Figure 5.

Reducing translation elongation rate partially rescues the translocation defect caused by loss of positive charge in the n-region of the SP. A, 293T cells were transfected with preproinsulin-WT or R6C. At 40 h post-transfection, the cells were labeled with [³⁵S]Met/Cys in the presence of 0, 0.5, or 1 μg/ml CHX for 10 min without chase. The newly synthesized preproinsulin molecules were immunoprecipitated with anti-insulin and analyzed using SDS-4–12% NuPAGE. B, untranslocated preproinsulin-R6C and processed proinsulin from three independent experiments were quantified using ImageJ. The percentages of the untranslocated pPI-R6C in total newly synthesized preproinsulin are shown as mean ± S.D., * indicates p < 0.05.