TY - JOUR T1 - Interdomain Cytoplasmic Interactions Govern the Intracellular Trafficking, Gating, and Modulation of the Kv2.1 Channel JF - The Journal of Neuroscience JO - J. Neurosci. SP - 4982 LP - 4994 DO - 10.1523/JNEUROSCI.0186-08.2008 VL - 28 IS - 19 AU - Durga P. Mohapatra AU - Dominic F. Siino AU - James S. Trimmer Y1 - 2008/05/07 UR - http://www.jneurosci.org/content/28/19/4982.abstract N2 - Voltage-gated potassium (Kv) channels comprise four transmembrane α subunits, often associated with cytoplasmic β subunits that impact channel expression and function. Here, we show that cell surface expression, voltage-dependent activation gating, and phosphorylation-dependent modulation of Kv2.1 are regulated by cytoplasmic N/C interaction within the α subunit. Kv2.1 surface expression is greatly reduced by C-terminal truncation. Tailless Kv2.1 channels exhibit altered voltage-dependent gating properties and lack the bulk of the phosphorylation-dependent modulation of channel gating. Remarkably, the soluble C terminus of Kv2.1 associates with tailless channels and rescues their expression, function, and phosphorylation-dependent modulation. Soluble N and C termini of Kv2.1 can also interact directly. We also show that the N/C-terminal interaction in Kv2.1 is governed by a 34 aa motif in the juxtamembrane cytoplasmic C terminus, and a 17 aa motif located in the N terminus at a position equivalent to the β subunit binding site in other Kv channels. Deletion of either motif disrupts N/C-terminal interaction and surface expression, function, and phosphorylation-dependent modulation of Kv2.1 channels. These findings provide novel insights into intrinsic mechanisms for the regulation of Kv2.1 trafficking, gating, and phosphorylation-dependent modulation through cytoplasmic N/C-terminal interaction, which resembles α/β subunit interaction in other Kv channels. ER -