GTPase
GTPases are a family of hydrolase enzymes that bind to the nucleotide guanosine triphosphate (GTP) and hydrolyze it to guanosine diphosphate (GDP).
A GTPase, or guanosine triphosphatase, is an enzyme that hydrolyzes the guanosine triphosphate (GTP) molecule to guanosine diphosphate (GDP) and inorganic phosphate (Pi).
GTPases are crucial for regulating various cellular processes, including signal transduction, protein synthesis, cytoskeletal rearrangements, vesicle trafficking, and cell division.
GTPases are classified into two main categories based on their functions and structures: monomeric
GTPases and trimeric GTPases.
Monomeric GTPases, such as the Ras superfamily, play essential roles in controlling cell growth, differentiation, and survival by transmitting signals from extracellular stimuli to intracellular effectors.
Trimeric GTPases, also known as G protein-coupled receptors (GPCRs), are involved in transducing signals across the cell membrane in response to various stimuli.
Some well-known GTPase families include Ras, Rho, Rab, and Arf.
Mutations or dysregulation of GTPases can lead to various diseases, including cancer,
GTPases function as molecular switches or timers in many fundamental cellular processes.
GTPase, or guanosine triphosphatase, is an enzyme that hydrolyzes GTP (guanosine triphosphate) into GDP (guanosine diphosphate) and inorganic phosphate.
GTPases are involved in a number of cellular processes and are crucial for regulating signaling pathways, cell division, protein synthesis, and many other essential functions within the cell.
One well-known group of GTPases is the RAS protein family, which plays a key role in cell growth, differentiation, and survival.
Another important group is the G-proteins, which are involved in transmitting signals from outside the cell to the cell’s interior.
The activity of GTPases is tightly regulated within the cell.
GTPase-activating proteins (GAPs) promoting GTP hydrolysis and guanine nucleotide exchange factors (GEFs) stimulating the exchange of GDP for GTP, activating the GTPase.
Dysregulation of GTPase activity has been linked to cancer, neurodegenerative disorders, and other diseases, making them potential targets for therapeutic interventions.
GYPase activities:
Signal transduction in response to activation of cell surface receptors, including transmembrane receptors such as those mediating taste, smell and vision.
Protein biosynthesis at the ribosome.
Regulation of cell differentiation, proliferation, division and movement.
Translocation of proteins through membranes.
Transport of vesicles within the cell, and vesicle-mediated secretion and uptake, through GTPase control of vesicle coat assembly.
GTPases are active when bound to GTP and inactive when bound to GDP.
Signaling GTPases act as transducers to regulate the activity of effector proteins.
Translation factor family GTPases play important roles in initiation, elongation and termination of protein biosynthesis.
When activated, a heterotrimeric G protein dissociates into activated, GTP-bound alpha subunit and separate beta-gamma subunit, each of which can perform distinct signaling roles.
G protein signaling is terminated by hydrolysis of bound GTP to bound GDP.
Small GTPases generally serve as molecular switches and signal transducers for a number of cellular signaling events, often involving membranes, vesicles or cytoskeleton.