Fig. 4. The PKC constructs retain biological activity. Eggs were incubated in Sr²⁺-containing medium 2 hours after microinjection of CA-^E25PKC cRNA (n=20). Eggs that had not been injected with the PKC construct showed a typical spiking pattern, which led to a completion of meiosis (n=20). However, following Sr²⁺ addition, eggs expressing CA-^E25PKC showed an immediate and long-lasting elevation in the fura2 signal, consistent with the reported role of PKCs in SOCE (Halet et al., 2004). We conclude that the PKC constructs used here retain biological activity.