Localization in the cell of the protein forming ATP-dependent potassium-selective channels in a bilayer lipid membrane. An ultrastructural study

The localization in cell of the protein forming in BLM the ATP-dependent potassium-selective channels was studied. The electron-microscopic investigation of rat liver and heart tissue sections after their incubation with Abs against the studied protein and visualization of the protein with secondary Abs conjugated with colloid gold were carried out. The colloid gold particles were observed both in mitochondrial membranes and in membranes of endoplasmic and sarcoplasmic reticulum. In heart mitochondria these particles were significantly greater then in liver mitochondria. The detection of the channel-protein localization both in mitochondria and reticulum, as well as structural similarity between the mitochondrial channel and the precursor of calreticulin suggests that the channel protein belongs to the calreticulin family. The possible function of the studied protein as a channel subunit of the mitochondrial ATP-dependent potassium channel is discussed.