Figure 2.

Cell type–specific modulation of Kv4.2-encoded I_A channels by accessory (dipeptidyl peptidase-like protein 6 [DPP6]) subunits. Schematic representation of Kv4.2 (red) distribution in hippocampal pyramidal neurons (PN) and cerebellar granule cells (GC) in wild type (WT) mice and in mice lacking DPP6. (A) In WT neurons, Kv4.2 (red) expression and I_A densities display a somatodendritic gradient, increasing from the proximal to distal segments (Chen and others 2006; Sheng and others 1992). Targeted deletion of DPP6 (DPP6^−/−) eliminates the somatodendritic gradient of Kv4.2 expression and I_A densities and increases the amplitudes of bAPs without altering I_A or intrinsic excitability in the soma (Sun and others 2011). (B) In WT cerebellar granule cells, in contrast, I_A is robustly expressed in the soma and acute “knockdown” of DPP6 reduces somatic I_A densities and alters action potential waveforms recorded from the soma (Nadin and Pfaffinger 2010).