GO:0061769 nicotinate riboside kinase activity

Nicotinate riboside kinase activity (GO:0061769) is a molecular function defined by the reaction N-ribosylnicotinate + ATP = ADP + 2 H+ + nicotinate mononucleotide. This activity sits at the intersection of nucleoside salvage and NAD+ biosynthesis, because it converts a ribosylated form of nicotinic acid into a mononucleotide that can enter pyridine nucleotide pools. For researchers, the term provides a precise ontology handle for annotating enzymes that phosphorylate nicotinate riboside rather than nicotinamide riboside or free nicotinic acid. The reaction is ATP-dependent and produces ADP and protons, making it experimentally tractable by kinase assays, mass spectrometry, and pH-sensitive readouts. In plants, nicotinate riboside kinase activity was demonstrated in mungbean seedlings, supporting the existence of a salvage route for nicotinate riboside. In human cells, nicotinic acid riboside is imported by equilibrative nucleoside transporters, after which intracellular phosphorylation can generate nicotinate mononucleotide. Because NAD+ metabolism is central to redox biology, DNA repair, and signaling, enzymes annotated with GO:0061769 are of interest in metabolic, cancer, and neurodegeneration research [1,2]. This article summarizes the definition, mechanism, related genes, disease links, and experimental strategies for studying nicotinate riboside kinase activity.

GO:0061769, nicotinate riboside kinase activity, is a molecular function describing catalysis of the reaction N-ribosylnicotinate + ATP = ADP + 2 H+ + nicotinate mononucleotide. In simpler terms, it is the enzyme activity that attaches a phosphate group from ATP onto nicotinate riboside, producing nicotinate mononucleotide, ADP, and protons. The term is synonymous with nicotinic acid riboside kinase activity, ribosylnicotinate kinase activity, and ribosylnicotinic acid kinase activity. It is classified under molecular_function in the Gene Ontology and is mechanistically related to other riboside kinases that feed NAD+ salvage pathways [1,2].

Nicotinate riboside kinase activity is important because it provides a direct enzymatic route from nicotinate riboside to nicotinate mononucleotide, a key intermediate in NAD+ biosynthesis. NAD+ is required for redox reactions, DNA repair, and signaling, so enzymes that control its salvage intermediates can influence cellular stress responses and metabolic homeostasis [1,2]. In human cells, the availability of nicotinic acid riboside depends on equilibrative nucleoside transporters, making this kinase activity part of a transport-metabolism axis. In plants, the detection of nicotinate riboside kinase in mungbean seedlings indicates that this salvage activity operates in diverse organisms. Researchers studying metabolic disease, cancer, and neurodegeneration therefore need reliable tools to test whether candidate genes carry this activity [1,2].

The following genes and proteins are relevant to nicotinate riboside kinase activity, either as candidate enzymes, transporters, or pathway components supported by the cited literature.

Regulation of nicotinate riboside kinase activity is not fully resolved in the available literature. The activity depends on ATP and N-ribosylnicotinate, so energy status and substrate supply are likely regulatory inputs. In human cells, equilibrative nucleoside transporters mediate the import of nicotinamide riboside and nicotinic acid riboside, thereby controlling substrate availability for intracellular phosphorylation. In plants, detection of the activity in mungbean seedlings suggests developmental or tissue-specific control of nicotinate riboside salvage. Researchers should therefore assess transporter expression, ATP levels, and precursor availability when studying this activity [1,2].

Nicotinate riboside kinase activity contributes to NAD+ salvage by converting nicotinate riboside to nicotinate mononucleotide. Because NAD+ is central to redox balance and cellular stress responses, altered flux through this step could influence metabolic phenotypes. In human cells, the import of nicotinic acid riboside by equilibrative nucleoside transporters links this activity to precursor availability and metabolic state.

Cancer cells often depend on NAD+ salvage to support rapid proliferation, making enzymes in pyridine nucleotide pathways of interest. Although direct disease associations for GO:0061769 are not established in the provided literature, the activity feeds nicotinate mononucleotide, a precursor for NAD+. Transport-mediated uptake of nicotinic acid riboside in human cells further supports a potential role in precursor-driven NAD+ supply.

NAD+ depletion is implicated in neuronal stress and degeneration, and salvage pathways help maintain NAD+ pools. Nicotinate riboside kinase activity represents one route into nicotinate mononucleotide, which can support NAD+ biosynthesis. Human cells can import nicotinic acid riboside via equilibrative nucleoside transporters, connecting this activity to precursor-based interventions.

Direct measurement of nicotinate riboside kinase activity can be performed by incubating N-ribosylnicotinate with ATP and detecting ADP or nicotinate mononucleotide formation. Such assays were used to demonstrate the activity in mungbean seedlings. Coupling to ATP-regenerating or ADP-detecting systems allows quantitative comparison across samples.

Metabolomic profiling can quantify nicotinate mononucleotide and related pyridine nucleotides after precursor supply. In human cells, nicotinic acid riboside import by equilibrative nucleoside transporters can be combined with metabolomics to trace flux into NAD+ intermediates. Stable-isotope labeling can further resolve the contribution of GO:0061769 to NAD+ pools.

Because nicotinic acid riboside uptake is mediated by equilibrative nucleoside transporters, uptake assays are important for interpreting kinase activity in intact cells. Knockout or inhibition of SLC29A1 and SLC29A2 can reveal how transport limits substrate availability. These assays complement direct enzymatic measurements [1,2].

CRISPR knockout and overexpression models can test whether candidate genes are required for nicotinate riboside-dependent NAD+ production. Point mutations can separate catalytic activity from scaffolding functions. Combining genetic models with metabolomics provides causal evidence for GO:0061769 in cellular metabolism [1,2].

Researchers studying nicotinate riboside kinase activity-related genes often need to determine whether a candidate gene is causally involved in the reaction N-ribosylnicotinate + ATP = ADP + 2 H+ + nicotinate mononucleotide. This requires precise genetic models that can remove, mutate, tag, or overexpress the candidate gene and then measure downstream metabolites [1,2]. EDITGENE provides CRISPR-based services tailored to these needs.

Nicotinate riboside kinase activity (GO:0061769) is a defined molecular function that converts nicotinate riboside to nicotinate mononucleotide using ATP. Its connection to NAD+ salvage and precursor transport makes it relevant to metabolic, cancer, and neurodegeneration research [1,2]. Biochemical evidence in plants and transport-linked studies in human cells provide a foundation for further mechanistic work [1,2]. CRISPR-based knockout, point-mutation, knock-in, and overexpression models offer robust ways to test candidate genes and their metabolic consequences.