Abstract: GlcNAc-1-phosphotransferase (GNPT) catalyzes the initial step in the formation of the mannose-6-phosphate tag that labels 60 lysosomal proteins for transport. Mutations in GNPT cause lysosomal storage disorders such as mucolipidoses. However, the molecular mechanism of GNPT remains unclear. Mammalian GNPTs are 222 hexamers in which. The UDP-GlcNAc:lysosomal enzyme, N-acetylglucosamine-1-phosphotransferase (GlcNAc-1-PT), is an α2β2γ2hexamer that mediates the initial step in the formation of the mannose 6-phosphate targeting signal on newly synthesized lysosomal acid hydrolases
GlcNAc-1-phosphotransferase helps prepare certain newly made enzymes for transport to lysosomes. Lysosomes are compartments within the cell that use digestive enzymes called hydrolases to break down large molecules into smaller ones that can be reused by cells . It is a key component of bacterial cell wall peptidoglycan, fungal cell wall chitin, and the extracellular matrix of animal cells The functions of distinct domains of the GlcNac-1-phosphotransferase α/β subunit precursor in catalytic activity, oligomerization of subunits, and interaction with other proteins remain to be investigated. The availability of animal models of mucolipidosis II will provide new insights into the pathomechanisms of the disease Both mutations lead to complete loss of GlcNAc-1-phosphotransferase activity, consistent with the severe clinical MLII phenotype of the patients. Our study expands the genotypic spectrum of MLII and provides novel insights into structural requirements to ensure GlcNAc-1-phosphotransferase activity
GlcNAc-1-phosphotransferase is an α 2 β 2 γ 2 hexamer encoded by two genes (GNPTAB and GNPTG). We have reported that the α/β subunits are able to phosphorylate most lysosomal enzymes in the absence of γ. 11 Therefore, we used a construct encoding only the α/β precursor as the starting source of mannose phosphorylating activity Mucolipidosis types II and III are autosomal recessive inherited diseases caused by a deficiency in the lysosomal enzyme N-acetylglucosamine-1 phosphotransferase (GlcNAc-phosphotransferase), which adds phosphate to function as a recognition marker for the uptake and transport of lysosomal enzymes UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase is an α 2 β 2 γ 2 hexamer that mediates the first step in the synthesis of the mannose 6-phosphate recognition marker on lysosomal acid hydrolases. Using a multifaceted approach, including analysis of acid hydrolase phosphorylation in mice and fibroblasts lacking the γ subunit along with kinetic studies of recombinant α. UDP-GlcNAc:lysosomal enzyme N -acetylglucosamine-1-phosphotransferase (GlcNAc-1-phosphotransferase) is an α 2 β 2 γ 2 heterohexamer that mediates the initial step in the formation of the mannose 6-phosphate recognition signal on lysosomal acid hydrolases
Question: E Why Does The Loss Of Function Of GlcNac Phosphotransferase Lead To I-cell Disease? . Why Does The Loss Of Function Of N-acetylglucosamine Phosphoglycosidase Lead To I-cell Disease? . A Defect In The Mannose-6-phosphate Receptor (M6PR) Would Also Lead To I-cell Disease Symptoms GlcNac-phosphotransferase catalyzes the transfer of a GlcNAc-1-phosphate residue from UDP-GlcNAc to C6 positions of selected mannoses in high-manose type oligosaccharides of the hydrolases. Then, the uncovering enzyme removes the terminal GlcNAc, exposing the M6P recognition signal Role of spacer-1 in the maturation and function of GlcNAc-1-phosphotransferase Lin Liu, Wang-Sik Lee, Balraj Doray and Stuart Kornfeld Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO, USA Correspondence S. Kornfeld, Department of Internal Medicine, Hematology Division, Campu photransferase(GlcNAc-1-phosphotransferase)mediatesthefirst step in the synthesis of the mannose 6-phosphate recognition markeronacidhydrolases.Thetransferaseexistsasan 2 the two (2). The deficiency of GlcNAc-1-phosphotransferase 2 2 hex-americcomplexwiththe -and -subunitsderivedfromasingle precursor molecule. The catalytic function of the. 2 GlcNAc-1-phosphotransferase (GNPT) catalyzes the initial step in the formation of the 3 mannose-6-phosphate tag that labels ~60 lysosomal proteins for transport. Mutations in GNPT 4 cause lysosomal storage disorders such as mucolipidoses. However, the molecular mechanism 5 of GNPT remains unclear. Mammalian GNPTs are α2β2γ2 hexamers in.
Soluble GlcNAc phosphotransferase Dec 21, 2001 - NOVAZYME PHARMACEUTICALS, INC. The present invention relates to a soluble GlcNAc phosphotransferase, a method of making the same and a method of phosphorylating with the same GlcNAc phosphotransferase of the lysosomal targeting pathway . Aug 9, 2005 - Genzyme Corporation. The present invention provides nucleotide and amino sequences of the lysosomal targeting pathway enzyme GlcNAc-phosphotransferase, methods of producing and methods of purifying this enzyme UDP-N-acetylglucosamine:lysosomal-enzyme N-acetylglucosamine-1-phosphotransferase (GlcNAc-phosphotransferase; EC 22.214.171.124) catalyzes the initial step in the synthesis of the mannose 6-phosphate determinant required for efficient intracellular targeting of newly synthesized lysosomal hydrolases to the lysosome.GlcNAc-phosphotransferase is an alpha-2/beta-2/gamma-2 hexameric complex
domain was identified in a region of the α-subunit that is required for maximum GlcNAc-1-phosphotransferase activity (De Pace et al, 2015; Velho et al, 2016a). Whereas the - and -subunit harbour the substrate binding sites and the catalytic center of the GlcNAc-1-phosphotransferase, the functions of the -subunits are poorly defined UDP-GlcNAc:lysosomal enzyme N -acetylglucosamine-1-phosphotransferase (GlcNAc-1-phosphotransferase) is an α2β2γ2 heterohexamer that mediates the initial step in the formation of the mannose 6-phosphate recognition signal on lysosomal acid hydrolases. We previously reported that the specificity of the reaction is determined by the ability of the α/β subunits to recognize a conformation. GlcNAc-phosphotransferase was then eluted from the column with 0.10 M Tris-HCI, pH 10.0, 0.005 M MgCl 2, 0.3% Lubrol and neutralized with 1/10th volume of 1 M Tris-HCI, pH 6.0. Recovery is typically 20-50% of the GlcNAc-phosphotransferase activity present in the homogenized tissue, and approximately 0.5 mg of enzyme is recovered per 10 kg of. GlcNAc-1-phosphotransferase is a Golgi-resident oligomeric enzyme complex composed of the α, β and γ subunits. The primary function of GlcNAc-1-phosphotransferase is to transfer GlcNAc-1-phosphate (GlcNAc-1-P) from UDP-GlcNAc to mannose residues in high-mannose-type N-linked glycans of more than 60 lysosomal acid hydrolases . Removal of.
function of GlcNAc- 1 -phosphotransferase (9). Notch modules are present in the Notch-receptor family, where they regulate the li-gand-induced proteolytic cleavage of the Notch-receptor by an unclear mechanism (10). The DMAP interaction domain of DNA methyltransferase 1 (DNMT1) has been proposed to serve a Dong et al. (2018) determined the crystal structures of human DPAGT1 and DPAGT1 in complex with UDP-GlcNAc or tunicamycin at 3.1- to 3.6-angstrom resolution. DPAGT1 exists predominantly as a noncovalent dimer in solution, and dimerization is important for its stability. DPAGT1 consists of 10 transmembrane helices (TMHs) with both termini in the endoplasmic reticulum (ER) lumen Defects in GlcNAc-1-phosphotransferase cause bone loss, dental abnormalities and B-cell functions 2 nd Glycobiology World Congress August 29-31, 2016 Atlanta, USA. Thomas Braulke. University Medical Center Hamburg-Eppendorf, Germany . Posters & Accepted Abstracts: J Glycobiol. Abstract
The UDP-GlcNAc:lysosomal enzyme, N-acetylglucosamine-1-phosphotransferase (GlcNAc-1-PT), is an α 2 β 2 γ 2 hexamer that mediates the initial step in the formation of the mannose 6-phosphate targeting signal on newly synthesized lysosomal acid hydrolases. The GNPTAB gene encodes the 1256 amino acid long α/β precursor which is normally cleaved at K928 in the early Golgi by Site-1 protease. Defective GlcNAc‐1‐phosphotransferase results in missorting of lysosomal enzymes and accumulation of non‐degradable macromolecules in lysosomes, strongly impairing cellular function
Mucolipidosis II (ML II) is a fatal lysosomal storage disorder resulting from defects in the multimeric GlcNAc-1-phosphotransferase responsible for the initial step in the generation of the. . The UDP-GlcNAc:lysosomal enzyme, N-acetylglucosamine-1-phosphotransferase (GlcNAc-1-PT), is an α 2 β 2 γ 2 hexamer that mediates the initial step in the formation of the mannose 6-phosphate targeting signal on newly synthesized lysosomal acid hydrolases. The GNPTAB gene encodes the 1256 amino acid long α/β precursor which is normally cleaved at K928 in the early Golgi by Site-1.
Function. It is made up of two alpha (α), two betas (β), and two gammas (γ) subunits. GNPTAB produces the alpha and beta subunits, GNPTG produces the gamma subunit. GlcNAc-1-phosphotransferase functions to prepare newly made enzymes for lysosome transportation (lysosomal hydrolases to the lysosome). Lysosomes, a part of an animal cell, helps. . These sources can be accessed via the tabs below UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase (GlcNAc-1-phosphotransferase) is an α 2 β 2 γ 2 heterohexamer that mediates the initial step in the formation of the mannose 6-phosphate recognition signal on lysosomal acid hydrolases. We previously reported that the specificity of the reaction is determined by the ability of the α/β subunits to recognize a conformation. Discussion GlcNAc-1-phosphotransferase-c promoted secretion of M- 6-PR-dependent lysosomal enzymes GlcNAc-1-phosphotransferase catalyzes the addition of phosphate residues to mannoses linked to proteins To further investigate the function of GlcNAc-1- under modification, an initial step of M-6-P modifica- phosphotransferase-g, we ectopically. They, however, appear not to inhibit transfer of GlcNAc; for example, while tunicamycin inhibits the GlcNAc phosphotransferase, that transfers GlcNAc-1-phosphate to dolichol-P (Tkacz and Lampen 1975), it does not inhibit the GlcNAc transferase that adds the second GlcNAc to form dolichol-PP-GlcNAc-GlcNAc (Kaushal and Elbein 1986)
phosphotransferase (GlcNAc-P-T) is an α In gain-of-function experiments, residues of the lysosomal protease cathepsin D have been substituted into the homologous secretory protease glycopepsinogen. These studies revealed that selected lysine residues have a critical role in the interaction wit Compound 1 was synthesized to mimic the l-Rha-α(1→3)-d-GlcNAc disaccharide moiety of the linker unit, and we recorded a K D of 58.71 µM. However, our binding data clearly demonstrate that the ligand with highest affinity for Mtb Lcp1 is the tetrasaccharide Galf 2-Rha-GlcNAc-O-C 8 (compound 2) with a K D of 5.13 µM
GlcNAc-phosphotransferase is an α 2 β 2 γ 2 hexameric complex whose protein subunits are encoded by two genes. The phosphotransferase is a low abundance membrane-associated enzyme possessing two activities. One activity is responsible for the recognition of enzymes that need to be targeted to the lysosomal compartment and the other activity. Mucolipidosis III is caused by a mutation in a gene called GNPTAB, which results reduced activity of the enzyme GlcNAc-1-phosphotransferase, which lysosomes require to properly break down large molecules inside the body's cells 5. This groundbreaking paper demonstrates that the function of the GlcNAc-1-phosphotransferase enzyme can actually be improved if certain regions of the amino acid sequence are removed. The resulting form of the enzyme is capable of adding more mannose-6-phosphate to many lysosomal hydrolases than the wild type version of the enzyme Summary: Site-1 protease-mediated cleavage of the Golgi-resident a/b-subunit precursor of the GlcNAc-1-phosphotransferase is prerequisite for its activation, the efficient transport of lysosomal enzymes generation of mannose-6-phosphate targeting signals on lysosomal enzymes and function of lysosomes.We aim to investigate mechanisms regulating the cleavage of the a/b-subunit precursor in.
. The uncovering enzyme then removes the terminal GlcNAc, exposing the M6P recognition site. 1) GlcNAc-1-phosphotransferase. 2) The uncovering enzym Mannose 6-phosphate receptor - Mechanism of targeting. In the Trans-Golgi a GlcNAc phosphotransferase ( EC 126.96.36.199) adds a GlcNAc-1-phosphate residue onto the 6-hydroxyl group of a specific mannose residue within the oligosaccharide. This forms a phosphodiester: Man-phosphate-GlcNAc. Once the phosphodiester has been formed the lysosomal enzyme will be translocated through the Golgi apparatus. As actual disease severity correlates with residual GlcNAc-1-phosphotransferase activity and resultant lysosomal function, rather than the variably elevated levels of extracellular enzyme activity (representing a combined effect of mis-targeting and upregulation) it remains unclear whether the HSCT-responsive cases could actually be due to.
Molecular Biology of Pseudo-Hurler Polydystrophy. GlcNAc-phosphotransferase is an α 2 β 2 γ 2 hexameric complex whose protein subunits are encoded by two genes. The α- and β-subunits of the phosphotransferase are encoded by the GNPTAB gene and the γ-subunits are encoded by the GNPTG gene GlcNAc-1-phosphotransferase (EC188.8.131.52) is a hexameric complex consisting of three different subunits (2 alpha, 2 beta and 2 gamma subunits). Alpha and beta subunits are encoded by GNPTAB and gamma is encoded by another gene GNPTG [ 21 ]
GlcNAc-1-phosphotransferase (mucolipidosis type II or Gnptab −/− mice), the enzyme that initiates the addition of the mannose 6-phosphate lysosomal sorting signal on acid hydrolases, exhibited extensive vacuolization of their exocrine gland cells, while the liver, brain, and mus Abstract UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase (GlcNAc-1-phosphotransferase) is an α2β2γ2 heterohexamer that mediates the initial step in the formation of the mannose 6-phosphate recognition signal on lysosomal acid hydrolases The GlcNAc-phosphotransferase enzyme encoded by GNPTAB/G acts in the pathway that generates the mannose-6-phosphate targeting signal that directs enzymes to the lysosome 21 Following [2-3H]mannose labeling, the degree of N-glycan phosphorylation of the lysosomal proteins was determined. Values obtained with the various mutants are compared with WT / , which is set to 100% (n 23). - Multiple Domains of GlcNAc-1-phosphotransferase Mediate Recognition of Lysosomal Enzymes The GlcNAc-1-phosphotransferase is a heterohexameric complex of three subunits ( 2 2 2), which are encoded by two genes ( 4-6 ). The - and -subunits of the GlcNAc-1-phosphotransferase are synthesized in the ER as a single, highly N-glycosylated, 190 kDa, type III membrane protein ( 6 ). For the transport to the Golgi apparatus, combinatorial.
Literature citations. Analysis of mucolipidosis II/III GNPTAB missense mutations identifies domains of UDP-GlcNAc:lysosomal enzyme GlcNAc-1-phosphotransferase involved in catalytic function and lysosomal enzyme recognition Analysis of mucolipidosis II/III GNPTAB missense mutations identifies domains of UDP-GlcNAc:lysosomal enzyme GlcNAc-1-phosphotransferase involved in catalytic function and lysosomal enzyme recognition. The Journal Of Biological Chemistry Y Qian, E van Meel, H Flanagan-Steet, A Yox, R Steet, S Kornfeld Publication Date: 2015-01-3 UDP-GlcNAc:lysosomal enzyme N-acetylglucosamine-1-phosphotransferase is an α2β2γ2 hexamer that mediates the first step in the synthesis of the mannose 6-phosphate recognition marker on lysosomal acid hydrolases. Using a multifaceted approach, including analysis of acid hydrolase phosphorylation in mice and fibroblasts lacking the γ subunit. An MRH domain is the only recognized domain in the gamma subunit of GlcNAc phosphotransferase. This enzyme catalyzes the first step in the biosynthesis of M6P sorting signals in the cis-Golgi (see above) and the MRH domain may be involved in the recognition of substrate glycans. GlcNAc phoshotransferase is present only in organisms which also. This process is initiated by GlcNAc-1-phosphotransferase, a multi-subunit enzyme encoded by the GNPTAB and GNPTG genes. The GNPTAB gene products (the α and ß subunits) are Analyses of disease-related GNPTAB mutations define a novel GlcNAc-1-phosphotransferase interaction domain and an alternative site-1 protease cleavage site
At present, it is unclear whether N642 is glycosylated in vivo and the loss of this N-glycosylation site affects the function of the GlcNAc-1-phosphotransferase complex. The 31-year-old MLIII alpha/beta patient #5 was found to be compound heterozygous for the non-sense and missense mutations R587X and C505Y, respectively ALG7 encodes the dolichyl-P-dependent N-acetylglucosamine-1-P transferase (GPT) that catalyzes the first step in the synthesis of lipid-linked oligosaccharides (LLO's): addition of the first N-acetylglucosamine to dolichyl phosphate on the cytosolic side of the endoplasmic reticulum ( 3, 7 ) Defective GlcNAc‐1‐phosphotransferase results in missorting of lysosomal enzymes and accumulation of non‐degradable macromolecules in lysosomes, strongly impairing cellular function. MLII‐affected patients have coarse facial features, cessation of statural growth and neuromotor development, severe skeletal abnormalities, organomegaly. The GNPTAB gene encodes a portion of the enzyme GlcNAc-phosphotransferase (EC 184.108.40.206). This enzyme acts in the first step of the so-called lysosomal enzyme-targeting pathway. This pathway functions to generate the mannose-6-phosphate targeting signal that serves as a marker, recognized by the mannose-6-phosphate receptors, that direct a large group of degradative hydrolases (~60) to the. m value for UDP-GlcNAc is approximately 3 × 10−6 M. The actual amount of tunicamycin needed to inhibit glycosylation varies in different cells (0.1- 10 μg/ml), possibly because of variable uptake and culture conditions or differences in the level of expression of the phosphotransferase. Given the key role of N
Defects in the proper targeting of glycoproteins to the lysosomes can also lead to clinical complications: Deficiencies in the enzyme responsible for the transfer of GlcNAc-1-P to Man residues (GlcNAc phosphotransferase) in lysosomal enzymes leads to the formation of dense inclusion bodies formation in the fibroblasts. Two disorders related to. Targeting of soluble lysosomal enzymes requires mannose 6-phosphate (M6P) signals whose formation is initiated by the hexameric N-acetylglucosamine (GlcNAc)-1-phosphotransferase complex (α2β2γ2). Upon proteolytic cleavage by site-1 protease, the α/β-subunit precursor is catalytically activated but the functions of γ-subunits (Gnptg) in M6P modification of lysosomal enzymes are unknown
I-cell disease is a particularly severe lysosomal storage disease that can be caused by several different mutations that lead to impaired function of the N-acetylglucosamine phosphotransferase (GlcNAc-PT) enzyme discussed in Question 2 GlcNAc-1-phosphotransferase plays a key role in the generation of mannose 6-phosphate, a recognition marker essential for efficient transport of lysosomal hydrolases to lysosomes. The enzyme complex is composed of six subunits (α2β2γ2). The α- and β-subunits are catalytically active, whereas the function of the γ-subunit is still unclear Functions of the α, β, and γ Subunits of UDP-GlcNAc:Lysosomal Enzyme N-Acetylglucosamine-1-phosphotransferase * Yi Qian, Intaek Lee, Wang Sik Lee, Meiqian Qian, Mariko Kudo, William M. Canfield.
In common with other anaerobes, the clostridia show a marked dependence on the phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS) to accumulate sugars and sugar derivatives. In this study, we demonstrate that extracts of Clostridium beijerinckii grown on N-acetylglucosamine (GlcNAc) exhibit PTS activity for the amino sugar Bovine GlcNAc-phosphotransferase has recently been purified as a 54-kDa complex composed of 3 different subunits (α 2, β 2, and γ 2) . GlcNAc-phosphotransferase is the product of 2 genes, 1 encoding the α and β subunits, the second encoding the γ subunit (W.M. Canfield, unpublished study) Functions of the Alpha, Beta, and Gamma Subunits of UDP-GlcNAc:Lysosomal Enzyme N-Acetylglucosamine-1-Phosphotransferase Qian Y, Lee I, Lee WS, Qian M, Kudo M, Canfield WM, Lobel P, Kornfeld S J Biol Chem 2010 Jan 29;285(5):3360-7
N-linked oligosaccharides arise when blocks of 14 sugars are added cotranslationally to newly synthesized polypeptides in the endoplasmic reticulum (ER). These glycans are then subjected to extensive modification as the glycoproteins mature and move through the ER via the Golgi complex to their final destinations inside and outside the cell. In the ER and in the early secretory pathway, where. Mislocalization of phosphotransferase as a cause of mucolipidosis III alphabeta. lysosomal enzyme GlcNAc-1-phosphotransferase involved in catalytic function and lysosomal enzyme recognition. (I-cell disease) and mucolipidosis IIIA (classical pseudo-Hurler polydystrophy) are caused by mutations in the GlcNAc-phosphotransferase alpha/beta. Summary of the causation of I-cell disease (MIM 252500) Mutations in DNA Mutant GlcNAc phosphotransferase Lack of normal transfer of GlcNAc 1-P to specific mannose residues of certain enzymes destined for lysosomes These enzymes consequently lack Man 6-P and are secreted from cells (eg, into the plasma) rather than targeted to lysosomes. The phosphotransferase is a hexameric complex whose protein subunits are encoded by 2 genes. The α- and β-subunits of the phosphotransferase are encoded by the GNPTAB gene. The second reaction (catalyzed by GlcNAc-1-phosphodiester-N-acetylglucosaminidase) removes the GlcNAc, leaving mannose residues phosphorylated in the 6 position: Man-6-P. The objective of this research proposal is to obtain a molecular understanding of the phosphomannosyl targeting system which functions in the delivery of newly synthesized acid hydrolases to lysosomes..
We also demonstrate that the purified XcbA protein is an N-acetylglucosamine-1-phosphotransferase that transfers N-acetylglucosamine-1-phosphate from UDP-GlcNAc to the 4-hydroxyl of an N-acetylglucosamine-1-phosphate oligosaccharide. Oligosaccharides fluorescently labeled at the aglycon are extended by XcbA only after the 4-phosphate occupying. Synonyms: Anti-GlcNAc-1-phosphotransferase subunit γ antibody produced in rabbit, Anti-UDP-N-Acetylglucosamine-1-phosphotransferase, subunit γ antibody produced in rabbit, Anti-N-Acetylglucosamine-1-phosphotransferase subunit γ precursor antibody produced in rabbit. Product Number. Clonality. Application. Species Reactivity