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Calcium‐Independent Phospholipase A 2 in Rabbit Ventricular Myocytes
Author(s) -
Beckett Caroline S.,
McHowat Jane
Publication year - 2008
Publication title -
lipids
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.601
H-Index - 120
eISSN - 1558-9307
pISSN - 0024-4201
DOI - 10.1007/s11745-008-3201-6
Subject(s) - biology , gene isoform , phospholipase , cytosol , myocyte , phospholipase a , phospholipase a2 , medicine , endocrinology , microbiology and biotechnology , biochemistry , enzyme , gene
We have previously reported that the majority of phospholipase A 2 (PLA 2 ) activity in rabbit ventricular myocytes is membrane‐associated, calcium‐independent (iPLA 2 ), selective for arachidonylated plasmalogen phospholipids and inhibited by the iPLA 2 ‐selective inhibitor bromoenol lactone (BEL). Here, we identified the presence of iPLA 2 in rabbit ventricular myocytes, determined the full length sequences for rabbit iPLA 2 β and iPLA 2 γ and compared their homology to the human isoforms. Rabbit iPLA 2 β encoded a protein with a predicated molecular mass of 74 kDa that is 91% identical to the human iPLA 2 β short isoform. Full length iPLA 2 γ protein has a predicated molecular mass of 88 kDa and is 88% identical to the human isoform. Immunoblot analysis of iPLA 2 β and γ in membrane and cytosolic fractions from rabbit and human cardiac myocytes demonstrated a similar pattern of distribution with both isoforms present in the membrane fraction, but no detectable protein in the cytosol. Membrane‐associated iPLA 2 activity was inhibited preferentially by the R enantiomer of bromoenol lactone [( R )‐BEL], indicating that the majority of activity is due to iPLA 2 γ.