Biology subjects

Roddy, T. P.

Publications and source records attributed to Roddy, T. P..

2 recordsLinked to original sources

bioRxiv2025

Purine nucleotides are competitive inhibitors of apo-GOT1

The malate-aspartate shuttle (MAS) plays a key role in cellular metabolism by transferring electrons from cytosolic NADH into the mitochondrial matrix, thereby supporting oxidative phosphorylation, in addition to the citric acid cycle and amino acid metabolism. Here, we sought to identify allosteric regulatory metabolites of the MAS enzymes cytosolic glutamic-oxaloacetic transaminase 1 (GOT1) and mitochondrial GOT2. Using the Atavistik Metabolite Proprietary Screening platform, we identified several structurally similar metabolite hits-- most notably deoxyadenosine monophosphate (dAMP) and deoxyguanosine monophosphate (dGMP)--as candidate interactors with GOT1. Follow-up thermal shift assays revealed that dAMP and dGMP destabilize GOT1 in the absence of its cofactor, pyridoxal 5-phosphate (PLP), but have no destabilizing effect when PLP is present. Crystallographic analysis confirmed that dAMP and dGMP bind in the PLP pocket of GOT1, suggesting competitive binding. Together, these results indicate that nucleotide metabolites can interact with GOT1, offering potential insights into MAS regulation and therapeutic intervention strategies.

molecular biology↗

bioRxiv2023

13C metabolite tracing reveals glutamine and acetate as critical in vivo fuels for CD8+ T cells

Infusion of 13C-labeled metabolites provides a gold-standard for understanding the metabolic processes used by T cells during immune responses in vivo. Through infusion of 13C-labeled metabolites (glucose, glutamine, acetate) in Listeria monocytogenes (Lm)-infected mice, we demonstrate that CD8+ T effector (Teff) cells utilize metabolites for specific pathways during specific phases of activation. Highly proliferative early Teff cells in vivo shunt glucose primarily towards nucleotide synthesis and leverage glutamine anaplerosis in the tricarboxylic acid (TCA) cycle to support ATP and de novo pyrimidine synthesis. Additionally, early Teff cells rely on glutamic-oxaloacetic transaminase 1 (Got1)--which regulates de novo aspartate synthesis--for effector cell expansion in vivo. Importantly, Teff cells change fuel preference over the course of infection, switching from glutamine-to acetate-dependent TCA cycle metabolism late in infection. This study provides insights into the dynamics of Teff metabolism, illuminating distinct pathways of fuel consumption associated with Teff cell function in vivo. TeaserInterrogating dynamics of fuel utilization by CD8+ T cells in vivo reveals new metabolic checkpoints for immune function in vivo.

immunology↗