Calcium-dependent translocation of cytosolic phospholipase A2 in pancreatic beta-cells

Biochem Biophys Res Commun. 2003 Jan 24;300(4):889-93. doi: 10.1016/s0006-291x(02)02969-8.

Abstract

Cytosolic phospholipase A(2)(cPLA(2)), an enzyme responsible for the generation of arachidonic acid, is located in the cytosolic compartment in most tissues and it translocates to membrane compartments when activated. We found that cPLA(2) distribution in pancreatic beta-cells is different from that of most other mammalian cells: it is evenly distributed throughout the beta-cell, in both cytoplasmic and nuclear compartments. Agents that increased intracellular Ca(2+) in the MIN6 beta-cell line also stimulated a redistribution of cPLA(2) immunoreactivity such that the majority of the enzyme moved from the nucleus to the cytoplasm. The time course of events was compatible with the elevation in Ca(2+) being responsible for translocation of cPLA(2). These observations suggest that cPLA(2) may be compartmentalised in unstimulated beta-cells, perhaps to limit its access to substrate prior to elevations in intracellular Ca(2+).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Calcium / metabolism*
  • Cell Nucleus / metabolism
  • Cytoplasm / enzymology*
  • Cytoplasm / metabolism
  • Humans
  • Hypoglycemic Agents / pharmacology
  • Immunohistochemistry
  • Islets of Langerhans / cytology
  • Islets of Langerhans / drug effects
  • Islets of Langerhans / enzymology*
  • Phospholipases A / metabolism*
  • Phospholipases A2
  • Protein Transport*
  • Time Factors
  • Tolbutamide / pharmacology
  • Tumor Cells, Cultured

Substances

  • Hypoglycemic Agents
  • Tolbutamide
  • Phospholipases A
  • Phospholipases A2
  • Calcium