The expression and function of a group VIA calcium-independent phospholipase A2 (iPLA2beta) in beta-cells.
Many cells express a Group VIA phospholipase A2, designated iPLA2beta, that does not require calcium for activation, is stimulated by ATP, and is sensitive to inhibition by a bromoenol lactone suicide substrate (BEL). Studies in various cell systems have led to the suggestion that iPLA2beta has a role in phospholipid remodeling, signal transduction, cell proliferation, and apoptosis. We have found that pancreatic islets, beta-cells, and glucose-responsive insulinoma cells express an iPLA2beta that participates in glucose-stimulated insulin secretion but is not involved in membrane phospholipid remodeling. Additionally, recent studies reveal that iPLA2beta is involved in pathways that contribute to beta-cell proliferation and apoptosis, and that various phospholipid-derived mediators are involved in these processes. Detailed characterization of the enzyme suggests that the beta-cells express multiple isoforms of iPLA2beta, and we hypothesize that these participate in different cellular functions.
Turk
John
J
Mass Spectometry Resource, Division of Endocrinology, Metabolism and Lipid Research, Department of Medicine, Washington University School of Medicine, St. Louis, MO 63110, USA.
Ramanadham
Sasanka
S
D000595:Amino Acid Sequence / Q000235:genetics; D000818:Animals; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology*; D054522:Group VI Phospholipases A2; D006801:Humans; D007515:Islets of Langerhans / Q000166:cytology / Q000378:metabolism*; D008969:Molecular Sequence Data; D010741:Phospholipases A / Q000096:biosynthesis* / Q000235:genetics; D054467:Phospholipases A2
D010741:Phospholipases A; D054522:Group VI Phospholipases A2; C516475:PLA2G6 protein, human; D054467:Phospholipases A2