LSM

LSm is an acronym that can refer to more than one concept in computing and biology. The most common reference in computing is the Linux Security Module (LSM) framework, a kernel interface designed to support pluggable security policies. The LSM provides a set of hooks at security-sensitive points in the Linux kernel; security policies implemented as modules can be loaded to enforce access control decisions without modifying kernel code. Registered modules are consulted during permission checks and can allow or deny operations such as file access, capability checks, process transitions, and network actions. Popular LSM implementations include SELinux, AppArmor, Smack, and TOMO. Policies may be configured at boot or loaded at runtime, depending on kernel support, and multiple policies can be stacked or selectively enabled.

LSm proteins, or Sm-like proteins, are a family of evolutionarily conserved RNA-binding proteins. They assemble into ring-shaped complexes that regulate RNA metabolism in cells. In many eukaryotes, two main forms exist: a cytoplasmic LSm1-7 complex implicated in mRNA decay and deadenylation, and nuclear forms related to LSm2-7 (sometimes including LSm8) that participate in pre-mRNA splicing and U6 snRNA stabilization. LSm rings bind RNA ends rich in uridines and recruit or stabilize other RNA-processing factors, integrating into pathways for RNA maturation, turnover, and gene expression control. In humans, LSM genes range from LSM1 to LSM8, encoding diverse protein components that contribute to these RNA pathways.