Essential role for the d-Asb11 cul5 Box domain for proper notch signaling and neural cell fate decisions in vivo.

ECS (Elongin BC-Cul2/Cul5-SOCS-box protein) ubiquitin ligases recruit substrates to E2 ubiquitin-conjugating enzymes through a SOCS-box protein substrate receptor, an Elongin BC adaptor and a cullin (Cul2 or Cul5) scaffold which interacts with the RING protein. In vitro studies have shown that the conserved amino acid sequence of the cullin box in SOCS-box proteins is required for complex formation and function. However, the in vivo importance of cullin boxes has not been addressed.

d-Asb11 is an essential mediator of canonical Delta-Notch signalling.

In canonical Delta-Notch signalling, expression of Delta activates Notch in neighbouring cells, leading to downregulation of Delta in these cells. This process of lateral inhibition results in selection of either Delta-signalling cells or Notch-signalling cells. Here we show that d-Asb11 is an important mediator of this lateral inhibition.