Abstract: The present invention relates, in general, to an angiostatin receptor and, in particular, to an angiostatin receptor present on cellular plasma membranes. More particularly, the present invention relates to the human angiostatin receptor, ATP synthase, or subunit or portion thereof, and to the use thereof in assays designed to screen compounds for their ability to serve as agonists or antagonists of human angiostatin. The invention further relates to nucleic acid sequences encoding ATP synthase, or subunit or portion thereof, and to host cells transformed therewith. The invention also relates to antibodies specific for ATP synthase.