...The Fahlman Lab...

Our Reseasrch

New Directions in tRNA Research.

RNA participates in diverse cellular processes. RNA is most broadly known for its role in protein synthesis (translation), where a messenger RNA (mRNA) is decoded by ribosomes via precise pairing between the codon sequences of the mRNA and the anti codons of transfer RNA (tRNA).

Our interest is with small RNAs (tRNA and miRNA) and their roles outside the boundary of the central dogma of molecular biology (DNA -> RNA -> Protein). In particular we are investigating the role of tRNAs in both ribosome free peptide bond formation and as a signaling molecule for an organisms nutritional status.

Figure 1.

research

Our research leads us into using a variety of techniques and investigating a range of cellular processess. Some examples include investigations on apoptosis (upper caption), structure function studies of protein based peptidyl transferases (lower left), and mass spectroscopy (lower right).

Post Translational Addition of Amino Acids. Both prokaryotic and eukaryotic organisms possess aminoacyl-tRNA transferase. Aminoacyl-tRNA transferases transfer an activated amino acid from a charged tRNA to the N-termini of a target protein (Figure 2). The identity of the amino acid which is transfered is inherent to the aminoacyl-tRNA tranderase. The L/F-transferase or aat from prokaryotes will transfer leucine or phenylalanine to the N-terminus of a substrate protein. The eukaryotic R-transferase or ATE1 exclusively transfers arginine (see Figure 2).

Figure 2.
aa-transferase

Our research with these aminoacyl transferases is their role in the degradation of proteolytic products generated after protease activatio.

Starvation Related Signalling . In all organisms, the accumulation of uncharged tRNAs in the cytoplasm results in the activation of starvation related signalling networks. In some organisms this results in the activation of the enes involved in amino acid biosynthesis, while in higher organisms it results in eating behavior modification. In the case of prokaryotes, such as E. coli, the molecular steps resulting in the cellular signalling has been refered to Stringency Responce (See Figure 3).

Figure 3.

RelA