FIG. 6.

GADD34 binds the α isoform of PP1 and dictates its subcellular distribution. (A) Immunoprecipitation (IP) of FLAG-GADD34(1-674) and FLAG-GADD34(180-674) from HEK293T cells was undertaken using anti-FLAG M2 beads. The lysates and immunoprecipitates were subjected to immunoblotting with antibodies specific for the α, β, and γ₁ isoforms of PP1, as well as with anti-FLAG and anti-PP1 (pan) antibodies, to assess levels of FLAG-GADD34 and total PP1. (B) Immunostaining untreated COS-7 cells (control) and cells treated with 5 μg of tunicamycin (TN)/ml for 8 h with anti-PP1α (red). The ER was costained using DiOC6 (green), and the panels were merged as described in Materials and Methods.