Structural basis for Atg8 interacting motif (AIM)/LC3 interacting region (LIR) binding to ubiquitin-like protein Atg8 and orthologs. UBLs are shown in yellow, AIM or LIR peptides or proteins in green, and key interacting residues are shown in sticks. (a)Ubiquitin from a complex with E1116. (b) Atg8 from a complex with E1, with distinctive N-terminal helices colored in orange24,69. (c) Overall similar modes of interactions with Atg8, LC3, and GABARAP as in an Atg8 complex with the AIM peptide from Atg1922. (d) LC3B complex with the LIR peptide from SQSTM1/p6222,44. (e) GABARAPL1 complex with the LIR peptide from NBR145. (f) LC3C complex with the CLIR from CALCOCO2/NDP5248. (g) LC3B complex with the phosphor-LIR from OPTN50. (h) GABARAP complex with a synthetic high-affinity inverse LIR peptide51. (i) Close-up views highlighting selected variations in LIR binding to LC3 and GABARAP family members from structures of LC3B bound to a conventional LIR (left), LC3C bound to the CLIR (middle), and LC3B bound to phosphor-LIR (right).