title: Active transducin alpha subunit carries PDE6 to detergent-resistant membranes in rod photoreceptor outer segments.
abstract: cGMP-Phosphodiesterase 6 (PDE6) is the central effector enzyme in the phototransduction system of vertebrate photoreceptors. We have recently found that PDE6 accumulates in a detergent-resistant membrane (DRM) fraction in response to excitation of bovine rod phototransduction system. Here, we studied the molecular mechanism of the PDE6 translocation to DRM. Pertussis toxin inhibited the translocation of PDE6. Upon addition of AlF(4)(-) to dark-adapted ROS, PDE6 translocated to DRM along with a minor fraction of the alpha subunit of transducin (T alpha). The addition of an excess of the inhibitory subunit of PDE6 blocked its accumulation in the DRM, but did not block the translocation of the minor fraction of T alpha. These data suggested that the formation of a complex between activated T alpha and PDE6 imparted upon T alpha a high affinity for the DRM. The translocation of PDE6 to the DRM may be involved in the spatiotemporal regulation of its activity on disk membranes.
authors.affiliation: Graduate School of Science and Technology, Kobe University, Japan.
authors.forename: Han
authors.initials: H
authors.lastname: Liu
authors.forename: Keiji
authors.initials: K
authors.lastname: Seno
authors.forename: Fumio
authors.initials: F
authors.lastname: Hayashi
mesh_terms: D000818:Animals; D001665:Binding Sites; D015153:Blotting, Western; D002417:Cattle; D002462:Cell Membrane / Q000378:metabolism; D054707:Cyclic Nucleotide Phosphodiesterases, Type 6; D003902:Detergents / Q000494:pharmacology*; D004591:Electrophoresis, Polyacrylamide Gel; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D008027:Light; D021962:Membrane Microdomains / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism*; D021381:Protein Transport; D012374:Rod Cell Outer Segment / Q000378:metabolism*; D015293:Transducin / Q000737:chemistry* / Q000502:physiology*
chemical_list: D003902:Detergents; D010710:Phosphates; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D010727:Phosphoric Diester Hydrolases; D054707:Cyclic Nucleotide Phosphodiesterases, Type 6; D015293:Transducin