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On the activation of phosphodiesterase by a 26 kDa protein
S S Nikonov1, G N Filatov, E E Fesenko
1Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow Region.
Abstract:
The effects of a 26 kDa protein isolated from vertebrate retina rod outer segments (ROS) and its reconstituted analog on the phosphodiesterase (PDE) activity and cGMP-dependent conductance have been studied [Nature 313 (1985) 310-313]. Using the patch-clamp technique it was shown that the 26 kDa protein in concentrations up to 1 microM accelerates hydrolysis of cGMP by near-membrane PDE by 1-2 orders of magnitude. This process is suggested to be mediated by some intracellular agent. At the same concentrations the 26 kDa protein was shown to inhibit cGMP-dependent conductance of the photoreceptor membrane. A possible role of these effects in the processes of phototransduction and adaptation is discussed.