TableEdit

Nadal, MS, Ozaita, A, Amarillo, Y, Vega-Saenz de Miera, E, Ma, Y, Mo, W, Goldberg, EM, Misumi, Y, Ikehara, Y, Neubert, TA and Rudy, B (2003) The CD26-related dipeptidyl aminopeptidase-like protein DPPX is a critical component of neuronal A-type K+ channels. Neuron 37:449-61

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.

PubMed

Amino Acid Sequence; Animals; Cell Adhesion/physiology; Cerebellum/cytology; Dendrites/enzymology; Dipeptidyl Peptidase 4/genetics; Extracellular Matrix/metabolism; Membrane Proteins/chemistry; Membrane Proteins/genetics; Membrane Proteins/metabolism; Molecular Sequence Data; Nerve Tissue Proteins/chemistry; Nerve Tissue Proteins/genetics; Nerve Tissue Proteins/metabolism; Neurons/enzymology; Neurons/ultrastructure; Oocytes/physiology; Potassium Channels/chemistry; Potassium Channels/genetics; Potassium Channels/metabolism; Potassium Channels, Voltage-Gated; Precipitin Tests; Protein Transport/physiology; Rats; Rats, Sprague-Dawley; Shal Potassium Channels; Xenopus