Probable E3 ubiquitin-protein ligase DTX3 is a protein that in humans is encoded by the DTX3 gene. It is expressed in three isoform variants differing on the N-terminal end: DTX3a, DTX3b, and DTX3c. DTX3a and DTX3b have distinct sets of 7 or 10 N-terminal amino acids, while DTX3c has both consecutively with one amino acid substitution.
DTX3 functions as an E3 ubiquitin ligase. Most but not all studies have found it to have a tumor-suppressing effect on human cancer: exceptions may be due to the failure to distinguish between different isoforms.