PROSITE documentation PDOC51959

Eukaryotic uridylate-specific endoribonuclease (EndoU) domain profile

EndoU is a family of metal-dependent endoribonucleases that is broadly conserved among eukaryotes [1,2]. EndoU family members have RNA-binding and endoribonuclease activities and appear to be involved in many aspects of biology, including small nucleolar RNA biogenesis, endoplasmic reticulum (ER) network formation, immune response, and neurodegeneration:

• Xenopus laevis endoribonuclease XendoU is responsible for processing the intron encoded U16 and U86 small nucleolar RNAs (snoRNAs) [3,4].
• Human EndoU, also known as PP11 (placental protein 11), has an endoribonuclease activity with placental tissue specificity [5,6].
• Drosophila melanogaster CG2145 and DendoU endoribonucleases [7].
• Caenorhabditis elegans endu-2 regulates nucleotide metabolism and germ cell proliferation in response to nucleotide imbalance and other genotoxic stress [8].

EndoU family members share a common domain, that carries out a conserved RNA processing function. The EndoU domain cleaves RNA at uridylates and release 2',3'-cyclic phosphodiester ends.

The EndoU domain is an α+β domain, that contains nine α-helices and three antiparallel β-sheets; the latter are clustered on one side of the domain, whereas the α-helices are largely on the other side (see <PDB:2C1W>) [3]. It contains a conserved trio of catalytic residues, two histidines and a lysine.

The profile we developed covers the entire EndoU domain.