Figure 5.

Characterization of the secretion of a processed form of PDZD2. (A) Schematic representation of mutant constructs (mutants 1–3). The underlined residues indicate the positions of aspartate residues in the wild-type PDZD2 protein that have been substituted for alanine in mutants 2 and 3. (B) Analysis of secretion of the secreted form of PDZD2 (sPDZD2). Conditioned media and whole-cell lysates were harvested from Chinese hamster ovary cells that were transfected with the different constructs. The media and lysates were then analysed by immunoblotting using the anti-PDZD2 antiserum. sPDZD2 secretion is lost with mutants 1 and 2 but not with mutant 3. (C) Effect of caspase inhibitor. The inhibitor B-D-FMK (+) or its inactive structural homologue Z-FA-FMK (−) were added to the serum-free medium during sPDZD2 collection at 0.5 μg ml⁻¹ or 10 μg ml⁻¹. B-D-FMK but not Z-FA-FMK inhibits sPDZD2 secretion.