GCAP2 has been proposed to mediate the Ca2+ -dependent structural changes of ribbons based on the following observations: i) GCAP2 interacts with Ribeye, the main protein component of synaptic ribbons; ii) GCAP2 colocalizes with Ribeye at ribbon synapses; and iii) GCAP2 overexpression in photoreceptor cells achieved by viral infection of retinal explants led to the disassembly of the synaptic ribbon in a high percentage of synaptic terminals [19]. Here, CTBP2 is linked to viral infectious disease.