Figure 1.

BRAG1 binds Ca²⁺-free calmodulin. A, Domain organization of the three BRAG family members. B, Consensus sequence for IQ motifs, compared with the IQ-like motif in wild-type BRAG1. The bottom sequence shows mutations introduced to generate BRAG1-IQ. C, CaM binding to wild-type and mutant BRAG1. HeLa cells were transiently transfected with myc-tagged BRAG1-WT, BRAG1-EK, BRAG1-IQ, or BRAG1-ΔN and lysed in the presence of either 2 mm EGTA or 2 mm CaCl₂. Cell lysates were then incubated with CaM-Sepharose, and BRAG1 binding was analyzed by anti-myc immunoblotting. Binding was quantified by densitometry. The signal for BRAG1-WT was normalized to a value of 1 and relative binding values are shown. The blot shown is representative of three independent experiments.