Premium
Oryza sativa actin‐interacting protein 1 is required for rice growth by promoting actin turnover
Author(s) -
Shi Meng,
Xie Yurong,
Zheng Yiyan,
Wang Junmin,
Su Yi,
Yang Qiuying,
Huang Shanjin
Publication year - 2013
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1111/tpj.12065
Subject(s) - cofilin , actin remodeling , mdia1 , actin remodeling of neurons , profilin , microbiology and biotechnology , actin binding protein , actin , depolymerization , actin cytoskeleton , biology , chemistry , cytoskeleton , biochemistry , cell , organic chemistry
Summary Rapid actin turnover is essential for numerous actin‐based processes. However, how it is precisely regulated remains poorly understood. Actin‐interacting protein 1 ( AIP 1) has been shown to be an important factor by acting coordinately with actin‐depolymerizing factor ( ADF )/cofilin in promoting actin depolymerization, the rate‐limiting factor in actin turnover. However, the molecular mechanism by which AIP 1 promotes actin turnover remains largely unknown in plants. Here, we provide a demonstration that AIP 1 promotes actin turnover, which is required for optimal growth of rice plants. Specific down‐regulation of Os AIP 1 increased the level of filamentous actin and reduced actin turnover, whereas over‐expression of Os AIP 1 induced fragmentation and depolymerization of actin filaments and enhanced actin turnover. In vitro biochemical characterization showed that, although Os AIP 1 alone does not affect actin dynamics, it enhances ADF ‐mediated actin depolymerization. It also caps the filament barbed end in the presence of ADF , but the capping activity is not required for their coordinated action. Real‐time visualization of single filament dynamics showed that Os AIP 1 enhanced ADF ‐mediated severing and dissociation of pointed end subunits. Consistent with this, the filament severing frequency and subunit off‐rate were enhanced in OsAIP1 over‐expressors but decreased in RNA i protoplasts. Importantly, Os AIP 1 acts coordinately with ADF and profilin to induce massive net actin depolymerization, indicating that AIP 1 plays a major role in the turnover of actin, which is required to optimize F‐actin levels in plants.