Search results for UGGT1

Showing 4 results out of 4

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Species

Types

Compartments

Reaction types

Search properties

Protein (1 results from a total of 1)

Identifier: R-HSA-548864
Species: Homo sapiens
Compartment: endoplasmic reticulum lumen
Primary external reference: UniProt: UGGT1: Q9NYU2

Set (1 results from a total of 1)

Identifier: R-HSA-548881
Species: Homo sapiens
Compartment: endoplasmic reticulum lumen

Reaction (1 results from a total of 1)

Identifier: R-HSA-548884
Species: Homo sapiens
Compartment: endoplasmic reticulum quality control compartment
The UDP-glucose:glycoprotein glucosyltransferases 1 and 2 (UGGT1 and 2) are able to distinguish proteins with minor folding defects in the ERQC and reglucosylate them, by transferring a glucose (from dolichyl beta-D-glucosyl phosphate, DbGP) onto the alpha 1,3 mannose of the b (or c, not shown here) branch (Arnold et al. 2000, Arnold et al. 2003). The major affinity of these enzymes for proteins with minor folding defects has been demonstrated, but the exact mechanism that enable them to distinguish proteins with major and minor defects is still unknown (Pearse et al. 2008).

Pathway (1 results from a total of 1)

Identifier: R-HSA-901032
Species: Homo sapiens
Proteins that are released from the CNX or CRT complex with folding defects accumulate in a compartment of the ER called ERQC (Kamhi-Nesher et al. 2001). Here, the enzymes UGGG1 or UGGG2 are able to recognize glycoproteins with minor folding process and re-add the glucose on the alpha,1,3 branch; this is a signal for the transport of these glycoproteins back to the ER, where they can interact again with CNX or CRT in order to achieve a correct folding. At the same time that the glycoprotein is in the ERQC, the enzyme ER mannosidase I progressively removes the mannoses at positions 1A, 2A, B, C on N-glycans; when the mannose on 1A is trimmed, UDP-Glc:glycoprotein glucosyltransferases 1 and 2 (UGGT1 and 2) are no longer able to re-add the glucose, and therefore the protein is destined for ERAD. Glycoproteins subject to endoplasmic reticulum-associated degradation (ERAD) undergo reglucosylation, deglucosylation, and mannose trimming to yield Man6GlcNAc2 and Man5GlcNAc2. These structures lack the mannose residue that is the acceptor of glucose transferred by UGGT1 and 2. For years it has been thought that the removal of the mannose in position B of the N-glycan was the signal to direct proteins to degradation. However, this mechanism has been described better by Avezov et al (Avezov et al. 2008) and it has been demonstrated that even glycoproteins with Man8 or Man7 glycans can be re-glucosylated and interact again with CNX or CRT (for a review on this topic, see Lederkremer 2009 and Maattanen P et al, 2010).
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