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Article: Activators of protein kinase C depolarize insulin-secreting cells by closing K+ channels.

TitleActivators of protein kinase C depolarize insulin-secreting cells by closing K+ channels.
Authors
KeywordsChemicals And Cas Registry Numbers
Issue Date1988
PublisherNature Publishing Group. The Journal's web site is located at http://www.nature.com/emboj/index.html
Citation
Embo Journal, 1988, v. 7 n. 8, p. 2443-2449 How to Cite?
Abstract
Carbohydrate stimuli of insulin secretion depolarize the pancreatic B cell and the B-cell line RINm5F by inhibiting ATP-sensitive K+ channels. We examined the possibility that this effect is mediated by activation of protein kinase C. In RINm5F cells, the triose D-glyceraldehyde evoked a rapid increase of the mass of 1,2-diacylglycerol, the endogenous activator of protein kinase C. This effect is mainly due to de novo synthesis of the lipid from glycolytic intermediates, as glyceraldehyde carbon was incorporated into 1,2-diacylglycerol within 1 min of exposure to 14C-labelled glyceraldehyde. The effects of two exogenous activators of kinase C, 4-beta-12-phorbol-myristate 13-acetate (PMA) and 1,2-didecanoylglycerol (DC10) on single K+ channel currents were examined in RINm5F cell-attached membrane patches. Both PMA and DC10 depolarized the cells and decreased the open-state probability of the ATP-sensitive K+ channels. These actions were not due to changes in cellular ATP content, since PMA, like glyceraldehyde, failed to alter cellular ATP. As is the case for glyceraldehyde, PMA and DC10 raised cytosolic free Ca2+ [( Ca2+]i) and stimulated insulin secretion. Both of these effects are inhibited in the absence of external Ca2+. This, and the attenuation of the [Ca2+]i rise by verapamil, suggest that all three stimuli raise [Ca2+]i by promoting Ca2+ influx through voltage-gated channels in turn leading to insulin secretion. As the exogenous activators of protein kinase C mimic the effects of glyceraldehyde, it is proposed that the carbohydrate-mediated production of 1,2-diacylglycerol constitutes the link between metabolism and membrane depolarization.(ABSTRACT TRUNCATED AT 250 WORDS)
Persistent Identifierhttp://hdl.handle.net/10722/132779
ISSN
2013 Impact Factor: 10.748
ISI Accession Number ID

 

Author Affiliations
  1. Université de Genève
DC FieldValueLanguage
dc.contributor.authorWollheim, CBen_HK
dc.contributor.authorDunne, MJen_HK
dc.contributor.authorPeterRiesch, Ben_HK
dc.contributor.authorBruzzone, Ren_HK
dc.contributor.authorPozzan, Ten_HK
dc.contributor.authorPetersen, OHen_HK
dc.date.accessioned2011-03-28T09:28:55Z-
dc.date.available2011-03-28T09:28:55Z-
dc.date.issued1988en_HK
dc.identifier.citationEmbo Journal, 1988, v. 7 n. 8, p. 2443-2449en_HK
dc.identifier.issn0261-4189en_HK
dc.identifier.urihttp://hdl.handle.net/10722/132779-
dc.description.abstractCarbohydrate stimuli of insulin secretion depolarize the pancreatic B cell and the B-cell line RINm5F by inhibiting ATP-sensitive K+ channels. We examined the possibility that this effect is mediated by activation of protein kinase C. In RINm5F cells, the triose D-glyceraldehyde evoked a rapid increase of the mass of 1,2-diacylglycerol, the endogenous activator of protein kinase C. This effect is mainly due to de novo synthesis of the lipid from glycolytic intermediates, as glyceraldehyde carbon was incorporated into 1,2-diacylglycerol within 1 min of exposure to 14C-labelled glyceraldehyde. The effects of two exogenous activators of kinase C, 4-beta-12-phorbol-myristate 13-acetate (PMA) and 1,2-didecanoylglycerol (DC10) on single K+ channel currents were examined in RINm5F cell-attached membrane patches. Both PMA and DC10 depolarized the cells and decreased the open-state probability of the ATP-sensitive K+ channels. These actions were not due to changes in cellular ATP content, since PMA, like glyceraldehyde, failed to alter cellular ATP. As is the case for glyceraldehyde, PMA and DC10 raised cytosolic free Ca2+ [( Ca2+]i) and stimulated insulin secretion. Both of these effects are inhibited in the absence of external Ca2+. This, and the attenuation of the [Ca2+]i rise by verapamil, suggest that all three stimuli raise [Ca2+]i by promoting Ca2+ influx through voltage-gated channels in turn leading to insulin secretion. As the exogenous activators of protein kinase C mimic the effects of glyceraldehyde, it is proposed that the carbohydrate-mediated production of 1,2-diacylglycerol constitutes the link between metabolism and membrane depolarization.(ABSTRACT TRUNCATED AT 250 WORDS)en_HK
dc.languageengen_US
dc.publisherNature Publishing Group. The Journal's web site is located at http://www.nature.com/emboj/index.htmlen_HK
dc.relation.ispartofEMBO Journalen_HK
dc.subjectChemicals And Cas Registry Numbersen_US
dc.titleActivators of protein kinase C depolarize insulin-secreting cells by closing K+ channels.en_HK
dc.typeArticleen_HK
dc.identifier.emailBruzzone, R: bruzzone@hkucc.hku.hken_HK
dc.identifier.authorityBruzzone, R=rp01442en_HK
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.pmid3056715en_HK
dc.identifier.scopuseid_2-s2.0-0024062566en_HK
dc.identifier.volume7en_HK
dc.identifier.issue8en_HK
dc.identifier.spage2443en_HK
dc.identifier.epage2449en_HK
dc.identifier.isiWOS:A1988P464000021-
dc.publisher.placeUnited Kingdomen_HK
dc.identifier.scopusauthoridWollheim, CB=7103171309en_HK
dc.identifier.scopusauthoridDunne, MJ=7102428507en_HK
dc.identifier.scopusauthoridPeterRiesch, B=6602087149en_HK
dc.identifier.scopusauthoridBruzzone, R=7006793327en_HK
dc.identifier.scopusauthoridPozzan, T=7102571129en_HK
dc.identifier.scopusauthoridPetersen, OH=35508725600en_HK

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