Role of the ISK protein in the IminK channel complex.

The ISK (also called minK) protein, although it is structurally unrelated to any other ion channel subunit, induces slowly activating, voltage-dependent K+ channels (IminK) in Xenopus oocytes or HEK293 cells. The quaternary structure of the IminK channel complex has long remained a mystery, but recent studies suggest an interaction of the ISK protein with a traditional K+ channel subunit, identified in man as KVLQT1. It is unclear at this point what the mechanism of this interaction is, or whether the ISK protein may also interact with other ion channel subunits. However, there is an abundance of information regarding the role and regulation of the ISK protein in the IminK channel complex, discussed in this review by Andreas Busch and Hartmut Suessbrich. The ISK protein is expressed in different tissues, where IminK activation may have distinct net effects on cell function. This fact makes IminK an excellent target for pharmacological agents.