Aminopeptidase O (MEROPS identifier M01.028) is an intracellular aminopeptidase. There is a nucleolar location signal located between the peptidase and ARM-repeat domains. Aminopeptidase O has been localized to the nucleolus, and in the mouse a shorter isoform, generated by alternative initiation, is found in adult and embryonic blood vessels, mainly in the endothelial and smooth muscle cells []. The AOPEP gene also includes a cluster of microRNAs, one of which modulates expression of the Mef2c gene which encodes myocyte-specific enhancer factor 2C []. It is possible that aminopeptidase O is involved in development of vasculature in the embryo and control of blood pressure.
