Endocrinology and Reproductive Physiology Graduate Program, School of Medicine and Public Health, University of Wisconsin, Madison, Wisconsin.
Department of Pediatrics, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin.
Am J Physiol Cell Physiol. 2022 Sep 1;323(3):C772-C782. doi: 10.1152/ajpcell.00112.2022. Epub 2022 Aug 1.
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 channels responsible for maintaining membrane potential and extracellular K concentrations. Studies of the 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 Müller 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 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.
通道蛋白对于在体内传导离子至关重要，尤其与视网膜生理学相关。内向整流钾（Kir）通道是一类负责维持膜电位和细胞外钾浓度的 K 通道。对 基因（编码 Kir 蛋白）表达的研究确定了在视网膜或视网膜色素上皮（RPE）中存在所有亚类（Kir1-7）的 Kir 通道。然而，功能研究已经确立了 Kir4.1 同源四聚体和 Kir4.1/5.1 异源四聚体在 Muller 胶质细胞、Kir2.1 在双极细胞以及 Kir7.1 在 RPE 细胞生理学中的参与。在这里，我们根据对大脑、胰腺和心脏组织功能的生理贡献，提出了 Kir 通道在视网膜中的潜在作用。关于在视网膜和 RPE 中表达的 基因存在几个悬而未决的问题。例如，为什么 Kir 通道亚型基因表达与蛋白表达不对应？采用多组学或功能性“组学”方法可能会揭示影响视网膜内 Kir 亚基 mRNA 翻译的转录后变化，这可能会影响我们的视力。
