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O-GlcNAcylation regulates OTX2's proteostasis.
Eugenia Wulff-Fuentes1, Jeffrey Boakye2, Kaeley Kroenke1
1Department of Biochemistry, Medical College of Wisconsin, Milwaukee, WI 53226, USA.
Iscience
|November 29, 2023
Summary
O-GlcNAcylation enhances OTX2 protein solubility, preventing harmful aggregation. This post-translational modification is crucial for brain development and has implications for treating brain disorders and cancer.
Area of Science:
- Biochemistry
- Cell Biology
- Neuroscience
Background:
- O-GlcNAcylation is a critical post-translational modification involved in cell signaling, particularly in brain development.
- The homeobox protein OTX2 is implicated in various brain disorders, including pituitary hormone deficiency, retinopathy, and medulloblastoma.
Purpose of the Study:
- To investigate the role of O-GlcNAcylation in regulating OTX2.
- To understand the mechanisms controlling OTX2 levels and aggregation.
- To explore the therapeutic potential of targeting OTX2 in cancer.
Main Methods:
- Investigated OTX2 degradation pathways (proteasomal and macroautophagy).
- Assessed the impact of O-GlcNAcylation on OTX2 solubility and aggregation.
- Identified protein interactions with OTX2 at O-GlcNAc sites using co-immunoprecipitation.
- Evaluated the effect of OTX2 O-GlcNAcylation status on cancer cell proliferation.
Main Results:
- Under normal conditions, OTX2 is degraded by the proteasome.
- Elevated OTX2 levels lead to oligomerization and aggregation, cleared by macroautophagy.
- O-GlcNAcylation increases OTX2 solubility, inhibiting aggregate formation.
- O-GlcNAcylation sites on OTX2 interact with the chaperone CCT5, preventing aggregation.
- Physiologically, OTX2 promotes cell proliferation, but O-GlcNAc-depleted OTX2 is detrimental to cancer cells.
Conclusions:
- O-GlcNAcylation is a key regulator of OTX2 stability and aggregation.
- The OTX2-CCT5 interaction mediated by O-GlcNAcylation is crucial for preventing OTX2 pathology.
- Modulating OTX2 O-GlcNAcylation presents a potential therapeutic strategy for brain disorders and cancer.
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