title: The diphthamide modification pathway from Saccharomyces cerevisiae--revisited.
abstract: Diphthamide is a conserved modification in archaeal and eukaryal translation elongation factor 2 (EF2). Its name refers to the target function for diphtheria toxin, the disease-causing agent that, through ADP ribosylation of diphthamide, causes irreversible inactivation of EF2 and cell death. Although this clearly emphasizes a pathobiological role for diphthamide, its physiological function is unclear, and precisely why cells need EF2 to contain diphthamide is hardly understood. Nonetheless, the conservation of diphthamide biosynthesis together with syndromes (i.e. ribosomal frame-shifting, embryonic lethality, neurodegeneration and cancer) typical of mutant cells that cannot make it strongly suggests that diphthamide-modified EF2 occupies an important and translation-related role in cell proliferation and development. Whether this is structural and/or regulatory remains to be seen. However, recent progress in dissecting the diphthamide gene network (DPH1-DPH7) from the budding yeast Saccharomyces cerevisiae has significantly advanced our understanding of the mechanisms required to initiate and complete diphthamide synthesis on EF2. Here, we review recent developments in the field that not only have provided novel, previously overlooked and unexpected insights into the pathway and the biochemical players required for diphthamide synthesis but also are likely to foster innovative studies into the potential regulation of diphthamide, and importantly, its ill-defined biological role.
authors.affiliation: Department of Genetics, University of Leicester, Leicester, LE1 7RH, UK; Institut für Biologie, Abteilung Mikrobiologie, Universität Kassel, 34132, Kassel, Germany.
authors.forename: Raffael
authors.initials: R
authors.lastname: Schaffrath
authors.forename: Wael
authors.initials: W
authors.lastname: Abdel-Fattah
authors.forename: Roland
authors.initials: R
authors.lastname: Klassen
authors.forename: Michael J R
authors.initials: MJ
authors.lastname: Stark
mesh_terms: D019143:Evolution, Molecular; D006639:Histidine / Q000031:analogs & derivatives* / Q000235:genetics / Q000378:metabolism; D020652:Peptide Elongation Factor 2 / Q000737:chemistry / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism
chemical_list: D020652:Peptide Elongation Factor 2; D029701:Saccharomyces cerevisiae Proteins; D006639:Histidine; C027527:diphthamide