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Nature Communications May 2023Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are two primary components of the eukaryotic membrane and play essential roles in the maintenance of membrane...
Phosphatidylcholine (PC) and phosphatidylethanolamine (PE) are two primary components of the eukaryotic membrane and play essential roles in the maintenance of membrane integrity, lipid droplet biogenesis, autophagosome formation, and lipoprotein formation and secretion. Choline/ethanolamine phosphotransferase 1 (CEPT1) catalyzes the last step of the biosynthesis of PC and PE in the Kennedy pathway by transferring the substituted phosphate group from CDP-choline/ethanolamine to diacylglycerol. Here, we present the cryo-EM structures of human CEPT1 and its complex with CDP-choline at resolutions of 3.7 Å and 3.8 Å, respectively. CEPT1 is a dimer with 10 transmembrane segments (TMs) in each protomer. TMs 1-6 constitute a conserved catalytic domain with an interior hydrophobic chamber accommodating a PC-like density. Structural observations and biochemical characterizations suggest that the hydrophobic chamber coordinates the acyl tails during the catalytic process. The PC-like density disappears in the structure of the complex with CDP-choline, suggesting a potential substrate-triggered product release mechanism.
Topics: Humans; Ethanolamines; Choline; Phosphatidylcholines; Cytidine Diphosphate Choline; Phosphotransferases; Catalysis
PubMed: 37137909
DOI: 10.1038/s41467-023-38290-2 -
Advances in Biological Regulation Jan 2021Inositol phosphate encompasses a large multifaceted family of signalling molecules that originate from the combinatorial attachment of phosphate groups to the inositol...
Inositol phosphate encompasses a large multifaceted family of signalling molecules that originate from the combinatorial attachment of phosphate groups to the inositol ring. To date, four distinct inositol kinases have been identified, namely, IPK, ITPK, IPPK (IP5-2K), and PPIP5K. Although, ITPKs have recently been identified in archaea, eukaryotes have taken advantage of these enzymes to create a sophisticated signalling network based on inositol phosphates. However, it remains largely elusive what fundamental biochemical principles control the signalling cascade. Here, we present an evolutionary approach to understand the development of the 'inositol phosphate code' in eukaryotes. Distribution analyses of these four inositol kinase groups throughout the eukaryotic landscape reveal the loss of either ITPK, or of PPIP5K proteins in several species. Surprisingly, the loss of IPPK, an enzyme thought to catalyse the rate limiting step of IP (phytic acid) synthesis, was also recorded. Furthermore, this study highlights a noteworthy difference between animal (metazoan) and plant (archaeplastida) lineages. While metazoan appears to have a substantial amplification of IPK enzymes, archaeplastida genomes show a considerable increase in ITPK members. Differential evolution of IPK and ITPK between plant and animal lineage is likely reflective of converging functional adaptation of these two types of inositol kinases. Since, the IPK family comprises three sub-types IPMK, IP6K, and IP3-3K each with dedicated enzymatic specificity in metazoan, we propose that the amplified ITPK group in plant could be classified in sub-types with distinct enzymology.
Topics: Animals; Eukaryotic Cells; Humans; Inositol Phosphates; Multigene Family; Phosphotransferases; Phylogeny; Plants; Signal Transduction
PubMed: 33422459
DOI: 10.1016/j.jbior.2020.100782 -
PloS One 2020Cells respond to changes in environmental conditions by activating signal transduction pathways and gene expression programs. Here we present a dataset to explore the...
Cells respond to changes in environmental conditions by activating signal transduction pathways and gene expression programs. Here we present a dataset to explore the relationship between environmental stresses, kinases, and global gene expression in yeast. We subjected 28 drug-sensitive kinase mutants to 10 environmental conditions in the presence of inhibitor and performed mRNA deep sequencing. With these data, we reconstructed canonical stress pathways and identified examples of crosstalk among pathways. The data also implicated numerous kinases in novel environment-specific roles. However, rather than regulating dedicated sets of target genes, individual kinases tuned the magnitude of induction of the environmental stress response (ESR)-a gene expression signature shared across the set of perturbations-in environment-specific ways. This suggests that the ESR integrates inputs from multiple sensory kinases to modulate gene expression and growth control. As an example, we provide experimental evidence that the high osmolarity glycerol pathway is an upstream negative regulator of protein kinase A, a known inhibitor of the ESR. These results elaborate the central axis of cellular stress response signaling.
Topics: Cyclic AMP-Dependent Protein Kinases; Gene Expression Regulation, Fungal; Mitogen-Activated Protein Kinases; Phosphotransferases; RNA, Messenger; Saccharomyces cerevisiae; Saccharomyces cerevisiae Proteins; Signal Transduction; Stress, Physiological; Transcription Factors
PubMed: 32160258
DOI: 10.1371/journal.pone.0230246 -
Chembiochem : a European Journal of... Jan 2021Post-translational modifications (PTMs) within the first 17 amino acids (Nt17) of exon 1 of the Huntingtin protein (Httex1) play important roles in modulating its...
Post-translational modifications (PTMs) within the first 17 amino acids (Nt17) of exon 1 of the Huntingtin protein (Httex1) play important roles in modulating its cellular properties and functions in health and disease. In particular, phosphorylation of threonine and serine residues (T3, S13, and/or S16) has been shown to inhibit Htt aggregation in vitro and inclusion formation in cellular and animal models of Huntington's disease (HD). In this paper, we describe a new and simple methodology for producing milligram quantities of highly pure wild-type or mutant Httex1 proteins that are site-specifically phosphorylated at T3 or at both S13 and S16. This advance was enabled by 1) the discovery and validation of novel kinases that efficiently phosphorylate Httex1 at S13 and S16 (TBK1), at T3 (GCK) or T3 and S13 (TNIK and HGK), and 2) the development of an efficient methodology for producing recombinant native Httex1 proteins by using a SUMO-fusion expression and purification strategy. As a proof of concept, we demonstrate how this method can be applied to produce Httex1 proteins that are both site-specifically phosphorylated and fluorescently or isotopically labeled. Together, these advances should increase access to these valuable tools and expand the range of methods and experimental approaches that can be used to elucidate the mechanisms by which phosphorylation influences Httex1 or HTT structure, aggregation, interactome, and function(s) in health and disease.
Topics: Exons; Humans; Huntingtin Protein; Mutation; Phosphorylation; Phosphotransferases; Protein Aggregates; Protein Conformation; Recombinant Proteins
PubMed: 32805086
DOI: 10.1002/cbic.202000508 -
Reviews in Medical Virology May 2016Human cytomegalovirus (HCMV) infection is a major cause of morbidity and mortality in allogeneic hematopoietic stem cell transplant recipients. The significant clinical... (Review)
Review
Human cytomegalovirus (HCMV) infection is a major cause of morbidity and mortality in allogeneic hematopoietic stem cell transplant recipients. The significant clinical impact of HCMV infection and progression to HCMV disease among allogeneic hematopoietic stem cell transplant recipients has been reduced by prophylactic, preemptive, and curative treatments using ganciclovir, valganciclovir, foscarnet, and cidofovir. Resistance to (val)ganciclovir results from mutations localized in HCMV UL97 gene (encoding the pUL97 phosphotransferase), UL54 gene (encoding the pUL54 DNA polymerase), or both genes, whereas foscarnet and cidofovir resistance results from mutations localized within UL54 gene only. This review is focused on HCMV antiviral drug resistance, including the functions of target genes of antivirals, the mechanisms of antiviral resistance, the different mutations in pUL97 and pUL54 that have been identified in either clinical isolates or laboratory strains, and their impact on HCMV susceptibility to antiviral drugs. It emphasizes the importance of proving that observed genetic changes confer resistance so they can be distinguished from polymorphisms. Because of the emergence of HCMV resistance to currently available drugs, novel drugs are urgently needed for the therapeutic management of HCMV-resistant infections in hematopoietic stem cell transplant patients.
Topics: Antiviral Agents; Cytomegalovirus; Cytomegalovirus Infections; DNA-Directed DNA Polymerase; Disease Management; Drug Resistance, Viral; Genotype; Hematopoietic Stem Cell Transplantation; Host-Pathogen Interactions; Humans; Mutation; Phenotype; Phosphotransferases (Alcohol Group Acceptor); Viral Proteins
PubMed: 26990717
DOI: 10.1002/rmv.1873 -
Journal of Genetics and Genomics = Yi... May 2015Deoxyribonucleoside kinases (dNKs) phosphorylate deoxyribonucleosides to their corresponding monophosphate compounds. dNks also phosphorylate deoxyribonucleoside... (Review)
Review
Deoxyribonucleoside kinases (dNKs) phosphorylate deoxyribonucleosides to their corresponding monophosphate compounds. dNks also phosphorylate deoxyribonucleoside analogues that are used in the treatment of cancer or viral infections. The study of the mammalian dNKs has therefore always been of great medical interest. However, during the last 20 years, research on dNKs has gone into non-mammalian organisms. In this review, we focus on non-viral dNKs, in particular their diversity and their practical applications. The diversity of this enzyme family in different organisms has proven to be valuable in studying the evolution of enzymes. Some of these newly discovered enzymes have been useful in numerous practical applications in medicine and biotechnology, and have contributed to our understanding of the structural basis of nucleoside and nucleoside analogue activation.
Topics: Animals; Humans; Phosphotransferases (Alcohol Group Acceptor); Polyphosphates; Species Specificity
PubMed: 26059771
DOI: 10.1016/j.jgg.2015.01.003 -
The Journal of Nutrition Nov 2023Selenoprotein I (SELENOI) has been demonstrated to be an ethanolamine phosphotransferase (EPT) characterized by a nonselenoenzymatic domain and to be involved in the... (Review)
Review
Selenoprotein I (SELENOI) has been demonstrated to be an ethanolamine phosphotransferase (EPT) characterized by a nonselenoenzymatic domain and to be involved in the main synthetic branch of phosphatidylethanolamine (PE) in the endoplasmic reticulum. Therefore, defects of SELENOI may affect the health status through the multiple functions of PE. On the other hand, selenium (Se) is covalently incorporated into SELENOI as selenocysteine (Sec) in its peptide, which forms a Sec-centered domain as in the other members of the selenoprotein family. Unlike other selenoproteins, Sec-containing SELENOI was formed at a later stage of animal evolution, and the high conservation of the structural domain for PE synthesis across a wide range of species suggests the importance of EPT activity in supporting the survival and evolution of organisms. A variety of factors, such as species characteristics (age and sex), diet and nutrition (dietary Se and fat intakes), SELENOI-specific properties (tissue distribution and rank in the selenoproteome), etc., synergistically regulate the expression of SELENOI in a tentatively unclear interaction. The N- and C-terminal domains confer 2 distinct biochemical functions to SELENOI, namely PE regulation and antioxidant potential, which may allow it to be involved in numerous physiological processes, including neurological diseases (especially hereditary spastic paraplegia), T cell activation, tumorigenesis, and adipocyte differentiation. In this review, we summarize advances in the biology and roles of SELENOI, shedding light on the precise regulation of SELENOI expression and PE homeostasis by dietary Se intake and pharmaceutical or transgenic approaches to modulate the corresponding pathological status.
Topics: Animals; Antioxidants; Biology; Ethanolamines; Phosphotransferases; Selenium; Selenocysteine; Selenoproteins; Humans
PubMed: 36963501
DOI: 10.1016/j.tjnut.2023.03.023 -
Viruses Oct 2020Phosphoinositides account for only a small proportion of cellular phospholipids, but have long been known to play an important role in diverse cellular processes, such... (Review)
Review
Phosphoinositides account for only a small proportion of cellular phospholipids, but have long been known to play an important role in diverse cellular processes, such as cell signaling, the establishment of organelle identity, and the regulation of cytoskeleton and membrane dynamics. As expected, given their pleiotropic regulatory functions, they have key functions in viral replication. The spatial restriction and steady-state levels of each phosphoinositide depend primarily on the concerted action of specific phosphoinositide kinases and phosphatases. This review focuses on a number of remarkable examples of viral strategies involving phosphoinositide kinases to ensure effective viral replication.
Topics: Animals; Caenorhabditis elegans Proteins; Humans; Organelles; Phosphatidylinositol Phosphates; Phosphatidylinositols; Phosphoric Monoester Hydrolases; Phosphotransferases; Phosphotransferases (Alcohol Group Acceptor); Signal Transduction; Virus Diseases; Virus Replication; Viruses
PubMed: 33022924
DOI: 10.3390/v12101124 -
International Journal of Molecular... Jan 2022Inorganic polyphosphate (polyP) has been implicated in an astonishing array of biological functions, ranging from phosphorus storage to molecular chaperone activity to... (Review)
Review
Inorganic polyphosphate (polyP) has been implicated in an astonishing array of biological functions, ranging from phosphorus storage to molecular chaperone activity to bacterial virulence. In bacteria, polyP is synthesized by polyphosphate kinase (PPK) enzymes, which are broadly subdivided into two families: PPK1 and PPK2. While both enzyme families are capable of catalyzing polyP synthesis, PPK1s preferentially synthesize polyP from nucleoside triphosphates, and PPK2s preferentially consume polyP to phosphorylate nucleoside mono- or diphosphates. Importantly, many pathogenic bacteria such as and encode at least one of each PPK1 and PPK2, suggesting these enzymes may be attractive targets for antibacterial drugs. Although the majority of bacterial polyP studies to date have focused on PPK1s, PPK2 enzymes have also begun to emerge as important regulators of bacterial physiology and downstream virulence. In this review, we specifically examine the contributions of PPK2s to bacterial polyP homeostasis. Beginning with a survey of the structures and functions of biochemically characterized PPK2s, we summarize the roles of PPK2s in the bacterial cell, with a particular emphasis on virulence phenotypes. Furthermore, we outline recent progress on developing drugs that inhibit PPK2 enzymes and discuss this strategy as a novel means of combatting bacterial infections.
Topics: Bacteria; Enzyme Inhibitors; Phosphotransferases (Phosphate Group Acceptor); Polyphosphates; Virulence; Virulence Factors
PubMed: 35054854
DOI: 10.3390/ijms23020670 -
Current Drug Targets 2015Cancer kinome is now well organized as an important target for a new class of cancer drugs. There are more than 500 members in the kinase family in which some of them... (Review)
Review
Cancer kinome is now well organized as an important target for a new class of cancer drugs. There are more than 500 members in the kinase family in which some of them are clinically analysed, while the rest are under investigation for potential therapeutic applications. Phosphorylation, major function of kinases is one of the most significant signal transduction mechanism in which intercellular signals regulate intracellular processes like ion transport, hormone responses and cellular proliferation. Any deregulation of kinase function may lead to tumor progression and other disorders such as immunological, neurological , metabolic including also infectious diseases. This led to the necessity in the development of kinase inhibitors as therapeutic agent. Herein we discuss about different types of kinases and their inhibitors in various types of cancers. This review portrays a broad overview of the origin of kinases, discovery, the characterization and mode of action of kinase inhibitors in cancer therapy.
Topics: Antineoplastic Agents; Humans; Nanotechnology; Neoplasms; Phosphotransferases; Signal Transduction
PubMed: 25882221
DOI: 10.2174/1389450116666150416120108