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Protein kinase C activation antagonizes melatonin-induced pigment aggregation in Xenopus laevis melanophores

The pineal hormone, melatonin (5-methoxy N-acetyltryptamine) induces a rapid aggregation of melanin-containing pigment granules in isolated melanophores of Xenopus laevis. Treatment of melanophores with activators of protein kinase C (PKC), including phorbol esters, mezerein and a synthetic diacylgl...

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Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1992
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2289739/
https://www.ncbi.nlm.nih.gov/pubmed/1334961
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collection PubMed
description The pineal hormone, melatonin (5-methoxy N-acetyltryptamine) induces a rapid aggregation of melanin-containing pigment granules in isolated melanophores of Xenopus laevis. Treatment of melanophores with activators of protein kinase C (PKC), including phorbol esters, mezerein and a synthetic diacylglycerol, did not affect pigment granule distribution but did prevent and reverse melatonin-induced pigment aggregation. This effect was blocked by an inhibitor of PKC, Ro 31- 8220. The inhibitory effect was not a direct effect on melatonin receptors, per se, as the slow aggregation induced by a high concentration of an inhibitor of cyclic AMP-dependent protein kinase (PKA), adenosine 3',5'-cyclic monophosphothioate, Rp-diastereomer (Rp- cAMPS), was also reversed by PKC activation. Presumably activation of PKC, like PKA activation, stimulates the intracellular machinery involved in the centrifugal translocation of pigment granules along microtubules. alpha-Melanocyte stimulating hormone (alpha-MSH), like PKC activators, overcame melatonin-induced aggregation but this response was not blocked by the PKC inhibitor, Ro 31-8220. This data indicates that centrifugal translocation (dispersion) of pigment granules in Xenopus melanophores can be triggered by activation of either PKA, as occurs after alpha-MSH treatment, or PKC. The very slow aggregation in response to inhibition of PKA with high concentrations of Rp-cAMPS, suggests that the rapid aggregation in response to melatonin may involve multiple intracellular signals in addition to the documented Gi-mediated inhibition of adenylate cyclase.
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spelling pubmed-22897392008-05-01 Protein kinase C activation antagonizes melatonin-induced pigment aggregation in Xenopus laevis melanophores J Cell Biol Articles The pineal hormone, melatonin (5-methoxy N-acetyltryptamine) induces a rapid aggregation of melanin-containing pigment granules in isolated melanophores of Xenopus laevis. Treatment of melanophores with activators of protein kinase C (PKC), including phorbol esters, mezerein and a synthetic diacylglycerol, did not affect pigment granule distribution but did prevent and reverse melatonin-induced pigment aggregation. This effect was blocked by an inhibitor of PKC, Ro 31- 8220. The inhibitory effect was not a direct effect on melatonin receptors, per se, as the slow aggregation induced by a high concentration of an inhibitor of cyclic AMP-dependent protein kinase (PKA), adenosine 3',5'-cyclic monophosphothioate, Rp-diastereomer (Rp- cAMPS), was also reversed by PKC activation. Presumably activation of PKC, like PKA activation, stimulates the intracellular machinery involved in the centrifugal translocation of pigment granules along microtubules. alpha-Melanocyte stimulating hormone (alpha-MSH), like PKC activators, overcame melatonin-induced aggregation but this response was not blocked by the PKC inhibitor, Ro 31-8220. This data indicates that centrifugal translocation (dispersion) of pigment granules in Xenopus melanophores can be triggered by activation of either PKA, as occurs after alpha-MSH treatment, or PKC. The very slow aggregation in response to inhibition of PKA with high concentrations of Rp-cAMPS, suggests that the rapid aggregation in response to melatonin may involve multiple intracellular signals in addition to the documented Gi-mediated inhibition of adenylate cyclase. The Rockefeller University Press 1992-12-02 /pmc/articles/PMC2289739/ /pubmed/1334961 Text en This article is distributed under the terms of an Attribution–Noncommercial–Share Alike–No Mirror Sites license for the first six months after the publication date (see http://www.rupress.org/terms). After six months it is available under a Creative Commons License (Attribution–Noncommercial–Share Alike 4.0 Unported license, as described at http://creativecommons.org/licenses/by-nc-sa/4.0/).
spellingShingle Articles
Protein kinase C activation antagonizes melatonin-induced pigment aggregation in Xenopus laevis melanophores
title Protein kinase C activation antagonizes melatonin-induced pigment aggregation in Xenopus laevis melanophores
title_full Protein kinase C activation antagonizes melatonin-induced pigment aggregation in Xenopus laevis melanophores
title_fullStr Protein kinase C activation antagonizes melatonin-induced pigment aggregation in Xenopus laevis melanophores
title_full_unstemmed Protein kinase C activation antagonizes melatonin-induced pigment aggregation in Xenopus laevis melanophores
title_short Protein kinase C activation antagonizes melatonin-induced pigment aggregation in Xenopus laevis melanophores
title_sort protein kinase c activation antagonizes melatonin-induced pigment aggregation in xenopus laevis melanophores
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2289739/
https://www.ncbi.nlm.nih.gov/pubmed/1334961