ISSN:
1432-1440
Schlagwort(e):
Cellular effectors
;
Cellular signaling
;
G protein
;
Heptahelical receptor
;
Signal transduction
Quelle:
Springer Online Journal Archives 1860-2000
Thema:
Medizin
Notizen:
Abstract Seven-transmembrane receptors signal through nucleotide-binding proteins (G proteins) into the cell. G proteins are membrane-associated proteins composed of three subunits termed α, β and γ, of which the Gα subunit classifies the heterotrimer. So far, 23 different mammalian Gα subunits are known, which are grouped in four subfamilies (Gs, Gi, Gq, G12) on the basis of their amino acid similarity. They carry an endogenous GTPase activity allowing reversible functional coupling between ligand-bound receptors and effectors such as enzymes and ion channels. In addition, five Gβ and seven Gγ subunits have been identified which form tightly associated βγ heterodimers. Upon activation by a ligand-bound receptor the G protein dissociates into Gα and Gβγ, which both transmit signal by interacting with effectors. On the G protein level, specificity and selectivity of the incoming signal is accomplished by G protein trimers composed of distinct subunits. On the other hand, many receptors have been shown to activate different G proteins, thereby regulating diverse signal transduction pathways.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1007/BF00198240
Permalink