- Synthetic peptide mapping to the 3rd extracellular loop of human KCNN4 (Accession O15554).
Human CD8+ T cells (Chimote, A.A. et al. (2018) Sci. Signal. 11, 527.).
- Live intact human LNCaP prostate carcinoma cells.
- Expression of KCNN4 in live intact human LNCaP prostate carcinoma cellsCell surface detection (green) of KCNN4 in live intact human LNCaP prostate carcinoma cells with Mouse Anti-KCNN4 (KCa3.1, SK4) (extracellular)-ATTO Fluor-488 Antibody (#ALM-051-AG), (1:15) (A). B. Live view of the cells. C. Merge of the two images.
KCa3.1 (KCNN4, SK4) is a member of the Ca2+ activated K+ channel family that shares the characteristic of being activated by intracellular Ca2+. The channel has an intermediate conductance, is voltage insensitive and is activated by Ca2+ in the submicromolar range. The channel has a similar topology to that of KV channels, that is, six transmembrane domains and intracellular N- and C-termini.
KCa3.1 is widely expressed in epithelial, endothelial and cells of hematopoietic origin. In erythrocytes (red blood cells) it has been identified as the molecular correlate of the so-called Gardos channel.
The functional role of the channel is to set the cell membrane potential at negative values so as to aid in the electrochemical transport of other ions such as Cl- and Ca2+. Indeed, KCa3.1 has a key role in sustaining the Ca2+ influx in activated T lymphocytes and in regulating Cl- secretion from colon epithelium. Therefore, specific blockers of the KCa3.1 channel have been proposed for the treatment of several diseases including autoimmune diseases, secretory diarrhea and sickle cell anemia.