Fig 2: ATR deletion upregulates presynaptic proteins SYT2 and PROT.a Western blot analysis of the indicated proteins in whole-cell extract (S1) and synaptosome (P2) fractions of 3-month-old hippocampus of control (Ctr) and ATR-FB? (FB?) mice. GAPDH controls loading. Note, GAD67 expression is controlled by a separate control GAPDH below. The right panel shows the quantification of the indicated proteins after normalization with GAPDH. The data is represented as relative fold change in protein expression in P2 fraction, compared to control mice. N = 3 mice for each genotype. The vertical dashed line in the graph indicates control mice. Data are mean values ± SD. Student’s t-test (unpaired, one-tailed for ATR, SYT2 and PROT, two-tailed for others). P value: ATR, p = 0.025; SYT, p = 0.001; PROT, p = 0.029. *p < 0.05, **p < 0.01. b ATR interacts with SYT2 and PROT in vitro. Murine neuroblastoma cells (N2a) were transfected with Tomato-SYT2 or Tomato-PROT treated with or without with 2 µM ATR inhibitor VE-821. SYT2 and PROT were immunoprecipitated with Tomato antibody and blotted by indicated antibodies. The experiment was repeated four times. c Immunoprecipitation of protein extract from hippocampi and cerebella using antibodies as indicated. IP against IgG serves as control. Histone H3 serves as loading control for the inputs. IgG light chain was used to control the amount of antibodies used for IP. Note, an overloading of IgG in IP-IgG lanes correlates with unspecific binding signals in these samples. The number indicates individual mice. The experiment was repeated twice. Source data are provided as a Source Data file.