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Literature summary for 2.4.1.109 extracted from

  • Manya, H.; Akasaka-Manya, K.; Nakajima, A.; Kawakita, M.; Endo, T.
    Role of N-glycans in maintaining the activity of protein O-mannosyltransferases POMT1 and POMT2 (2009), J. Biochem., 147, 337-344.
    View publication on PubMed

Cloned(Commentary)

Cloned (Comment) Organism
expressed in HEK-293T cells Homo sapiens
transfection of expression plasmids with wild-type and mutant enzyme variants into HEK-293T cells Homo sapiens

Protein Variants

Protein Variants Comment Organism
additional information single site mutations defective in potential glycosylation sites do not change enzyme activity, mutaions of all such sites cause a loss of enzyme activity, probably due to decreased hydrophilicity Homo sapiens
additional information single site mutations defective in potential glycosylation sites do not change enzyme activity, mutations of all such sites cause a loss of enzyme activity, probably du to decreased hydrophilicity Homo sapiens
additional information mutations of all N-glycosylation sites of either isoform POMT1 or POMT2 cause a loss of enzyme activity Homo sapiens
N16Q not smaller than wild-type, may be too close to membrane for a glycosylation site, single mutation with about 70% of wild-type activity Homo sapiens
N16Q the mutant shows a lower enzymatic activity to about 70% of wild type Homo sapiens
N16Q/N435Q/N471Q/N539Q together with POMT2 mutant N98Q/N330Q/N445Q/N528Q/N583Q, significantly lower activity than double wild-type, a lack of glycosylation prevents solubilization Homo sapiens
N16Q/N435Q/N471Q/N539Q together with wild-type POMT2, significantly lower activity than double wild-type, a lack of glycosylation prevents solubilization Homo sapiens
N330Q 2-3 kDa smaller than wild-type corresponding to single N-glycan chain, single mutation with no effect on activity Homo sapiens
N435Q 2-3 kDa smaller than wild-type corresponding to single N-glycan chain, single mutation with about 70% of wild-type activity Homo sapiens
N435Q the mutant shows about wild type activity Homo sapiens
N435Q the mutant shows a lower enzymatic activity to about 70% of wild type Homo sapiens
N445Q 2-3 kDa smaller than wild-type corresponding to single N-glycan chain, single mutation with no effect on activity Homo sapiens
N445Q the mutant shows about wild type activity Homo sapiens
N471Q 2-3 kDa smaller than wild-type corresponding to single N-glycan chain, single mutation with about 70% of wild-type activity Homo sapiens
N471Q the mutant shows a lower enzymatic activity to about 70% of wild type Homo sapiens
N528Q 2-3 kDa smaller than wild-type corresponding to single N-glycan chain, single mutation with no effect on activity Homo sapiens
N528Q the mutant shows about wild type activity Homo sapiens
N539Q 2-3 kDa smaller than wild-type corresponding to single N-glycan chain, single mutation with no effect on activity Homo sapiens
N539Q the mutant shows about wild type activity Homo sapiens
N583Q 2-3 kDa smaller than wild-type corresponding to single N-glycan chain, single mutation with no effect on activity Homo sapiens
N583Q the mutant shows about wild type activity Homo sapiens
N98Q 2-3 kDa smaller than wild-type corresponding to single N-glycan chain, single mutation with about 50% of wild-type activity Homo sapiens
N98Q the mutant shows a lower enzymatic activity to about 50% of wild type Homo sapiens
N98Q/N330Q/N445Q/N528Q/N583Q together with POMT1 mutant N16Q/N435Q/N471Q/N539Q, significantly lower activity than double wild-type, a lack of glycosylation prevents solubilization Homo sapiens
N98Q/N330Q/N445Q/N528Q/N583Q together with wild-type POMT1, significantly lower activity than double wild-type, a lack of glycosylation prevents solubilization Homo sapiens

Localization

Localization Comment Organism GeneOntology No. Textmining
endoplasmic reticulum
-
Homo sapiens 5783
-

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
70000
-
x * 70000, SDS-PAGE Homo sapiens
73000
-
rough estimate from SDS-PAGE figure, fully glycosylated enzyme, 2-3 kDa lower than wild-type corresponds to lack of a single N-glycan chain Homo sapiens

Organism

Organism UniProt Comment Textmining
Homo sapiens
-
-
-

Posttranslational Modification

Posttranslational Modification Comment Organism
glycoprotein POMT1, 3 of 4 potential glycosylation sites, inhibition of glycosylation with tunicamycin inactivates enzyme, mutation of all sites prevents solubilization of the enzyme Homo sapiens
glycoprotein POMT2, all of 5 potential glycosylation sites, inhibition of glycosylation with tunicamycin inactivates enzyme, mutation of all sites prevents solubilization of the enzyme Homo sapiens
glycoprotein three of the four POMT1 sites (Asn435, Asn471 and Asn539) and all five of the POMT2 N-glycosylation sites (Asn98, Asn330, Asn445, Asn528 and Asn583) are N-glycosylated Homo sapiens

Purification (Commentary)

Purification (Comment) Organism
glutathione-Sepharose 4B bead chromatography Homo sapiens
isolation of microsome fraction: cells are homogenized in 10 mM Tris-HCl, pH 7.4, EDTA, sucrose, DTT, protease inhibitors, centrifugation, supernatant ultracentrifuged, precipitate used as microsomal fraction, solubilized in 20 mM Tris-HCl, pH 8.0, 2-mercaptoethanol, EDTA, n-octyl-beta-D-thioglucoside, centrifugation, supernatant used as solubilized microsome preparation, separation with SDS-PAGE and antibody staining Homo sapiens

Source Tissue

Source Tissue Comment Organism Textmining
HEK-293T cell human embryonic kidney Homo sapiens
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
dolichyl phosphate D-mannose + glutathione-S-transferase fusion alpha-dystroglycan tritium-labeled sugar donor, 20 mM Tris-HCl, pH 8.0, 2-mercaptoethanol, EDTA, n-octyl-beta-D-thiogucoside, 22°C Homo sapiens dolichyl phosphate + O-D-mannosyl-[alpha-dystroglycan]
-
?
dolichyl phosphate D-mannose + glutathione-S-transferase fusion alpha-dystroglycan
-
Homo sapiens dolichyl phosphate + O-D-mannosyl-glutathione-S-transferase fusion alpha-dystroglycan
-
?

Subunits

Subunits Comment Organism
? x * 70000, SDS-PAGE Homo sapiens

Synonyms

Synonyms Comment Organism
POMT1
-
Homo sapiens
POMT1 isoform Homo sapiens
POMT2
-
Homo sapiens
POMT2 isoform Homo sapiens
protein O-mannosyltransferase
-
Homo sapiens
protein O-mannosyltransferase 1
-
Homo sapiens
protein O-mannosyltransferase 2
-
Homo sapiens

General Information

General Information Comment Organism
malfunction mutation in either one of the complex forming enzymes can lead to Walker-Warburg syndrome, a congenital muscular dystrophy with abnormal neuronal migration Homo sapiens
metabolism a complex of protein O-mannosyltransferase 1 and 2 catalyzes the initial step of O-mannosyl glycan biosynthesis Homo sapiens
metabolism isoforms POMT1 and POMT2 catalyze the initial step of O-mannosyl glycan biosynthesis Homo sapiens