Immunoprecipitation (IP) of FLAG-BBS9 or FLAG-BBS8 proteins from whole cell extracts (WCEs). Proteins were immunoprecipitated using anti-FLAG affinity beads and western blots were developed (AP) using polyclonal anti-FLAG. (A) IP from cells expressing FLAG-BBS9 (Test) and control cells expressing the FLAG plasmid (Control). Closed arrow indicates FLAG-BBS9. (B) IP from cells expressing FLAG-BBS8 (Test) and control cells expressing the FLAG plasmid (Control). Open arrow indicates FLAG-BBS8. Both blots show a molecular weight marker (M) and a 37 kDa FLAG-fusion protein as a positive control (P). Below is an example of a loading control from the FLAG-BBS9 IP. Protein concentrations were determined using a Pierce assay before solubilization to ensure equal amounts of protein were used for both the Test and Contol IP. The loading control blot was probed with anti-tubulin (50 kD).