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Control of mRNA decapping by Dcp2: An open and shut case?

Stephen N. Floor, Brittnee N. Jones and John D. Gross

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mRNA decapping by Dcp2 is a critical step in several major eukaryotic mRNA decay pathways. Dcp2 forms the catalytic core of a mRNP that is configured for processing diverse substrates by pathway-specific activators. Here we elaborate a model of catalysis by Dcp2 which posits that activity is controlled by a conformational equilibrium between an open, inactive and closed, active form of the enzyme. Structural studies on yeast Dcp2 indicate that the general activator Dcp1 and substrate promote the closed form of the enzyme. Kinetic studies indicate the catalytic step of decapping is rate-limiting and accelerated by Dcp1. We propose that regulation of conformational transitions in Dcp2 during a rate-limiting step after assembly of the decapping mRNP provides a checkpoint for determining if an mRNA is degraded or recycled to translation.

Authors

Stephen N. Floor

University of California, San Francisco; Mission Bay Campus; San Francisco, California USA

Brittnee N. Jones

University of California, San Francisco; Mission Bay Campus; San Francisco, California USA

John D. Gross

University of California, San Francisco; Mission Bay Campus; San Francisco, California USA

 Download PDF

If the document does not open, please right-click on the link (control-click on a Macintosh) and select the option to save the file to disk.