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Zhao B, Cao Z, Zheng Y, Nguyen P, Bowen A, Edwards RH, Stroud RM, Zhou Y, Van Lookeren Campagne M, Li F. Structural and mechanistic insights into a lysosomal membrane enzyme HGSNAT involved in Sanfilippo syndrome. Nat Commun 2024; 15:5388. [PMID: 38918376 PMCID: PMC11199644 DOI: 10.1038/s41467-024-49614-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Accepted: 06/11/2024] [Indexed: 06/27/2024] Open
Abstract
Heparan sulfate (HS) is degraded in lysosome by a series of glycosidases. Before the glycosidases can act, the terminal glucosamine of HS must be acetylated by the integral lysosomal membrane enzyme heparan-α-glucosaminide N-acetyltransferase (HGSNAT). Mutations of HGSNAT cause HS accumulation and consequently mucopolysaccharidosis IIIC, a devastating lysosomal storage disease characterized by progressive neurological deterioration and early death where no treatment is available. HGSNAT catalyzes a unique transmembrane acetylation reaction where the acetyl group of cytosolic acetyl-CoA is transported across the lysosomal membrane and attached to HS in one reaction. However, the reaction mechanism remains elusive. Here we report six cryo-EM structures of HGSNAT along the reaction pathway. These structures reveal a dimer arrangement and a unique structural fold, which enables the elucidation of the reaction mechanism. We find that a central pore within each monomer traverses the membrane and controls access of cytosolic acetyl-CoA to the active site at its luminal mouth where glucosamine binds. A histidine-aspartic acid catalytic dyad catalyzes the transfer reaction via a ternary complex mechanism. Furthermore, the structures allow the mapping of disease-causing variants and reveal their potential impact on the function, thus creating a framework to guide structure-based drug discovery efforts.
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Affiliation(s)
- Boyang Zhao
- Amgen Research, Department of Structural biology, South San Francisco, CA, USA
| | - Zhongzheng Cao
- Amgen Research, Department of Inflammation, South San Francisco, CA, USA
| | - Yi Zheng
- Amgen Research, Department of Discovery Protein Science, South San Francisco, CA, USA
| | - Phuong Nguyen
- Department of Biochemistry and Biophysics, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
- Laboratory for Genomics Research, UCSF School of Medicine, San Francisco, CA, USA
| | - Alisa Bowen
- Department of Biochemistry and Biophysics, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
- Adanate, Alameda, CA, USA
| | - Robert H Edwards
- Departments of Neurology and Physiology, UCSF School of Medicine, San Francisco, CA, USA
| | - Robert M Stroud
- Department of Biochemistry and Biophysics, University of California San Francisco (UCSF) School of Medicine, San Francisco, CA, USA
| | - Yi Zhou
- Amgen Research, Department of Inflammation, South San Francisco, CA, USA
| | | | - Fei Li
- Amgen Research, Department of Structural biology, South San Francisco, CA, USA.
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2
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Johnson ET, Lyon R, Zaitlin D, Khan AB, Jairajpuri MA. A comparison of transporter gene expression in three species of Peronospora plant pathogens during host infection. PLoS One 2023; 18:e0285685. [PMID: 37262030 PMCID: PMC10234565 DOI: 10.1371/journal.pone.0285685] [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: 09/13/2022] [Accepted: 04/28/2023] [Indexed: 06/03/2023] Open
Abstract
Protein transporters move essential metabolites across membranes in all living organisms. Downy mildew causing plant pathogens are biotrophic oomycetes that transport essential nutrients from their hosts to grow. Little is known about the functions and gene expression levels of membrane transporters produced by downy mildew causing pathogens during infection of their hosts. Approximately 170-190 nonredundant transporter genes were identified in the genomes of Peronospora belbahrii, Peronospora effusa, and Peronospora tabacina, which are specialized pathogens of basil, spinach, and tobacco, respectively. The largest groups of transporter genes in each species belonged to the major facilitator superfamily, mitochondrial carriers (MC), and the drug/metabolite transporter group. Gene expression of putative Peronospora transporters was measured using RNA sequencing data at two time points following inoculation onto leaves of their hosts. There were 16 transporter genes, seven of which were MCs, expressed in each Peronospora species that were among the top 45 most highly expressed transporter genes 5-7 days after inoculation. Gene transcripts encoding the ADP/ATP translocase and the mitochondrial phosphate carrier protein were the most abundant mRNAs detected in each Peronospora species. This study found a number of Peronospora genes that are likely critical for pathogenesis and which might serve as future targets for control of these devastating plant pathogens.
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Affiliation(s)
- Eric T Johnson
- United States Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Crop Bioprotection Unit, Peoria, Illinois, United States of America
| | - Rebecca Lyon
- United States Department of Agriculture, Agricultural Research Service, National Center for Agricultural Utilization Research, Crop Bioprotection Unit, Peoria, Illinois, United States of America
| | - David Zaitlin
- Kentucky Tobacco Research & Development Center, University of Kentucky, Lexington, Kentucky, United States of America
| | - Abdul Burhan Khan
- Department of Biosciences, Jamia Millia Islamia University, New Delhi, India
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Nyonda MA, Boyer JB, Belmudes L, Krishnan A, Pino P, Couté Y, Brochet M, Meinnel T, Soldati-Favre D, Giglione C. N-Acetylation of secreted proteins is widespread in Apicomplexa and independent of acetyl-CoA ER-transporter AT1. J Cell Sci 2022; 135:275539. [PMID: 35621049 DOI: 10.1242/jcs.259811] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 05/05/2022] [Indexed: 11/20/2022] Open
Abstract
Acetyl-CoA participates in post-translational modification of proteins, central carbon and lipid metabolism in several cell compartments. In mammals, the acetyl-CoA transporter 1 (AT1) facilitates the flux of cytosolic acetyl-CoA into the endoplasmic reticulum (ER), enabling the acetylation of proteins of the secretory pathway, in concert with dedicated acetyltransferases including NAT8. However, the implication of the ER acetyl-CoA pool in acetylation of ER-transiting proteins in Apicomplexa is unknown. We identify homologues of AT1 and NAT8 in Toxoplasma gondii and Plasmodium berghei. Proteome-wide analyses revealed widespread N-terminal acetylation marks of secreted proteins in both parasites. Such acetylation profile of N-terminally processed proteins was never observed so far in any other organisms. AT1 deletion resulted in a considerable reduction of parasite fitness. In P. berghei, AT1 is important for growth of asexual blood stages and production of female gametocytes and male gametocytogenesis impaling its requirement for transmission. In the absence of AT1, the lysine and N-terminal acetylation sites remained globally unaltered, suggesting an uncoupling between the role of AT1 in development and active acetylation occurring along the secretory pathway.
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Affiliation(s)
- Mary Akinyi Nyonda
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Jean-Baptiste Boyer
- Université Paris-Saclay, CEA, CNRS, Institute for Intergrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Lucid Belmudes
- Université Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Aarti Krishnan
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Paco Pino
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland.,ExcellGene SA, CH1870 Monthey, Switzerland
| | - Yohann Couté
- Université Grenoble Alpes, INSERM, CEA, UMR BioSanté U1292, CNRS, CEA, FR2048, 38000 Grenoble, France
| | - Mathieu Brochet
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Thierry Meinnel
- Université Paris-Saclay, CEA, CNRS, Institute for Intergrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
| | - Dominique Soldati-Favre
- Department of Microbiology and Molecular Medicine, University of Geneva, Geneva, Switzerland
| | - Carmela Giglione
- Université Paris-Saclay, CEA, CNRS, Institute for Intergrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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4
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Abstract
The mercapturic acid pathway is a major route for the biotransformation of xenobiotic and endobiotic electrophilic compounds and their metabolites. Mercapturic acids (N-acetyl-l-cysteine S-conjugates) are formed by the sequential action of the glutathione transferases, γ-glutamyltransferases, dipeptidases, and cysteine S-conjugate N-acetyltransferase to yield glutathione S-conjugates, l-cysteinylglycine S-conjugates, l-cysteine S-conjugates, and mercapturic acids; these metabolites constitute a "mercapturomic" profile. Aminoacylases catalyze the hydrolysis of mercapturic acids to form cysteine S-conjugates. Several renal transport systems facilitate the urinary elimination of mercapturic acids; urinary mercapturic acids may serve as biomarkers for exposure to chemicals. Although mercapturic acid formation and elimination is a detoxication reaction, l-cysteine S-conjugates may undergo bioactivation by cysteine S-conjugate β-lyase. Moreover, some l-cysteine S-conjugates, particularly l-cysteinyl-leukotrienes, exert significant pathophysiological effects. Finally, some enzymes of the mercapturic acid pathway are described as the so-called "moonlighting proteins," catalytic proteins that exert multiple biochemical or biophysical functions apart from catalysis.
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Affiliation(s)
- Patrick E Hanna
- Department of Medicinal Chemistry, University of Minnesota, Minneapolis, MN, USA
| | - M W Anders
- Department of Pharmacology and Physiology, University of Rochester Medical Center, Rochester, NY, USA
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5
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Electrospray ionization ion mobility mass spectrometry provides novel insights into the pattern and activity of fetal hippocampus gangliosides. Biochimie 2017; 139:81-94. [DOI: 10.1016/j.biochi.2017.05.016] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 05/24/2017] [Indexed: 12/19/2022]
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Pehar M, Puglielli L. Lysine acetylation in the lumen of the ER: a novel and essential function under the control of the UPR. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:686-97. [PMID: 23247107 DOI: 10.1016/j.bbamcr.2012.12.004] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2012] [Revised: 12/03/2012] [Accepted: 12/05/2012] [Indexed: 01/15/2023]
Abstract
The N(ε)-amino group of lysine residues can be transiently modified by the addition of an acetyl group. Recognized functions of N(ε)-lysine acetylation include regulation of activity, molecular stabilization and conformational assembly of a protein. For more than forty years lysine acetylation was thought to occur only in the cytosol and nucleus. Targets included cytoskeletal-associated proteins as well as transcription factors, histone proteins and proteins involved in DNA recombination and repair. However, in 2007 we reported that a type I membrane protein involved in the pathogenesis of Alzheimer's disease was transiently acetylated on the ε amino group of seven lysine residues while transiting along the secretory pathway. Surprisingly, the acetylation occurred in the lumen of the endoplasmic reticulum (ER) forcing us to reconsider old paradigms. Indeed, if lysine acetylation can occur in the lumen of the ER, then all the essential biochemical elements of the reaction must be available in the lumen of the organelle. Follow-up studies revealed the existence of ER-based acetyl-CoA:lysine acetyltransferases as well as a membrane transporter that translocates acetyl-CoA from the cytosol into the ER lumen. Large-scale proteomics showed that the list of substrates of the ER-based acetylation machinery includes both transiting and resident proteins. Finally, genetic studies revealed that this machinery is tightly linked to human diseases. Here, we describe these exciting findings as well as recent biochemical and cellular advances, and discuss possible impact on both human physiology and pathology.
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Affiliation(s)
- Mariana Pehar
- Department of Medicine, University of Wisconsin-Madison, VA Medical Center, Madison, WI 53705, USA
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7
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Shu DP, Chen BL, Hong J, Liu PP, Hou DX, Huang X, Zhang FT, Wei JL, Guan WT. Global transcriptional profiling in porcine mammary glands from late pregnancy to peak lactation. OMICS-A JOURNAL OF INTEGRATIVE BIOLOGY 2012; 16:123-37. [PMID: 22401658 DOI: 10.1089/omi.2011.0116] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Sow milk yield and quality is crucial for the survival and growth of piglets. To understand the molecular mechanisms of lactogenesis and lactation, mammary tissue samples were taken from six sows at -17(±2), 1 and 17(±2) days relative to parturition. Mammary tissues from two sows in the same stage were used to extract RNA, which were subsequently pooled in equal amounts. Nine pooled samples were hybridized to porcine Affymetrix GeneChips. Totally 1,524 genes were detected as significantly differentially expressed over the time course tested (p<0.01, q<0.01, fold change≥2 or ≤-2), including 709 upregulated and 575 downregulated genes identified at peak lactation compared to late pregnancy. Gene ontology analysis revealed that most of the upregulated genes were involved in transport, biosynthetic processes, and homeostasis, whereas most of the downregulated genes were involved in intracellular signaling cascades, cell cycle, and DNA replication. Furthermore, we identified 64 differentially expressed genes of the solute carrier families. Taken together, our microarray analysis provides insights into previously uncharacterized changes in transcriptome between late pregnancy and peak lactation in the porcine mammary gland. The solute carrier genes and other differentially expressed genes identified in this study will guide further characterization of their function to enhance milk yield and piglet growth.
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Affiliation(s)
- Dan-Ping Shu
- College of Animal Science, South China Agricultural University, Guangzhou 510642, People's Republic of China
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8
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Mancinelli R, Pietrangelo T, Burnstock G, Fanò G, Fulle S. Transcriptional profile of GTP-mediated differentiation of C2C12 skeletal muscle cells. Purinergic Signal 2011; 8:207-21. [PMID: 22127439 DOI: 10.1007/s11302-011-9266-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2010] [Accepted: 10/03/2011] [Indexed: 02/01/2023] Open
Abstract
Several purine receptors have been localised on skeletal muscle membranes. Previous data support the hypothesis that extracellular guanosine 5'-triphosphate (GTP) is an important regulatory factor in the development and function of muscle tissue. We have previously described specific extracellular binding sites for GTP on the plasma membrane of mouse skeletal muscle (C2C12) cells. Extracellular GTP induces an increase in intracellular Ca(2+) concentrations that results in membrane hyperpolarisation through Ca(2+)-activated K(+) channels, as has been demonstrated by patch-clamp experiments. This GTP-evoked increase in intracellular Ca(2+) is due to release of Ca(2+) from intracellular inositol-1,4,5-trisphosphate-sensitive stores. This enhances the expression of the myosin heavy chain in these C2C12 myoblasts and commits them to fuse into multinucleated myotubes, probably via a phosphoinositide-3-kinase-dependent signal-transduction mechanism. To define the signalling of extracellular GTP as an enhancer or modulator of myogenesis, we investigated whether the gene-expression profile of differentiated C2C12 cells (4 and 24 h in culture) is affected by extracellular GTP. To investigate the nuclear activity and target genes modulated by GTP, transcriptional profile analysis and real-time PCR were used. We demonstrate that in the early stages of differentiation, GTP up-regulates genes involved in different pathways associated with myogenic processes, including cytoskeleton structure, the respiratory chain, myogenesis, chromatin reorganisation, cell adhesion, and the Jak/Stat pathway, and down-regulates the mitogen-activated protein kinase pathway. GTP also increases the expression of three genes involved in myogenesis, Pp3ca, Gsk3b, and Pax7. Our data suggests that in the myogenic C2C12 cell line, extracellular GTP acts as a differentiative factor in the induction and sustaining of myogenesis.
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Affiliation(s)
- Rosa Mancinelli
- Department of Neuroscience and Imaging, University G. d'Annunzio Chieti-Pescara, Chieti, Italy.
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9
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Jonas MC, Pehar M, Puglielli L. AT-1 is the ER membrane acetyl-CoA transporter and is essential for cell viability. J Cell Sci 2010; 123:3378-88. [PMID: 20826464 DOI: 10.1242/jcs.068841] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The transient or permanent modification of nascent proteins in the early secretory pathway is an essential cellular function that ensures correct folding and maturation of membrane and secreted proteins. We have recently described a new form of post-translational regulation of the membrane protein β-site APP cleaving enzyme 1 (BACE1) involving transient lysine acetylation in the lumen of the endoplasmic reticulum (ER). The essential components of this process are two ER-based acetyl-CoA:lysine acetyltransferases, ATase1 and ATase2, and a membrane transporter that translocates acetyl-CoA into the lumen of the ER. Here, we report the functional identification of acetyl-CoA transporter 1 (AT-1) as the ER membrane acetyl-CoA transporter. We show that AT-1 regulates the acetylation status of ER-transiting proteins, including the membrane proteins BACE1, low-density lipoprotein receptor and amyloid precursor protein (APP). Finally, we show that AT-1 is essential for cell viability as its downregulation results in widespread cell death and induction of features characteristic of autophagy.
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Affiliation(s)
- Mary Cabell Jonas
- Department of Medicine, University of Wisconsin-Madison, Madison, WI 53705, USA
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10
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A total of 220 patients with autosomal dominant spastic paraplegia do not display mutations in the SLC33A1 gene (SPG42). Eur J Hum Genet 2010; 18:1065-7. [PMID: 20461110 DOI: 10.1038/ejhg.2010.68] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
The most frequent causes of autosomal dominant (AD) hereditary spastic paraplegias (HSP) (ADHSP) are mutations in the SPAST gene (SPG4 locus). However, roughly 60% of patients are negative for SPAST mutations, despite their family history being compatible with AD inheritance. A mutation in the gene for an acetyl-CoA transporter (SLC33A1) has recently been reported in one Chinese family to cause ADHSP-type SPG42. In this study, we screened 220 independent SPAST mutation-negative ADHSP samples for mutations in the SLC33A1 gene by high-resolution melting curve analysis. Conspicuous samples were validated by direct sequencing. Moreover, copy number variations affecting SLC33A1 were screened by multiplex ligation-dependent probe amplification assay. We could not identify potentially disease-causing mutations in our patients either by mutation scanning or by gene dosage analysis, as for the latter specific positive controls are not available to date. As our sample represents ADHSP patients for whom SPAST mutations and almost in all cases ATL1 and REEP1 mutations had been excluded, we consider SLC33A1 gene mutations as being very rare in a European ADHSP cohort, if present at all. To date, as SPG42 has still not been identified in a second, unrelated family, systematic genetic testing for SLC33A1 mutations is not recommended.
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11
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Dion PA, Daoud H, Rouleau GA. Genetics of motor neuron disorders: new insights into pathogenic mechanisms. Nat Rev Genet 2009; 10:769-82. [DOI: 10.1038/nrg2680] [Citation(s) in RCA: 228] [Impact Index Per Article: 15.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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12
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He L, Vasiliou K, Nebert DW. Analysis and update of the human solute carrier (SLC) gene superfamily. Hum Genomics 2009; 3:195-206. [PMID: 19164095 PMCID: PMC2752037 DOI: 10.1186/1479-7364-3-2-195] [Citation(s) in RCA: 236] [Impact Index Per Article: 15.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The solute-carrier gene (SLC) superfamily encodes membrane-bound transporters. The SLC superfamily comprises 55 gene families having at least 362 putatively functional protein-coding genes. The gene products include passive transporters, symporters and antiporters, located in all cellular and organelle membranes, except, perhaps, the nuclear membrane. Transport substrates include amino acids and oligopeptides, glucose and other sugars, inorganic cations and anions (H+, HCO3-, Cl-, Na+, K+, Ca2+, Mg2+, PO43-, HPO42-, H2PO4-, SO42-, C2O42-, OH-,CO32-), bile salts, carboxylate and other organic anions, acetyl coenzyme A, essential metals, biogenic amines, neurotransmitters, vitamins, fatty acids and lipids, nucleosides, ammonium, choline, thyroid hormone and urea. Contrary to gene nomenclature commonly assigned on the basis of evolutionary divergence http://www.genenames.org/, the SLC gene superfamily has been named based largely on transporter function by proteins having multiple transmembrane domains. Whereas all the transporters exist for endogenous substrates, it is likely that drugs, non-essential metals and many other environmental toxicants are able to 'hitch-hike' on one or another of these transporters, thereby enabling these moieties to enter (or leave) the cell. Understanding and characterising the functions of these transporters is relevant to medicine, genetics, developmental biology, pharmacology and cancer chemotherapy.
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Affiliation(s)
- Lei He
- Massachusetts General Hospital Cancer Center and Harvard Medical School, Boston, MA 02114, USA
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13
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Lin P, Li J, Liu Q, Mao F, Li J, Qiu R, Hu H, Song Y, Yang Y, Gao G, Yan C, Yang W, Shao C, Gong Y. A missense mutation in SLC33A1, which encodes the acetyl-CoA transporter, causes autosomal-dominant spastic paraplegia (SPG42). Am J Hum Genet 2008; 83:752-9. [PMID: 19061983 DOI: 10.1016/j.ajhg.2008.11.003] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2008] [Revised: 10/14/2008] [Accepted: 11/05/2008] [Indexed: 01/11/2023] Open
Abstract
Hereditary spastic paraplegias (HSPs), characterized by progressive and bilateral spasticity of the legs, are usually caused by developmental failure or degeneration of motor axons in the corticospinal tract. There are considerable interfamilial and intrafamilial variations in age at onset and severity of spasticity. Genetic studies also showed that there are dozens of genetic loci, on multiple chromosomes, that are responsible for HSPs. Through linkage study of a pedigree of HSP with autosomal-dominant inheritance, we mapped the causative gene to 3q24-q26. Screening of candidate genes revealed that the HSP is caused by a missense mutation in the gene for acetyl-CoA transporter (SLC33A1). It is predicted that the missense mutation, causing the change of the highly conserved serine to arginine at the codon 113 (p. S113R), disrupts the second transmembrane domain in the transporter and reverses the orientation of all of the descending domains. Knockdown of Slc33a1 in zebrafish caused a curve-shaped tail and defective axon outgrowth from the spinal cord. Although the wild-type human SLC33A1 was able to rescue the phenotype caused by Slc33a1 knockdown in zebrafish, the mutant SLC33A1 (p.S113R) was not, suggesting that S113R mutation renders SLC33A1 nonfunctional and one that wild-type allele is not sufficient for sustaining the outgrowth and maintenance of long motor axons in human heterozygotes. Thus, our study illustrated a critical role of acetyl-CoA transporter in motor-neuron development and function.
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Affiliation(s)
- Pengfei Lin
- Key Laboratory for Experimental Teratology of the Ministry of Education and Institute of Medical Genetics, Shandong University School of Medicine, Shandong, China
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14
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Costantini C, Ko M, Jonas M, Puglielli L. A reversible form of lysine acetylation in the ER and Golgi lumen controls the molecular stabilization of BACE1. Biochem J 2007; 407:383-95. [PMID: 17425515 PMCID: PMC2275071 DOI: 10.1042/bj20070040] [Citation(s) in RCA: 93] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The lipid second messenger ceramide regulates the rate of beta cleavage of the Alzheimer's disease APP (amyloid precursor protein) by affecting the molecular stability of the beta secretase BACE1 (beta-site APP cleaving enzyme 1). Such an event is stimulated in the brain by the normal process of aging, and is under the control of the general aging programme mediated by the insulin-like growth factor 1 receptor. In the present study we report that BACE1 is acetylated on seven lysine residues of the N-terminal portion of the nascent protein. This process involves lysine acetylation in the lumen of the ER (endoplasmic reticulum) and is followed by deacetylation in the lumen of the Golgi apparatus, once the protein is fully mature. We also show that specific enzymatic activities acetylate (in the ER) and deacetylate (in the Golgi apparatus) the lysine residues. This process requires carrier-mediated translocation of acetyl-CoA into the ER lumen and is stimulated by ceramide. Site-directed mutagenesis indicates that lysine acetylation is necessary for nascent BACE1 to leave the ER and move ahead in the secretory pathway, and for the molecular stabilization of the protein.
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Affiliation(s)
- Claudio Costantini
- *Department of Medicine, University of Madison-Wisconsin, Madison, WI 53705, U.S.A
| | - Mi Hee Ko
- *Department of Medicine, University of Madison-Wisconsin, Madison, WI 53705, U.S.A
| | - Mary Cabell Jonas
- *Department of Medicine, University of Madison-Wisconsin, Madison, WI 53705, U.S.A
- †Cellular and Molecular Biology Program, University of Wisconsin-Madison, Madison, WI 53705, U.S.A
| | - Luigi Puglielli
- *Department of Medicine, University of Madison-Wisconsin, Madison, WI 53705, U.S.A
- †Cellular and Molecular Biology Program, University of Wisconsin-Madison, Madison, WI 53705, U.S.A
- ‡Geriatric Research Education Clinical Center, VA Medical Center, Madison, Wisconsin 53705, U.S.A
- To whom correspondence should be addressed (email )
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15
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Csala M, Marcolongo P, Lizák B, Senesi S, Margittai E, Fulceri R, Magyar JE, Benedetti A, Bánhegyi G. Transport and transporters in the endoplasmic reticulum. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2007; 1768:1325-41. [PMID: 17466261 DOI: 10.1016/j.bbamem.2007.03.009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2006] [Revised: 03/08/2007] [Accepted: 03/15/2007] [Indexed: 12/12/2022]
Abstract
Enzyme activities localized in the luminal compartment of the endoplasmic reticulum are integrated into the cellular metabolism by transmembrane fluxes of their substrates, products and/or cofactors. Most compounds involved are bulky, polar or even charged; hence, they cannot be expected to diffuse through lipid bilayers. Accordingly, transport processes investigated so far have been found protein-mediated. The selective and often rate-limiting transport processes greatly influence the activity, kinetic features and substrate specificity of the corresponding luminal enzymes. Therefore, the phenomenological characterization of endoplasmic reticulum transport contributes largely to the understanding of the metabolic functions of this organelle. Attempts to identify the transporter proteins have only been successful in a few cases, but recent development in molecular biology promises a better progress in this field.
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Affiliation(s)
- Miklós Csala
- Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary
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16
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Fagone P, Sriburi R, Ward-Chapman C, Frank M, Wang J, Gunter C, Brewer JW, Jackowski S. Phospholipid Biosynthesis Program Underlying Membrane Expansion during B-lymphocyte Differentiation. J Biol Chem 2007; 282:7591-605. [PMID: 17213195 DOI: 10.1074/jbc.m608175200] [Citation(s) in RCA: 70] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Stimulated B-lymphocytes differentiate into plasma cells committed to antibody production. Expansion of the endoplasmic reticulum and Golgi compartments is a prerequisite for high rate synthesis, assembly, and secretion of immunoglobulins. The bacterial cell wall component lipopolysaccharide (LPS) stimulates murine B-cells to proliferate and differentiate into antibody-secreting cells that morphologically resemble plasma cells. LPS activation of CH12 B-cells augmented phospholipid production and initiated a genetic program, including elevated expression of the genes for the synthesis, elongation, and desaturation of fatty acids that supply the phospholipid acyl moieties. Likewise, many of the genes in phospholipid biosynthesis were up-regulated, most notably those encoding Lipin1 and choline phosphotransferase. In contrast, CTP:phosphocholine cytidylyltransferase alpha (CCTalpha) protein, a key control point in phosphatidylcholine biosynthesis, increased because of stabilization of protein turnover rather than transcriptional activation. Furthermore, an elevation in cellular diacylglycerol and fatty acid correlated with enhanced allosteric activation of CCTalpha by the membrane lipids. This work defines a genetic and biochemical program for membrane phospholipid biogenesis that correlates with an increase in the phospholipid components of the endoplasmic reticulum and Golgi compartments in LPS-stimulated B-cells.
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Affiliation(s)
- Paolo Fagone
- Department of Infectious Diseases, St. Jude Children's Research Hospital, Memphis, Tennessee 38105-2794, USA
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