May act as a substrate recognition component of an ECS (Elongin BC-CUL5-SOCS-box protein) E3 ubiquitin ligase complex which mediates the ubiquitination and subsequent proteasomal degradation of target proteins. May bind to the methyltransferase cofactor S- adenosylmethionine (AdoMet) via the N-terminal AdoMet binding motif, but probably does not display methyltransferase activity. . This is the function of PCMTD2 (protein-L-isoaspartate (D-aspartate) O-methyltransferase domain containing 2, Ensembl gene identifier ENSG00000203880).