U6 snRNA-Associated Sm-Like Protein LSm1 (LSM1) belongs to the snRNP Sm proteins family. The Sm-like proteins are thought to form a stable heteromer present in tri-snRNP particles, which plays an important role in pre-mRNA splicing. LSM1 binds specifically to the 3-terminal U-tract of U6snRNA. LSM1 can interact with SLBP when histone mRNA is being rapidly degraded during the S phase. In addition, LSM1 is associated with cellular transformation and the progression of several malignancies including mesothelioma, lung cancer and breast cancer.