Islet complex lipids: involvement in the actions of group VIA calcium-independent phospholipase A(2) in beta-cells

Diabetes. 2004 Feb;53 Suppl 1(0 1):S179-85. doi: 10.2337/diabetes.53.2007.s179.

Abstract

The beta-isoform of group VIA calcium-independent phospholipase A(2) (iPLA(2)beta) does not require calcium for activation, is stimulated by ATP, and is sensitive to inhibition by a bromoenol lactone suicide substrate. Several potential functions have been proposed for iPLA(2)beta. Our studies indicate that iPLA(2)beta is expressed in beta-cells and participates in glucose-stimulated insulin secretion but is not involved in membrane phospholipid remodeling. If iPLA(2)beta plays a signaling role in glucose-stimulated insulin secretion, then conditions that impair iPLA(2)beta functions might contribute to the diminished capacity of beta-cells to secrete insulin in response to glucose, which is a prominent characteristic of type 2 diabetes. Our recent studies suggest that iPLA(2)beta might also participate in beta-cell proliferation and apoptosis and that various phospholipid-derived mediators are involved in these processes. Detailed characterization of the iPLA(2)beta protein level reveals that beta-cells express multiple isoforms of the enzyme, and our studies involve the hypothesis that different isoforms have different functions.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.
  • Review

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Ankyrins / chemistry
  • Calcium / physiology
  • Islets of Langerhans / enzymology
  • Islets of Langerhans / physiology*
  • Molecular Sequence Data
  • Phospholipases A / chemistry
  • Phospholipases A / classification
  • Phospholipases A / metabolism*
  • Phospholipids / metabolism*
  • Rats

Substances

  • Ankyrins
  • Phospholipids
  • Phospholipases A
  • Calcium