The T0 domain of rabbit Kv1.3 regulates steady state channel protein level

The Shaker superfamily encodes voltage-gated potassium (Kv) channels. The a mino (N) terminus is important for channel assembly and mediates fast inact ivation. We recently isolated a Kv channel from rabbit kidney, denoted rabK v1.3 (Yao et aI., J. Clin. Invest. 97, 2525-2533, 1996) and found that dele ting a region (TO domain, amino acids 3-39) proximal to the T1 recognition domain (a,a 42-185) leads to a 13-fold amplification of Ky current as compa red to wild type channels (Yao ct al,, BBRC 249,492-498). Here we show that deleting the TO domain affects neither single channel conductance nor chan nel open probability, Instead, it increases the absolute number of channel proteins present in the membrane. We conclude that the TO N-terminal regula tory region that modulates steady state channel protein density in the plas ma membrane. (C) 1999 Academic Press.