGROUND Noonan syndrome, cardio-facio-cutaneous syndrome (CFC) and Costello syndrome constitute a group of developmental disorders with an overlapping pattern of congenital anomalies. Each of these conditions can be caused by germline mutations in key components of the highly conserved Ras-MAPK pathway, possibly reflecting a similar pathogenesis underlying the three disorders. Germline mutations in KRAS have recently been identified in a small number of patients with Noonan syndrome and CFC. METHODS AND RESULTS 260 patients were screened for KRAS mutations by direct sequencing. Overall, we detected KRAS mutations in 12 patients, including three known and eight novel sequence alterations. All mutations are predicted to cause single amino acid substitutions. Remarkably, our cohort of individuals with KRAS mutations showed a high clinical variability, ranging from Noonan syndrome to CFC, and also included two patients who met the clinical criteria of Costello syndrome. CONCLUSION Our findings reinforce the picture of a clustered distribution of disease associated KRAS germline alterations. We further defined the phenotypic spectrum associated with KRAS missense mutations and provided the first evidence of clinical differences in patients with KRAS mutations compared with Noonan syndrome affected individuals with heterozygous PTPN11 mutations and CFC patients carrying a BRAF, MEK1 or MEK1 alteration, respectively. We speculate that the observed phenotypic variability may be related, at least in part, to specific genotypes and possibly reflects the central role of K-Ras in a number of different signalling pathways.
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Affiliation(s)
- Martin Zenker
- Institute of Human Genetics, University of Erlangen-Nuremberg, Germany
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Abstract
Signal transduction down the Ras/MAPK pathway, including that critical to T cell activation, proliferation, and differentiation, has been generally considered to occur at the plasma membrane. It is now clear that the plasma membrane does not represent the only platform for Ras/MAPK signaling. Moreover, the plasma membrane itself is no longer considered a uniform structure but rather a patchwork of microdomains that can compartmentalize signaling. Signaling on internal membranes was first recognized on endosomes. Genetically encoded fluorescent probes for signaling events such as GTP/GDP exchange on Ras have revealed signaling on a variety of intracellular membranes, including the Golgi apparatus. In fibroblasts, Ras is activated on the plasma membrane and Golgi with distinct kinetics. The pathway by which Golgi-associated Ras becomes activated involves PLCgamma and RasGRP1 and may also require retrograde trafficking of Ras from the plasma membrane to the Golgi as a consequence of depalmitoylation. Thus, the Ras/MAPK pathway represents a clear example of compartmentalized signaling.
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Affiliation(s)
- Adam Mor
- Department of Medicine, New York University Medical Center, New York, NY 10016-6402, USA.
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14
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Ahn JH, Kim NY, Kim TW, Son JM, Kang TJ, Park CG, Choi CY, Kim DM. Effect of temperature and ATP supply on the efficiency of programmed nonsense suppression. Anal Biochem 2005; 345:110-5. [PMID: 16137633 DOI: 10.1016/j.ab.2005.07.010] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2005] [Revised: 07/01/2005] [Accepted: 07/12/2005] [Indexed: 11/19/2022]
Abstract
Chemical diversity of protein molecules can be expanded through in vitro incorporation of unnatural amino acids in response to a nonsense codon. Chemically misacylated tRNAs are used for tethering unnatural amino acids to a nonsense-mutated target codon (nonsense suppression). In the course of experiments to introduce S-(2-nitrobenzyl)cysteine (NBC) into a targeted location of human erythropoietin, we found that NBC incorporates more efficiently at lower temperatures. In addition, at a fixed reaction temperature, more NBC was incorporated with a reduced supply of ATP. Since the rate of peptide elongation was remarkably higher at the elevated temperature or with enhanced supply of ATP, these results indicate that the efficiency of nonsense suppression is inversely correlated to the peptide elongation rate. Therefore, maximal yield of nonsense-suppressed proteins is obtained at a compromised elongation rate. The present result will offer a primary guideline to optimize the reaction conditions for in vitro production of protein molecules containing unnatural amino acids.
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Affiliation(s)
- Jin-Ho Ahn
- Interdisciplinary Program for Biochemical Engineering and Biotechnology, College of Engineering, Seoul National University, Seoul 151-742, Korea
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Tchaicheeyan O. Is peptide bond cis/trans isomerization a key stage in the chemo-mechanical cycle of motor proteins? FASEB J 2004; 18:783-9. [PMID: 15117883 DOI: 10.1096/fj.03-1027hyp] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Motor proteins such as myosin and kinesin are responsible for actively directed movement in vivo. The physicochemical mechanism underlying their function is still obscure. A novel and unifying model concerning the motors driving mechanism is suggested here. This model resides within the framework of the well-studied "swinging lever-arm" hypothesis, stating that cis/trans peptide bond isomerization (CTI) is a key stage in the chemo-mechanical coupling within actomyosin--the complex of the motor (myosin) and its specific track (actin). CTI is suggested to propel myosin's lever-arm swing. The model addresses on the submolecular level a broad spectrum of actomyosin's functional characteristics, such as kinetics, energetics, force exertion, stepping, and directionality. The model may be tested first with relative ease in kinesin--a smaller motor that could be specifically modified with unnatural amino acids using bacterial expression. Suggested modifications may be used for labeling and functional decoupling.
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Affiliation(s)
- Oren Tchaicheeyan
- Biomedical Engineering Department, Technion-Israel Institute of Technology, Haifa, 32000, Israel.
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Soares TA, Miller JH, Straatsma TP. Revisiting the structural flexibility of the complex p21(ras)-GTP: the catalytic conformation of the molecular switch II. Proteins 2001; 45:297-312. [PMID: 11746677 DOI: 10.1002/prot.1150] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The hydrolysis of GTP in p21(ras) triggers conformational changes that regulate the ras/ERK signaling pathway. An important active site residue is Gln61, which has been found to be mutated in 30% of human tumors. The dynamics of the active site conformation is studied by using molecular dynamics simulation of two independent structures of the GTP-bound uncomplexed enzyme. Two distinct conformations of the enzyme are observed, in which the side-chain residue Gln61 is in different orientations. Essential dynamics analysis is used to describe the essential motions in the transition between the two conformations. Results are compared with earlier simulations of p21(ras) and its complex with GTPase activating protein p21-GAP.
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Affiliation(s)
- T A Soares
- Environmental Molecular Sciences Laboratory, Pacific Northwest National Laboratory, Richland, Washington 99352, USA
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Farrar CT, Ma J, Singel DJ, Halkides CJ. Structural changes induced in p21Ras upon GAP-334 complexation as probed by ESEEM spectroscopy and molecular-dynamics simulation. Structure 2000; 8:1279-87. [PMID: 11188692 DOI: 10.1016/s0969-2126(00)00532-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
BACKGROUND The means by which the protein GAP accelerates GTP hydrolysis, and thereby downregulates growth signaling by p21Ras, is of considerable interest, particularly inasmuch as p21 mutants are implicated in a number of human cancers. A GAP "arginine finger," identified by X-ray crystallography, has been suggested as playing the principal role in the GTP hydrolysis. Mutagenesis studies, however, have shown that the arginine can only partially account for the 10(5)-fold increase in the GAP-accelerated GTPase rate of p21. RESULTS We report electron spin-echo envelope modulation (ESEEM) studies of GAP-334 complexed with GMPPNP bound p21 in frozen solution, together with molecular-dynamics simulations. Our results indicate that, in solution, the association of GAP-334 with GTP bound p21 induces a conformational change near the metal ion active site of p21. This change significantly reduces the distances from the amide groups of p21 glycine residues 60 and 13 to the divalent metal ion. CONCLUSIONS The movement of glycine residues 60 and 13 upon the binding of GAP-334 in solution provides a physical basis to interpret prior mutagenesis studies, which indicated that Gly-60 and Gly-13 of p21 play important roles in the GAP-dependent GTPase reaction. Gly-60 and Gly-13 may play direct catalytic roles and stabilize the attacking water molecule and beta,gamma-bridging oxygen, respectively, in p21. The amide proton of Gly-60 could also play an indirect role in catalysis by supplying a crucial hydrogen bonding interaction that stabilizes loop L4 and therefore the position of other important catalytic residues.
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Affiliation(s)
- C T Farrar
- Department of Chemistry, Harvard University, Cambridge, Massachusetts 02138, USA
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18
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Scheidig AJ, Burmester C, Goody RS. The pre-hydrolysis state of p21(ras) in complex with GTP: new insights into the role of water molecules in the GTP hydrolysis reaction of ras-like proteins. Structure 1999; 7:1311-24. [PMID: 10574788 DOI: 10.1016/s0969-2126(00)80021-0] [Citation(s) in RCA: 157] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
BACKGROUND In numerous biological events the hydrolysis of guanine triphosphate (GTP) is a trigger to switch from the active to the inactive protein form. In spite of the availability of several high-resolution crystal structures, the details of the mechanism of nucleotide hydrolysis by GTPases are still unclear. This is partly because the structures of the proteins in their active states had to be determined in the presence of non-hydrolyzable GTP analogues (e.g. GppNHp). Knowledge of the structure of the true Michaelis complex might provide additional insights into the intrinsic protein hydrolysis mechanism of GTP and related nucleotides. RESULTS The structure of the complex formed between p21(ras) and GTP has been determined by X-ray diffraction at 1.6 A using a combination of photolysis of an inactive GTP precursor (caged GTP) and rapid freezing (100K). The structure of this complex differs from that of p21(ras)-GppNHp (determined at 277K) with respect to the degree of order and conformation of the catalytic loop (loop 4 of the switch II region) and the positioning of water molecules around the gamma-phosphate group. The changes in the arrangement of water molecules were induced by the cryo-temperature technique. CONCLUSIONS The results shed light on the function of Gln61 in the intrinsic GTP hydrolysis reaction. Furthermore, the possibility of a proton shuffling mechanism between two attacking water molecules and an oxygen of the gamma-phosphate group can be proposed for the basal GTPase mechanism, but arguments are presented that render this protonation mechanism unlikely for the GTPase activating protein (GAP)-activated GTPase.
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Affiliation(s)
- A J Scheidig
- Abteilung für Physikalische Biochemie, Max-Planck Institute for Molecular Physiology, Dortmund, 44227, Germany.
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Sisido M, Hohsaka T. Extension of Protein Functions by the Incorporation of Nonnatural Amino Acids. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1999. [DOI: 10.1246/bcsj.72.1409] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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20
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Farrar CT, Halkides CJ, Singel DJ. The frozen solution structure of p21 ras determined by ESEEM spectroscopy reveals weak coordination of Thr35 to the active site metal ion. Structure 1997; 5:1055-66. [PMID: 9309221 DOI: 10.1016/s0969-2126(97)00257-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
BACKGROUND The G protein p21 ras is a molecular switch in the signal transduction pathway for cellular growth and differentiation. Hydrolysis of tightly bound GTP alters the conformation of p21, terminating the signal. The coordination of the p21 residue Thr35 to Mg2+ in its active site, which has been observed in the crystal structure of p21 in complex with a GTP-analog GMPPNP but not with GDP, has been proposed to drive the conformational change accompanying nucleotide substitution and may have a role in the GTP hydrolysis reaction itself. However, previous electron spin-echo envelope modulation (ESEEM) studies of selectively 2H beta-threonine and 15N-threonine labeled p21.Mn2+ GMPPNP suggest that Thr35 only weakly coordinates the metal ion in the growth-active GTP-bound state of p21. RESULTS A 13C beta-Thr35 to Mn2+ distance of 4.3 +/- 0.2 A and a 15N epsilon-Lys16 to Mn2+ distance of 5.3 +/- 0.2 A were determined from ESEEM spectra of the selectively 13C beta-Thr and 15N epsilon-Lys labeled p21.Mn2+ GMPPNP frozen solution structure. The 13C beta-Thr35 to Mn2+ distance is greater than that (3.16 A) observed in the crystal structure. In contrast, the 15N epsilon-Lys16 to Mn2+ distance is in good agreement with the 5.1 A crystal structure distance. CONCLUSIONS The 13C beta of Thr35 is more distant from the active site Mn2+ in the frozen solution structure than in the crystal structure of p21.Mg2+ GMPPNP, indicating that Thr35 only weakly coordinates the metal ion in frozen solution. Thr35 coordination of the metal ion is therefore unlikely to drive the conformational change between GTP- and GDP-bound states of p21. Thr35 may be essential for GTPase-activating protein (GAP)-stimulated GTP hydrolysis and/or signal transduction for other reasons.
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Affiliation(s)
- C T Farrar
- Department of Chemistry, Harvard University, Cambridge, MA 02138, USA
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21
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Rao SN, Chan MF, Balaji VN. Conformational Studies Using Molecular Mechanics on Model Peptides with 1-Aminocycloalkane 1-Carboxylic Acid Residues. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1997. [DOI: 10.1246/bcsj.70.293] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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22
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Muegge I, Schweins T, Langen R, Warshel A. Electrostatic control of GTP and GDP binding in the oncoprotein p21ras. Structure 1996; 4:475-89. [PMID: 8740369 DOI: 10.1016/s0969-2126(96)00052-4] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND p21ras is one of the GTP-binding proteins that act as intercellular molecular switches. The GTP-bound form of p21ras sends a growth-promoting signal that is terminated once the protein is cycled back into its GDP-bound form. The interaction of guanine-nucleotide-exchange factors (GEFs) with p21ras leads to activation of the protein by promoting GDP --> GTP exchange. Oncogenic mutations of p21ras trap the protein in its biological active GTP-bound form. Other mutations interfere with the activity of GEF. Thus, it is important to explore the structural basis for the action of different mutations. RESULTS The crystal structures of p21ras are correlated with the binding affinities of GTP and GDP by calculating the relevant electrostatic energies. It is demonstrated that such calculations can provide a road map to the location of 'hot' residues whose mutations are likely to change functional properties of the protein. Furthermore, calculations of the effect of specific mutations on GTP and GDP binding are consistent with those observed. This helps to analyze and locate functionally important parts of the protein. CONCLUSIONS Our calculations indicate that the protein main chain provides a major contribution to the binding energies of nucleotides and probably plays a key role in relaying the effect of GEF action. Analysis of p21ras mutations in residues that are important for the proper function of GEFs suggests that the region comprising residues 62-67 in p21ras is the major GEF-binding site. This analysis and our computer simulations indicate that the effect of GEF is probably propagated to the P-loop (residues 10-17) through interaction between Gly60 and Gly12. This then reduces the interaction between the main-chain dipoles of the P-loop and the nucleotide. Finally, the results also suggest a possible relationship between the GTP --> GDP structural transition and the catalytic effect of the GTPase-activating protein.
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Affiliation(s)
- I Muegge
- Department of Chemistry, University of Southern California, Los Angeles 90089-1062, USA
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23
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Zhao Z, Liu X, Shi Z, Danley L, Huang B, Jiang RT, Tsai MD. Mechanism of Adenylate Kinase. 20. Probing the Importance of the Aromaticity in Tyrosine-95 and the Ring Size in Proline-17 with Unnatural Amino Acids. J Am Chem Soc 1996. [DOI: 10.1021/ja9600901] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Zhong Zhao
- Departments of Chemistry and Biochemistry and Ohio State Biochemistry Program The Ohio State University, Columbus, Ohio 43210 Department of Chemistry, University of California at Berkley, Berkley, California 94720
| | - Xiaohong Liu
- Departments of Chemistry and Biochemistry and Ohio State Biochemistry Program The Ohio State University, Columbus, Ohio 43210 Department of Chemistry, University of California at Berkley, Berkley, California 94720
| | - Zhengtao Shi
- Departments of Chemistry and Biochemistry and Ohio State Biochemistry Program The Ohio State University, Columbus, Ohio 43210 Department of Chemistry, University of California at Berkley, Berkley, California 94720
| | - Lora Danley
- Departments of Chemistry and Biochemistry and Ohio State Biochemistry Program The Ohio State University, Columbus, Ohio 43210 Department of Chemistry, University of California at Berkley, Berkley, California 94720
| | - Baohua Huang
- Departments of Chemistry and Biochemistry and Ohio State Biochemistry Program The Ohio State University, Columbus, Ohio 43210 Department of Chemistry, University of California at Berkley, Berkley, California 94720
| | - Ru-Tai Jiang
- Departments of Chemistry and Biochemistry and Ohio State Biochemistry Program The Ohio State University, Columbus, Ohio 43210 Department of Chemistry, University of California at Berkley, Berkley, California 94720
| | - Ming-Daw Tsai
- Departments of Chemistry and Biochemistry and Ohio State Biochemistry Program The Ohio State University, Columbus, Ohio 43210 Department of Chemistry, University of California at Berkley, Berkley, California 94720
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24
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Cornish VW, Mendel D, Schultz PG. Untersuchungen von Struktur und Funktion von Proteinen mit einem erweiterten genetischen Code. Angew Chem Int Ed Engl 1995. [DOI: 10.1002/ange.19951070604] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Klebe C, Bischoff FR, Ponstingl H, Wittinghofer A. Interaction of the nuclear GTP-binding protein Ran with its regulatory proteins RCC1 and RanGAP1. Biochemistry 1995; 34:639-47. [PMID: 7819259 DOI: 10.1021/bi00002a031] [Citation(s) in RCA: 263] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The guanine nucleotide dissociation and GTPase reactions of Ran, a Ras-related nuclear protein, have been investigated using different fluorescence techniques to determine how these reactions are stimulated by the guanine nucleotide exchange factor RCC1 and the other regulatory protein, RanGAP1 (GTPase-activating protein). The intrinsic GTPase of Ran is one-tenth of the rate of p21ras and is even lower in the Ran(Q69L) mutant. Under saturating conditions the rate constant for the RanGAP1 stimulated GTPase reaction is 2.1 s-1 at 25 degrees C, which is a 10(5)-fold stimulation, whereas RanGAP1 has no effect on Ran(Q69L). The intrinsic guanine nucleotide dissociation rates of Ran are also very low and are likewise increased 10(5)-fold by the exchange factor RCC1. Methods to describe the reaction kinetically are presented. The Ran(T24N) mutant, which is analogous to the S17N mutant of p21ras, has decreased relative affinities for both GDP/GTP and favors GDP binding. However, it was found to interact almost normally with RCC1. The combination of these properties leads to stabilization of the Ran(T24N)-RCC1 complex and may result in vivo in depletion of RCC1 available for stimulating guanine nucleotide exchange.
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Affiliation(s)
- C Klebe
- Max-Planck-Institut für molekulare Physiologie, Dortmund, Germany
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26
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Structural features of the GTP-binding defective Rab5 mutants required for their inhibitory activity on endocytosis. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36671-1] [Citation(s) in RCA: 87] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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