Rab G proteins, also known as Ras-related in brain (Rab) proteins, are a family of small GTPases that play a crucial role in regulating intracellular vesicle trafficking in eukaryotic cells. They are found in all eukaryotes, from yeast to humans, and are known to be involved in various cellular processes such as membrane fusion, organelle biogenesis, and vesicle docking.
Rab G proteins are primarily localized on cellular membranes, including the endoplasmic reticulum, Golgi apparatus, endosomes, and transport vesicles. They act as key regulators of vesicular transport by cycling between an inactive GDP-bound form and an active GTP-bound form. The transition between these two states is facilitated by guanine nucleotide exchange factors (GEFs) and GTPase-activating proteins (GAPs), which stimulate GTP binding and hydrolysis, respectively.
These proteins regulate vesicle trafficking by recruiting specific effector proteins that mediate membrane fusion, cargo sorting, and vesicle tethering. By serving as molecular switches, Rab G proteins control the specificity and timing of vesicle fusion events, ensuring that cargo is delivered to the correct destination within the cell.
Mutations or dysregulation in Rab G proteins have been associated with various diseases, including neurodegenerative disorders, cancer, and metabolic disorders. Their dysfunctions can disrupt normal cellular trafficking pathways, leading to aberrant vesicle transport, impaired organelle formation, and defective cellular communication.
In conclusion, Rab G proteins are a diverse family of small GTPases found in eukaryotic cells, which play a crucial role in regulating intracellular vesicle trafficking. They serve as molecular switches to control the specificity and efficiency of vesicle fusion events,
