Fig. 6: A combined activation mechanism of AtSLAC1.

The combined activation model consists of the initial dissociation phase (inhibition-release) and the subsequent activation phase (binding-activation). In the dissociation phase, phosphorylation of the TMD-distal ICD causes destabilization of the plug and latch. In the activation phase, negatively charged phospho-serine/threonine residues on the TMD-distal ICD are perceived by the positively charged ICL2, leading to the intracellular helical rearrangement. TMD in the closed state is colored in yellow and that in the open state in teal; and TMD in the closed state when overlapped with that in the open state in pale gray. ICL2 in blue and ICL3 in red; the plug in pink, the latch in cyan and the patch 1 in green. Numbers indicate TM numbers. The positively charged residues are denoted as pluses in open circles and the phosphorylated residues as P in yellow filled circles. Thick curved black arrows indicate plausible conformational changes. Unstructured regions are depicted as dotted thick lines in corresponding colors. The pore is shown as black dotted lines. Membrane is described as two gray lines. Ext extracellular side, and int intracellular side. See the text for details.