Calcium-modulated guanylate cyclase transduction machinery in the photoreceptor-bipolar synaptic region

TY - JOUR

T1 - Calcium-modulated guanylate cyclase transduction machinery in the photoreceptor-bipolar synaptic region

AU - Venkataraman, Venkateswar

AU - Duda, Teresa

AU - Vardi, Noga

AU - Koch, Karl Wilhelm

AU - Sharma, Rameshwar K.

PY - 2003/5/20

Y1 - 2003/5/20

N2 - Rod outer segment membrane guanylate cyclase (ROS-GC) transduction system is a central component of the Ca2+-sensitive phototransduction machinery. The system is composed of two parts: Ca2+ sensor guanylate cyclase activating protein (GCAP) and ROS-GC. GCAP senses Ca2+ impulses and inhibits the cyclase. This operational feature of the cyclase is considered to be unique and exclusive in the phototransduction machinery. A combination of reconstitution, peptide competition, cross-linking, and immunocytochemical studies has been used in this study to show that the GCAP1/ROS-GC1 transduction system also exists in the photoreceptor synaptic (presynaptic) termini. Thus, the presence of this system and its linkage is not unique to the phototransduction machinery. A recent study has demonstrated that the photoreceptor-bipolar synaptic region also contains a Ca2+-stimulated ROS-GC1 transduction system [Duda, T., et al. (2002) EMBO J. 21, 2547-2556]. In this case, S100β senses Ca2+ and stimulates the cyclase. The inhibitory and stimulatory Ca2+-modulated ROS-GC1 sites are distinct. These findings allow the formation of a new topographic model of ROS-GC1 transduction. In this model, the catalytic module of ROS-GC1 at its opposite ends is flanked by GCAP1 and S100β modules. GCAP1 senses the Ca2+ impulse and inhibits the catalytic module; S100β senses the impulse and stimulates the catalytic module. Thus, ROS-GC1 acts as a bimodal Ca2+ signal transduction switch in the photoreceptor bipolar synapse.

AB - Rod outer segment membrane guanylate cyclase (ROS-GC) transduction system is a central component of the Ca2+-sensitive phototransduction machinery. The system is composed of two parts: Ca2+ sensor guanylate cyclase activating protein (GCAP) and ROS-GC. GCAP senses Ca2+ impulses and inhibits the cyclase. This operational feature of the cyclase is considered to be unique and exclusive in the phototransduction machinery. A combination of reconstitution, peptide competition, cross-linking, and immunocytochemical studies has been used in this study to show that the GCAP1/ROS-GC1 transduction system also exists in the photoreceptor synaptic (presynaptic) termini. Thus, the presence of this system and its linkage is not unique to the phototransduction machinery. A recent study has demonstrated that the photoreceptor-bipolar synaptic region also contains a Ca2+-stimulated ROS-GC1 transduction system [Duda, T., et al. (2002) EMBO J. 21, 2547-2556]. In this case, S100β senses Ca2+ and stimulates the cyclase. The inhibitory and stimulatory Ca2+-modulated ROS-GC1 sites are distinct. These findings allow the formation of a new topographic model of ROS-GC1 transduction. In this model, the catalytic module of ROS-GC1 at its opposite ends is flanked by GCAP1 and S100β modules. GCAP1 senses the Ca2+ impulse and inhibits the catalytic module; S100β senses the impulse and stimulates the catalytic module. Thus, ROS-GC1 acts as a bimodal Ca2+ signal transduction switch in the photoreceptor bipolar synapse.

UR - https://www.scopus.com/pages/publications/0037952920

UR - https://www.scopus.com/pages/publications/0037952920#tab=citedBy

U2 - 10.1021/bi034025x

DO - 10.1021/bi034025x

M3 - Article

C2 - 12741820

SN - 0006-2960

VL - 42

SP - 5640

EP - 5648

JO - Biochemistry

JF - Biochemistry

IS - 19

ER -