Many calmodulin-dependent biological phenomena are regulated by calmodulin-dependent phosphorylation and dephosphorylation. In Dictyostelium discoideum, cell and pronuclear fusion during fertilization are both calmodulin-dependent biomembrane fusion events. Calmodulin-dependent phosphorylation and dephosphorylation activity was present in sexually developing D. discoideum cells suggesting it has a role during fertilization. In support of this, a discrete calmodulin-independent kinase was present only during cell and pronuclear fusion.