Lifetimes of Arabidopsis cryptochrome signaling states in vivo. (15th March 2013)

• Record Type: Journal Article
• Authors: Herbel, Vera; Orth, Christian; Wenzel, Ringo; Ahmad, Margaret; Bittl, Robert; Batschauer, Alfred
• Is Part Of: Plant journal. Volume 74:Number 4(2013:May)
• Page Start: 583
• Page End: 592
• Publication Date: 2013-03-15
• Subjects: Plant molecular biology -- Periodicals; Plant cells and tissues -- Periodicals; Botany -- Periodicals; 580
• DOI: 10.1111/tpj.12144
• Languages: English
• ISSNs: 0960-7412

Abstract

<abstract abstract-type="main" xml:lang="en" id="tpj12144-abs-0001"> <title>Summary</title> <p>One crucial component in light signaling is the quantity of photoreceptor present in the active signaling state. The lifetime of the signaling state of a photoreceptor is limited because of thermal or otherwise back reversion of the chromophore to the ground state, and/or degradation of the photoreceptor in the light‐activated state. It was previously shown that the lit state of plant cryptochromes contains flavin‐neutral semiquinone, and that the half‐lives of the lit state were in the range of 3–4 min <italic>in vitro</italic>. However, it was unknown how long‐lived the signaling states of plant cryptochromes are <italic>in situ</italic>. Based on the loss of degradation of cry2 after prolonged dark incubation and loss of reversibility of photoactivated cry1 by a pulse of green light, we estimate the <italic>in vivo</italic> half‐lives of the signaling states of cry1 and cry2 to be in the range of 5 and 16 min, respectively. Based on electron paramagnetic resonance measurements, the lifetime of the Arabidopsis cry1 lit state in insect cells was found to be ~6 min, and thus very similar to the lifetime of the signaling state <italic>in planta</italic>. Thus, the signaling state lifetimes of plant cryptochromes are not, or are only moderately, stabilized <italic>in planta</italic>.</p> </abstract>