Inward rectifier potassium (Kir) channels in the retina: living our vision

Channel proteins are vital for conducting ions throughout the body and are especially relevant to retina physiology. Inward rectifier potassium (Kir) channels are a class of K thorn channels responsible for maintaining membrane potential and extracellular K thorn concentrations. Studies of the KCNJ gene (that encodes Kir protein) expression identified the presence of all of the subclasses (Kir 1-7) of Kir channels in the retina or retinal-pigmented epithelium (RPE). However, functional studies have established the involvement of the Kir4.1 homotetramer and Kir4.1/5.1 heterotetramer in Mueuroller glial cells, Kir2.1 in bipolar cells, and Kir7.1 in the RPE cell physiology. Here, we propose the potential roles of Kir channels in the retina based on the physiological contributions to the brain, pancreatic, and cardiac tissue functions. There are several open questions regarding the expressed KCNJ genes in the retina and RPE. For example, why does not the Kir channel subtype gene expression correspond with protein expression? Catching up with multiomics or functional omics approaches might shed light on posttranscriptional changes that might influence Kir subunit mRNA translation within the retina that guides our vision.

Automated summary

This article discusses the potential roles of Kir channels in the retina and their connections with the functions of other tissues. Studies on the expression of KCNJ genes have identified the presence of all subclasses of Kir channels in the retina and RPE. However, the inconsistency between the expression of subtype genes and protein expression remains a mystery. The use of multiomics or functional omics approaches can shed light on posttranscriptional changes that may influence Kir subunit mRNA translation in the retina.