Angiopoietin-2, a natural antagonist for Tie2 that disrupts in vivo angiogenesis.
Maisonpierre PC, Suri C, Jones PF, Bartunkova S, Wiegand SJ, Radziejewski C, Compton D, McClain J, Aldrich TH, Papadopoulos N, et al. Science. 1997 Jul 4; 277(5322):55-60.