A ribonucleoprotein complex that contains small nuclear RNA U2, a heptameric ring of Sm proteins, as well as several proteins that are unique to the U2 snRNP, most of which remain associated with the U2 snRNA both while the U2 snRNP is free or assembled into a series of spliceosomal complexes.
Comment
U2 snRNP refers to the U2 small nuclear RNA and the proteins that associate with it. U2 snRNP is not considered to be a type of spliceosomal complex by itself.