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Predicate | Object |
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rdf:type | |
lifeskim:mentions | |
pubmed:issue |
31
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pubmed:dateCreated |
1993-11-29
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pubmed:abstractText |
Mastoparan, a tetradecapeptide from wasp venom, stimulated exocytosis in a concentration-dependent manner, which was enhanced by pertussis toxin pre-treatment, in the insulin secreting beta-cell line RINm5F. Mastoparan (3-20 microM) also elevated cytosolic free calcium concentration ([Ca2+]i), a rise that was not attenuated by nitrendipine. Divalent cation-free Krebs-Ringer bicarbonate (KRB) medium with 0.1 mM EGTA nullified the mastoparan-induced increase in [Ca2+]i, suggesting that the peptide increased Ca2+ influx but not through the L-type voltage-dependent Ca2+ channel. Depletion of the intracellular Ca2+ pool did not affect the mastoparan-induced elevation of [Ca2+]i. Remarkably, in divalent cation-free KRB medium with 0.1 mM EGTA and 2 microM thapsigargin in which mastoparan reduced [Ca2+]i, the mastoparan-stimulated insulin release was similar to that in normal Ca(2+)-containing KRB medium. Inhibitors of protein kinase C, such as bisindolylmaleimide, staurosporine, and 1-O-hexadecyl-2-O-methyl-rac-glycerol did not suppress the mastoparan-stimulated insulin release. Mastoparan at 10-20 microM did not increase cellular cAMP levels, nor did mastoparan at 5-10 microM affect [3H]arachidonic acid release. In conclusion, although mastoparan increased [Ca2+]i, this increase was not involved in the stimulation of insulin release. Rather, the data suggest that mastoparan directly stimulates exocytosis in a Ca(2+)-independent manner. As GTP-binding proteins (G proteins) are thought to be involved in the process of exocytosis and as mastoparan is known to exert at least some of its effects by activation of G proteins, an action of mastoparan to activate the putative stimulatory Ge (exocytosis) protein is likely.
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pubmed:language |
eng
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pubmed:journal | |
pubmed:citationSubset |
IM
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pubmed:chemical |
http://linkedlifedata.com/resource/pubmed/chemical/Calcium,
http://linkedlifedata.com/resource/pubmed/chemical/Forskolin,
http://linkedlifedata.com/resource/pubmed/chemical/Hydroquinones,
http://linkedlifedata.com/resource/pubmed/chemical/Insulin,
http://linkedlifedata.com/resource/pubmed/chemical/Nitrendipine,
http://linkedlifedata.com/resource/pubmed/chemical/Peptides,
http://linkedlifedata.com/resource/pubmed/chemical/Pertussis Toxin,
http://linkedlifedata.com/resource/pubmed/chemical/Terpenes,
http://linkedlifedata.com/resource/pubmed/chemical/Thapsigargin,
http://linkedlifedata.com/resource/pubmed/chemical/Virulence Factors, Bordetella,
http://linkedlifedata.com/resource/pubmed/chemical/Wasp Venoms,
http://linkedlifedata.com/resource/pubmed/chemical/mastoparan
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pubmed:status |
MEDLINE
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pubmed:month |
Nov
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pubmed:issn |
0021-9258
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pubmed:author | |
pubmed:issnType |
Print
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pubmed:day |
5
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pubmed:volume |
268
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pubmed:owner |
NLM
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pubmed:authorsComplete |
Y
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pubmed:pagination |
23297-306
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pubmed:dateRevised |
2011-11-17
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pubmed:meshHeading |
pubmed-meshheading:8226853-Animals,
pubmed-meshheading:8226853-Calcium,
pubmed-meshheading:8226853-Cell Line,
pubmed-meshheading:8226853-Exocytosis,
pubmed-meshheading:8226853-Forskolin,
pubmed-meshheading:8226853-Hydroquinones,
pubmed-meshheading:8226853-Insulin,
pubmed-meshheading:8226853-Islets of Langerhans,
pubmed-meshheading:8226853-Nitrendipine,
pubmed-meshheading:8226853-Peptides,
pubmed-meshheading:8226853-Pertussis Toxin,
pubmed-meshheading:8226853-Rats,
pubmed-meshheading:8226853-Secretory Rate,
pubmed-meshheading:8226853-Terpenes,
pubmed-meshheading:8226853-Thapsigargin,
pubmed-meshheading:8226853-Virulence Factors, Bordetella,
pubmed-meshheading:8226853-Wasp Venoms
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pubmed:year |
1993
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pubmed:articleTitle |
Mastoparan stimulates exocytosis at a Ca(2+)-independent late site in stimulus-secretion coupling. Studies with the RINm5F beta-cell line.
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pubmed:affiliation |
Department of Pharmacology, College of Veterinary Medicine, Cornell University, Ithaca, New York 14853.
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pubmed:publicationType |
Journal Article,
In Vitro
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