Dataset Information

Mammalian Cell Proliferation Requires Noncatalytic Functions of O-GlcNAc Transferase

ABSTRACT: O-GlcNAc transferase (OGT), found in the nucleus and cytoplasm of all mammalian cell types, is essential for cell proliferation. Why OGT is required for cell growth is not known. OGT performs two enzymatic reactions in the same active site. In one, it glycosylates thousands of different proteins, and in the other, it proteolytically cleaves another essential protein involved in gene expression. Deconvoluting OGT’s myriad cellular roles has been challenging because genetic deletion is lethal; complementation methods have not been established. Here, we developed approaches to replace endogenous OGT with separation-of-function variants to investigate the importance of OGT’s enzymatic activities for cell viability. Using genetic complementation, we found that OGT’s glycosyltransferase function is required for cell growth but its protease function is dispensable. We next used complementation to construct a cell line with degron-tagged wild-type OGT. When OGT was degraded to very low levels, cells stopped proliferating but remained viable. Adding back catalytically-inactive OGT rescued growth. Therefore, OGT has an essential noncatalytic role that is necessary for cell proliferation. By developing a method to quantify how OGT’s catalytic and noncatalytic activities affect protein abundance, we found that OGT’s noncatalytic functions often affect different proteins from its catalytic functions. Proteins involved in oxidative phosphorylation and the actin cytoskeleton were especially impacted by the noncatalytic functions. We conclude that OGT integrates both catalytic and noncatalytic functions to control cell physiology.

INSTRUMENT(S): Orbitrap Fusion

ORGANISM(S): Homo Sapiens (human)

SUBMITTER: Joao Paulo

LAB HEAD: Joao A. Paulo

PROVIDER: PXD022654 | Pride | 2021-09-09

REPOSITORIES: Pride

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Publications

Mammalian cell proliferation requires noncatalytic functions of O-GlcNAc transferase.

Levine Zebulon G ZG Potter Sarah C SC Joiner Cassandra M CM Fei George Q GQ Nabet Behnam B Sonnett Matthew M Zachara Natasha E NE Gray Nathanael S NS Paulo Joao A JA Walker Suzanne S

Proceedings of the National Academy of Sciences of the United States of America 20210101 4

O-GlcNAc transferase (OGT), found in the nucleus and cytoplasm of all mammalian cell types, is essential for cell proliferation. Why OGT is required for cell growth is not known. OGT performs two enzymatic reactions in the same active site. In one, it glycosylates thousands of different proteins, and in the other, it proteolytically cleaves another essential protein involved in gene expression. Deconvoluting OGT's myriad cellular roles has been challenging because genetic deletion is lethal; com ...[more]

PMID: 33419956

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Project description:Objective: The loss of insulin-secreting β-cells, ultimately characterizing most diabetes forms, demands the development of cell replacement therapies. The common endpoint for all ex vivo strategies is transplantation into diabetic patients. However, the effects of hyperglycemia environment on the transplanted cells were not yet properly assessed. Thus, the main goal of this study was to characterize global effect of brief and prolonged in vivo hyperglycemia exposure on the cell fate acquisition and maintenance of transplanted human pancreatic progenitors. Methods: To rigorously study the effect of hyperglycemia, in vitro differentiated human induced pluripotent stem cells (hiPSC)-derived pancreatic progenitors were xenotransplanted in normoglycemic and diabetic NSG RIP-DTR mice. The transplants were retrieved after one-week or one-month exposure to overt hyperglycemia and analyzed by large-scale microscopy or global proteomics. For this study we pioneer the use of the NSG RIP-DTR system in the transplantation of hiPSC, making use of its highly reproducible specific and absolute β-cell ablation property in the absence of inflammation or other organ toxicity. Results: Here we show for the first time that besides the presence of an induced oxidative stress signature, the cell fate and proteome landscape response to hyperglycemia was different, involving largely different mechanisms, according to the period spent in the hyperglycemic environment. Surprisingly, brief hyperglycemia exposure increased the bihormonal cell number by impeding the activity of specific islet lineage determinants. Moreover it activated antioxidant and inflammation protection mechanisms signatures in the transplanted cells. In contrast, the prolonged exposure was characterized by decreased numbers of hormone+ cells, low/absent detoxification signature, augmented production of oxygen reactive species and increased apoptosis. Conclusion: Hyperglycemia exposure induced distinct, period-dependent, negative effects on xenotransplanted human pancreatic progenitor, affecting their energy homeostasis, cell fate acquisition and survival.

Dataset Information

Mammalian Cell Proliferation Requires Noncatalytic Functions of O-GlcNAc Transferase

Publications

Mammalian cell proliferation requires noncatalytic functions of O-GlcNAc transferase.

Similar Datasets

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