2‐Aminoethoxydiphenyl borate (2‐APB) is a reliable blocker of store‐operated Ca 2+ entry but an inconsistent inhibitor of InsP 3 ‐induced Ca 2+ release

ABSTRACT Since its introduction to Ca 2+ signaling in 1997, 2‐aminoethoxydiphenyl borate (2‐APB) has been used in many studies to probe for the involvement of inositol 1,4,5‐trisphosphate receptors in the generation of Ca 2+ signals. Due to reports of some nonspecific actions of 2‐APB, and the fact that its principal antagonistic effect is on Ca 2+ entry rather than Ca 2+ release, this compound may not have the utility first suggested. However, 2‐APB has thrown up some interesting results, particularly with respect to store‐operated Ca 2+ entry in nonexcitable cells. These data indicate that although it must be used with caution, 2‐APB can be useful in probing certain aspects of Ca 2+ signaling.—Bootman, M.…