The C-terminal half of the D domain is
necessary for intracellular retention of Dd-PDI. (A) A stable clonal
cell line was created and shown to express about threefold more
Dd-PDIΔC (●) than the endogenous Dd-PDI (▴), as revealed by
anti-PDI immunoblotting. This cell line was then
investigated for secretion/retention of Dd-PDI and recombinant
Dd-PDIΔC by pulse/chase labeling with [35S]Met followed
by anti-PDI immunoprecipitation. At the indicated times, aliquots were
retrieved and cells (B, intracellular) were separated from medium (C,
extracellular) by centrifugation and analyzed separately. After
quantification by phosphorimager, the normalized signals corresponding
to full-length Dd-PDI (▴) and Dd-PDIΔC (●) were plotted as a
function of time.