HOIL-1L has cell type–specific roles in NF-κB activation. (a) WT and HOIL-1L^−/− MEFs and BMDMs were stimulated with 1 ng/ml TNF or 10 ng/ml LPS for 0, 15, or 30 min and probed for indicated protein levels by immunoblotting. Data are representative of three independent experiments. (b) The mRNA transcript abundance for selected NF-κB–regulated genes was quantified after 2 h of 10 ng/ml LPS stimulation by qRT-PCR (biological n = 2). Data are representative of two independent experiments. (c) IL-6 secretion was quantified by ELISA at 24 h after LPS treatment (biological n = 3). Data are representative of three independent experiments. Protein size markers are indicated in kD. All data are presented as the mean ± SEM by a Student’s t test. *, P = 0.013; **, P = 0.015; ***, P = 0.034; #, P = 10⁻⁶.