Potassium Large Conductance Calcium Activated Channel Subfamily M Beta 2 (KCNMb2)

Sequence analysis predicted that the 235-amino acid KCNMB2 protein, which shares 43% amino acid identity and 53% similarity with KCNMB1, is distinct from KCNMB1 in that it contains an N-terminal extension of 31 amino acids, a slightly longer extracellular loop, and 5 additional amino acids at the C terminus. Like KCNMB1, it has 2 putative transmembrane domains, 3 potential N-glycosylation sites, and 4 conserved cys residues. RNA dot blot analysis revealed high expression of KCNMB2 in fetal but not adult kidney.Whereas the MaxiK alpha subunit (KCNMA1) alone produces sustained currents that do not inactivate, coexpression of KCNMA1 with KCNMB2 induced fast inactivating currents that could be increased by voltage and intracellular calcium.