Inhibition of phosphatases and increased Ca2+ channel activity by inositol hexakisphosphate

Research output: Contribution to journalArticlepeer-review


  • Olof Larsson
  • Christopher J. Barker
  • Åke Sjöholm
  • Håkan Carlqvist
  • Alejandro Bertorello
  • Thomas Nilsson
  • Richard E. Honkanen
  • Georg W. Mayr
  • Jean Zwiller
  • Per Olof Berggren

Colleges, School and Institutes

External organisations

  • Department of Medicine, Center for Molecular Medicine, Karolinska Institutet, Karolinska University Hospital, Stockholm, Sweden.
  • Novum Unit
  • School of Biochemistry
  • University of South Alabama
  • University Hospital of Hamburg-Eppendorf


Inositol hexakisphosphate (InsP6), the dominant inositol phosphate in insulin-secreting pancreatic β cells, inhibited the serine-threonine protein phosphatases type 1, type 2A, and type 3 in a concentration-dependent manner. The activity of voltage-gated L-type calcium channels is increased in cells treated with inhibitors of serine-threonine protein phosphatases. Thus, the increased calcium channel activity obtained in the presence of InsP6 might result from the inhibition of phosphatase activity. Glucose elicited a transient increase in InsP6 concentration, which indicates that this inositol polyphosphate may modulate calcium influx over the plasma membrane and serve as a signal in the pancreatic β cell stimulus-secretion coupling.


Original languageEnglish
Pages (from-to)471-474
Number of pages4
Issue number5337
Publication statusPublished - 17 Oct 1997

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