Current Projects

1. Describing the archaeal N-glycosylation pathway - Relying on bioinformatics, genetics, biochemical and structural approaches, a set of proteins involved in the N-glycosylation of the Haloferax volcanii S-layer glycoprotein have been described. Efforts aimed at defining the behavior of each N-glycosylation gene and their encoded protein (i.e. the Agl proteins) at the transcriptional, translational and functional levels are on-going. In addition, interactions between the various components of the N-glycosylation system with each other, as well as with elements of other systems involved in protein processing are being studied.
2. Delineating the archaeal O-glycosylation pathway - In addition to N-glycosylation, the reporter glycoprotein, the H. volcanii S-layer glycoprotein, also experiences O-glycosylation at the cluster of threonine residues found near the C-terminus of the protein. Components of the pathway responsible for this modification are being defined through gene deletion and mass spectrometry approaches.
3. Assessing sequon modification in Archaea - Little is known of the rules governing the N-glycosylation process in Archaea. As in Eukarya and Bacteria, archaeal N-glycosylation takes place at the Asn residues of Asn-X-Ser/Thr sequons. Since not all sequons are modified, it is clear that other factors, including the context in which a sequon exists, affect glycosylation efficiency. The rules governing archaeal sequon modification are being addressed.
4. Characterizing the archaeal oligosaccharide transferase - Oligosaccharide transferases, responsible for the transfer of lipid-linked oligosaccharides to target protein sequons, are central players in realizing this post-translational modification. Presently, very little is known of AglB, the oligosaccharide transferase of Archaea.Towards a better understanding of oligosaccharide transferase activity in Archaea and hence, across evolution, AglB from H. volcanii is being studied.

Recent Publications

Yurist-Doutsch, S., Magidovich, H., Ventura, V.V., Hitchen, P.G., Dell, A. and Eichler, J. (2010) N-glycosylation in Archaea: On the coordinated actions of Haloferax volcanii AglF and AglM. Mol. Microbiol., 75, 1047-1058.

Magidovich, H., and Eichler, J. (2009) Glycosyltransferases and oligosaccharyltransferases in Archaea: Putative components of the N-glycosylation pathway in the third domain of life. FEMS Microbiol. Lett., 300, 122-130.

Yurist-Doutsch, S., and Eichler, J. (2009) Manual annotation, transcriptional analysis and protein expression studies reveal novel genes in the agl cluster responsible for N-glycosylation in the halophilic archaeon Haloferax volcanii, J. Bacteriol., 191, 3068-3075.

Abu-Qarn, M., Eichler, J. and Sharon, N. (2008) Not just for Eukarya anymore:N-glycosylation in Bacteria and Archaea. Curr. Opin. Struct. Biol.,18, 544-550

Yurist-Doutsch, S., Abu-Qarn, M., Battaglia, F., Morris, H.R., Hitchen, P.G., Dell, A. and Eichler, J. (2008) aglF, aglG and aglI, novel members of a gene cluster involved in the N-glycosylation of the Haloferax volcanii S-layer glycoprotein. Mol. Microbiol. 69, 1234-1245.