7ntf

<table><tr><td colspan='2'>[[7ntf]] is a 2 chain structure. Full crystallographic information is available from [http://oca.weizmann.ac.il/oca-bin/ocashort?id=7NTF OCA]. For a <b>guided tour on the structure components</b> use [https://proteopedia.org/fgij/fg.htm?mol=7NTF FirstGlance]. <br>

</td></tr><tr id='activity'><td class="sblockLbl"><b>Activity:</b></td><td class="sblockDat"><span class='plainlinks'>[https://en.wikipedia.org/wiki/Protein_O-GlcNAc_transferase Protein O-GlcNAc transferase], with EC number [https://www.brenda-enzymes.info/php/result_flat.php4?ecno=2.4.1.255 2.4.1.255] </span></td></tr>

== Disease ==

[[https://www.uniprot.org/uniprot/OGT1_HUMAN OGT1_HUMAN]] Regulation of OGT activity and altered O-GlcNAcylations are implicated in diabetes and Alzheimer disease. O-GlcNAcylation of AKT1 affects insulin signaling and, possibly diabetes. Reduced O-GlcNAcylations and resulting increased phosphorylations of MAPT/TAU are observed in Alzheimer disease (AD) brain cerebrum.

== Function ==

[[https://www.uniprot.org/uniprot/OGT1_HUMAN OGT1_HUMAN]] Catalyzes the transfer of a single N-acetylglucosamine from UDP-GlcNAc to a serine or threonine residue in cytoplasmic and nuclear proteins resulting in their modification with a beta-linked N-acetylglucosamine (O-GlcNAc). Glycosylates a large and diverse number of proteins including histone H2B, AKT1, PFKL, KMT2E/MLL5, MAPT/TAU and HCFC1. Can regulate their cellular processes via cross-talk between glycosylation and phosphorylation or by affecting proteolytic processing. Involved in insulin resistance in muscle and adipocyte cells via glycosylating insulin signaling components and inhibiting the 'Thr-308' phosphorylation of AKT1, enhancing IRS1 phosphorylation and attenuating insulin signaling. Involved in glycolysis regulation by mediating glycosylation of 6-phosphofructokinase PFKL, inhibiting its activity. Component of a THAP1/THAP3-HCFC1-OGT complex that is required for the regulation of the transcriptional activity of RRM1. Plays a key role in chromatin structure by mediating O-GlcNAcylation of 'Ser-112' of histone H2B: recruited to CpG-rich transcription start sites of active genes via its interaction with TET proteins (TET1, TET2 or TET3). As part of the NSL complex indirectly involved in acetylation of nucleosomal histone H4 on several lysine residues.<ref>PMID:12150998</ref> <ref>PMID:18288188</ref> <ref>PMID:19451179</ref> <ref>PMID:19377461</ref> <ref>PMID:20018852</ref> <ref>PMID:20018868</ref> <ref>PMID:20200153</ref> <ref>PMID:20824293</ref> <ref>PMID:21285374</ref> <ref>PMID:22121020</ref> <ref>PMID:22923583</ref> <ref>PMID:23353889</ref> <ref>PMID:23222540</ref> <ref>PMID:15361863</ref> <ref>PMID:21240259</ref> Isoform 2: the mitochondrial isoform (mOGT) is cytotoxic and triggers apoptosis in several cell types including INS1, an insulinoma cell line.<ref>PMID:12150998</ref> <ref>PMID:18288188</ref> <ref>PMID:19451179</ref> <ref>PMID:19377461</ref> <ref>PMID:20018852</ref> <ref>PMID:20018868</ref> <ref>PMID:20200153</ref> <ref>PMID:20824293</ref> <ref>PMID:21285374</ref> <ref>PMID:22121020</ref> <ref>PMID:22923583</ref> <ref>PMID:23353889</ref> <ref>PMID:23222540</ref> <ref>PMID:15361863</ref> <ref>PMID:21240259</ref>

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== Publication Abstract from PubMed ==

The O-linked beta-N-acetylglucosamine modification is a core signalling mechanism, with erroneous patterns leading to cancer and neurodegeneration. Although thousands of proteins are subject to this modification, only a single essential glycosyltransferase catalyses its installation, the O-GlcNAc transferase, OGT. Previous studies have provided truncated structures of OGT through X-ray crystallography, but the full-length protein has never been observed. Here, we report a 5.3 A cryo-EM model of OGT. We show OGT is a dimer, providing a structural basis for how some X-linked intellectual disability mutations at the interface may contribute to disease. We observe that the catalytic section of OGT abuts a 13.5 tetratricopeptide repeat unit region and find the relative positioning of these sections deviate from the previously proposed, X-ray crystallography-based model. We also note that OGT exhibits considerable heterogeneity in tetratricopeptide repeat units N-terminal to the dimer interface with repercussions for how OGT binds protein ligands and partners.

 

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== References ==

[[Category: Blaza, J N]]

[[Category: Davies, G J]]

[[Category: Meek, R W]]

[[Category: Transferase]]