G protein

A G protein is a protein switch whose activity depends on the bound guanine nucleotide. The three-subunit G proteins coupled to G protein-coupled receptors relay activation to other proteins; they are distinct from the receptors themselves. See the Alberts reference under G protein-coupled receptor.

A small-molecule inhibitor that stabilizes a GDP-bound arrangement of Gαq and inhibits nucleotide exchange.^[ref]

A small GTPase is a relatively small nucleotide-switch protein that cycles between GDP- and GTP-bound states. Ras family proteins illustrate signaling mechanisms distinct from the three-subunit organization of a heterotrimeric G protein.

A small GTPase participating in protrusion and polarity in migrating cells.

A Rab-family regulator associated with late endosomal and degradative trafficking.

A Rab-family regulator associated with early endosomal membrane domains.

Replacement of an early Rab-regulated membrane identity by a later one, exemplified by Rab5 loss and Rab7 acquisition during endosome maturation.

A heterotrimeric G protein is a signaling assembly with $\alpha$, $\beta$ and $\gamma$ subunits. Receptor-promoted nucleotide exchange on $\alpha$ regulates interactions with $\beta \gamma$ and effectors; both signaling components can contribute downstream.

The associated β and γ subunits of a heterotrimeric G protein. Their interactions with downstream effectors transmit signals as well as support heterotrimer assembly.

The guanine-nucleotide-binding subunit of a heterotrimeric G protein. Nucleotide state changes its interactions with receptors, Gβγ and effectors.

A Gα family member that can inhibit adenylyl cyclase.

A Gα family member that can stimulate adenylyl cyclase.

A Gα family member that activates phospholipase C signalling.