FIGURE 3.
A polar asparagine is the sole determinant for binding of TMD4 of PS1 to Pen2. A, HEK293 cells were transiently transfected with CD4 variants and GFP-tagged Pen2. Immunoprecipitation was performed with anti-CD4 antibodies, and after processing for Western blotting, membranes were probed with antibodies against CD4, GFP, and actin as loading control. B, Swe cells stably expressing PE variants as indicated were lysed or subjected to immunoprecipitation with anti-GFP antibodies (IP GFP), loaded on SDS gels, blotted, and probed with antibodies against Nct, PS1CTF, and Pen2. Note that due to GFP moiety, the endogenous PS1CTF is much smaller (17 kDa) than the PECTF; therefore, they are on different parts of the membrane. nt, non-transfected Swe cells; mat/im, mature/immature; endo, endogenous. Representative blots of at least three independent experiments are shown.