<i>Arabidopsis</i> SH3P2 is an ubiquitin-binding protein that functions together with ESCRT-I and the deubiquitylating enzyme AMSH3

Abstract

Significance The endosomal sorting of integral proteins is essential for controlling signaling pathways at the plasma membrane. Posttranslational modification by ubiquitin is key to proper degradation of plasma membrane proteins as the ubiquitylated transmembrane proteins are recognized by multiple ubiquitin adaptor proteins and trafficked to the vacuole for degradation. Although plants lack orthologs of the yeast and metazoan endosomal sorting complex required for transport-0 heterodimer that functions as an ubiquitin adaptor, plants appear to have evolved other strategies to recognize and concentrate ubiquitylated proteins that have been endocytosed. Here, we report the SH3P2 protein as a yet-unknown ubiquitin adaptor protein in Arabidopsis and its molecular function in regulating the endocytic transport and degradation.