Protein associated with the U5 snRNP, during its maturation and its post-splicing recycling and which is required for spliceosomal tri-snRNP complex assembly in the nucleus (, ). Has a molecular sequestering activity and transiently hinders SNRNP200 binding sites for constitutive splicing factors that intervene later during the assembly of the spliceosome and splicing . Together with its molecular sequestering activity, may also function as a molecular adapter and placeholder, coordinating the assembly of the U5 snRNP and its association with the U4/U6 di-snRNP .
Subcellular locations: Nucleus, Cytoplasm
Shuttles between the cytoplasm and the nucleus, associated with the U5 snRNP.
Expressed in fetal brain, lung, liver and kidney. Widely expressed in adult tissues.