Figure 4.

2-ME Enhances the Intracellular Traffic of Zeolin.

Protoplasts from transgenic tobacco expressing zeolin 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 20 mM 2-ME. Total homogenates were prepared from protoplasts or incubation medium, using homogenation buffer supplemented with 2-ME (medium) or without the reducing agent (protoplasts), and immunoselected using anti-phaseolin antiserum. Analysis was by SDS-PAGE and fluorography. (A) and (B) show results from fully independent experiments. The positions of zeolin (arrowheads), the 45-kD form (arrows), phaseolin fragments (vertical bars), and the 95-kD putative O-glycosylated zeolin (asterisks) are indicated. Numbers at left indicate the positions of molecular mass markers in kD.