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. 2021 Jun 30;23(11):2202–2207. doi: 10.1038/s41436-021-01249-z

Fig. 1. Enzyme activity is decreased but not absent in all patients, and IARS, LARS, and FARSB patient fibroblasts are increased sensitive to isoleucine, leucine and phenylalanine deprivation, respectively.

Fig. 1

(a) Enzyme activity is decreased but not absent in all patients. Aminoacylation activity in fibroblasts of PIARS, PIARS-2, PLARS, PFARSB, and two siblings with the same homozygous variant as PSARS, presented as percentage of age-matched controls. GARS activity was measured as an internal control. All measurements were performed in triplicate (n = 3), except IARS controls (n = 6) and GARS controls (n = 12). Error bars show standard deviation. Unpaired t-test: ns p ≥ 0.05, *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001. (b–e) IARS, LARS, and FARSB patient fibroblasts are sensitive to isoleucine, leucine, and phenylalanine deprivation, respectively. Seventy-two hours proliferation of fibroblasts of PIARS, PIARS-2, PLARS, PFARSB, and two siblings with the same homozygous variant as PSARS, compared to age-matched control fibroblasts, exposed to decreasing concentrations of isoleucine (b: PIARS/PIARS-2), leucine (c: PLARS), phenylalanine (d: PFARSB), or serine (e: two siblings of PSARS), shown as normalized impedance, measured with an xCELLigence MP. Amino acid concentrations were compared to average plasma concentrations. Every donor was measured once (a; n = 1 each) or twice (b–d; n = 2 each). Two (a–c) or three (d) controls were measured once (n = 1 each). Error bars show standard deviation. Unpaired t-test: ns p ≥ 0.05, *p < 0.05, **p < 0.01, ***p < 0.001. (f–i) LARS and FARS activity deteriorate in LARS and FARSB patient fibroblasts, respectively. Aminoacylation activity in fibroblasts of PIARS and PIARS-2 (f), PLARS (g), PFARSB (h), and two siblings with the same homozygous variant as PSARS (i) at 37  °C, 38.5  °C, and 40 °C. Data are presented compared to the enzymatic activity at 37 °C. All measurements were performed in triplicate (n = 3). Error bars show standard deviation. Unpaired t-test: ns p ≥ 0.05, *p < 0.05, **p < 0.01.