Articles publicats en revistes (Bioquímica i Biomedicina Molecular)

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Current efficacy of immune checkpoint inhibitors in microsatellite unstable colorectal cancer and potential biomarkers
(Open Exploration, 2025-02-18) Rojas, Mariam; Rodrigo, Clara; Moreno, Reinaldo; Cascante i Serratosa, Marta; Maurel Santasusana, Joan
Microsatellite unstable (MSI) colorectal cancer (CRC) tumors have a high mutational load (particularly frame-shift mutations) that creates numerous neoantigens that are presented to major histocompatibility complex molecules and recognized by T cells. Consequently, MSI tumors have a higher presence of tumor-infiltrating lymphocytes than mismatch repair-proficient tumors. Colorectal cancer patients with MSI constitute a rare group of immune checkpoint inhibitor (ICI)-responsive patients. Nonetheless, complete radiological responders comprise between 3% and 16% of MSI advanced CRC patients, which compares poorly with the 45% to 87% rate of pathological complete response in early MSI CRC patients treated with ICIs. In this review, we address the efficacy of current ICIs and the biological differences between early and advanced MSI CRC to potentially increase the efficacy of ICIs in both settings.
Metabolic plasticity drives specific mechanisms of chemotherapy and targeted therapy resistance in metastatic colorectal cancer
(Open Exploration, 2025-09-23) Rojas, Mariam; Manzi, Malena; Madurga Díez, Sergio; García Velásquez, Fernando Enrique; Romero, Maira Alejandra; Marín Martínez, Silvia; Cascante i Serratosa, Marta; Maurel Santasusana, Joan
Microsatellite-stable metastatic colorectal cancer (MSS mCRC) is currently treated with chemotherapy and targeted agents based on RAS and BRAF mutational status. Although these therapies offer initial benefit, most patients rapidly develop resistance, with fewer than 20% remaining progression-free at two years. This review aims to synthesize emerging evidence on the metabolic mechanisms driving treatment resistance in MSS mCRC, with a particular focus on the immune-metabolic signature (IMMETCOLS) classification. We conducted a comprehensive review of preclinical models, transcriptomic datasets, and clinical trial results addressing metabolic adaptations to chemotherapy and targeted therapies in MSS mCRC. The IMMETCOLS framework defines three metabolic subtypes—IMC1, IMC2, and IMC3—each associated with distinct resistance mechanisms. IMC1 exhibits glycolysis and transforming growth factor-β (TGF-β)-dependent signaling enriched in inflammatory fibroblasts, conferring resistance to chemotherapy. IMC2 relies on oxidative phosphorylation and glutamine metabolism, supporting antioxidant defenses and resistance to both cytotoxic agents and anti-EGFR therapies. IMC3 demonstrates lactate-fueled respiration and pentose phosphate pathway activation, contributing to redox balance, DNA repair, and resistance to targeted therapies such as anti-BRAF or KRAS inhibitors. All subtypes display metabolic plasticity under therapeutic pressure. Emerging clinical data support tailoring targeted therapy combinations based on IMMETCOLS subtype, particularly in BRAF- and HER2-positive populations. Understanding subtype-specific metabolic rewiring in MSS mCRC offers novel opportunities to overcome drug resistance. Targeting the metabolic vulnerabilities defined by the IMMETCOLS signature may improve response durability and inform precision treatment strategies.
Success and Limitations of Current Force Fields for the Description of RNA–Ligand Complexes
(American Chemical Society, 2025-10-31) Fernández Migens, Paula; Serrano Chacón, Israel; Orozco López, Modesto; Battistini, Federica
We present a systematic assessment of the last generation of RNA force fields to reproduce the structures and dynamics of ligand−RNA complexes. Our comprehensive analysis helped not only to define the more reliable force field to represent complex structures but also suggests details that can be improved and provide a critical analysis of the quality of experimental structures in complex systems that are expected to be very flexible and environment dependent.
Using control bias to identify initial targets for bioproduction improvement
(Elsevier B.V., 2025-11-25) Binns, Michael; Atauri Carulla, Ramón de; Cascante i Serratosa, Marta; Theodoropoulos, Constantinos
Sensitivity analysis of bioprocess metabolic reaction networks analysis allows the prediction of system parameters such as those associated with the enzyme activity of certain reaction steps which significantly affect the overall production. However, uncertainties in kinetic rate expressions and in the resulting steady-state flux distributions limit the accuracy of these predictions. Starting from minimal information (reaction stoichiometry, and external fluxes in/out of the system and potentially identification of steps at equilibrium) a new preliminary method is proposed using sampling of elasticities and metabolic fluxes to calculate the control bias. The calculated control bias identifies steps which are likely to have positive control, negative control or negligible/uncertain control. This is intended to give initial guidance before further detailed investigation is carried out, identifying targets for any organism to enhance production of valuable chemicals. As a case study, this methodology is applied to succinic acid bioproduction using Actinobacillus succinogenes and analysis successfully reveals the reaction steps having the greatest positive and negative influence on biosuccinic acid production.
Circulating metabolic markers after surgery identify patients at risk for severe postoperative complications: a prospective cohort study in colorectal cancer
(Elsevier, 2024-03-01) Montcusí, Blanca; Pera Román, Miguel; Madrid Gambín, Francisco Javier; Pozo Mendoza, Óscar J., 1975-; Marco Colás, Santiago; Marín Martínez, Silvia; Mayol, Xavier; Pascual Damieta, Marta; Alonso-Gonçalves, Sandra; Silvia Salvans Ruiz; Jiménez-Toscano, Marta; Cascante i Serratosa, Marta
Background: Early detection of postoperative complications after colorectal cancer (CRC) surgery is associated with improved outcomes. The aim was to investigate early metabolomics signatures capable to detect patients at risk for severe postoperative complications after CRC surgery. Materials and methods: Prospective cohort study of patients undergoing CRC surgery from 2015 to 2018. Plasma samples were collected before and after surgery, and analyzed by mass spectrometry obtaining 188 metabolites and 21 ratios. Postoperative complications were registered with Clavien–Dindo Classification and Comprehensive Complication Index. Results: One hundred forty-six patients were included. Surgery substantially modified metabolome and metabolic changes after surgery were quantitatively associated with the severity of postoperative complications. The strongest positive relationship with both Clavien–Dindo and Comprehensive Complication Index (β=4.09 and 63.05, P<0.001) corresponded to kynurenine/tryptophan, against an inverse relationship with lysophosphatidylcholines (LPCs) and phosphatidylcholines (PCs). Patients with LPC18:2/PCa36:2 below the cut-off 0.084 µM/µM resulted in a sevenfold higher risk of major complications (OR=7.38, 95% CI: 2.82–21.25, P<0.001), while kynurenine/tryptophan above 0.067 µM/µM a ninefold (OR=9.35, 95% CI: 3.03–32.66, P<0.001). Hexadecanoylcarnitine below 0.093 µM displayed a 12-fold higher risk of anastomotic leakage-related complications (OR=11.99, 95% CI: 2.62–80.79, P=0.004). Conclusion: Surgery-induced phospholipids and amino acid dysregulation is associated with the severity of postoperative complications after CRC surgery, including anastomotic leakage-related outcomes. The authors provide quantitative insight on metabolic markers, measuring vulnerability to postoperative morbidity that might help guide early decision-making and improve surgical outcomes.
Transcriptomic profiling of endothelial progenitor cells in post-COVID-19 patients: Insights at 3- and 6-month post-infection
(Elsevier, 2025-11-21) Poyatos Dorado, Paula; Gratacòs-Aurich, Miquel; Aguilar, Daniel; Luque, Neus; Bonnin Vilaplana, Marc; Eizaguirre, Saioa; Cascante i Serratosa, Marta; Orriols Martínez, Ramon; Tura-Ceide, Olga
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused significant global morbidity since 2019. Long COVID, characterized by persistent symptoms after acute infection, may involve endothelial injury. We analyzed endothelial colony-forming cells (ECFCs) from post-COVID-19 patients at 3- and 6-month post-infection, comparing them with healthy controls and stratifying by prior pulmonary embolism (PE). Transcriptomic profiling identified differentially expressed genes (DEGs) associated with endothelial homeostasis, inflammation, oxidative stress, and thrombosis. Post-COVID ECFCs showed downregulation of NOS3, KLF2, ANGPT1, PIK3R3, GBX2, GDF6, SMAD6, SRC, and TGFB1, and upregulation of CASP1, CXCL5, IL12A, SOD2, TIMP3, and TLR2. Minimal differences were observed between 3 and 6-month samples. PE patients showed downregulation of thrombosis-related genes such as PTGS2 and ACKR3. These findings indicate sustained endothelial dysfunction and inflammation up to 6 months post-infection, highlighting the importance of long-term monitoring and potential therapeutic strategies to support vascular health in post-COVID-19 patients.
Caffeine increases striatal dopamine D2/D3 receptor availability in the human brain
(Nature Publishing Group, 2015-04-14) Volkow, Nora D., 1956-; Wang, Gene-Jack; Logan, Jean; Alexoff, David; Fowler, Joanna S.; Thanos, Panayotis K.; Wong, Christopher T.; Casadó, Vicent; Ferré, Sergi; Tomasi, Dardo
Caffeine, the most widely consumed psychoactive substance in the world, is used to promote wakefulness and enhance alertness. Like other wake-promoting drugs (stimulants and modafinil), caffeine enhances dopamine (DA) signaling in the brain, which it does predominantly by antagonizing adenosine A2A receptors (A2AR). However, it is unclear if caffeine, at the doses consumed by humans, increases DA release or whether it modulates the functions of postsynaptic DA receptors through its interaction with adenosine receptors, which modulate them. We used positron emission tomography and [11C]raclopride (DA D2/D3 receptor radioligand sensitive to endogenous DA) to assess if caffeine increased DA release in striatum in 20 healthy controls. Caffeine (300 mg p.o.) significantly increased the availability of D2/D3 receptors in putamen and ventral striatum, but not in caudate, when compared with placebo. In addition, caffeine-induced increases in D2/D3 receptor availability in the ventral striatum were associated with caffeine-induced increases in alertness. Our findings indicate that in the human brain, caffeine, at doses typically consumed, increases the availability of DA D2/D3 receptors, which indicates that caffeine does not increase DA in the striatum for this would have decreased D2/D3 receptor availability. Instead, we interpret our findings to reflect an increase in D2/D3 receptor levels in striatum with caffeine (or changes in affinity). The association between increases in D2/D3 receptor availability in ventral striatum and alertness suggests that caffeine might enhance arousal, in part, by upregulating D2/D3 receptors.
Design of a true bivalent ligand with picomolar affinity for a G protein-coupled receptor homodimer
(American Chemical Society, 2018-10-25) Pulido, Daniel; Casadó Anguera, Verònica; Pérez-Benito, Laura; Moreno Guillén, Estefanía; Cordomí, Arnau; López, Laura; Cortés Tejedor, Antonio; Ferré, Sergi; Pardo, Leonardo; Casadó, Vicent; Royo Expósito, Miriam
Bivalent ligands have emerged as chemical tools to study G protein-coupled receptor dimers. Using a combination of computational, chemical, and biochemical tools, here we describe the design of bivalent ligand 13 with high affinity (KDB1=21 pM) for the dopa-mine D2 receptor (D2R) homodimer. Bivalent ligand 13 enhances the binding affinity relative to monovalent compound 15 by 37-fold, indicating simultaneous binding at both protomers. Using synthetic peptides with amino acid sequences of transmembrane (TM) domains of D2R, we provide evidence that TM6 forms the interface of the homodimer. Notably, the disturber peptide TAT-TM6 decreased the binding of bivalent ligand 13 by 52-fold and had no effect on monovalent compound 15, confirming the D2R homodimer through TM6 ex-vivo. In conclusion, using a versatile multivalent chemical platform, we have developed a precise strategy to generate a true bivalent ligand that simultaneously targets both orthosteric sites of the D2R homodimer
Nucleotide sequence of a rice cDNA encoding a transkelotase-like protein homologous to the Arabidopsis CLA1gene product (Accession No. AF024512) (PGR 97-169)
(American Society of Plant Biologists, 1997) Campos Martínez, Narciso; Lois Rojas, Luisa María; Boronat i Margosa, Albert
The Arabidopsis gene CLA1 is required for normal chloroplast development. Disruption of this gene has a recessive pleiotropic effect consisting on arrest of chloroplast development at an early stage, reduction of the expression of several photosynthetic genes, and absence of accumulation of photosynthetic pigments. Database searches show that the protein encoded by the CLA 1gene is highly conserved in evolution. We report the sequencing of a cDNA clone from rice that is homologous to the Arabidopsis CLA1. This is the first homolog of CLA1 characterized in monocot plants. The cDNA is 1785 basepairs in length. It contains an open reading frame (ORF) coding for 594 amino acids. The TPP binding sequence of the Arabidopsis CLA1 (residues 217 to 247) is well conserved in the rice homolog. The product of the CLA1 gene has significant similarity to transketolases and other enzymes that require thiamin pyrophosphate (TPP) as cofactor, suggesting an enzymatic function for this protein. It could may have a novel catalytic activity necessary for chloroplast development.
A heterobivalent ligand for the adenosine A2A-dopamine D2 receptor heteromer
(American Chemical Society, 2022-01-04) Pulido, Daniel; Casadó Anguera, Verònica; Gómez-Autet, Marc; Llopart, Natàlia; Moreno Guillén, Estefanía; Casajuana-Martin, Nil; Ferré, Sergi; Pardo, Leonardo; Casadó, Vicent; Royo Expósito, Miriam
A G protein-coupled receptor heteromer that fulfills the established criteria for its existence in vivo is the complex between adenosine A2A (A2AR) and dopamine D2 (D2R) receptors. Here, we have designed and synthesized heterobivalent ligands for the A2AR−D2R heteromer with various spacer lengths. The indispensable simultaneous binding of these ligands to the two different orthosteric sites of the heteromer has been evaluated by radioligand competition-binding assays in the absence and presence of specific peptides that disrupt the formation of the heteromer, label-free dynamic mass redistribution assays in living cells, and molecular dynamic simulations. This combination of techniques has permitted us to identify compound 26 [KDB1 (A2AR) = 2.1 nM, KDB1 (D2R) = 0.13 nM], with a spacer length of 43-atoms, as a true bivalent ligand that simultaneously binds to the two different orthosteric sites. Moreover, bioluminescence resonance energy transfer experiments indicate that 26 favors the stabilization of the A2AR−D2R heteromer.
Determination of 3-Hydroxy-3-methylglutaryl CoA Reductase Activity in Plants
(Springer Science + Business Media, 2014-01-01) Campos Martínez, Narciso; Arró i Plans, Montserrat; Ferrer i Prats, Albert; Boronat i Margosa, Albert
The enzyme 3-hydroxy-3-methylglutaryl CoA (HMG-CoA) reductase catalyzes the NADPH-mediated reductive deacylation of HMG-CoA to mevalonic acid, which is the first committed step of the mevalonate pathway for isoprenoid biosynthesis. In agreement with its key regulatory role in the pathway, plant HMG-CoA reductase is modulated by many diverse external stimuli and endogenous factors and can be detected to variable levels in every plant tissue. A fine determination of HMG-CoA reductase activity levels is required to understand its contribution to plant development and adaptation to changing environmental conditions. Here, we report a procedure to reliably determine HMG-CoA reductase activity in plants. The method includes the sample collection and homogenization strategies as well as the specific activity determination based on a classical radiochemical assay.
α_2A- and α_2C-Adrenoceptors as significant targets for dopamine and dopamine receptor ligands
(Humana Press., 2018-11-01) Sánchez Soto, Marta; Casadó Anguera, Verònica; Yano, Hideaki; Bender, Brian Joseph; Ning Sheng, Cai; Moreno Guillén, Estefanía; Canela Campos, Enric I. (Enric Isidre), 1949-; Cortés Tejedor, Antonio; Meiler, Jens; Casadó, Vicent; Ferré, Sergi
The poor norepinephrine innervation and high density ofGi/o-coupled α2A- andα2C-adrenoceptors in the striatum and the dense striatal dopamine innervation have prompted the possibility that dopamine could be an effective adrenoceptor ligand. Nevertheless, the reported adrenoceptor agonistic properties of dopamine are still inconclusive. In this study, we analyzed the binding of norepinephrine, dopamine, and several compounds reported as selective dopamine D2-like receptor ligands, such as the D3 receptor agonist 7-OH-PIPAT and the D4 receptor agonist RO-105824, to α2-adrenoceptors in cortical and striatal tissue, which express α2A-adrenoceptors and both α2A- and α2C-adrenoceptors, respectively. The affinity of dopamine for α2-adrenoceptors was found to be similar to that for D1-like and D2-like receptors.Moreover, the exogenous dopamine receptor ligands also showed high affinity for α2A- andα2C-adrenoceptors. Their ability to activate Gi/o proteins through α2A- and α2C-adrenoceptors was also analyzed in transfected cells with bioluminescent resonance energy transfer techniques. The relative ligand potencies and efficacies were dependent on the Gi/o protein subtype. Furthermore, dopamine binding to α2-adrenoceptors was functional, inducing changes in dynamic mass redistribution, adenylyl cyclase activity, and ERK1/2 phosphorylation. Binding events were further studied with computer modeling of ligand docking. Docking of dopamine at α2A- and α2C-adrenoceptors was nearly identical to its binding to the crystallized D3 receptor. Therefore, we provide conclusive evidence that α2A- and α2C-adrenoceptors are functional receptors for norepinephrine, dopamine, and other previously assumed selective D2-like receptor ligands, which calls for revisiting previous studies with those ligands.
Reinterpreting anomalous competitive binding experiments within G protein-coupled receptor homodimers using a dimer receptor model
(Elsevier B.V., 2019-01-01) Casadó Anguera, Verònica; Moreno Guillén, Estefanía; Mallol Montero, Josefa; Ferré, Sergi; Canela Campos, Enric I. (Enric Isidre), 1949-; Cortés Tejedor, Antonio; Casadó, Vicent
An increasing number of G protein-coupled receptors (GPCRs) have been reported to be expressed in the plasma membrane as dimers. Since most ligand binding data are currently fitted by classical equations developed only for monomeric receptors, the interpretation of data could be misleading in the presence of GPCR dimers. On the other hand, the equations developed from dimer receptor models assuming the existence of two orthosteric binding sites within the dimeric molecule offer the possibility to directly calculate macroscopic equilibrium dissociation constants for the two sites, an index of cooperativity (DC) that reflects the molecular communication within the dimer and, importantly, a constant of radioligand-competitor allosteric interaction (KDAB) in competitive assays. Here, we provide a practical way to fit competitive binding data that allows the interpretation of apparently anomalous results, such as competition curves that could be either bell-shaped, monophasic or biphasic depending on the assay conditions. The consideration of a radioligand-competitor allosteric interaction allows fitting these curve patterns both under simulation conditions and in real radioligand binding experiments, obtaining competitor affinity parameters closer to the actual values. Our approach is the first that, assuming the formation of receptor homodimers, is able to explain several experimental results previously considered erroneous due to their impossibility to be fitted. We also deduce the radioligand concentration responsible for the conversion of biphasic to monophasic or to bell-shaped curves in competitive radioligand binding assays. In conclusion, bell-shaped curves in competitive binding experiments constitute evidence for GPCR homodimerization.
Unique pharmacodynamic properties and low abuse liability of the µ-opioid receptor ligand (S)-methadone
(Nature Publishing Group, 2024-03-01) Walther, Donna; Glatfelter, Grant C.; Weinshenker, David; Zarate, Carlos A.; Casadó, Vicent; Baumann, Michael H.; Pardo, Leonardo; Ferré, Sergi; Michaelides, Michael; Levinstein, Marjorie; De Oliveira, Paulo A.; Casajuana-Martin, Nil; Quiroz, César; Budinich, Reece C.; Rais, Rana; Rea, William; Ventriglia, Emilya; Llopart, Natàlia; Casadó Anguera, Verònica; Moreno Guillén, Estefanía
(R,S)-methadone ((R,S)-MTD) is a µ-opioid receptor (MOR) agonist comprised of (R)-MTD and (S)-MTD enantiomers. (S)-MTD is being developed as an antidepressant and is considered an N-methyl-D-aspartate receptor (NMDAR) antagonist. We compared the pharmacology of (R)-MTD and (S)-MTD and found they bind to MORs, but not NMDARs, and induce full analgesia. Unlike (R)-MTD, (S)-MTD was a weak reinforcer that failed to affect extracellular dopamine or induce locomotor stimulation. Furthermore, (S)-MTD antagonized motor and dopamine releasing effects of (R)-MTD. (S)-MTD acted as a partial agonist at MOR, with complete loss of efficacy at the MOR-galanin Gal1 receptor (Gal1R) heteromer, a key mediator of the dopaminergic effects of opioids. In sum, we report novel and unique pharmacodynamic properties of (S)-MTD that are relevant to its potential mechanism of action and therapeutic use. One-sentence summary: (S)-MTD, like (R)-MTD, binds to and activates MORs in vitro, but (S)-MTD antagonizes the MOR-Gal1R heteromer, decreasing its abuse liability.
Targeting and topology in the membrane of plant 3-hydroxy-3-methylglutaryl Coenzyme A reductase
(American Society of Plant Physiologists, 1995-12-01) Campos Martínez, Narciso; Boronat i Margosa, Albert
The enzyme 3-hydroxy-3-methylglutaryl coenzyme A reductase (HMGR) catalyzes the synthesis of mevalonate. This is the first committed step of isoprenoid biosynthesis. A common feature of all known plant HMGR isoforms is the presence of two highly conserved hydrophobic sequences in the N-terminal quarter of the protein. Using an in vitro system, we showed that the two hydrophobic sequences of Arabidopsis HMGR1S function as internal signal sequences. Specific recognition of these sequences by the signal recognition particle mediates the targeting of the protein to microsomes derived from the endoplasmic reticulum. Arabidopsis HMGR is inserted into the microsomal membrane, and the two hydrophobic sequences become membrane-spanning segments. The N-terminal end and the C-terminal catalytic domain of Arabidopsis HMGR are positioned on the cytosolic side of the membrane, whereas only a short hydrophilic sequence is exposed to the lumen. Our results suggest that the plant HMGR isoforms known to date are primarily targeted to the endoplasmic reticulum and have the same topology in the membrane. This reinforces the hypothesis that mevalonate is synthesized only in the cytosol. The possibility that plant HMGRs might be located in different regions of the endomembrane system is discussed.
Hints on the Lateralization of Dopamine Binding to D-1 Receptors in Rat Striatum
(Humana Press., 2016-10-01) Franco Fernández, Rafael; Casadó Anguera, Verònica; Muñoz, Ana; Petrovic, Milos; Navarro Brugal, Gemma; Moreno Guillén, Estefanía; Lanciego, José Luis; Labandeira-García, José Luis; Cortés Tejedor, Antonio; Casadó, Vicent
Dopamine receptors in striatum are important for healthy brain functioning and are the target of levodopa-based therapy in Parkinson's disease. Lateralization of dopaminergic neurotransmission in striata from different hemispheres occurs in patients, but also in healthy individuals. Our data show that the affinity of dopamine binding to dopamine D-1 receptors is significantly higher in left than in right striatum. Analysis of data from radioligand binding to striatal samples from na < ve, 6-hydroxydopamine lesioned, levodopa-treated and levodopa-induced dyskinetic rats shows differential receptor structure and gives hints on the causes of right/left lateralization of dopamine binding to striatal D-1 receptors. Moreover, binding data showed loss of lateralization in levodopa (L-DOPA)-induced dyskinetic rats.
1-Deoxy-D-xylulose 5-phosphate reductoisomerase and plastid isoprenoid biosynthesis during tomato fruit ripening
(John Wiley & Sons, 2001) Rodríguez Concepción, Manuel; Ahumada, Iván; Diez Juez, Ester; Sauret-Güeto, Susanna; Lois Rojas, Luisa María; Gallego, Francisco; Carretero Paulet, Lorenzo; Campos Martínez, Narciso; Boronat i Margosa, Albert
The recently discovered 2-C-methyl-D-erythritol 4-phosphate (MEP) pathway for the biosynthesis of plastid isoprenoids (including carotenoids) is not fully elucidated yet despite its central importance for plant life. It is known, however, that the first reaction completely specific to the pathway is the conversion of 1-deoxy-D-xylulose 5-phosphate (DXP) into MEP by the enzyme DXP reductoisomerase (DXR). We have identified a tomato cDNA encoding a protein with homology to DXR and in vivo activity, and show that the levels of the corresponding DXR mRNA and encoded protein in fruit tissues are similar before and during the massive accumulation of carotenoids characteristic of fruit ripening. The results are consistent with a non-limiting role of DXR, and support previous work proposing DXP synthase (DXS) as the first regulatory enzyme for plastid isoprenoid biosynthesis in tomato fruit. Inhibition of DXR activity by fosmidomycin showed that plastid isoprenoid biosynthesis is required for tomato fruit carotenogenesis but not for other ripening processes. In addition, dormancy was reduced in seeds from fosmidomycin-treated fruit but not in seeds from the tomato yellow ripe mutant (defective in phytoene synthase-1, PSY1), suggesting that the isoform PSY2 might channel the production of carotenoids for abscisic acid biosynthesis. Furthermore, the complete arrest of tomato seedling development using fosmidomycin confirms a key role of the MEP pathway in plant development.
Mevalonate biosynthesis in plants
(CRC Press, 1999) Bach, Thomas J.; Boronat i Margosa, Albert; Campos Martínez, Narciso; Ferrer i Prats, Albert; Vollack, Kai-Uwe
The enzyme 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase (HMGR, R-mevalonate: NADP+ oxidoreductase, CoA-acylating, EC 1.1.1.34) catalyzes the reductive conversion of HMG-CoA to mevalonic acid (MVA). This reaction is generally considered as a key controlling step in plant isoprenoid biosynthesis.1–4 However, the role of HMGR in the overall control of plant isoprenoid biosynthesis has not yet been unequivocally established. In spite of the interest in plant HMGR, the molecular characterization of this enzyme was hampered by the fact that it is membrane bound and difficult to purify (see Bach et al.3,5 for literature). That is why many of the molecular properties of plant HMGR did not emerge until the genes encoding the enzyme had been cloned. After characterization of a considerable number of HMGR genes (for literature see Stermer et al.4), it now seems clear that plant HMGR is encoded by multigene families. The number of genes comprising each multigene family varies, depending on the species, ranging from the two genes found in Arabidopsis thaliana6,7 to the at least seven genes reported to occur in potato.4 This is in sharp contrast with animal systems in which the enzyme is encoded by a single gene. The presence of multiple plant HMGR isozymes is consistent with the proposed key role of this enzyme in plant isoprenoid biosynthesis. Up to now, Arabidopsis is the only plant species from which all the HMGR genes have been cloned and characterized.6,7 The simplicity of the Arabidopsis HMGR gene family, together with the well recognized advantages of this plant for molecular and genetic studies, make Arabidopsis an attractive model system to elucidate the regulatory role of HMGR in plant isoprenoid biosynthesis.
Isoprenoid biosynthesis via the methylerythritol phosphate pathway: accumulation of 2-C-methyl-erythritol2,4-cyclodiphosphate in a gcpE deficient mutant of Escherichia coli
(Elsevier Ltd., 2002-01-28) Seemann, Myriam; Campos Martínez, Narciso; Rodríguez Concepción, Manuel; Hoeffler, Jean François; Grosdemange Billiard, Catherine; Boronat i Margosa, Albert; Rohmer, Michel
In the bacterium Escherichiacoli, gcpE is an essential gene in the methylerythritol phosphate pathway for isoprenoid biosynthesis. Incubation of [1-3H]methylerythritol with an E. coli mutant defective in the gcpE gene resulted in the accumulation of [1-3H]methylerythritol 2,4-cyclodiphosphate. This suggests that the GCPE protein is involved in the further conversion of methylerythritol cyclodiphosphate into isoprenoids.
Isoprenoid biosynthesis in Escherichia coli via the methylerythritol phosphate pathway: enzymatic conversion of methylerythritol cyclodiphosphate into a phosphorylated derivative of (E)-2-methylbut-2-ene-1,4-diol
(Elsevier Ltd., 2002-02-18) Seemann, Myriam; Campos Martínez, Narciso; Rodríguez Concepción, Manuel; Ibañez, Esther; Duvold, Tore; Tritsch, Denis; Boronat i Margosa, Albert; Rohmer, Michel
A crude cell-free system from an Escherichia coli strain overexpressing the cluster containing the three genes yfgA, yfgB, and gcpE converted 2-C-methyl-d-erythritol 2,4-cyclodiphosphate (1) into a phosphorylated derivative of (E)-2-methylbut-2-ene-1,4-diol (6), which most probably represents a novel intermediate in the methylerythritol phosphate pathway for isoprenoid biosynthesis. The free diol 6 was accumulated by phosphatase treatment of the crude enzyme preparation and was identified by comparison with a synthetic reference.

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