The current study examined the signal transduction steps involved in the selective release of arachidonic acid (AA) induced by the addition of secretory phospholipase A 2 (sPLA 2) isotypes to bone marrow-derived mast cells (BMMC). Overexpression of sPLA 2 receptors caused a marked increase in AA and PGD 2 release after stimulation of BMMC, implicating sPLA 2 receptors in this process. The hypothesis that the release of AA by sPLA 2 involved activation of cytosolic PLA 2 (cPLA 2) was next tested. Addition of group IB PLA 2 to BMMC caused a transient increase in cPLA 2 activity and translocation of this activity to membrane fractions. Western analyses revealed that these changes in cPLA 2 were accompanied by a time-dependent gel shift of cPLA 2 induced by phosphorylation of cPLA 2 at various sites. A noncatalytic ligand of the sPLA 2 receptor, p-amino-phenyl-α-d-mannopyranoside BSA, also induced an increase in cPLA 2 activity in BMMC. sPLA 2 receptor ligands induced the phosphorylation of p44/p42 mitogen-activated protein kinase. Additionally, an inhibitor of p44/p42 mitogen-activated protein kinase (PD98059) significantly inhibited sPLA 2-induced cPLA 2 activation and AA release. sPLA 2 receptor ligands also increased Ras activation while an inhibitor of tyrosine phosphorylation (herbimycin) inhibited the increase in cPLA 2 activation and AA release. Addition of partially purified sPLA 2 from BMMC enhanced cPLA 2 activity and AA release. Similarly, overexpression of mouse groups IIA or V PLA 2 in BMMC induced an increase in AA release. These data suggest that sPLA 2 mediate the selective release of AA by binding to cell surface receptors and then inducing signal transduction events that lead to cPLA 2 activation.