SPP binds specifically to HEK293 cells expressing EDG-6. HEK293 cells were transiently transfected with an expression plasmid containing the EDG-6 open reading frame (solid bars) or with vector alone (white bars); and binding of 0.5 nmol/L [³²P]SPP was measured in the absence (total) or presence of a 1000-fold excess of the indicated lipids as competitors as described in “Materials and methods.” Results are means ± SD of triplicate determinations. Similar results were obtained in at least 3 independent experiments.