Diptheria Toxin Resistance Protein Required For Diphthamide Biosynthesis Like Protein 2 (DPH2L2)

DPH2L2 is one of two human genes similar to the yeast gene dph2. The yeast gene was identified by its ability to complement a diphthamide mutant strain, and thus probably functions in diphthamide biosynthesis. Diphthamide is a post-translationally modified histidine residue present in elongation factor 2 (EF2) that is the target of diphtheria toxin ADP-ribosylation. Two transcript variants encoding different isoforms have been found for this gene.

Mouse Dph2 could complement the DT-resistant phenotype of diphthamide-deficient mutant Chinese hamster ovary cell lines. Immunoprecipitation analysis revealed that yeast and mouse Dph1 and Dph2 interacted, suggesting that these enzymes may function in diphthamide biosynthesis as a dimer or multimer.