Analysis of Autophosphorylating Kinase Activities of Arabidopsis and Human Cryptochromes

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• 作者：Sezgin Ö ; zg&uuml ; r ; Aziz Sancar
• 刊名：Biochemistry
• 出版年：2006
• 出版时间：November 7, 2006
• 年：2006
• 卷：45
• 期：44
• 页码：13369 - 13374
• 全文大小：294K
• 年卷期：v.45,no.44(November 7, 2006)
• ISSN：1520-4995

文摘

Cryptochromes are FAD-based blue-light photoreceptors that regulate growth and developmentin plants and the circadian clock in animals. Arabidopsis thaliana and humans possess two cryptochromes.Recently, it was found that Arabidopsis cryptochrome 1 (AtCry1) binds ATP and exhibits autokinaseactivity that is simulated by blue light. Similarly, it was reported that human cryptochrome 1 (HsCry1)exhibited autophosphorylation activity under blue light. To test the generality of light stimulated kinasefunction of cryptochromes, we purified AtCry1, AtCry2, HsCry1, and HsCry2 and probed them for kinaseactivity under a variety of conditions. We find that AtCry1, which contains near stoichiometric amountsof FAD and human HsCry1 and HsCry2 (which contain only trace amounts of FAD), has autokinaseactivity, but AtCry2, which also contains stoichiometric amounts of FAD, does not. Finally, we find thatthe kinase activity of AtCry1 is not significantly affected by light or the redox status of the flavin cofactor.