dictyNews Electronic Edition Volume 41, number 9 May 1, 2015 Please submit abstracts of your papers as soon as they have been accepted for publication by using the form at http://dictybase.org/db/cgi-bin/dictyBase/abstract_submit. Back issues of dictyNews, the Dicty Reference database and other useful information is available at dictyBase - http://dictybase.org. Follow dictyBase on twitter: http://twitter.com/dictybase ========= Abstracts ========= Evolutionary diversity of social amoebae N-glycomes may support interspecific autonomy Christa L. Feasley, Hanke van der Wel, and Christopher M. West Dept. of Biochemistry & Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, Oklahoma City, OK USA 73104 USA Glycoconjugate Journal, in press Multiple species of cellular slime mold (CSM) amoebae share overlapping subterranean environments near the soil surface. Despite similar life-styles, individual species form independent starvation-induced fruiting bodies whose spores can renew the life cycle. N-glycans associated with the cell surface glycocalyx have been predicted to contribute to interspecific avoidance, resistance to pathogens, and prey preference. N-glycans from five CSM species that diverged 300-600 million years ago and whose genomes have been sequenced were fractionated into neutral and acidic pools and profiled by MALDI-TOF-MS. Glycan structure models were refined using linkage specific antibodies, exoglycosidase digestions, MALDI-MS/MS, and chromatographic studies. Amoebae of the type species Dictyostelium discoideum express modestly trimmed high mannose N-glycans variably modified with core alpha-3-linked Fuc and peripherally decorated with 0-2 residues each of beta-GlcNAc, Fuc, methylphosphate and/or sulfate, as reported previously. Comparative analyses of D. purpureum, D. fasciculatum, Polysphondylium pallidum, and Actyostelium subglobosum revealed that each displays a distinctive spectrum of high-mannose species with quantitative variations in the extent of these modifications, and qualitative differences including retention of Glc, mannose methylation, and absence of a peripheral GlcNAc, fucosylation, or sulfation. Starvation-induced development modifies the pattern in all species but, except for universally observed increased mannose-trimming, the N-glycans do not converge to a common profile. Correlations with glycogene repertoires will enable future reverse genetic studies to eliminate N-glycomic differences to test their functions in interspecific relations and pathogen evasion. Submitted by Chris West [westcm@uga.edu] ---------------------------------------------------------------------- Oxygen Sensing by Protozoans: How They Catch Their Breath Christopher M. West (1) and Ira J. Blader (2) (1) Department of Biochemistry & Molecular Biology, Oklahoma Center for Medical Glycobiology, University of Oklahoma Health Sciences Center, 975 NE 10th St. - BRC 417, Oklahoma City, OK 73104 USA (2) Department of Microbiology and Immunology, University at Buffalo School of Medicine, 347 Biomedical Research Building, 3435 Main Street, Buffalo, NY 14214 USA Current Opinion in Microbiology, in press Cells must know the local levels of available oxygen and either adapt accordingly or relocate to more favorable environments. Prolyl 4-hydroxylases are emerging as universal cellular oxygen sensors. In animals, these oxygen sensors respond to decreased oxygen availability by up-regulating hypoxia-inducible transcription factors. In protozoa, the prolyl 4-hydroxylases appear to activate E3-SCF ubiquitin ligase complexes potentially to turn over their proteomes. Intracellular parasites are impacted by both types of oxygen-sensing pathways. Since parasites are exposed to diverse oxygen tensions during their life cycles, this review identifies emerging oxygen-sensing mechanisms and discusses how these mechanisms likely contribute to the regulation of unicellular eukaryotes. Submitted by Chris West [westcm@uga.edu] ---------------------------------------------------------------------- Dictyostelium acetoacetyl-CoA thiolase is a dual-localizing enzyme that localizes to peroxisomes, mitochondria, and the cytosol Nana Isezaki(1), Atsushi Sekiba(1), Shoko Itagaki(1), Koki Nagayama(1) , Hiroshi Ochiai(1,2), and Tetsuo Ohmachi(1)* (1) Department of Biochemistry and Molecular Biology, Faculty of Agriculture and Life Science, Hirosaki University, Hirosaki, Japan, (2) Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo, Japan  Present address: Department of Life Science, University of Manchester, Manchester, M13 9PT, UK Microbiology, in press Acetoacetyl-CoA thiolase (Acat) is an enzyme that catalyzes both the CoA-dependent thiolytic cleavage of acetoacetyl-CoA and the reverse condensation reaction. In Dictyostelium disciodeum, acetoacetyl-CoA thiolase (DdAcat) is encoded by a single acat gene. The aim of this study was to assess the localization of DdAcat and to determine the mechanism of its cellular localization. Subcellular localization of DdAcat was investigated using its fusion protein with the green fluorescent protein (GFP), and it was found to be localized to peroxisomes. The findings showed that the targeting signal of DdAcat to peroxisomes is a unique nonapeptide sequence (15RMYTTAKNL23) similar to the conserved peroxisomal targeting signal-2 (PTS-2). Cell fractionation experiments revealed that DdAcat also exists in the cytosol. Distribution in the cytosol was caused by translational initiation from the second Met codon at position 16. The first 18 N-terminal residues also exhibited function as a mitochondrial targeting signal (MTS). These results indicate that DdAcat is a dual-localizing enzyme that localizes to peroxisomes, mitochondria, and the cytosol using both PTS-2 and MTS signals, which overlap each other near the N terminus, and the alternative utilisation of start codons. Submitted by Tetsuo Ohmachi [tohmachi@hirosaki-u.ac.jp] ============================================================== [End dictyNews, volume 41, number 9]