Figure 3. AKAP79 directly binds to the leucine zipper motif in the C-terminus of the L-type calcium channel CaV1.2. (A) Amino acid sequence of the leucine zipper like motif in the C-terminal domain of CaV1.2. (B) Top: Schematic representation of the location of the II-III loop and the leucine zipper motif along the CaV1.2 channel sequence. Bottom: Yeast-two hybrid assay between AKAP79 and either the domain II-III linker, or the C-terminal leucine zipper motif of CaV1.2. pGAD was used as a negative control. Note the yeast growth in the leucine zipper/AKAP79 transformation. (C) In vitro binding of 6xHis CaV1.2 C-terminal and 6xHis Cav1.2 leucine zipper to immobilized AKAP79(GST). The western blot was probed using an anti-Xpress antibody (Invitrogen). Both the carboxy terminus and the Leucine Zipper motif bind to AKAP79.