SV40 induces the release of B12 from Erlin1 and Erlin2.

<p>(A) CV-1 cells transfected with GFP-FLAG or Erlin2-FLAG were mock-infected or infected with SV40 for 16 h in the absence or presence of BFA. Cells were then harvested and lysed. The resulting whole cell lysates were subjected to immunoprecipitation using FLAG antibody-conjugated agarose beads and the immunoprecipitated samples analyzed by immunoblotting with the indicated antibodies. (B) As in A, except that Erlin1-FLAG was used. (C) As in A, except that an antibody against TMUB1 was used for immunoblotting. (D) The immunoprecipitated B12 band intensity in A was quantified using ImageJ (NIH). Data were normalized against mock-infected cells expressing Erlin2-FLAG, and represent the means ± standard deviations of data from at least 3 independent experiments. Student two-tailed <i>t</i> test was used to determine statistical significance. (E) As in D, except the immunoprecipitated B12 band intensity in B was quantified. (F) As in D, except the immunoprecipitated TMUB1 band intensity in C was quantified. (G) SV40 (WT) and SV40 (ΔVP3) were analyzed with SDS-PAGE, followed by immunoblotting with antibodies against VP1 and VP3. (H) As in A, except that CV-1 cells transfected with Erlin2-FLAG were mock-infected, infected with SV40 (WT), or infected with SV40 (ΔVP3) for 16 h. The immunoprecipitated B12 band intensity in A was quantified using ImageJ (NIH) and shown below the B12 band.