Table of Contents
Advances in Vascular Medicine
Volume 2014, Article ID 689815, 11 pages
http://dx.doi.org/10.1155/2014/689815
Review Article

Diverse Functions of Secretory Phospholipases A2

1Department of Internal Medicine, Division of Endocrinology and Cardiovascular Research Center, University of Kentucky, 900 S. Limestone, 567 Wethington Building, Lexington, KY 40536-0200, USA
2Molecular and Biomedical Pharmacology, University of Kentucky, Lexington, KY 40536-0200, USA

Received 7 May 2014; Accepted 21 June 2014; Published 15 July 2014

Academic Editor: David Tanne

Copyright © 2014 Preetha Shridas and Nancy R. Webb. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Phospholipase A2 enzymes (PLA2s) catalyze the hydrolysis of glycerophospholipids at their sn-2 position releasing free fatty acids and lysophospholipids. Mammalian PLA2s are classified into several categories of which important groups include secreted PLA2s (sPLA2s) and cytosolic PLA2s (cPLA2s) that are calcium-dependent for their catalytic activity and calcium-independent cytosolic PLA2s (iPLA2s). Platelet-activating factor acetylhydrolases (PAF-AHs), lysosomal PLA2s, and adipose-specific PLA2 also belong to the class of PLA2s. Generally, cPLA2 enzymes are believed to play a major role in the metabolism of arachidonic acid, the iPLA2 family to membrane homeostasis and energy metabolism, and the sPLA2 family to various biological processes. The focus of this review is on recent research developments in the sPLA2 field. sPLA2s are secreted enzymes with low molecular weight (with the exception of GIII sPLA2), Ca2+-requiring enzymes with a His-Asp catalytic dyad. Ten enzymatically active sPLA2s and one devoid of enzymatic activity have been identified in mammals. Some of these sPLA2s are potent in arachidonic acid release from cellular phospholipids for the biosynthesis of eicosanoids, especially during inflammation. Individual sPLA2 enzymes exhibit unique tissue and cellular localizations and specific enzymatic properties, suggesting their distinct biological roles. Recent studies indicate that sPLA2s are involved in diverse pathophysiological functions and for most part act nonredundantly.