Cell surface expression of GPR56 and its mutant protein.

<p>(<b>A</b>). Schematic representation of GPR56 protein with three GPR56^C mutations indicated. (<b>B</b>). Detection of membrane expressed GPR56 by biotinylation experiments. Cells transfected with wild type <i>Gpr56</i> and L640R mutant cDNA have comparable cell surface expression of GPR56^C, whereas cells transfected with either E496K or R565W show much reduced or absent cell surface expression of GPR56^C. (<b>C</b>). Bar graphs depict optical density of the western blot of GPR56^C in (B). (<b>D</b>) Analysis of the N- and C- terminal fragment association on plasma membrane by coimmunoprecipitation (IP) experiments. The association of GPR56^N and GPR56^C was observed in both wild type and L640R mutant receptors. (<b>E</b>). Detection of colocalization of GPR56^N and GPR56^C on cell plasma membrane by immunostaining. Scale bar: 10 µm.