Subthreshold-activating somatodendritic A-type potassium channels have fundamental roles in neuronal signaling and plasticity which depend on their unique cellular localization, voltage dependence, and kinetic properties. Some of the components of A-type K(+) channels have been identified; however, these do not reproduce the properties of the native channels, indicating that key molecular factors have yet to be unveiled. We purified A-type K(+) channel complexes from rat brain membranes and found that DPPX, a protein of unknown function that is structurally related to the dipeptidyl aminopeptidase and cell adhesion protein CD26, is a novel component of A-type K(+) channels. DPPX associates with the channels' pore-forming subunits, facilitates their trafficking and membrane targeting, reconstitutes the properties of the native channels in heterologous expression systems, and is coexpressed with the pore-forming subunits in the somatodendritic compartment of CNS neurons.
Nadal MS, Ozaita A, Amarillo Y, Vega-Saenz de Miera E, Ma Y, Mo W, Goldberg EM, Misumi Y, Ikehara Y, Neubert TA, Rudy B (2003) The CD26-related dipeptidyl aminopeptidase-like protein DPPX is a critical component of neuronal A-type K+ channels Neuron37: 449-61
Nadal MS, Ozaita A, Amarillo Y, Vega-Saenz de Miera E, Ma Y, Mo W, Goldberg EM, Misumi Y, Ikehara Y, Neubert TA, Rudy B (2003) Neuron37: 449-61