TRIM21 interacts with autophagy regulators and effectors. (A and B) Coimmunoprecipitation analyses of GFP-TRIM21 (T21) with Myc-ULK1 (A) and Flag-Beclin 1 (B) in HEK293 cells extracts. (C) GST pull-down analysis of binding between radiolabeled Myc-TRIM21 and GST-mAtg8s. (top) Autoradiogram of pull-down products. (bottom) CBB-stained SDS-polyacrylamide gel with GST-mAtg8s. (D) TRIM21 domains and deletion constructs used. (E) GST pull-down analysis of binding between radiolabeled Myc-TRIM21 deletion mutants and GST-GABARAP and GST-p62. Asterisks and squares denote presence or absence of Myc-TRIM21, respectively. (F) p62 domains and deletion constructs used. (G) GST pull-down analysis of interaction between radiolabeled Myc-TRIM21 and GST-tagged p62. Data representative of three or more experiments. IP, immunoprecipitation; WB, Western blotting.