Regulation of XXXX release and cytosolic phospholipase A2 activation.

@entity1472 @entity22704 @entity19 @entity4515 @entity1426 @entity460 @entity3365 @entity18398
The 85-kDa @entity22704 ( @entity22704 ) mediates agonist-induced @entity1426 release in many cell models, including @entity19 peritoneal macrophages. @entity22704 is regulated by an increase in intracellular @entity460 , which binds to an @entity1472 -terminal C2 domain and induces its translocation to the nuclear envelope and endoplasmic reticulum. Phosphorylation of @entity22704 on S505 by mitogen-activated protein kinases (MAPK) also contributes to activation. In macrophages, zymosan induces a transient increase in intracellular @entity460 and activation of MAPK, which together fully activate @entity22704 and synergistically promote @entity1426 release. There are alternative pathways for regulating @entity22704 in macrophages because @entity4515 and @entity18398 induce @entity1426 release without increasing @entity460 . The baculovirus expression system is a useful model to study @entity22704 activation. Sf9 cells expressing @entity22704 release @entity1426 to either @entity3365 or @entity18398 . @entity22704 is phosphorylated on multiple sites in Sf9 cells, and phosphorylation of S727 is preferentially induced by @entity18398 . However, the phosphorylation sites are non-essential and only S505 phosphorylation partially contributes to @entity22704 activation in this model. Although @entity18398 does not increase intracellular @entity460 in Sf9 cells, @entity460 binding by the C2 domain is necessary for @entity1426 release. @entity3365 and @entity18398 activate @entity22704 by different mechanisms, yet both induce translocation to the nuclear envelope in Sf9 cells. The results demonstrate that alternative regulatory pathways can lead to @entity22704 activation and @entity1426 release.
