Phosphorylation differentially regulates LIRs, FIRs, and TIRs. (A) Phosphomimetic peptide variants were generated for each LIR peptide containing phosphorylatable residues (Ser or Thr) at the −2 or −1 positions relative to the core LIR motif. The phosphomimetic LIR peptide array was probed with 100 nM GST-LC3A, GST-GABARAPL1, GST-FIP200^Claw, or TAX1BP1^CC2-MBP. The array was visualized with antibody-HRP conjugates and imaged simultaneously with the native LIR array in Fig. 2 A to allow direct comparison. Peptide spots that bound none of the four protein probes (“never-binders”) are labeled with red asterisk and excluded from further analysis. Probe images of P-CCPG and P-TNIP were previously presented in Fig. 2 B and are re-presented here for comparison. (B) Comparison of spot intensity between native (Fig. 2 A) and phosphomimetic variant peptides (A) using a nonparametric t test with Wilcoxon matched pairs signed rank test. **, P < 0.01; ****, P < 0.0001; ns, not significant.