Protein kinases: Tuners of the BKCa channel in smooth muscle

Large-conductance, Ca2+-activated K+ (BKCa) channels in smooth muscle cells are unique because they integrate changes in both intracellular Ca2+ and membrane potential. Protein kinases such as cAMP-dependent protein kinase, cGMP-dependent protein kinase and protein kinase C can affect tissue function by 'tuning' the apparent Ca2+- and/or voltage-sensitivity of the BKCa channel to physiological changes in both Ca2+ concentrations and membrane potential. However, despite the central importance of kinase-mediated modulation of BKCa channels in different smooth muscle tissues, many key issues, including the sites and mechanisms of actions of protein kinases, remain unresolved. In this article, the role of protein kinases in the regulation of BKCa channels is discussed.