Mice disrupted for the KvLQT1 potassium channel regulator IsK gene accumulate mature T cells

The IsK protein associates with KvLQT1 potassium channels to generate the s low component of the outward rectifying K+ current involved in human cardia c repolarization, Mutations in either KCNE1 (encoding IsK) or KCNQ1 (encodi ng KvLQT1) genes have been associated with the long QT syndrome, a genetic disorder leading to prolonged cardiac repolarization and sudden death. We n ow report that the IsK protein is also involved in mature T cell homeostasi s, In KCNE1 gene knockout mice, we observed a significant increase in the T cell compartment, Thymus and peripheral lymphoid organs of KCNE1-/- mice d isplayed a significant increase in mature T cells, The immunological phenot ype of KCNE1-/- is age-dependent and only expressed in adult mice. Both IsK and KvLQT1 mRNA are expressed in murine thymus, Our data suggest that, in addition to its role in myocardial repolarization, the IsK-KvLQT1 tandem al so plays a crucial role in T cell homeostasis, (C) 2001 Academic Press.