Phosphorylated adapter RNA export protein (PHAX) is a phosphoprotein adapter involved in the XPO1-mediated U snRNA export from the nucleus. Bridge components required for U snRNA export, the cap binding complex (CBC)-bound snRNA on the one hand and the GTPase Ran in its active GTP-bound form together with the export receptor XPO1 on the other. PHAX also plays a role in the biogenesis of U3 small nucleolar RNA (snoRNA). It is involved in the U3 snoRNA transport from nucleoplasm to Cajal bodies. Binds strongly to m7G-capped U3, U8 and U13 precursor snoRNAs and weakly to trimethylated (TMG)-capped U3, U8 and U13 snoRNAs [taken from the Universal Protein Resource (UniProt) www.uniprot.org/uniprot/Q9H814].