The present invention relates to regulation of angiogenesis. More particularly, the present invention is directed to nucleic acids encoding C1-angiogenesis protein, also called integrin-linked kinase associated protein (“ILKAP”) and ILKAP protein, which is involved in modulation of angiogenesis. The invention further relates to methods for identifying and using agents, including small organic molecules, antibodies, peptides, cyclic peptides, nucleic acids, antisense nucleic acids, and ribozymes, that modulate angiogenesis via modulation of ILKAP and ILKAP-related cascades; as well as to the use of expression profiles and compositions in diagnosis and therapy of angiogenesis.