Fig. 1: PKM1 activates NAD synthesis in mouse cells more robustly than PKM2.

a Isolation and transformation of Pkm^M1/M1 or Pkm^M2/M2 LE cells and MEFs. b Steady state levels of cellular NAD (left) and poly-ADP-ribosylated protein (PAR) (right) in Pkm^M1/M1 and Pkm^M2/M2 LE-Kras cells. n = 3 biological replicates from 3 LE lines for each genotype. P = 0.0002. The blot shown is representative of three independent experiments. c NAD levels in Pkm^M1/M1 and Pkm^M2/M2 MEF-Kras cells before and after medium change (4 or 8 h). n = 6 (0 h), 4 (4 h, M2/M2) or 5 (others) biological replicates from two MEF lines for each genotype. P = 0.0197 (4 h). d Diagram of NAD synthetic pathways in mammals. Nam nicotinamide, NA nicotinic acid, NAR nicotinic acid riboside, NR nicotinamide riboside, NMN nicotinamide mononucleotide, NAMN nicotinic acid mononucleotide, NAAD nicotinic acid adenine dinucleotide. e Enrichment of labeled NAD (labeled vs total NAD) in Pkm^M1/M MEF-Kras cells cultured in the presence of [¹⁵N (amide)]-Nam for indicated times. Shown are data from two independent MEF lines. f NAD synthesis from Nam in Pkm^M1/M1 and Pkm^M2/M2 MEF-Kras cells. Cellular ¹⁵N-NAD (NAD, m+1) levels were measured 4 hours after ¹⁵N-Nam loading. n = 5 (M1/M1) or 4 (M2/M2) biological replicates from two MEF lines per genotype. P = 0.0202. g Levels of total (left) and glucose-derived (right) PRPP (m+5) in Pkm^M1/M1 and Pkm^M2/M2 MEF-Kras cells loaded 4 h in medium containing [U-¹³C]-glucose. Shown are the average of three independent MEF lines per genotype with duplicates. P = 0.0062 (Total); P = 0.0047 (Gluc-derived). h Levels of total (left) and glucose-derived (right) ATP, determined as in (g). Shown is the average of three independent MEF lines per genotype, with duplicates. P = 0.0269 (Total); P = 0.0248 (Gluc-derived). i Potential crosstalk between glucose-metabolism and NAD synthesis. Data are presented as mean plus the range (e) or SEM (b, c, f, g, h). *P < 0.05, **P < 0.01, ***P < 0.001 as determined by two-tailed t test (b, c, f–h). Source data are provided as a Source Data file.