FIGURE 8.
Current-voltage relationship of Ch-43* and deletion constructs Ch-e43 and Ch-ΔICDI, co-expressed with ICDI-containing peptide. A, schematic representation of the various constructs. The channel backbone consists of CaV1.2 (white box), whereas the cytosolic tail consists of CaV1.4 containing exon 43* (Ch-43*) or deleted at amino acid positions 1718 (Ch-e43) or 1878 (Ch-ΔICDI). A co-expression construct consisting of a 100-amino acid peptide encompassing the ICDI fused to the mCherry fluorescent protein (ICDI-mCherry). The stop codon for 43* is indicated by a black filled circle. Amino acid positions are numbered according to the CaV1.4 sequence, GenBankTM accession number NP005174. B–D, normalized I-V plots for IBa of Ch-43*, Ch-e43, and Ch-ΔICDI co-expressed with either ICDI-mCherry (black) or mCherry (gray). The curves were fitted with the equation described under “Experimental Procedures.” In parentheses are the numbers of cells recorded. E–G, same as B–D but for ICa.