Figure 1. Epsins mediate VEGFR2 ubiquitination and endocytosis.

(A) VEGFR2 receptors on the plasma membrane undergo ubiquitination as a result of VEGF binding. Ubiquitinated receptors bind to proteins called epsins through a ubiquitin-interacting motif. (B) In EC-iDKO mice, the epsins are inactivated, blocking VEGFR2 receptor degradation. As a result, there is increased VEGF/VEGFR2 signaling, resulting in aberrant nonfunctional vessels that do not support tumor growth.