Modulation of retinal transducin and phosphodiesterase activities by synthetic peptides of the phosphodiesterase γ‐subunit

Morrison, Daniel F.; Rider, Maureen A.; Takemoto, Dolores J.

doi:10.1016/0014-5793(87)80383-6

Cited by 26 publications

(15 citation statements)

References 21 publications

(17 reference statements)

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“…Such a high concentration of the peptide is needed for its phosphorylation because only a small amount of peptide may be in the correct conformation. A high concentration of the peptide was also required for inhibition of PDE (16).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Phosphatidylinositol-stimulated phosphorylation of an inhibitory subunit of cGMP phosphodiesterase in vertebrate rod photoreceptors.

Hayashi

Lin

Matsumoto

et al. 1991

Proc. Natl. Acad. Sci. U.S.A.

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An inhibitory subunit (Py) of cGMP phosphodiesterase from vertebrate rod photoreceptors (frog, toad, and bovine) was phosphorylated by cytosolic protein kinase(s) derived from intact frog rod outer segments. The phosphorylation offrog Py was stimulated by phosphatidylinositol but not by cAMP or cGMP. One-and two-dimensional gel electrophoresis revealed that 70-80% of Py was phosphorylated with 1 mol of phosphate per frog Py under optimal conditions. A peptide that derived from an active domain of bovine Py was also phosphorylated. Phosphorylation of frog Py was inhibited by addition of the peptide to the reaction mixture. Phosphorylation of frog Py was also inhibited by addition of transducin subunits or active (Py-less) cGMP phosphodiesterase. Okadaic acid, on the other hand, enhanced Py phosphorylation, suggesting the presence of protein phosphatase(s) in the cytosolic fraction. These data suggest another mechanism for the regulation of cGMP phosphodiesterase in vertebrate rod photoreceptors.

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Section: Resultsmentioning

confidence: 99%

“…The cDNA sequence and corresponding amino acid sequences of bovine Py have been determined (21). A published report (16) has suggested that an active site of bovine Py for PDE inhibition is a region corresponding to residues 31-45, which is rich in lysine residues but contains only a single threonine and a single serine residue. Fig.…”

Section: Resultsmentioning

confidence: 99%

Phosphatidylinositol-stimulated phosphorylation of an inhibitory subunit of cGMP phosphodiesterase in vertebrate rod photoreceptors.

Hayashi

Lin

Matsumoto

et al. 1991

Proc. Natl. Acad. Sci. U.S.A.

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“…Two functional regions in the ␥ subunit of PDE-6, a polycationic (amino acids 24 -46) and a C-terminal domain, interact with both transducin and PDE-6 catalytic subunits (31)(32)(33)(34). The C-terminal domain is essential for both the inhibitory action against PDE-6 (26, 31, 32, 35) and for stimulating transducin GTPase (36).…”

Section: Discussionmentioning

confidence: 99%

The Regulation of the cGMP-binding cGMP Phosphodiesterase by Proteins That Are Immunologically Related to γ Subunit of the Photoreceptor cGMP Phosphodiesterase

Lochhead¹,

Nekrasova²,

Arshavsky³

et al. 1997

Journal of Biological Chemistry

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The cGMP phosphodiesterase from retinal rods (PDE-6) is an ␣␤␥ 2 heterotetramer. The ␣ and ␤ subunits contain catalytic sites for cGMP hydrolysis, whereas the ␥ subunits serve as a protein inhibitor of the enzyme. Visual excitation of photoreceptors enables the activated GTP-bound form of the G-protein transducin to remove the inhibitory action of the ␥ subunit, thereby triggering PDE-6 activation. The type 5 phosphodiesterase (PDE-5) isoform shares a number of similar characteristics with PDE-6, including binding of cGMP to noncatalytic sites, the cyclic nucleotide specificity, and inhibitor sensitivities. Although the functional role of PDE-5 remains unclear, it has been shown to be activated by protein kinase A (PKA) (Burns, F., Rodger, I. W. & Pyne, N. J. (1992) Biochem. J. 283, 487-491). Here we report that both the recombinant ␥ subunit and a peptide corresponding to amino acids 24 -46 in this protein inhibited the activation of PDE-5 by PKA. Furthermore, immunoblotting airway smooth muscle membranes with a specific antibody against amino acids 24 -46 of the PDE-6 ␥ subunit identified two major immunoreactive small molecular mass proteins of 14 and 18 kDa (p14 and p18). These appear to form a complex with PDE-5, because PDE activity was immunoprecipitated using antibody against the PDE-6 ␥ subunit. p14 and p18 were also substrates for phosphorylation by a unidentified kinase that was stimulated by a pertussis toxin-sensitive Gprotein. Phosphorylation of p14/p18 in membranes treated with guanine nucleotides correlated with a concurrent reduction in the activation of PDE-5 by PKA. We suggest that p14 and p18 share an epitope common to PDE-6 ␥ and that this region may interact with PDE-5 to prevent its activation by PKA.

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“…The PDE holoenzyme is tightly regulated by the Pγ inhibitory subunits. Much work has been done with bovine PDE to elucidate the important sites of interaction of Pγ with Pαβ [10][11][12][13][14][15][16][17][18][19][20][21]. It has been found that Pγ contains two distinct domains that interact with Pαβ : a central cationic region (residues approx.…”

Section: Introductionmentioning

confidence: 99%

Regulation of photoreceptor phosphodiesterase catalysis by its non-catalytic cGMP-binding sites

D'Amours

Cote

1999

Biochemical Journal

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The photoreceptor 3':5'-cyclic nucleotide phosphodiesterase (PDE) is the central enzyme of visual excitation in rod photoreceptors. The hydrolytic activity of PDE is precisely regulated by its inhibitory gamma subunit (Pgamma), which binds directly to the catalytic site. We examined the inhibition of frog rod outer segment PDE by endogenous Pgamma, as well as by synthetic peptides corresponding to its central and C-terminal domains, to determine whether the non-catalytic cGMP-binding sites on the catalytic alphabeta dimer of PDE allosterically regulate PDE activity. We found that the apparent binding affinity of Pgamma for PDE was 28 pM when cGMP occupied the non-catalytic sites, whereas Pgamma had an apparent affinity only 1/16 of this when the sites were empty. The elevated basal activity of PDE with empty non-catalytic sites can be decreased by the addition of nanomolar levels of cGMP, demonstrating that the high-affinity non-catalytic sites on the PDE catalytic dimer mediate this effect. No evidence for a direct allosteric effect of the non-catalytic sites on catalysis could be detected for the activated enzyme lacking bound Pgamma. The intrinsic affinity of a synthetic C-terminal (residues 63-87) Pgamma peptide to bind and to inhibit the hydrolytic activity of activated PDE was enhanced 300-fold in the presence of cGMP compared with cAMP. We conclude that the binding of cGMP to the non-catalytic sites of PDE induces an allosteric change in the structure of the catalytic domain that greatly enhances the interaction of the C-terminus of Pgamma with the catalytic domain.

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Modulation of retinal transducin and phosphodiesterase activities by synthetic peptides of the phosphodiesterase γ‐subunit

Cited by 26 publications

References 21 publications

Phosphatidylinositol-stimulated phosphorylation of an inhibitory subunit of cGMP phosphodiesterase in vertebrate rod photoreceptors.

Phosphatidylinositol-stimulated phosphorylation of an inhibitory subunit of cGMP phosphodiesterase in vertebrate rod photoreceptors.

The Regulation of the cGMP-binding cGMP Phosphodiesterase by Proteins That Are Immunologically Related to γ Subunit of the Photoreceptor cGMP Phosphodiesterase

Regulation of photoreceptor phosphodiesterase catalysis by its non-catalytic cGMP-binding sites

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