Expression of Ca²⁺-Binding Buffer Proteins in the Human and Mouse Retinal Neurons

Ca²⁺-binding buffer proteins (CaBPs) are widely expressed by various neurons throughout the central nervous system (CNS), including the retina. While the expression of CaBPs by photoreceptors, retinal interneurons and the output ganglion cells in the mammalian retina has been extensively studied, a general description is still missing due to the differences between species, developmental expression patterns and study-to-study discrepancies. Furthermore, CaBPs are occasionally located in a compartment-specific manner and two or more CaBPs can be expressed by the same neuron, thereby sharing the labor of Ca²⁺ buffering in the intracellular milieu. This article reviews this topic by providing a framework on CaBP functional expression by neurons of the mammalian retina with an emphasis on human and mouse retinas and the three most abundant and extensively studied buffer proteins: parvalbumin, calretinin and calbindin.