Figure 3.

Secdin Retains PM Proteins in the Late Endosomal Compartments.

(A) Treatment with Secdin in the presence of CHX induced a rapid decrease in the PM pool of PIN2-GFP with a concomitant increase in the intracellular protein fraction. At least 35 cells per treatment were analyzed for quantification of the PM/intracellular PIN2-GFP fluorescence intensity ratio.

(B) Time course of BOR1-GFP internalization under high-boron conditions in the presence of Secdin. BOR1-GFP-expressing seedlings were grown on low-boron (0.3 µM H₃BO₃) solid medium and then incubated with 100 µM H₃BO₃ in liquid medium to induce internalization in the presence of either DMSO (0.5%) or Secdin (50 µM). At least 40 cells per treatment were analyzed to assess the PM/intracellular BOR1-GFP fluorescence intensity ratio. Error bars indicate se. ***P < 0.001 and ** P < 0.01 (Student’s t test) relative to the DMSO control. Bars = 10 µm.