Fig. 1: Coordination of the distinct auxin perception and signaling pathways.
From: The new horizon of plant auxin signaling via cell-surface co-receptors
In response to extracellular auxin (red stars) and intracellular auxin, the plasma membrane ABP1/ABL–TMK co-receptors and the nuclear TIR1/AFB–IAA co-receptor complex play overlapping, antagonizing, or specific roles to control diverse biological processes in plants. Known TMK phosphorylation substrates are marked (P). AFB1 is a newly discovered cytoplasmic auxin receptor. More ABLs could bind auxin and interact with TMKs. K protein kinase domain, ARFs auxin-responsive transcription factors, IAA indole-3-acetic acid, IAAs auxin-responsive repressors, AHA H+-pump ATPase, CNGC14 calcium channel, TAA1 tryptophan aminotransferase of Arabidopsis 1, ABI1/2 ABA-insensitive PP2C.
