A role for calreticulin in functioning of mitochondrial ATP-dependent potassium channel

Homology of the amino acid sequence of the mitochondrial potassium-transporting protein (MW 57 kDa), having the properties of a channel subunit of the mitochondrial ATP-dependent potassium channel, and calreticulin (MW 55 kDa) was detected by MALDI-TOF-TOF analysis method. Inhibitory analysis of ATP-dependent potassium transport in mitochondria with polyclonal antibodies to calreticulin was carried out. A dose-dependent inhibition of potassium transport in mitochondria by these antibodies was shown. The maximum value of inhibition was 55–60%. Based on these data it is hypothesized that at least two types of ATP-sensitive potassium channels are localized in mitochondrial membrane. It is expected that the type of mitochondrial ATP-dependent potassium channel, which includes homologous calreticulin protein is localized mainly at mitochondrial and reticulum membrane contact sites. © 2014, Pleiades Publishing, Inc.