Format

Send to

Choose Destination
J Biol Chem. 2001 Oct 5;276(40):37365-72. Epub 2001 Aug 8.

RGS9-G beta 5 substrate selectivity in photoreceptors. Opposing effects of constituent domains yield high affinity of RGS interaction with the G protein-effector complex.

Author information

1
Department of Ophthalmology, Harvard Medical School, Boston, Massachusetts 02114, USA.

Abstract

RGS proteins regulate the duration of G protein signaling by increasing the rate of GTP hydrolysis on G protein alpha subunits. The complex of RGS9 with type 5 G protein beta subunit (G beta 5) is abundant in photoreceptors, where it stimulates the GTPase activity of transducin. An important functional feature of RGS9-G beta 5 is its ability to activate transducin GTPase much more efficiently after transducin binds to its effector, cGMP phosphodiesterase. Here we show that different domains of RGS9-G beta 5 make opposite contributions toward this selectivity. G beta 5 bound to the G protein gamma subunit-like domain of RGS9 acts to reduce RGS9 affinity for transducin, whereas other structures restore this affinity specifically for the transducin-phosphodiesterase complex. We suggest that this mechanism may serve as a general principle conferring specificity of RGS protein action.

PMID:
11495924
DOI:
10.1074/jbc.M106431200
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for HighWire
Loading ...
Support Center