A possible role of RGS9 in phototransduction. A bridge between the cGMP-phosphodiesterase system and the guanylyl cyclase system

In the current concept of phototransduction, the concentration of cGMP in retinal rod outer segments is controlled by the balance of two enzyme activities: cGMP phosphodiesterase (PDE) and guanylyl cyclase (GC). However, no protein directly mediates these two enzyme systems. Here we show that RGS9,...

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Bibliographic Details
Published in:The Journal of biological chemistry 1998-08, Vol.273 (35), p.22169-22172
Main Authors: Seno, K. (Kobe University, Japan), Kishigami, A, Ihara, S, Maeda, T, Bondarenko, V.A, Nishizawa, Y, Usukura, J, Yamazaki, A, Hayashi, F
Format: Article
Language:English
Subjects:
3',5'-Cyclic-GMP Phosphodiesterases - metabolism
ACTIVIDAD ENZIMATICA
ACTIVITE ENZYMATIQUE
Amino Acid Sequence
AMINO ACID SEQUENCES
Animals
BINDING PROTEINS
BOVIN
CATTLE
CHEMICAL COMPOSITION
COMPOSICION QUIMICA
COMPOSITION CHIMIQUE
ENZYMIC ACTIVITY
EYES
GANADO BOVINO
GTPase-Activating Proteins
GUANYLATE CYCLASE
Guanylate Cyclase - metabolism
LIASAS
LYASE
LYASES
MOLECULAR SEQUENCE DATA
OEIL
OJOS
Protein Binding
PROTEINAS AGLUTINANTES
PROTEINE DE LIAISON
Proteins - chemistry
Proteins - metabolism
REGULATION
RETINA
Rod Cell Outer Segment - metabolism
ROD OUTER SEGMENTS
Sequence Homology, Amino Acid
Signal Transduction
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Description
Summary:In the current concept of phototransduction, the concentration of cGMP in retinal rod outer segments is controlled by the balance of two enzyme activities: cGMP phosphodiesterase (PDE) and guanylyl cyclase (GC). However, no protein directly mediates these two enzyme systems. Here we show that RGS9, which is suggested to control PDE activity through regulation of transducin GTPase activity (He, W., Cowan, C. W., and Wensel, T. G. (1998) Neuron 20, 95-102), directly interacts with GC. When proteins in the Triton X-100-insoluble fraction of bovine rod outer segments were isolated by two-dimensional gel electrophoresis and binding of GC to these proteins was examined using a GC-specific antibody, proteins (55 and 32 kDa) were found to interact with GC. However, the activity of GC bound to the 55-kDa protein was not detected. This observation was elucidated by the finding that the 55-kDa protein inhibited GC activity in a dose-dependent manner. Amino acid sequence showed that five peptides derived from the 55-kDa protein were identical to corresponding peptides of RGS9. Together with other biochemical characterization of the 55-kDa protein, these observations indicate that the 55-kDa protein is RGS9 and that RGS9 inhibits GC. RGS9 may serve as a mediator between the PDE and GC systems.
ISSN:0021-9258
1083-351X
DOI:10.1074/jbc.273.35.22169