Phosphorylation-independent binding of 14-3-3 to NtCDPK1 by a new mode
Phosphorylation-independent binding of 14-3-3 to NtCDPK1 by a new mode
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DOI：
10.4161/15592324.2014.977721
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发表时间：
2014-01-01
影响因子：
2.9
通讯作者：
Takahashi, Yohsuke
中科院分区：
文献类型：
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作者：
Ito, Takeshi;Nakata, Masaru;Takahashi, Yohsuke
14-3-3蛋白通过与靶蛋白直接结合在多种细胞过程中发挥重要作用。芽生长抑制因子（RSG）是烟草（Nicotiana tabacum）的一个转录因子，参与赤霉素（GA）的反馈调节。14-3-3蛋白依赖于Ser-114的RSG磷酸化而与RSG结合，并通过响应于GA将其隔离在细胞质中来负调节RSG。Ca 2+依赖性蛋白激酶NtCDPK 1被鉴定为RSG激酶，其通过RSG的磷酸化促进14-3-3与RSG的结合。14-33与NtCDPK 1以新的方式弱结合。NtCDPK 1的自身磷酸化是NtCDPK 1与14-3-3结合的形成所必需的，但不是维持结合所必需的。在这项研究中，我们发现，14-3-3结合到NtCDPK 1不需要自磷酸化时，RSG结合到NtCDPK 1。这些数据表明，14-3-3结合到NtCDPK 1中的未磷酸化基序，该基序通过NtCDPK 1中的构象变化而暴露，但不结合到NtCDPK 1的自磷酸化产生的磷酸基团。
14-3-3 proteins play essential roles in diverse cellular processes through the direct binding to target proteins. REPRESSION OF SHOOT GROWTH (RSG) is a tobacco (Nicotiana tabacum) transcription factor that is involved in gibberellin (GA) feedback regulation. The 14-3-3 proteins bind to RSG depending on the RSG phosphorylation of Ser-114 and negatively regulate RSG by sequestering it in the cytoplasm in response to GAs. The Ca2+-dependent protein kinase NtCDPK1 was identified as an RSG kinase that promotes 14-3-3 binding of RSG by phosphorylation of RSG. 14-33 weakly binds to NtCDPK1 by a new mode. The autophosphorylation of NtCDPK1 was necessary for the formation of the binding between NtCDPK1 and 14-3-3 but not for its maintenance. In this study, we showed that 14-3-3 binding to NtCDPK1 does not require the autophosphorylation when RSG was bound to NtCDPK1. These data suggest that 14-3-3 binds to an unphosphory-lated motif in NtCDPK1 exposed by a conformational change in NtCDPK1 but not to a phosphate group generated by autophosphorylation of NtCDPK1.