Biomaterial Database

[Nucleoside diphosphate kinase and GTP-binding proteins. Possible mechanisms of coupling]. 2008

D N Orlov, and N Ia Orlov

The results of numerous investigations during the last 20 years have shown that nucleoside diphosphate kinase (NDP kinase) is a multifunctional protein. In this paper, the current data are analyzed indicating that one of the possible mechanisms by which NDP kinase manifests its multifunctional role is its participation in the activation (or regulation) of heterotrimeric GTP-binding proteins (G proteins). We demonstrate that one of the NDP kinase isoforms dynamically interacts with the retinal rod G protein transducin (Gt) and phosphorylates its beta-subunit at histidine residue (His 266). It is also shown that it leads to the consecutive transfer of the phosphate group to the GDP in the active center of G protein alpha-subunit and G protein activation. The advantages of this mechanism are considered as compared to the classic G protein activation mechanism, GDP/GTP exchange.

UI	MeSH Term	Description	Entries
D007527	Isoenzymes	Structurally related forms of an enzyme. Each isoenzyme has the same mechanism and classification, but differs in its chemical, physical, or immunological characteristics.	Alloenzyme,Allozyme,Isoenzyme,Isozyme,Isozymes,Alloenzymes,Allozymes
D009701	Nucleoside-Diphosphate Kinase	An enzyme that is found in mitochondria and in the soluble cytoplasm of cells. It catalyzes reversible reactions of a nucleoside triphosphate, e.g., ATP, with a nucleoside diphosphate, e.g., UDP, to form ADP and UTP. Many nucleoside diphosphates can act as acceptor, while many ribo- and deoxyribonucleoside triphosphates can act as donor. EC 2.7.4.6.	Deoxynucleoside Diphosphate Kinases,GDP Kinase,Nucleoside Diphosphokinases,Nucleoside-Diphosphate Kinases,Diphosphate Kinases, Deoxynucleoside,Diphosphokinases, Nucleoside,Kinase, GDP,Kinase, Nucleoside-Diphosphate,Kinases, Deoxynucleoside Diphosphate,Kinases, Nucleoside-Diphosphate,Nucleoside Diphosphate Kinase,Nucleoside Diphosphate Kinases
D010766	Phosphorylation	The introduction of a phosphoryl group into a compound through the formation of an ester bond between the compound and a phosphorus moiety.	Phosphorylations
D000818	Animals	Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.	Animal,Metazoa,Animalia
D012243	Rhodopsin	A purplish-red, light-sensitive pigment found in RETINAL ROD CELLS of most vertebrates. It is a complex consisting of a molecule of ROD OPSIN and a molecule of 11-cis retinal (RETINALDEHYDE). Rhodopsin exhibits peak absorption wavelength at about 500 nm.	Visual Purple
D015293	Transducin	A heterotrimeric GTP-binding protein that mediates the light activation signal from photolyzed rhodopsin to cyclic GMP phosphodiesterase and is pivotal in the visual excitation process. Activation of rhodopsin on the outer membrane of rod and cone cells causes GTP to bind to transducin followed by dissociation of the alpha subunit-GTP complex from the beta/gamma subunits of transducin. The alpha subunit-GTP complex activates the cyclic GMP phosphodiesterase which catalyzes the hydrolysis of cyclic GMP to 5'-GMP. This leads to closure of the sodium and calcium channels and therefore hyperpolarization of the rod cells.	G-Protein, Inhibitory Gt,Gt, Transducin G-Protein,alpha-Transducin,beta-Transducin,gamma-Transducin,Transducin G-Protein (Gt),Transducin, alpha Subunit,Transducin, beta Subunit,Transducin, gamma Subunit,G Protein, Inhibitory Gt,G-Protein Gt, Transducin,Gt G-Protein, Inhibitory,Gt, Transducin G Protein,Inhibitory Gt G-Protein,Transducin G-Protein Gt,alpha Subunit Transducin,alpha Transducin,beta Subunit Transducin,beta Transducin,gamma Subunit Transducin,gamma Transducin
D015398	Signal Transduction	The intracellular transfer of information (biological activation/inhibition) through a signal pathway. In each signal transduction system, an activation/inhibition signal from a biologically active molecule (hormone, neurotransmitter) is mediated via the coupling of a receptor/enzyme to a second messenger system or to an ion channel. Signal transduction plays an important role in activating cellular functions, cell differentiation, and cell proliferation. Examples of signal transduction systems are the GAMMA-AMINOBUTYRIC ACID-postsynaptic receptor-calcium ion channel system, the receptor-mediated T-cell activation pathway, and the receptor-mediated activation of phospholipases. Those coupled to membrane depolarization or intracellular release of calcium include the receptor-mediated activation of cytotoxic functions in granulocytes and the synaptic potentiation of protein kinase activation. Some signal transduction pathways may be part of larger signal transduction pathways; for example, protein kinase activation is part of the platelet activation signal pathway.	Cell Signaling,Receptor-Mediated Signal Transduction,Signal Pathways,Receptor Mediated Signal Transduction,Signal Transduction Pathways,Signal Transduction Systems,Pathway, Signal,Pathway, Signal Transduction,Pathways, Signal,Pathways, Signal Transduction,Receptor-Mediated Signal Transductions,Signal Pathway,Signal Transduction Pathway,Signal Transduction System,Signal Transduction, Receptor-Mediated,Signal Transductions,Signal Transductions, Receptor-Mediated,System, Signal Transduction,Systems, Signal Transduction,Transduction, Signal,Transductions, Signal
D044387	GTP-Binding Protein beta Subunits	Heterotrimeric GTP-binding protein subunits that tightly associate with GTP-BINDING PROTEIN GAMMA SUBUNITS. A dimer of beta and gamma subunits is formed when the GTP-BINDING PROTEIN ALPHA SUBUNIT dissociates from the GTP-binding protein heterotrimeric complex. The beta-gamma dimer can play an important role in signal transduction by interacting with a variety of second messengers.	G-Protein beta Subunit,GTP-Binding Protein beta Subunit,G Protein beta Subunit,GTP Binding Protein beta Subunit,GTP Binding Protein beta Subunits,Subunit, G-Protein beta,beta Subunit, G-Protein
D019204	GTP-Binding Proteins	Regulatory proteins that act as molecular switches. They control a wide range of biological processes including: receptor signaling, intracellular signal transduction pathways, and protein synthesis. Their activity is regulated by factors that control their ability to bind to and hydrolyze GTP to GDP. EC 3.6.1.-.	G-Proteins,GTP-Regulatory Proteins,Guanine Nucleotide Regulatory Proteins,G-Protein,GTP-Binding Protein,GTP-Regulatory Protein,Guanine Nucleotide Coupling Protein,G Protein,G Proteins,GTP Binding Protein,GTP Binding Proteins,GTP Regulatory Protein,GTP Regulatory Proteins,Protein, GTP-Binding,Protein, GTP-Regulatory,Proteins, GTP-Binding,Proteins, GTP-Regulatory