POSH stimulates the ubiquitination and the clathrin-independent endocytosis of ROMK1 channels.

POSH (plenty of SH3) is a scaffold protein that has been shown to act as an E3 ubiquitin ligase. Here we report that POSH stimulates the ubiquitination of Kir1.1 (ROMK) and enhances the internalization of this potassium channel.