کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
2045615 1073496 2006 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Cytokinins Regulate a Bidirectional Phosphorelay Network in Arabidopsis
موضوعات مرتبط
علوم زیستی و بیوفناوری علوم کشاورزی و بیولوژیک علوم کشاورزی و بیولوژیک (عمومی)
پیش نمایش صفحه اول مقاله
Cytokinins Regulate a Bidirectional Phosphorelay Network in Arabidopsis
چکیده انگلیسی

SummaryThe cytokinin class of plant hormones plays key roles in regulating diverse developmental and physiological processes [1]. Arabidopsis perceives cytokinins with three related and partially redundant receptor histidine kinases (HKs): CRE1 (the same protein as WOL and AHK4), AHK2, and AHK3 (CRE-family receptors) 2, 3, 4 and 5. It is suggested that binding of cytokinins induces autophosphorylation of these HKs and subsequent transfer of the phosphoryl group to a histidine phosphotransfer protein (HPt) and then to a response regulator (RR), ultimately regulating downstream signaling events 6 and 7. Here we demonstrate that, in vitro and in a yeast system, CRE1 is not only a kinase that phosphorylates HPts in the presence of cytokinin but is also a phosphatase that dephosphorylates HPts in the absence of cytokinin. To explore the roles of these activities in planta, we replaced CRE1 with mutant versions of the gene or with AHK2. Replacing CRE1 with CRE1(T278I), which lacks cytokinin binding activity [8] and is locked in the phosphatase form, decreased cytokinin sensitivity. Conversely, replacing CRE1 with AHK2, which favors kinase activity, increased cytokinin sensitivity. These results indicate that in the presence of cytokinins, cytokinin receptors feed phosphate to phosphorelay-integrating HPt proteins. In the absence of cytokinins, CRE1 removes phosphate from HPt proteins, decreasing the system phosphoload.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: - Volume 16, Issue 11, 6 June 2006, Pages 1116–1122
نویسندگان
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