Intracellular Ca2+ requirements for zymosan-stimulated phosphoinositide hydrolysis in mouse peritoneal macrophages

The phosphatidylinositol cycle has been demonstrated to be involved in the control of Ca2+ cytosolic levels in several cellular types. The Ca2+ requirements of phospholipase C activity and the described stimulation of phosphoinositide hydrolysis by Ca2+ ionophores make unclear the relationship between phosphatidylinositol cycle and Ca2+ mobilization. The results reported here suggest that intracellular Ca2+ is necessary for zymosan-stimulated phospholipase C activation in macrophages.