Cancer Associated Sm Like Protein (CASM)

Sm-like proteins were identified in a variety of organisms based on sequence homology with the Sm protein family. Sm-like proteins contain the Sm sequence motif, which consists of 2 regions separated by a linker of variable length that folds as a loop. The Sm-like proteins are thought to form a stable heteromer present in tri-snRNP particles, which are important for pre-mRNA splicing.purified LSm proteins form a heteromer that is stable even in the absence of RNA and exhibits a doughnut-shaped structure similar to the Sm core RNP structure. the purified LSm heteromer binds specifically to the U6 snRNA at its 3-prime-terminal U-tract. the LSm proteins facilitate the formation of U4/U6 RNA duplexes in vitro and concluded that the LSm proteins may play a role in U4/U6 snRNP formation.