Dataset Information

Cobalamins function as allosteric activators of an Angelman syndrome-associated UBE3A/E6AP variant

ABSTRACT: Genetic aberrations of the maternal UBE3A allele, which encodes the E3 ubiquitin ligase E6AP, are the cause of Angelman syndrome (AS), an imprinting disorder. In most cases, the maternal UBE3A allele is not expressed. Yet, approximately 10 percent of AS individuals harbor distinct point mutations in the maternal allele resulting in the expression of full-length E6AP variants that frequently display compromised ligase activity. In a high-throughput screen, we identified cyanocobalamin, a vitamin B12-derivative, and several alloxazine derivatives as activators of the AS-linked E6AP-F583S variant. Furthermore, we show by cross-linking coupled to mass spectrometry that cobalamins affect the structural dynamics of E6AP-F583S and apply limited proteolysis coupled to mass spectrometry to obtain information about the regions of E6AP that are involved in, or are affected by, binding cobalamins and alloxazine derivatives. Our data suggest that dietary supplementation with vitamin B12 could be beneficial for AS individuals.

INSTRUMENT(S): Orbitrap Fusion, Q Exactive HF

ORGANISM(S): Homo Sapiens (human)

DISEASE(S): Angelman Syndrome

SUBMITTER: Florian Stengel

LAB HEAD: Prof. Dr. Florian Stengel

PROVIDER: PXD048963 | Pride | 2024-05-09

REPOSITORIES: Pride

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Publications

Cobalamins Function as Allosteric Activators of an Angelman Syndrome-Associated UBE3A/E6AP Variant.

Müller Franziska F Jansen Jasmin J Offensperger Fabian F Eichbichler Daniela D Stengel Florian F Scheffner Martin M

Chembiochem : a European journal of chemical biology 20240502 10

Genetic aberrations of the maternal UBE3A allele, which encodes the E3 ubiquitin ligase E6AP, are the cause of Angelman syndrome (AS), an imprinting disorder. In most cases, the maternal UBE3A allele is not expressed. Yet, approximately 10 percent of AS individuals harbor distinct point mutations in the maternal allele resulting in the expression of full-length E6AP variants that frequently display compromised ligase activity. In a high-throughput screen, we identified cyanocobalamin, a vitamin ...[more]

PMID: 38573110

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Project description:Purpose: Gastric cancer remains one of the deadliest neoplasms worldwide, with a high need for new therapeutic options. Efficacies of targeted therapies are often limited owing to the inter- and intratumoral heterogeneity of gastric cancer. Thus, drugs with broader mechanisms of action rather than relying on the inhibition of a single specific oncogene are needed. Preclinical studies have identified histone deacetylases (HDAC) and their respective isoforms as potential therapeutic targets in gastric cancer. However, clinical efficacies are moderate and the mechanism(s) of action of HDAC inhibitors (HDACi) are only partially understood. Methods: In a panel of gastric cancer cell lines with different molecular characteristics, tumor cell inhibitory effects of different HDACi were studied. Lipid peroxidation levels were measured using flow cytometry. Proteome analysis was performed for the in-depth characterization of molecular alterations upon HDAC inhibition. HDACi effects on important ferroptosis genes were validated on the mRNA (RT-qPCR) and protein level (Western Blot). Results: Upon HDACi treatment, lipid peroxidation levels were found increased in all tested cell lines. Class-I HDACi (VK1, entinostat) showed the same toxicity profile as the pan-HDACi vorinostat. Proteome analysis revealed significant and concordant alterations in the expression of proteins related to ferroptosis induction. Key enzymes like ACSL4, POR or SLC7A11 showed distinct alterations in their expression patterns, providing an explanation for the increased lipid peroxidation. Alterations of POR and SLC7A11 levels upon treatment were also confirmed in primary human gastric cancer tissue cultures as relevant ex vivo model. Conclusion: We identify the induction of ferroptosis as a new mechanism of action of class-I HDACi in gastric cancer. Notably, these findings were independent of the genetic background of the cell lines, thus introducing HDAC inhibition as a more general therapeutic principle besides other, less broadly usable targeted drugs.

Dataset Information

Cobalamins function as allosteric activators of an Angelman syndrome-associated UBE3A/E6AP variant

Publications

Cobalamins Function as Allosteric Activators of an Angelman Syndrome-Associated UBE3A/E6AP Variant.

Similar Datasets

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