Calcium-Dependent Assembly of Centrin-G-Protein Complex in Photoreceptor Cells
AUTOR(ES)
Pulvermüller, Alexander
FONTE
American Society for Microbiology
RESUMO
Photoexcitation of rhodopsin activates a heterotrimeric G-protein cascade leading to cyclic GMP hydrolysis in vertebrate photoreceptors. Light-induced exchanges of the visual G-protein transducin between the outer and inner segment of rod photoreceptors occur through the narrow connecting cilium. Here we demonstrate that transducin colocalizes with the Ca2+-binding protein centrin 1 in a specific domain of this cilium. Coimmunoprecipitation, centrifugation, centrin overlay, size exclusion chromatography, and kinetic light-scattering experiments indicate that Ca2+-activated centrin 1 binds with high affinity and specificity to transducin. The assembly of centrin-G-protein complex is mediated by the βγ-complex. The Ca2+-dependent assembly of a G protein with centrin is a novel aspect of the supply of signaling proteins in sensory cells and a potential link between molecular translocations and signal transduction in general.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=133667Documentos Relacionados
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