This domain can be found in the N terminus of the SERRATE (SE) from plants and its homologue, Ars2, from animals. They play a role in nuclear RNA metabolism. They interact with the nuclear cap-binding complex (CBC) and mediates interactions with diverse RNA processing and transport machineries in a transcript-dependent manner. Interestingly, the plant SERRATE does not have the RNA recognition motif (RRM) domain found in metazoans and S. pombe [1]. This domain has two completely conserved Y residues that may be functionally important.

1: Structural analysis of human ARS2 as a platform for co-transcriptional RNA sorting. Schulze WM, Stein F, Rettel M, Nanao M, Cusack S; Nat Commun. 2018;9:1701. PMID:29703953