YCL047C/POF1 Is a Novel Nicotinamide Mononucleotide Adenylyltransferase (NMNAT) in Saccharomyces cerevisiae

Kato, Michiko; Lin, Su

doi:10.1074/jbc.m114.558643

Cited by 25 publications

(37 citation statements)

References 50 publications

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“…Supporting this idea, deletions of genes encoding cytosolic nucleotidases Isn1 and Sdt1 (33) significantly decreased NR release (~40 % decrease) (33,162) but only slightly affected intracellular NR level (~15 % decrease) (34,162). Conversely, deleting PHO8 largely decreased intracellular NR level (50–70 % decrease) but only slightly affected the level of NR release (20–30 % decrease) (34,162). To date, the mechanisms of NR uptake and its transport between cellular compartments in higher eukaryotes are still unknown.…”

Section: Intracellular Compartmentalization Of the Nad+ Intermediamentioning

confidence: 89%

Regulation of NAD+ metabolism, signaling and compartmentalization in the yeast Saccharomyces cerevisiae

Kato

Lin

2014

DNA Repair

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Pyridine nucleotides are essential coenzymes in many cellular redox reactions in all living systems. In addition to functioning as a redox carrier, NAD+ is also a required co-substrate for the conserved sirtuin deacetylases. Sirtuins regulate transcription, genome maintenance and metabolism and function as molecular links between cells and their environment. Maintaining NAD+ homeostasis is essential for proper cellular function and aberrant NAD+ metabolism has been implicated in a number of metabolic- and age-associated diseases. Recently, NAD+ metabolism has been linked to the phosphate-responsive signaling pathway (PHO pathway) in the budding yeast Saccharomyces cerevisiae. Activation of the PHO pathway is associated with the production and mobilization of the NAD+ metabolite nicotinamide riboside (NR), which is mediated in part by PHO-regulated nucleotidases. Cross-regulation between NAD+ metabolism and the PHO pathway has also been reported; however, detailed mechanisms remain to be elucidated. The PHO pathway also appears to modulate the activities of common downstream effectors of multiple nutrient-sensing pathways (Ras-PKA, TOR, Sch9/AKT). These signaling pathways were suggested to play a role in calorie restriction-mediated beneficial effects, which have also been linked to Sir2 function and NAD+ metabolism. Here, we discuss the interactions of these pathways and their potential roles in regulating NAD+ metabolism. In eukaryotic cells, intracellular compartmentalization facilitates the regulation of enzymatic functions and also concentrates or sequesters specific metabolites. Various NAD+-mediated cellular functions such as mitochondrial oxidative phosphorylation are compartmentalized. Therefore, we also discuss several key players functioning in mitochondrial, cytosolic and vacuolar compartmentalization of NAD+ intermediates, and their potential roles in NAD+ homeostasis. To date, it remains unclear how NAD+ and NAD+ intermediates shuttle between different cellular compartments. Together, these studies provide a molecular basis for how NAD+ homeostasis factors and the interacting signaling pathways confer metabolic flexibility and contribute to maintaining cell fitness and genome stability.

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Section: Intracellular Compartmentalization Of the Nad+ Intermediamentioning

confidence: 89%

Regulation of NAD+ metabolism, signaling and compartmentalization in the yeast Saccharomyces cerevisiae

Kato

Lin

2014

DNA Repair

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“…We previously showed that intracellular NR level largely reflects the NR stored in the vacuole (produced mainly via Pho8) (10). On the other hand, released NR level reflects the NR produced in the cytoplasm (mainly via nucleotidases, Isn1 and Sdt1) (9) because cytoplasmic NR dynamically exchanges with the extracellular environment (4,10,28). It would be interesting to determine whether other NR homeostasis factors, such as Isn1 and Sdt1, also play a role in ssy5⌬-mediated NR salvaging.…”

Section: Discussionmentioning

confidence: 99%

“…For each qPCR reaction, 50 ng of cDNA and 500 nM concentrations of each primer were used. qPCR reaction was run on Roche LightCycler 480 using LightCycler 480 SYBR Green I Master Mix (Roche Applied Science) as previously described (28). Average size of the amplicon for each gene was ϳ150 bp.…”

Section: Methodsmentioning

confidence: 99%

Reduced Ssy1-Ptr3-Ssy5 (SPS) Signaling Extends Replicative Life Span by Enhancing NAD+ Homeostasis in Saccharomyces cerevisiae

Tsang

James

Kato

et al. 2015

Journal of Biological Chemistry

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“…This screen system was based on our observations that yeast cells release and transport NR back into the cell (19), a phenomenon that is also conserved in human cells (20). Our studies have identified novel NAD + homeostasis factors including the phosphate responsive signaling (PHO) pathway (17), the SPS amino acid sensing pathway (21), a conserved vacuolar NR transporter Fun26 (1,17) and several NAD + metabolic enzymes (22).…”

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A functional link between NAD+ homeostasis and N-terminal protein acetylation in Saccharomyces cerevisiae

Croft¹,

Raj²,

Salemi

et al. 2018

Journal of Biological Chemistry

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(Fig. 1D, upper panel).Similar to pnc1∆ mutant (Fig. 1B), both nat3∆and mdm20∆ released mostly NAM not NA (Fig.1D, lower panel). Fig. 1E (Fig. 2E, top panel) had a lesser effect (Fig. 2E, bottom (Fig. 3B). Next, we tested whether deleting ATG14 was sufficient to restore NAD + levels in the NatB mutants. As shown in Fig. 3C (left panel), deleting ATG14did not rescue the low NAD + levels in nat3∆ cells. Similarly, deleting other factors contributing to NR and NAM production ( Fig. 1A and Fig. 2E) in nat3∆ cells also failed to restore the NAD + level back to wild type ( shown to restore actin cable formation in NatB mutants (23,24,28,29). Interestingly, both TPM1-oe and TPM1-5 largely blocked NA/NAM release in the nat3∆ mutant (Fig. 3D) 1A). N-terminal acetyltransferases have specific targets that are largely determined by the sequence of the first two amino acids. NatB acetylates proteins with a MET-retained residue, followed by ASP, GLU, GLN, or ASN as the second residue (25,26,39,40). Nma1 and Nma2 have a MET-ASP N-terminus, but neither protein has been identified as a NatB target.Similar to nat3∆ mutant, nma1∆ cells showed decreased NAD + levels, which could not be rescued by supplementing NR (Fig. 4B). As for the controls, NR efficiently restored the NAD + level in the npt1∆ mutant, which has functional NR salvage (Fig. 4B). The similarities between nma1∆ and nat3∆ mutants suggested that Nma1and Nma2 activities are likely reduced in nat3∆ cells. Since N-terminal acetylation may affect the turnover of target proteins, we first determined whether reduced Nma1/Nma2 activities were due to decreased Nma1/Nma2 protein levels. As shown in Fig. 4C, Nma1 and Nma2 protein levels were indeed decreased in nat3∆ cells (Fig. 4C). In addition to Nma1 and Nma2, NAD + homeostasis factors Bna2, Bna5and Hst1 are also potential NatB targets. Bna2and Bna5 are biosynthesis enzymes in the de novo pathway (Fig. 1A) DISCUSSIONIn this study we characterized NatB complex as a novel NAD + homeostasis factor.Mutants lacking components of the NatB complex, NAT3 and MDM20, produce and release excess amount of NA and NAM. Our studies showed two pathways downstream of NatB contribute to NAD + homeostasis (Fig. 5).In one, NatB is important for proper NAD + biosynthesis by regulating Nma1/Nma2. NatB mutants have low NAD + levels (Fig. 2C), and all NAD + precursors examined failed to restore the NAD + levels ( Fig. 4A and 4B). This suggests that a NAD + biosynthesis factor(s) required for utilization of all NAD + precursors is defected in NatB mutants. Nma1 and Nma2 are such targets because they are the only factors required for all three NAD + biosynthesis pathways (de novo, NA/NAM salvage, and NR salvage) (Fig. 1A), and the N-terminal amino acid sequences are a match for NatB acetylation. In addition, nma1∆and nat3∆ mutants showed similar NAD + utilization defects (Fig. 4B). Although Nma2 is present in both mutants, Nma2 is known to play a minor role in NAD + metabolism. Supporting this model, decreased Nma1 protein level was observed in t...

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YCL047C/POF1 Is a Novel Nicotinamide Mononucleotide Adenylyltransferase (NMNAT) in Saccharomyces cerevisiae

Abstract: Background: Factors regulating NADϩ metabolism and homeostasis remain unclear because of the dynamic nature of

Cited by 25 publications

References 50 publications

Regulation of NAD+ metabolism, signaling and compartmentalization in the yeast Saccharomyces cerevisiae

Regulation of NAD+ metabolism, signaling and compartmentalization in the yeast Saccharomyces cerevisiae

Reduced Ssy1-Ptr3-Ssy5 (SPS) Signaling Extends Replicative Life Span by Enhancing NAD+ Homeostasis in Saccharomyces cerevisiae

A functional link between NAD+ homeostasis and N-terminal protein acetylation in Saccharomyces cerevisiae

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