The microtubule-associated protein END BINDING1b, auxin, and root responses to mechanical cues

The microtubule associated protein END BINDING1b (EB1b) is a regulator of root responses to mechanical cues. Here, three studies aimed at understanding the role of EB1b in these processes are presented. First, the relationship between EB1b and auxin during root responses to mechanical cues was assessed. The results suggest that EB1b and auxin transport/signaling affect root responses by different mechanisms. Next, the effects of altered EB1b expression levels and protein structure on root responses were investigated. Overexpression of EB1b reduced root responses, and the addition of GFP to the carboxy terminus of the protein abolished its ability to act as a repressor. Finally, evidence was obtained that supports a model in which root responses to mechanical cues are modulated by two competing processes, one activating and one repressing. In this model, repression by EB1b would provide a threshold which touch stimulation must overcome to elicit a response.