Ras subfamily
（重定向自RAS proteins）
![](/Images/godic/202502/06/Hras_surface_colored_by_conservation5441.png")
![HRas structure PDB 121p, ribbon showing strands in purple, helices in aqua, loops in gray. Also shown are the bound GTP analog and magnesium ion.](/Images/godic/202502/06/Hras_secondary_structure_ribbon5441.png")
![Overview of signal transduction pathways involved in apoptosis.](/Images/godic/202502/06/Signal_transduction_pathways.svg5441.png")
Ras is a family of related proteins which is ubiquitously expressed in all cell lineages and organs. All Ras protein family members belong to a class of protein called small GTPase, and are involved in transmitting signals within cells (cellular signal transduction). Ras is the prototypical member of the Ras superfamily of proteins, which are all related in 3D structure and regulate diverse cell behaviours.