dictyNews Electronic Edition Volume 38, number 11 April 20, 2012 Please submit abstracts of your papers as soon as they have been accepted for publication by sending them to dicty@northwestern.edu or 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 ========= The isoform B of the Dictyostelium long-chain fatty-acyl-coenzyme A synthetase is initially inserted into the ER and subsequently provides peroxisomes with an activity important for efficient phagocytosis. Peggy Paschke, Nadine Pawolleck, Frauke Haenel, Heike Otto, Harald Rźhling, and Markus Maniak Abteilung Zellbiologie, UniversitŠt Kassel, 34109 Kassel, Germany Eur. J. Cell Biol. in press Long-chain fatty-acyl-coenzymeA synthetases activate fatty acids for anabolic or catabolic metabolism. They often localize to more than one organelle within eukaryotic cells. Dictyostelium contains two of these proteins, FcsA and FcsB with the latter being targeted to the membrane of the endoplasmic reticulum by virtue of an N-terminal signal sequence and from there appears to move on to peroxisomes. Deletion of this signal favours the peripheral association of the protein with the mitochondrial surface instead. A strain lacking the activity of the FcsB enzyme was constructed by homologous recombination. It has a severe deficiency in the phagocytic uptake of particles, which can be partially alleviated by a peroxisomally targeted, soluble FcsA enzyme. It is, however, not rescued by expressing FcsA in the cytoplasm or targeting it to the ER, indicating that peroxisomal beta-oxidation is important for phagocytosis. In a fcsA-/B- double mutant phagocytosis efficiency is similar to fcsB- cells. However, unlike the single mutants, the fcsA-/B- strain is delayed in morphogenesis, but forms viable spores, albeit within a small fruiting body. This developmental defect is also seen in other mutants affecting peroxisomal enzymes involved in §-oxidation and the glyoxylate cycle. Submitted by Markus Maniak [maniak@uni-kassel.de] -------------------------------------------------------------------------------------- A lamin in lower eukaryotes? Petros Batsios, Tatjana Peter, Otto Baumann, Reimer Stick, Irene Meyer, Ralph GrŠf Dept. of Cell Biology, Institute for Biochemistry and Biology, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14469 Potsdam-Golm, Germany Nucleus, in press Lamins are the major components of the nuclear lamina and serve not only as a mechanical support, but are also involved in chromatin organization, epigenetic regulation, transcription, and mitotic events. Despite these universal tasks, lamins have so far been found only in metazoans. Yet, recently we have identified Dictyostelium NE81 as the first lamin-like protein in a lower eukaryote. Based on the current knowledge, we draw a model for nuclear envelope organization in Dictyostelium in this Extra View and we review the experimental data that justified this classification. Furthermore we provide unpublished data underscoring the requirement of posttranslational CaaX-box processing for proper protein localization at the nuclear envelope. Sequence comparison of NE81 sequences from four Dictyostelia with bona fide lamins illustrates the evolutional relationship between these proteins. Under certain conditions these usually unicellular social amoebae congregate to form a multicellular body. We propose that the evolution of the lamin-like NE81 went along with the invention of multicellularity. Submitted by Ralph GrŠf [rgraef@uni-potsdam.de] ============================================================== [End dictyNews, volume 38, number 11]