Poster abstracts

Poster number 60 submitted by Bethany Strunk

Characterizing the essential role of Fap7 ATPase activity in yeast ribosome assembly

Bethany Strunk (Chemical Biology , University of Michigan), Heather Woolls (Chemical Biology, University of Michigan), Jamie Van Etten (Chemical Biology, University of Michigan), Devon Riter (Department of Chemistry, University of Michigan), Katrin Karbstein (Department of Chemistry, University of Michigan)

Abstract:
In Saccharomyces cerevisiae, the final cytoplasmic step in the maturation of 40S ribosomes involves cleavage of 20S rRNA to generate the mature 3´ end of 18S rRNA. Several accessory factors are involved in this step, mutations of which lead to accumulation of 20S rRNA in the cytoplasm and failure to produce mature, active ribosomes (1). One such factor is Fap7 an essential protein with ATPase sequence homology believed to act through transient association with the maturing small subunit (2). Conserved amino acids predicted to be involved in ATP hydrolysis are required for Fap7\'s 18S rRNA processing activity (2). We are using ATPase assays as well as detection of changes in intrinsic tryptophan fluorescence upon nucleotide binding as tools to investigate Fap7´s essential role in ribosome assembly. Preliminary data indicate that purified Fap7 has weak ATPase activity and that this activity may be regulated by reversible disulfide bond formation. Interestingly, Fap7 has also been implicated in regulating the transcriptional response to oxidative stress (3) and may thus integrate transcriptional and translational response to oxidative stress using disulfide bond formation as a sensor.

References:
1. Peng et al. Cell. 2003 113(7): 919-33.
2. Granneman et al. Mol Cell Biol. 2005 25(23): 10352-64.
3. Juhnke et al. Mol Microbiol. 2000 35(4): 936-48.

Keywords: rRNA processing, yeast, Fap7