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Non‐canonical AUX/IAA protein IAA33 competes with canonical AUX/IAA repressor IAA5 to negatively regulate auxin signaling
First author: Bingsheng Lv; Affiliations: Shandong University (山東大學): Qingdao, China
Corresponding author: Zhaojun Ding
The phytohormone auxin controls plant growth and development via TIR1‐dependent protein degradation of canonical AUX/IAA proteins, which normally repress the activity of auxin response transcription factors (ARFs). IAA33 is a non‐canonical AUX/IAA protein lacking a TIR1‐binding domain, and its role in auxin signaling and plant development is not well understood. Here, we show that IAA33 maintains root distal stem cell identity and negatively regulates auxin signaling by interacting with ARF10 and ARF16. IAA33 competes with the canonical AUX/IAA repressor IAA5 for binding to ARF10/16 to protect them from IAA5‐mediated inhibition. In contrast to auxin‐dependent degradation of canonical AUX/IAA proteins, auxin stabilizes IAA33 protein via MITOGEN‐ACTIVATED PROTEIN KINASE 14 (MPK14) and does not affect IAA33 gene expression. Taken together, this study provides insight into the molecular functions of non‐canonical AUX/IAA proteins in auxin signaling transduction.
植物激素生長素通過TIR1依賴性的典型AUX/IAA蛋白降解來控制植物的生長和發育,而這些典型AUX/IAA蛋白通常情況下會抑制植物生長素反應轉錄因子ARF蛋白的活性。IAA33是一種缺乏TIR1結合域的非典型AUX/IAA蛋白,其在植物生長素信號轉導和發育中的作用尚不清楚。本文中,作者的研究顯示IAA33通過與ARF10/16相互作用來維持根末端幹細胞特徵,並負調節生長素信號轉導。IAA33與典型AUX/IAA抑制子IAA5競爭與ARF10/16的結合,從而保護其免受IAA5介導的抑制。與生長素介導的典型AUX/IAA蛋白降解相反,生長素通過絲裂原活化蛋白激酶MPK14維持IAA33蛋白的穩定,並且不影響IAA33基因的表達。綜上,該研究為非典型AUX/IAA蛋白在生長素信號轉導中的分子功能提供了新的視野。
通訊:丁兆軍(http://www.lifesci.sdu.edu.cn/info/1062/1658.htm)
個人簡介:1998年,聊城大學,學士;2003年,中國科學院植物研究所,博士;2004-2011年,德國馬普植物育種所、比利時根特大學,博士後。
研究方向:主要是從植物激素尤其是生長素和細胞分裂素調控的角度,綜合利用遺傳學、細胞學和分子生物學、轉錄組學和蛋白組學等各種手段,研究植物根在鋁,鉻及營養缺陷等各種非生物逆境脅迫條件下根尖幹細胞和根的可塑性生長發育的分子調控機制。
doi: https://doi.org/10.15252/embj.2019101515
Journal: The EMBO Journal
Published date: October 16, 2019