The structure, function, and distribution of gap junctions in the retina: Life cycle in health and disease

Gap junctions are essential channels of communication between cells including neurons in the central nervous system. These channels coordinate cell metabolic and electrical functions including such crucial ones for maintaining homeostasis as cell proliferation, differentiation, survival, and apoptosis. They create narrow passageways that allow rapid exchange of small molecules, ions, and secondary messengers between neighboring cells including the retina and optic nerve. Disruption in normal functioning of gap junctions may result in various neurodegenerative disorders. A comprehensive understanding of gap junction composition, function, and regulation is the key in determining novel approaches to neuroprotection and neuroregeneration. Here, we review the structure and the role of gap junctions in the retina and discuss the life cycle of connexins and their involvement in retinal neurodegenerations.