CALP2 TFA is a calmodulin (CaM) antagonist (Kd of 7.9 µM) with high affinity for binding to the CaM EF-hand/Ca2+-binding site. CALP2 TFA inhibits CaM-dependent phosphodiesterase activity and increases intracellular Ca2+ concentrations. CALP2 TFA potently inhibits of adhesion and degranulation. CALP2 TFA is also a strong activator of alveolar macrophages.