1
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Foster J, McPhee M, Yue L, Dellaire G, Pelech S, Ridgway ND. Lipid- and phospho-regulation of CTP:Phosphocholine Cytidylyltransferase α association with nuclear lipid droplets. Mol Biol Cell 2024; 35:ar33. [PMID: 38170618 PMCID: PMC10916874 DOI: 10.1091/mbc.e23-09-0354] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 12/12/2023] [Accepted: 12/19/2023] [Indexed: 01/05/2024] Open
Abstract
Fatty acids stored in triacylglycerol-rich lipid droplets are assembled with a surface monolayer composed primarily of phosphatidylcholine (PC). Fatty acids stimulate PC synthesis by translocating CTP:phosphocholine cytidylyltransferase (CCT) α to the inner nuclear membrane, nuclear lipid droplets (nLD) and lipid associated promyelocytic leukemia (PML) structures (LAPS). Huh7 cells were used to identify how CCTα translocation onto these nuclear structures are regulated by fatty acids and phosphorylation of its serine-rich P-domain. Oleate treatment of Huh7 cells increased nLDs and LAPS that became progressively enriched in CCTα. In cells expressing the phosphatidic acid phosphatase Lipin1α or 1β, the expanded pool of nLDs and LAPS had a proportional increase in associated CCTα. In contrast, palmitate induced few nLDs and LAPS and inhibited the oleate-dependent translocation of CCTα without affecting total nLDs. Phospho-memetic or phospho-null mutations in the P-domain revealed that a 70% phosphorylation threshold, rather than site-specific phosphorylation, regulated CCTα association with nLDs and LAPS. In vitro candidate kinase and inhibitor studies in Huh7 cells identified cyclin-dependent kinase (CDK) 1 and 2 as putative P-domain kinases. In conclusion, CCTα translocation onto nLDs and LAPS is dependent on available surface area and fatty acid composition, as well as threshold phosphorylation of the P-domain potentially involving CDKs.
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Affiliation(s)
- Jason Foster
- Departments of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, and
| | - Michael McPhee
- Departments of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, and
| | - Lambert Yue
- Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada V6T 2B5
| | - Graham Dellaire
- Departments of Pathology and Biochemistry & Molecular Biology, Dalhousie University, Halifax, Nova Scotia, Canada B3H4R2
| | - Steven Pelech
- Division of Neurology, Department of Medicine, University of British Columbia, Vancouver, BC, Canada V6T 2B5
- Kinexus Bioinformatics Corporation, Vancouver, BC, Canada V6P 6T3
| | - Neale D. Ridgway
- Departments of Pediatrics and Biochemistry & Molecular Biology, Atlantic Research Centre, and
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2
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Yu J, Boehr DD. Regulatory mechanisms triggered by enzyme interactions with lipid membrane surfaces. Front Mol Biosci 2023; 10:1306483. [PMID: 38099197 PMCID: PMC10720463 DOI: 10.3389/fmolb.2023.1306483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Accepted: 11/17/2023] [Indexed: 12/17/2023] Open
Abstract
Recruitment of enzymes to intracellular membranes often modulates their catalytic activity, which can be important in cell signaling and membrane trafficking. Thus, re-localization is not only important for these enzymes to gain access to their substrates, but membrane interactions often allosterically regulate enzyme function by inducing conformational changes across different time and amplitude scales. Recent structural, biophysical and computational studies have revealed how key enzymes interact with lipid membrane surfaces, and how this membrane binding regulates protein structure and function. This review summarizes the recent progress in understanding regulatory mechanisms involved in enzyme-membrane interactions.
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Affiliation(s)
| | - David D. Boehr
- Department of Chemistry, The Pennsylvania State University, University Park, PA, United States
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3
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Kim S, Oh MI, Swanson JMJ. Stressed Lipid Droplets: How Neutral Lipids Relieve Surface Tension and Membrane Expansion Drives Protein Association. J Phys Chem B 2021; 125:5572-5586. [PMID: 34014091 PMCID: PMC8796793 DOI: 10.1021/acs.jpcb.1c01795] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Lipid droplets (LDs) are intracellular storage organelles composed of neutral lipids, such as triacylglycerol (TG), surrounded by a phospholipid (PL) monolayer decorated with specific proteins. Herein, we investigate the mechanism of protein association during LD and bilayer membrane expansion. We find that the neutral lipids play a dynamic role in LD expansion by further intercalating with the PL monolayer to create more surface-oriented TG molecules (SURF-TG). This interplay both reduces high surface tension incurred during LD budding or growth and also creates expansion-specific surface features for protein recognition. We then show that the autoinhibitory (AI) helix of CTP:phosphocholine cytidylyltransferase, a protein known to target expanding monolayers and bilayers, preferentially associates with large packing defects in a sequence-specific manner. Despite the presence of three phenylalanines, the initial binding with bilayers is predominantly mediated by the sole tryptophan due to its preference for membrane interfaces. Subsequent association is dependent on the availability of large, neighboring defects that can accommodate the phenylalanines, which are more probable in the stressed systems. Tryptophan, once fully associated, preferentially interacts with the glycerol moiety of SURF-TG in LDs. The calculation of AI binding free energy, hydrogen bonding and depth analysis, and in silico mutation experiments support the findings. Hence, SURF-TG can both reduce surface tension and mediate protein association, facilitating class II protein recruitment during LD expansion.
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Affiliation(s)
- Siyoung Kim
- Pritzker School of Molecular Engineering, University of Chicago, Chicago, IL, 60637 USA
| | - Myong In Oh
- Department of Chemistry, University of Utah, Salt Lake City, UT, 84112 USA
| | - Jessica M. J. Swanson
- Department of Chemistry, University of Utah, Salt Lake City, UT, 84112 USA
- Corresponding author: Jessica M. J. Swanson,
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4
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Cornell RB. Membrane Lipids Assist Catalysis by CTP: Phosphocholine Cytidylyltransferase. J Mol Biol 2020; 432:5023-5042. [PMID: 32234309 DOI: 10.1016/j.jmb.2020.03.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 03/22/2020] [Accepted: 03/25/2020] [Indexed: 02/06/2023]
Abstract
While most of the articles in this issue review the workings of integral membrane enzymes, in this review, we describe the catalytic mechanism of an enzyme that contains a soluble catalytic domain but appears to catalyze its reaction on the membrane surface, anchored and assisted by a separate regulatory amphipathic helical domain and inter-domain linker. Membrane partitioning of CTP: phosphocholine cytidylyltransferase (CCT), a key regulatory enzyme of phosphatidylcholine metabolism, is regulated chiefly by changes in membrane phospholipid composition, and boosts the enzyme's catalytic efficiency >200-fold. Catalytic enhancement by membrane binding involves the displacement of an auto-inhibitory helix from the active site entrance-way and promotion of a new conformational ensemble for the inter-domain, allosteric linker that has an active role in the catalytic cycle. We describe the evidence for close contact between membrane lipid, a compact allosteric linker, and the CCT active site, and discuss potential ways that this interaction enhances catalysis.
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Affiliation(s)
- Rosemary B Cornell
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC, Canada V5A-1S6.
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5
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Yue L, McPhee MJ, Gonzalez K, Charman M, Lee J, Thompson J, Winkler DFH, Cornell RB, Pelech S, Ridgway ND. Differential dephosphorylation of CTP:phosphocholine cytidylyltransferase upon translocation to nuclear membranes and lipid droplets. Mol Biol Cell 2020; 31:1047-1059. [PMID: 32186954 PMCID: PMC7346725 DOI: 10.1091/mbc.e20-01-0014] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
CTP:phosphocholine cytidylyltransferase-alpha (CCTα) and CCTβ catalyze the rate-limiting step in phosphatidylcholine (PC) biosynthesis. CCTα is activated by association of its α-helical M-domain with nuclear membranes, which is negatively regulated by phosphorylation of the adjacent P-domain. To understand how phosphorylation regulates CCT activity, we developed phosphosite-specific antibodies for pS319 and pY359+pS362 at the N- and C-termini of the P-domain, respectively. Oleate treatment of cultured cells triggered CCTα translocation to the nuclear envelope (NE) and nuclear lipid droplets (nLDs) and rapid dephosphorylation of pS319. Removal of oleate led to dissociation of CCTα from the NE and increased phosphorylation of S319. Choline depletion of cells also caused CCTα translocation to the NE and S319 dephosphorylation. In contrast, Y359 and S362 were constitutively phosphorylated during oleate addition and removal, and CCTα-pY359+pS362 translocated to the NE and nLDs of oleate-treated cells. Mutagenesis revealed that phosphorylation of S319 is regulated independently of Y359+S362, and that CCTα-S315D+S319D was defective in localization to the NE. We conclude that the P-domain undergoes negative charge polarization due to dephosphorylation of S319 and possibly other proline-directed sites and retention of Y359 and S362 phosphorylation, and that dephosphorylation of S319 and S315 is involved in CCTα recruitment to nuclear membranes.
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Affiliation(s)
- Lambert Yue
- Department of Medicine, Division of Neurology, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Michael J McPhee
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Kevin Gonzalez
- Department of Medicine, Division of Neurology, University of British Columbia, Vancouver, BC V6T 2B5, Canada
| | - Mark Charman
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Jonghwa Lee
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Jordan Thompson
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
| | - Dirk F H Winkler
- Kinexus Bioinformatics Corporation, Vancouver, BC V6P 6T3, Canada
| | - Rosemary B Cornell
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, BC V5A 1S6, Canada
| | - Steven Pelech
- Department of Medicine, Division of Neurology, University of British Columbia, Vancouver, BC V6T 2B5, Canada.,Kinexus Bioinformatics Corporation, Vancouver, BC V6P 6T3, Canada
| | - Neale D Ridgway
- Department of Pediatrics and Department of Biochemistry and Molecular Biology, Dalhousie University, Halifax, NS B3H 4R2, Canada
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6
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Caldo KMP, Xu Y, Falarz L, Jayawardhane K, Acedo JZ, Chen G. Arabidopsis CTP:phosphocholine cytidylyltransferase 1 is phosphorylated and inhibited by sucrose nonfermenting 1-related protein kinase 1 (SnRK1). J Biol Chem 2019; 294:15862-15874. [PMID: 31439667 PMCID: PMC6816107 DOI: 10.1074/jbc.ra119.008047] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 08/19/2019] [Indexed: 11/06/2022] Open
Abstract
De novo phosphatidylcholine (PC) biosynthesis via the Kennedy pathway involves highly endergonic biochemical reactions that must be fine-tuned with energy homeostasis. Previous studies have shown that CTP:phosphocholine cytidylyltransferase (CCT) is an important regulatory enzyme in this pathway and that its activity can be controlled at both transcriptional and posttranslational levels. Here we identified an important additional mechanism regulating plant CCT1 activity. Comparative analysis revealed that Arabidopsis CCT1 (AtCCT1) contains catalytic and membrane-binding domains that are homologous to those of rat CCT1. In contrast, the C-terminal phosphorylation domain important for stringent regulation of rat CCT1 was apparently missing in AtCCT1. Instead, we found that AtCCT1 contains a putative consensus site (Ser-187) for modification by sucrose nonfermenting 1-related protein kinase 1 (SnRK1 or KIN10/SnRK1.1), involved in energy homeostasis. Phos-tag SDS-PAGE coupled with MS analysis disclosed that SnRK1 indeed phosphorylates AtCCT1 at Ser-187, and we found that AtCCT1 phosphorylation substantially reduces its activity by as much as 70%. An S187A variant exhibited decreased activity, indicating the importance of Ser-187 in catalysis, and this variant was less susceptible to SnRK1-mediated inhibition. Protein truncation and liposome binding studies indicated that SnRK1-mediated AtCCT1 phosphorylation directly affects the catalytic domain rather than interfering with phosphatidate-mediated AtCCT1 activation. Overexpression of the AtCCT1 catalytic domain in Nicotiana benthamiana leaves increased PC content, and SnRK1 co-expression reduced this effect. Taken together, our results suggest that SnRK1 mediates the phosphorylation and concomitant inhibition of AtCCT1, revealing an additional mode of regulation for this key enzyme in plant PC biosynthesis.
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Affiliation(s)
- Kristian Mark P Caldo
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Yang Xu
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Lucas Falarz
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Kethmi Jayawardhane
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Jeella Z Acedo
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
| | - Guanqun Chen
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
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7
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Knowles DG, Lee J, Taneva SG, Cornell RB. Remodeling of the interdomain allosteric linker upon membrane binding of CCTα pulls its active site close to the membrane surface. J Biol Chem 2019; 294:15531-15543. [PMID: 31488548 DOI: 10.1074/jbc.ra119.009850] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/18/2019] [Indexed: 01/10/2023] Open
Abstract
The rate-limiting step in the biosynthesis of the major membrane phospholipid, phosphatidylcholine, is catalyzed by CTP:phosphocholine cytidylyltransferase (CCT), which is regulated by reversible membrane binding of a long amphipathic helix (domain M). The M domain communicates with the catalytic domain via a conserved ∼20-residue linker, essential for lipid activation of CCT. Previous analysis of this region (denoted as the αEC/J) using MD simulations, cross-linking, mutagenesis, and solvent accessibility suggested that membrane binding of domain M promotes remodeling of the αEC/J into a more compact structure that is required for enzyme activation. Here, using tryptophan fluorescence quenching, we show that the allosteric linker lies superficially on the membrane surface. Analyses with truncated CCTs show that the αEC/J can interact with lipids independently of the M domain. We observed strong FRET between engineered tryptophans in the αEC/J and vesicles containing dansyl-phosphatidylethanolamine that depended on the native J sequence. These data are incompatible with the extended conformation of the αE helix observed in the previously determined crystal structure of inactive CCT but support a bent αE helix conformation stabilized by J segment interactions. Our results suggest that the membrane-adsorbed, folded allosteric linker may partially cover the active site cleft and pull it close to the membrane surface, where cytidyl transfer can occur efficiently in a relatively anhydrous environment.
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Affiliation(s)
- Daniel G Knowles
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Jaeyong Lee
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Svetla G Taneva
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Rosemary B Cornell
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada .,Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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8
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Taneva SG, Lee J, Knowles DG, Tishyadhigama C, Chen H, Cornell RB. Interdomain communication in the phosphatidylcholine regulatory enzyme, CCTα, relies on a modular αE helix. J Biol Chem 2019; 294:15517-15530. [PMID: 31488547 DOI: 10.1074/jbc.ra119.009849] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2019] [Revised: 08/18/2019] [Indexed: 12/14/2022] Open
Abstract
CTP:phosphocholine cytidylyltransferase (CCT), the rate-limiting enzyme in phosphatidylcholine (PC) synthesis, is an amphitropic enzyme that regulates PC homeostasis. Recent work has suggested that CCTα activation by binding to a PC-deficient membrane involves conformational transitions in a helix pair (αE) that, along with a short linker of unknown structure (J segment), bridges the catalytic domains of the CCTα dimer to the membrane-binding (M) domains. In the soluble, inactive form, the αE helices are constrained into unbroken helices by contacts with two auto-inhibitory (AI) helices from domain M. In the active, membrane-bound form, the AI helices are displaced and engage the membrane. Molecular dynamics simulations have suggested that AI displacement is associated with hinge-like bending in the middle of the αE, positioning its C terminus closer to the active site. Here, we show that CCTα activation by membrane binding is sensitive to mutations in the αE and J segments, especially within or proximal to the αE hinge. Substituting Tyr-213 within this hinge with smaller uncharged amino acids that could destabilize interactions between the αE helices increased both constitutive and lipid-dependent activities, supporting a link between αE helix bending and stimulation of CCT activity. The solvent accessibilities of Tyr-213 and Tyr-216 suggested that these tyrosines move to new partially buried environments upon membrane binding of CCT, consistent with a folded αE/J structure. These data suggest that signal transduction through the modular αE helix pair relies on shifts in its conformational ensemble that are controlled by the AI helices and their displacement upon membrane binding.
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Affiliation(s)
- Svetla G Taneva
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Jaeyong Lee
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Daniel G Knowles
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Chanajai Tishyadhigama
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Hongwen Chen
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Rosemary B Cornell
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada .,Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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9
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Abstract
The proportion of phosphatidylcholine (PC) in the membrane is controlled by CTP:phosphocholine cytidylyltransferase α (CCTα), which is known to be regulated by a dual auto-inhibitory and membrane-binding domain. However, the detailed mechanism by which this domain regulates CCTα activity is not clear. Ramezanpour et al. use a combined computational and biochemical approach to define new details of this mechanism, providing an elegant illustration of how the lipid-sensing domain of a phospholipid biosynthetic enzyme controls membrane homeostasis.
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Affiliation(s)
- Neale D Ridgway
- From the Departments of Biochemistry and Molecular Biology and Pediatrics, Atlantic Research Centre, Dalhousie University, Halifax, Nova Scotia B3H4R2, Canada
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10
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Cornell RB, Taneva SG, Dennis MK, Tse R, Dhillon RK, Lee J. Disease-linked mutations in the phosphatidylcholine regulatory enzyme CCTα impair enzymatic activity and fold stability. J Biol Chem 2018; 294:1490-1501. [PMID: 30559292 DOI: 10.1074/jbc.ra118.006457] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 12/05/2018] [Indexed: 11/06/2022] Open
Abstract
CTP:phosphocholine cytidylyltransferase (CCT) is the key regulatory enzyme in phosphatidylcholine (PC) synthesis and is activated by binding to PC-deficient membranes. Mutations in the gene encoding CCTα (PCYT1A) cause three distinct pathologies in humans: lipodystrophy, spondylometaphyseal dysplasia with cone-rod dystrophy (SMD-CRD), and isolated retinal dystrophy. Previous analyses showed that for some disease-linked PCYT1A variants steady state levels of CCTα and PC synthesis were reduced in patient fibroblasts, but other variants impaired PC synthesis with little effect on CCT levels. To explore the impact on CCT stability and function we expressed WT and mutant CCTs in COS-1 cells, which have very low endogenous CCT. Over-expression of two missense variants in the catalytic domain (V142M and P150A) generated aggregated enzymes that could not be refolded after solubilization by denaturation. Other mutations in the catalytic core that generated CCTs with reduced solubility could be purified. Five variants destabilized the catalytic domain-fold as assessed by lower transition temperatures for unfolding, and three of these manifested defects in substrate Km values. A mutation (R223S) in a signal-transducing linker between the catalytic and membrane-binding domains also impaired enzyme kinetics. E280del, a single amino acid deletion in the autoinhibitory helix increased the constitutive (lipid-independent) enzyme activity ∼4-fold. This helix also participates in membrane binding, and surprisingly E280del enhanced the enzyme's response to anionic lipid vesicles ∼4-fold. These in vitro analyses on purified mutant CCTs will complement future measurements of their impact on PC synthesis in cultured cells and in tissues with a stringent requirement for CCTα.
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Affiliation(s)
- Rosemary B Cornell
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 Canada; Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 Canada.
| | - Svetla G Taneva
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 Canada
| | - Melissa K Dennis
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 Canada
| | - Ronnie Tse
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 Canada
| | - Randeep K Dhillon
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 Canada
| | - Jaeyong Lee
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6 Canada
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11
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Guca E, Nagy GN, Hajdú F, Marton L, Izrael R, Hoh F, Yang Y, Vial H, Vértessy BG, Guichou JF, Cerdan R. Structural determinants of the catalytic mechanism of Plasmodium CCT, a key enzyme of malaria lipid biosynthesis. Sci Rep 2018; 8:11215. [PMID: 30046154 PMCID: PMC6060094 DOI: 10.1038/s41598-018-29500-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2018] [Accepted: 07/10/2018] [Indexed: 11/13/2022] Open
Abstract
The development of the malaria parasite, Plasmodium falciparum, in the human erythrocyte, relies on phospholipid metabolism to fulfil the massive need for membrane biogenesis. Phosphatidylcholine (PC) is the most abundant phospholipid in Plasmodium membranes. PC biosynthesis is mainly ensured by the de novo Kennedy pathway that is considered as an antimalarial drug target. The CTP:phosphocholine cytidylyltransferase (CCT) catalyses the rate-limiting step of the Kennedy pathway. Here we report a series of structural snapshots of the PfCCT catalytic domain in its free, substrate- and product-complexed states that demonstrate the conformational changes during the catalytic mechanism. Structural data show the ligand-dependent conformational variations of a flexible lysine. Combined kinetic and ligand-binding analyses confirm the catalytic roles of this lysine and of two threonine residues of the helix αE. Finally, we assessed the variations in active site residues between Plasmodium and mammalian CCT which could be exploited for future antimalarial drug design.
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Affiliation(s)
- Ewelina Guca
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR 5235, CNRS, Université de Montpellier, Montpellier, France.,Institute for Research in Biomedicine, The Barcelona Institute of Science and Technology, Carrer de Baldiri Reixac 10, 08028, Barcelona, Spain
| | - Gergely N Nagy
- Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, Budapest, Hungary.,Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.,Division of Structural Biology, University of Oxford, Roosevelt Drive, Oxford, OX37BN, United Kingdom
| | - Fanni Hajdú
- Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, Budapest, Hungary.,Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Lívia Marton
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.,Doctoral School of Multidisciplinary Medical Science, University of Szeged, Szeged, Hungary
| | - Richard Izrael
- Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, Budapest, Hungary.,Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - François Hoh
- CNRS UMR5048, Centre de Biochimie Structurale, Université de Montpellier, Montpellier, France.,INSERM U1054, Montpellier, France
| | - Yinshan Yang
- CNRS UMR5048, Centre de Biochimie Structurale, Université de Montpellier, Montpellier, France.,INSERM U1054, Montpellier, France
| | - Henri Vial
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR 5235, CNRS, Université de Montpellier, Montpellier, France
| | - Beata G Vértessy
- Department of Applied Biotechnology and Food Science, Budapest University of Technology and Economics, Budapest, Hungary.,Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary
| | - Jean-François Guichou
- CNRS UMR5048, Centre de Biochimie Structurale, Université de Montpellier, Montpellier, France.,INSERM U1054, Montpellier, France
| | - Rachel Cerdan
- Dynamique des Interactions Membranaires Normales et Pathologiques, UMR 5235, CNRS, Université de Montpellier, Montpellier, France.
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