PT  - JOURNAL ARTICLE
AU  - Lin Sun
AU  - Elena Feraru
AU  - Mugurel I. Feraru
AU  - Krzysztof Wabnik
AU  - Jürgen Kleine-Vehn
TI  - PIN-LIKES coordinate brassinosteroid signalling with nuclear auxin input in <em>Arabidopsis thaliana</em>
AID  - 10.1101/646489
DP  - 2019 Jan 01
TA  - bioRxiv
PG  - 646489
4099  - http://biorxiv.org/content/early/2019/07/19/646489.short
4100  - http://biorxiv.org/content/early/2019/07/19/646489.full
AB  - Auxin and brassinosteroids (BR) are crucial growth regulators and display overlapping functions during plant development. Here, we reveal an alternative phytohormone crosstalk mechanism, revealing that brassinosteroid signaling controls nuclear abundance of auxin. We performed a forward genetic screen for imperial pils (imp) mutants that enhance the overexpression phenotypes of PIN-LIKES (PILS) putative intracellular auxin transport facilitator. Here we report that the imp1 mutant is defective in the brassinosteroid-receptor BRI1. Our data reveals that BR signaling transcriptionally and posttranslationally represses accumulation of PILS proteins at the endoplasmic reticulum, thereby increasing nuclear abundance and signaling of auxin. We demonstrate that this alternative phytohormonal crosstalk mechanism integrates BR signaling into auxin-dependent organ growth rates and likely has widespread importance for plant development.