Format

Send to:

Choose Destination
See comment in PubMed Commons below
Proc Natl Acad Sci U S A. 1998 Apr 28;95(9):5351-6.

High expression levels in cones of RGS9, the predominant GTPase accelerating protein of rods.

Author information

  • 1Verna and Marrs McLean Department of Biochemistry and Cell and Molecular Biology Graduate Program, Baylor College of Medicine, Houston, TX 77030, USA.

Abstract

RGS9 is a member of the RGS family of GTPase accelerating proteins (GAPs) for heterotrimeric G proteins. We have explored its contribution to GTPase acceleration in mammalian rod and cone photoreceptors. When RGS9 was specifically removed from detergent extracts of rod outer segments by immunodepletion, the extracts lost nearly all of their GAP activity stimulatable by the inhibitory subunit of cGMP phosphodiesterase. Immunolocalization using monoclonal antibodies and confocal microscopy revealed that RGS9 is present in cones at significantly higher levels than in rods. Thus, RGS9 is the predominant source of GAP activity in rod outer segments, and RGS9 concentration emerges as a potentially important determinant of the faster response kinetics and lower sensitivity of mammalian cones, as compared with rods.

PMID:
9560279
[PubMed - indexed for MEDLINE]
PMCID:
PMC20264
Free PMC Article
PubMed Commons home

PubMed Commons

0 comments
How to join PubMed Commons

    Supplemental Content

    Full text links

    Icon for HighWire Icon for PubMed Central
    Loading ...
    Write to the Help Desk