About RND / Rho Family GTPase:
The Rho family of GTPases, also RND, is a group of regulatory proteins that coordinate the actin cytoskeleton. These proteins are involved in many processes, including:
●Regulating the immune system.
RND Mechanism of Action
The mechanism of action for these proteins is not fully understood. However, they are known to activate the GTPase activity of actin. Actin polymerization and depolymerization regulate cellular functions such as endocytosis and cell locomotion. The Rho family members may facilitate the formation of stress fibers in stretched cells.
Rho GTPases regulate actin cytoskeleton dynamics indirectly. They activate the small guanosine triphosphatase Rac. The binding of Rho proteins with phospholipids may also play a role in regulating cell shape and adhesion.
Finally, some family members can stimulate or inhibit actin polymerization, while others may activate or hinder the process.
Rho Family GTPase Structure
There are 18 different members of the Rho family, which all have a very similar structure. The proteins consist of two domains: an amino-terminal domain and a carboxy-terminal GTPase domain.
The related protein Rac is composed only of one domain - it has no second C-terminus containing the autocatalytic GTPase domain. Instead, the amino-terminal domain binds to proteins and lipids, including membrane phospholipid PI(P) (phosphatidylinositol).
The carboxy terminus is a guanosine triphosphate binding site for guanine nucleotide exchange factors.
RND Cellular Functions
One study showed that the RhoA protein is expressed at high levels in neutrophils and platelets, while other family members are on various cell types.
Chemotaxis - Cells stimulated by chemoattractants such as cytokines can respond with directional locomotion called chemotaxis. The activity of Rho GTPases regulates the directionality and speed of chemotaxis.
Conclusively, the Rho family of proteins are essential regulators for many cellular processes.