Abstract
TET proteins oxidize 5-methylcytosine to 5-hydroxymethylcytosine, 5-formylcytosine, and 5-carboxylcytosine and thus provide a possible means for active DNA demethylation in mammals. Although their catalytic mechanism is well characterized and the catalytic dioxygenase domain is highly conserved, the function of the regulatory regions (the N terminus and the low-complexity insert between the two parts of the dioxygenase domains) is only poorly understood. Here, we demonstrate that TET proteins are subject to a variety of post-translational modifications that mostly occur at these regulatory regions. We mapped TET modification sites at amino acid resolution and show for the first time that TET1, TET2, and TET3 are highly phosphorylated. The O-linked GlcNAc transferase, which we identified as a strong interactor with all three TET proteins, catalyzes the addition of a GlcNAc group to serine and threonine residues of TET proteins and thereby decreases both the number of phosphorylation sites and site occupancy. Interestingly, the different TET proteins display unique post-translational modification patterns, and some modifications occur in distinct combinations. In summary, our results provide a novel potential mechanism for TET protein regulation based on a dynamic interplay of phosphorylation and O-GlcNAcylation at the N terminus and the low-complexity insert region. Our data suggest strong cross-talk between the modification sites that could allow rapid adaption of TET protein localization, activity, or targeting due to changing environmental conditions as well as in response to external stimuli.
Highlights
TET proteins oxidize 5-methylcytosine and contribute to active DNA demethylation
We demonstrate that TET proteins are phosphorylated and that this phosphorylation can be suppressed via O-GlcNAcylation by the glycosyltransferase OGT
Characterization of Anti-TET Antibodies—The three TET proteins share a common domain architecture: the C-terminal catalytic dioxygenase domain is split into two parts separated by a low-complexity insert region and is preceded by an extension enriched in cysteines [8]
Summary
TET proteins oxidize 5-methylcytosine and contribute to active DNA demethylation. Results: O-Linked GlcNAc transferase modifies TET proteins with GlcNAc and thereby reduces TET phosphorylation. TET proteins oxidize 5-methylcytosine to 5-hydroxymethylcytosine, 5-formylcytosine, and 5-carboxylcytosine and provide a possible means for active DNA demethylation in mammals Their catalytic mechanism is well characterized and the catalytic dioxygenase domain is highly conserved, the function of the regulatory regions (the N terminus and the low-complexity insert between the two parts of the dioxygenase domains) is only poorly understood. We show that TET proteins are subject to a large number of post-translational modifications (PTMs), predominantly occurring at the two low-complexity regions, which display only little sequence conservation: the N terminus and the insert region that separates the two parts of the catalytic dioxygenase domain and is predicted to be unstructured [8].
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
