The conserved threonine-rich region of the HCF-1PRO repeat activates promiscuous OGT:UDP-GlcNAc glycosylation and proteolysis activities

Content Provider	Scilit
Author	Kapuria, Vaibhav Röhrig, Ute F. Waridel, Patrice Lammers, Fabienne Borodkin, Vladimir S. van Aalten, Daan M. F. Zoete, Vincent Herr, Winship
Copyright Year	2018
Description	Journal: Journal of Biological Chemistry O-Linked GlcNAc transferase (OGT) possesses dual glycosyltransferase–protease activities. OGT thereby stably glycosylates serines and threonines of numerous proteins and, via a transient glutamate glycosylation, cleaves a single known substrate—the so-called $HCF-1_{PRO}$ repeat of the transcriptional co-regulator host-cell factor 1 (HCF-1). Here, we probed the relationship between these distinct glycosylation and proteolytic activities. For proteolysis, the $HCF-1_{PRO}$ repeat possesses an important extended threonine-rich region that is tightly bound by the OGT tetratricopeptide-repeat (TPR) region. We report that linkage of this $HCF-1_{PRO}$-repeat, threonine-rich region to heterologous substrate sequences also potentiates robust serine glycosylation with the otherwise poor $R_{p}$-αS-UDP-GlcNAc diastereomer phosphorothioate and UDP-5S-GlcNAc OGT co-substrates. Furthermore, it potentiated proteolysis of a $non-HCF-1_{PRO}$-repeat cleavage sequence, provided it contained an appropriately positioned glutamate residue. Using serine- or glutamate-containing $HCF-1_{PRO}$-repeat sequences, we show that proposed OGT-based or UDP-GlcNAc–based serine-acceptor residue activation mechanisms can be circumvented independently, but not when disrupted together. In contrast, disruption of both proposed activation mechanisms even in combination did not inhibit OGT-mediated proteolysis. These results reveal a multiplicity of OGT glycosylation strategies, some leading to proteolysis, which could be targets of alternative molecular regulatory strategies.
Related Links	https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6240873/pdf http://www.jbc.org/content/293/46/17754.full.pdf
Ending Page	17768
Page Count	15
Starting Page	17754
ISSN	00219258
e-ISSN	1083351X
DOI	10.1074/jbc.ra118.004185
Journal	Journal of Biological Chemistry
Issue Number	46
Volume Number	293
Language	English
Publisher	Elsevier BV
Publisher Date	2018-11-01
Access Restriction	Open
Subject Keyword	Journal: Journal of Biological Chemistry Biochemistry and Molecular Biology Host-cell Factor-1 O-linked N-acetylglucosamine (o-glcnac) Transferase (ogt) Post-translational Modification (ptm)
Content Type	Text
Resource Type	Article
Subject	Cell Biology Biochemistry Molecular Biology