Human enhancer of rudimentary is a molecular partner of PDIP46/SKAR, a protein interacting with DNA polymerase delta and S6K1 and regulating cell growth.

Enhancer of rudimentary (ER) is a small protein that has a unique amino acid sequence and structure. Its highly conserved gene has been found in all eukaryotic kingdoms with the exception of fungi. ER was proposed to be involved in the metabolism of pyrimidines and was reported to act as a transcriptional repressor in a cell type-specific manner.