Cooperative stability interactions modulate SRP receptor subunit levels. (A) Representative immunoblot analysis of whole-cell lysates collected from HeLa Cas9 WT, SRB KO1, and SRB KO2 clonal cell lines following 16 h treatment with the proteasome inhibitor, MG132, or DMSO control. (B) Representative immunoblot analysis of subcellular distributions ([C] cytosol extract, [ER] membrane fraction, inclusive of endoplasmic reticulum) of SR subunits (SRA and SRB), SRP subunit (SRP54), cytosolic protein (β-tubulin), and ER-resident protein (TRAPα) in HeLa Cas9 WT cells transfected with empty vector or SRB expression vector at 0.2 µg/mL or 0.4 µg/mL (2×). (C) as in (B), HeLa Cas9 WT cells transfected with empty vector and SRB KO1 and KO2 clones transfected with empty vector or SRB expression vector at two concentrations.
