Detection of secretory phospholipase A2s related but not identical to type IIA isozyme in cultured mast cells.
We previously reported that BALB/cJ mouse-derived bone marrow-derived mast cells (BMMC) exhibited two sequential phases of prostaglandin D2 (PGD2) generation in response to Fc(epsilon) receptor I (Fc(epsilon)RI) crosslinking and cytokine stimulation, the late phase of which was suppressed by an antibody raised against type IIA secretory phospholipase A2 (sPLA2). Here we report that BMMC derived from C57BL/6J mice, which are genetically deficient in type IIA sPLA2, display both immediate and delayed PGD2 generation normally. Lysates of C57BL/6J-derived BMMC contained a Ca2+-dependent PLA2 that was absorbed to a column conjugated with anti-type IIA sPLA2 antibody and had a similar molecular mass of 14 kDa, as assessed by immunoblotting. Therefore we speculate that a sPLA2 similar to, but distinct from, type IIA sPLA2 would compensate for type IIA sPLA2 deficiency in C57BL/6J-derived BMMC. We found that the two type IIA-related sPLA2 family members, type V and type IIC sPLA2s, were expressed in BMMC as well as in rat mastocytoma RBL-2H3 cells.
Murakami
M
M
Department of Health Chemistry, School of Pharmaceutical Sciences, Showa University, Tokyo, Japan.
Tada
K
K
Shimbara
S
S
Kambe
T
T
Sawada
H
H
Kudo
I
I
D000818:Animals; D001854:Bone Marrow Cells; D002478:Cells, Cultured; D051546:Cyclooxygenase 2; D005089:Exocytosis; D005796:Genes; D006863:Hydrogen-Ion Concentration; D007527:Isoenzymes / Q000096:biosynthesis / Q000737:chemistry / Q000378:metabolism*; D008407:Mast Cells / Q000201:enzymology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008970:Molecular Weight; D010741:Phospholipases A / Q000737:chemistry / Q000378:metabolism*; D054467:Phospholipases A2; D015230:Prostaglandin D2 / Q000096:biosynthesis; D011451:Prostaglandin-Endoperoxide Synthases / Q000096:biosynthesis; D012333:RNA, Messenger / Q000032:analysis
D007527:Isoenzymes; D012333:RNA, Messenger; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; D010741:Phospholipases A; D054467:Phospholipases A2; D015230:Prostaglandin D2