(A) Extracts derived from WT and TMEM41BKO HEK293T cells were resolved by SDS-PAGE followed by IB with indicated antibodies. All samples were normalized by total protein using a BCA assay prior to loading. I and II indicate the unmodified and lipidated forms of LC3. Bar graphs show the mean ± SD of each sample from 3 independent experiments. Protein levels in WT cells were normalized to 1; p-values were determined using a one-sample t test. *p < 0.05. (B) WT and TMEM41BKO HEK293T knockout cells were treated with 250 nM BafA1 for the times indicated. The corresponding cell extracts were normalized by total protein, resolved by SDS-PAGE, and analyzed by IB for LC3. I and II indicate the unmodified and lipidated forms of LC3. Bar graphs show the mean ± SD of each sample from 3 independent experiments; p-values were determined using a one-sample t test. *p < 0.05. Related to S3 Fig. Underlying data for all summary statistics can be found in S1 Data. BafA1, Bafilomycin A1; BCA, bicinchoninic acid; HEK, human embryonic kidney; IB, immunoblotting; LC3, microtubule-associated protein 1 light chain 3B; NDP52, nuclear dot protein 52; ns, not significant; SQSTM1, sequestosome 1; TAX1BP1, tax 1 binding protein 1; TMEM41B, transmembrane protein 41B; WT, wild type.