Figure 6.

Calcium imaging of intracellular loop 3 mutants. (A) Homology model of melanopsin depicting the region of mutations (darker purple color on the cytoplasmic extension of transmembrane helix 6) in the mutant melanopsin 280–285 Alanine, in which amino acids 280–285 are mutated to alanine residues. (B) Homology model depicting the electrostatic charge of the third cytoplasmic loop in wild-type melanopsin and (C) the mutant melanopsin ICL3 Null, in which all positively charged residues were mutated to alanines to neutralize the charge of this region (blue: positively charged; red: negatively charged; white: neutral). (D) Calcium imaging of melanopsin and the mutants depicted in (A) and (C). Error bars represent SEM of three independent transfections.