PC1 interacts with PP1α.

To determine whether PC1 can interact with PP1, 293T cells were transfected with plasmids encoding hemeagglutin (HA) epitope-tagged PP1α (^HAPP1α) and the C-terminal, cytosolic 193 amino acids of PC1 fused to the extracellular and transmembrane portion of the IL2 receptor (IL2-HT₁₉₃). Empty plasmid and an IL2 construct lacking PC1 sequence (IL2-0) were used as controls for ^HAPP1α and IL2-HT₁₉₃, respectively. Lysates from the transfected cells were immunoprecipitated (IP) with anti-HA antibodies to pull down PP1α. Antibody-bound and total fractions were resolved by SDS-PAGE and immunoblotted (IB) with anti-IL2 antibodies. Blots were then stripped and re-probed with anti-PP1α antibody. All IL2 and sIg fusion proteins (including IL2-0 and sIg-0) used in this study migrate as doublets, presumably due to a modification of the IL2- and sIg-portions of the fusion proteins. Asterisks are used to mark the IL2- and sIg-specific bands (or their positions were they to be present). Solid arrows are used to indicate the position of other proteins. Different parts of this same gel image (as well as other gel images represented in this manuscript) have been cut and rearranged for consistency and clarity. All other modifications, such as resizing or adjustments to contrast, are performed such that all groupings of images from different parts of the same gel are treated identically. Dashed lines indicate image borders that have been spliced together.