U4atac snRNP GO:0005690 A ribonucleoprotein complex that contains small nuclear RNA U4atac, a heptameric ring of Sm proteins, as well as several proteins that are unique to the U4atac snRNP, most of which remain associated with the U4atac snRNA both while the U4atac snRNP is free or assembled into the U4atac/U6atac complex or into a series of spliceosomal complexes. snRNP U4atac cellular_component spliceosomal snRNP complex