Aaron Straight, Postdoctoral Faculty Sponsor
Inactivation of DRG1, encoding a translation factor GTPase, causes a Recessive Neurodevelopmental Disorder.
Genetics in medicine : official journal of the American College of Medical Genetics
Developmentally-regulated GTP-binding protein 1 (DRG1) is a highly conserved member of a class of GTPases implicated in translation. Although the expression of mammalian DRG1 is elevated in the central nervous system (CNS) during development, and its function has been implicated in fundamental cellular processes, no pathogenic germline variants have yet been identified. Here, we characterize the clinical and biochemical consequences of DRG1 variants.We collate clinical information of four individuals with germline DRG1 variants and employ in silico, in vitro, and cell-based studies to study the pathogenicity of these alleles.We identified private germline DRG1 variants including three stop-gained p.Gly54*, p.Arg140*, p.Lys263* and a p.Asn248Phe missense variant. These alleles are recessively inherited in four affected individuals from three distinct families and cause a neurodevelopmental disorder with global developmental delay, primary microcephaly, short stature and craniofacial anomalies. We show that these loss-of-function variants: 1) severely disrupt DRG1 mRNA/protein stability in patient-derived fibroblasts, 2) impair its GTPase activity and 3) compromise its binding to partner protein ZC3H15. Consistent with the importance of DRG1 in humans, targeted inactivation of mouse Drg1 resulted in pre-weaning lethality.Our work defines a new Mendelian disorder of DRG1 deficiency. This study highlights DRG1's importance for normal mammalian development and underscores the significance of translation factor GTPases in human physiology and homeostasis.
View details for DOI 10.1016/j.gim.2023.100893
View details for PubMedID 37179472
Impaired protein hydroxylase activity causes replication stress and developmental abnormalities in humans.
The Journal of clinical investigation
Although protein hydroxylation is a relatively poorly characterized post-translational modification, it has received significant recent attention following seminal work uncovering its role in oxygen sensing and hypoxia biology. Although the fundamental importance of protein hydroxylases in biology is becoming clear, the biochemical targets and cellular functions often remain enigmatic. JMJD5 is a 'JmjC-only' protein hydroxylase that is essential for murine embryonic development and viability. However, no germline variants in JmjC-only hydroxylases, including JMJD5, have yet been described that are associated with any human pathology. Here we demonstrate that biallelic germline JMJD5 pathogenic variants are deleterious to JMJD5 mRNA splicing, protein stability, and hydroxylase activity, resulting in a human developmental disorder characterised by severe failure to thrive, intellectual disability, and facial dysmorphism. We show that the underlying cellular phenotype is associated with increased DNA replication stress and that this is critically dependent on the protein hydroxylase activity of JMJD5. This work contributes to our growing understanding of the role and importance of protein hydroxylases in human development and disease.
View details for DOI 10.1172/JCI152784
View details for PubMedID 36795492
First-in-Class Inhibitors of the Ribosomal Oxygenase MINA53
JOURNAL OF MEDICINAL CHEMISTRY
2021; 64 (23): 17031-17050
MINA53 is a JmjC domain 2-oxoglutarate-dependent oxygenase that catalyzes ribosomal hydroxylation and is a target of the oncogenic transcription factor c-MYC. Despite its anticancer target potential, no small-molecule MINA53 inhibitors are reported. Using ribosomal substrate fragments, we developed mass spectrometry assays for MINA53 and the related oxygenase NO66. These assays enabled the identification of 2-(aryl)alkylthio-3,4-dihydro-4-oxoypyrimidine-5-carboxylic acids as potent MINA53 inhibitors, with selectivity over NO66 and other JmjC oxygenases. Crystallographic studies with the JmjC demethylase KDM5B revealed active site binding but without direct metal chelation; however, molecular modeling investigations indicated that the inhibitors bind to MINA53 by directly interacting with the iron cofactor. The MINA53 inhibitors manifest evidence for target engagement and selectivity for MINA53 over KDM4-6. The MINA53 inhibitors show antiproliferative activity with solid cancer lines and sensitize cancer cells to conventional chemotherapy, suggesting that further work investigating their potential in combination therapies is warranted.
View details for DOI 10.1021/acs.jmedchem.1c00605
View details for Web of Science ID 000754727400006
View details for PubMedID 34843649
View details for PubMedCentralID PMC8667043
The emerging roles of ribosomal histidyl hydroxylases in cell biology, physiology and disease
CELLULAR AND MOLECULAR LIFE SCIENCES
2018; 75 (22): 4093-4105
Hydroxylation is a novel protein modification catalyzed by a family of oxygenases that depend on fundamental nutrients and metabolites for activity. Protein hydroxylases have been implicated in a variety of key cellular processes that play important roles in both normal homeostasis and pathogenesis. Here, in this review, we summarize the current literature on a highly conserved sub-family of oxygenases that catalyze protein histidyl hydroxylation. We discuss the evidence supporting the biochemical assignment of these emerging enzymes as ribosomal protein hydroxylases, and provide an overview of their role in immunology, bone development, and cancer.
View details for DOI 10.1007/s00018-018-2903-z
View details for Web of Science ID 000446544900002
View details for PubMedID 30151692
View details for PubMedCentralID PMC6182338