PP5 is expressed in OKP cells, a proximal tubule cell line, but minimally present in BBMV. Thirty micrograms of rat cortical WH, 30 μg of rat BBMV, 15 μg of OKP cells, or 15 μg of HEK cells were solubilized, separated by SDS-PAGE, and prepared for immunoblotting with anti-PP5 antibody.