Figure 9.

2-ME Inhibits the Assembly and Traffic of IgA/G.

Protoplasts from transgenic tobacco expressing IgA/G (heavy and light chains) were pulse-labeled with [³⁵S]Met and [³⁵S]Cys for 1 h and subjected to chase for the indicated times in the presence (+) or absence (−) of 2-ME. Protoplast or incubation medium homogenates were then immunoselected using with anti-IgG antiserum. Polypeptides were analyzed by nonreducing SDS-PAGE and fluorography The positions of assembled IgA/G tetramers (arrowhead), unassembled heavy (closed circle) and light (open circle) chains, and IgA/G vacuolar fragmentation products (asterisks) are indicated. Numbers at right indicate molecular mass markers in kD.