CALP3

CALP3, a Ca²⁺-like peptide, is a potent Ca²⁺ channel blocker that activates EF hand motifs of Ca²⁺-binding proteins. CALP3 can functionally mimic increased [Ca²⁺]_i by modulating the activity of Calmodulin (CaM), Ca²⁺ channels and pumps. CALP3 has the potential in controlling apoptosis in diseases such as AIDS or neuronal loss due to ischemia^[1][2]. In Vitro: CALP3 (50, 100, 150, 200 μM) inhibits glutamate caused a large sustained increase in [Ca²⁺]_i in a dose-dependent manner (IC₅₀=37.25 μM) in Fura-2-loaded neuronal cultures^[1].
CALP3 (50, 100, 150, 200 μM) inhibits glutamate-induced cytotoxicity in a dose-dependent manner (IC₅₀=50.97 μM) in cultured rat neocortical neurons. CALP3 causes dose-dependent inhibition of apoptosis (IC₅₀=33.41 μM)^[1].
CALP3 (100 μM) inhibits apoptosis induced by HIV gp120 and SAg in Human T cells^[1].
CALP3 (100?μM; 15?min pretreatment) reduces gossypol-induced necrosis and increases the fraction of live cells^[2].
Cyclic-CALP3 is synthesized starting from Fmoc-Asp(PEG-PS)-OAl. Cyclic CALP3 is unable to inhibit Ca21 influx, and this peptide served as a negative control. Cyclic CALP3 does not inhibit the effect of glutamate^[1].