Charles Pfister

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Retinal S antigen chromatographically purified from whole retina, induces experimental autoimmune uveoretinitis in laboratory animals. The 48K protein, a soluble protein found in rod outer segments, is purified through its specific binding to photoexcited rhodopsin and is involved in the quenching of light-induced guanosine(More)
Phosphodiesterase (PDE) in bovine retinal rod outer segments is activated when it forms a membrane-bound complex with the alpha-subunit of transducin loaded with GTP (T alpha*). At maximal activation, this complex contains two T alpha* and all the subunits of native PDE (PDE alpha, PDE beta, and two inhibitory PDE gamma). We observed previously (Pagès, F.,(More)
In the first step of the visual transduction cascade a photoexcited rhodopsin molecule, R*ret, binds to a GDP-carrying transducin molecule, TGDP. The R*-T interaction causes the opening of the nucleotide site in T and catalyzes the GDP/GTP exchange by allowing the release of the GDP. We have studied the influences on this R*-T transitory complex of the(More)
The GTP-binding subunit of transducin (T alpha) activates the cGMP phosphodiesterase (PDE) of bovine retinal rods by relieving the constraint imposed by the inhibitory subunit PDE gamma. We have isolated and characterized the complex T alpha.GTP gamma S-PDE gamma formed when T alpha is activated by the nonhydrolyzable analog GTP gamma S. Sedimentation and(More)
The generation of the physiological response of a retinal rod cell to an incident photon involves activation of a cGMP phosphodiesterase (PDE) by a GTP-binding protein, transducin (T). This activation has been shown to occur by formation of a membrane-bound T alpha GTP-PDE complex (Clerc, A., and Bennett, N. (1992) J. Biol. Chem. 267, 6620-6627; Catty, P.,(More)
" Interface free energy is the contribution to the free energy of a system due to the presence of an interface separating two coexisting phases at equilibrium ". It is also called interfacial free energy or surface tension. The content of the article is 1) the definition of the interface free energy from first principles of statistical mechanics; 2) a(More)
In bovine retinal rods, transducin loaded with GTP or GTP gamma S (T*) activates a cGMP phosphodiesterase (PDE) by forming a tightly membrane-bound complex with it [Catty, P., et al. (1992) J. Biol. Chem. 267, 19489-19493]. Up to two T*s are able to bind to PDE [Clerc, A., & Bennett, N. (1992) J. Biol. Chem. 267, 6620-6627]. We analyze here PDE activation(More)
The interaction of the GDP-bound form of the alpha-subunit of transducin (T alpha GDP) with the cGMP-specific phosphodiesterase, the effector enzyme in the visual system, has been studied. T alpha GDP is demonstrated to be able to activate the phosphodiesterase: (a) the basal activity in suspensions of dark-adapted retinal rod outer segments, examined in(More)