Figure 1.

A possible model for the effects of SUMO and Phospho tags on Kv2.1 gating. For simplicity, the cartoon depicts only two subunits of the Kv2.1 tetramer and shows intersubunit N/C interaction between only the N terminus of the green subunit and the C terminus of the blue subunit. Panels show Kv2.1 in both closed and open states: (A) lacking C-terminal modification; (B) with a SUMO tag only; (C) with Phospho tags only; and (D) with both SUMO and Phospho tags. The presence or absence of SUMO and Phospho tags affects the affinity of N/C interaction, which then impacts the closed-to-open–state transitions in the Kv2.1 channel that involve movement of N and C termini away from one another. These effects of SUMO and Phospho tags are reflected in the shifts in the voltage-dependent activation curves depicted in the top panel.