ESYT1 and breast carcinoma: In ER+ breast cancer MCF7 cells, E-Syt1 or E-Syt2 knockdown was without effect on TG-induced Ca2+ release from the internal stores but significantly attenuated Ca2+ entry, thus indicating that both proteins are required for the activation of SOCE in this cell line (Figure 2d–f; p < 0.01).