GTPase-activating protein

GTPase-activating protein (GAP) is a type of enzyme that regulates the activity of G proteins by increasing their rate of GTP hydrolysis. This process is crucial for the regulation of fundamental cellular processes such as signal transduction, cell division, and protein synthesis.

Function

GAPs function by binding to activated G proteins and stimulating their intrinsic GTPase activity, thereby accelerating the conversion of bound GTP to GDP. This results in the inactivation of the G protein and termination of the signaling event.

Types of GTPase-activating proteins

There are several types of GTPase-activating proteins, each with a specific set of target G proteins. These include:

• RhoGAP: These GAPs specifically target Rho family of G proteins, which are involved in regulating the cytoskeleton and cell migration.
• RasGAP: These GAPs target Ras subfamily of G proteins, which are involved in cell growth, differentiation, and survival.
• RabGAP: These GAPs target Rab family of G proteins, which are involved in vesicle trafficking.

Clinical significance

Mutations in GTPase-activating proteins have been implicated in several diseases, including cancer, neurological disorders, and cardiovascular diseases. For example, mutations in the NF1 gene, which encodes a RasGAP, are associated with Neurofibromatosis type I, a genetic disorder characterized by the growth of tumors along nerves in the skin, brain, and other parts of the body.

See also

• Guanine nucleotide exchange factor
• G protein-coupled receptor
• Signal transduction

References

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