Advanced

Enhancement of glucagon secretion in mouse and human pancreatic alpha cells by protein kinase C (PKC) involves intracellular trafficking of PKCalpha and PKCdelta.

De Marinis, Yang LU ; Zhang, Enming LU ; Amisten, Stefan LU ; Taneera, Jalal LU ; Renström, Erik LU ; Rorsman, Patrik LU and Eliasson, Lena LU (2010) In Diabetologia 53(4). p.717-729
Abstract
AIMS/HYPOTHESIS: Protein kinase C (PKC) regulates exocytosis in various secretory cells. Here we studied intracellular translocation of the PKC isoenzymes PKCalpha and PKCdelta, and investigated how activation of PKC influences glucagon secretion in mouse and human pancreatic alpha cells. METHODS: Glucagon release from intact islets was measured in static incubations, and the amounts released were determined by RIA. Exocytosis was monitored as increases in membrane capacitance using the patch-clamp technique. The expression of genes encoding PKC isoforms was analysed by real-time PCR. Intracellular PKC distribution was assessed by confocal microscopy. RESULTS: The PKC activator phorbol 12-myristate 13-acetate (PMA) stimulated glucagon... (More)
AIMS/HYPOTHESIS: Protein kinase C (PKC) regulates exocytosis in various secretory cells. Here we studied intracellular translocation of the PKC isoenzymes PKCalpha and PKCdelta, and investigated how activation of PKC influences glucagon secretion in mouse and human pancreatic alpha cells. METHODS: Glucagon release from intact islets was measured in static incubations, and the amounts released were determined by RIA. Exocytosis was monitored as increases in membrane capacitance using the patch-clamp technique. The expression of genes encoding PKC isoforms was analysed by real-time PCR. Intracellular PKC distribution was assessed by confocal microscopy. RESULTS: The PKC activator phorbol 12-myristate 13-acetate (PMA) stimulated glucagon secretion from mouse and human islets about fivefold (p < 0.01). This stimulation was abolished by the PKC inhibitor bisindolylmaleimide (BIM). Whereas PMA potentiated exocytosis more than threefold (p < 0.001), BIM inhibited alpha cell exocytosis by 60% (p < 0.05). In mouse islets, the PKC isoenzymes, PKCalpha and PKCbeta1, were highly abundant, while in human islets PKCeta, PKCepsilon and PKCzeta were the dominant variants. PMA stimulation of human alpha cells correlated with the translocation of PKCalpha and PKCdelta from the cytosol to the cell periphery. In the mouse alpha cells, PKCdelta was similarly affected by PMA, whereas PKCalpha was already present at the cell membrane in the absence of PMA. This association of PKCalpha in alpha cells was principally dependent on Ca(2+) influx through the L-type Ca(2+) channel. CONCLUSIONS/INTERPRETATION: PKC activation augments glucagon secretion in mouse and human alpha cells. This effect involves translocation of PKCalpha and PKCdelta to the plasma membrane, culminating in increased Ca(2+)-dependent exocytosis. In addition, we demonstrated that PKCalpha translocation and exocytosis exhibit differential Ca(2+) channel dependence. (Less)
Please use this url to cite or link to this publication:
author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Diabetologia
volume
53
issue
4
pages
717 - 729
publisher
Springer Verlag
external identifiers
  • wos:000275087100016
  • pmid:20020096
  • scopus:77949268993
ISSN
1432-0428
DOI
10.1007/s00125-009-1635-x
language
English
LU publication?
yes
id
1dc604a7-78c8-4d4c-bdad-c88901813ede (old id 1523488)
alternative location
http://www.ncbi.nlm.nih.gov/pubmed/20020096?dopt=Abstract
date added to LUP
2010-01-12 13:16:22
date last changed
2018-05-29 12:30:19
@article{1dc604a7-78c8-4d4c-bdad-c88901813ede,
  abstract     = {AIMS/HYPOTHESIS: Protein kinase C (PKC) regulates exocytosis in various secretory cells. Here we studied intracellular translocation of the PKC isoenzymes PKCalpha and PKCdelta, and investigated how activation of PKC influences glucagon secretion in mouse and human pancreatic alpha cells. METHODS: Glucagon release from intact islets was measured in static incubations, and the amounts released were determined by RIA. Exocytosis was monitored as increases in membrane capacitance using the patch-clamp technique. The expression of genes encoding PKC isoforms was analysed by real-time PCR. Intracellular PKC distribution was assessed by confocal microscopy. RESULTS: The PKC activator phorbol 12-myristate 13-acetate (PMA) stimulated glucagon secretion from mouse and human islets about fivefold (p &lt; 0.01). This stimulation was abolished by the PKC inhibitor bisindolylmaleimide (BIM). Whereas PMA potentiated exocytosis more than threefold (p &lt; 0.001), BIM inhibited alpha cell exocytosis by 60% (p &lt; 0.05). In mouse islets, the PKC isoenzymes, PKCalpha and PKCbeta1, were highly abundant, while in human islets PKCeta, PKCepsilon and PKCzeta were the dominant variants. PMA stimulation of human alpha cells correlated with the translocation of PKCalpha and PKCdelta from the cytosol to the cell periphery. In the mouse alpha cells, PKCdelta was similarly affected by PMA, whereas PKCalpha was already present at the cell membrane in the absence of PMA. This association of PKCalpha in alpha cells was principally dependent on Ca(2+) influx through the L-type Ca(2+) channel. CONCLUSIONS/INTERPRETATION: PKC activation augments glucagon secretion in mouse and human alpha cells. This effect involves translocation of PKCalpha and PKCdelta to the plasma membrane, culminating in increased Ca(2+)-dependent exocytosis. In addition, we demonstrated that PKCalpha translocation and exocytosis exhibit differential Ca(2+) channel dependence.},
  author       = {De Marinis, Yang and Zhang, Enming and Amisten, Stefan and Taneera, Jalal and Renström, Erik and Rorsman, Patrik and Eliasson, Lena},
  issn         = {1432-0428},
  language     = {eng},
  number       = {4},
  pages        = {717--729},
  publisher    = {Springer Verlag},
  series       = {Diabetologia},
  title        = {Enhancement of glucagon secretion in mouse and human pancreatic alpha cells by protein kinase C (PKC) involves intracellular trafficking of PKCalpha and PKCdelta.},
  url          = {http://dx.doi.org/10.1007/s00125-009-1635-x},
  volume       = {53},
  year         = {2010},
}