E3 ligases occupy a central place in the enzymatic
cascade leading to protein ubiquitylation
E3 ligase families and modes of
substrate recognition in cells
E3 ligases recognize their physiological targets
through short sequence motifs referred to as degrons.
Degrons can be constitutively accessible to an E3
ligase or formed only upon posttranslational modification.
While many degrons are linear sequence
motifs, structural degrons require a folded protein
domain.