dictyNews Electronic Edition Volume 41, number 8 April 24, 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 ========= The phenotypes of ATG9, ATG16 and ATG9/16 knock-out mutants imply autophagy-dependent and -independent functions Qiuhong Xiong1, Can †nal2,3, Jan Matthias1, Michael Steinert2,4 and Ludwig Eichinger1 1 Zentrum fźr Biochemie, Medizinische FakultŠt, UniversitŠt zu Kšln, Joseph-Stelzmann-Str. 52, D-50931 Kšln 2 Institut fźr Mikrobiologie, Technische UniversitŠt Braunschweig, Spielmannstr. 7, D-38106 Braunschweig 3 Fen Fakźltesi, Tźrk-Alman-†niversitesi, 34820, Istanbul, Turkey 4 Helmholtz Centre for Infection Research, 38124, Braunschweig, Germany Open Biol. 2015 Apr;5(4). pii: 150008. doi: 10.1098/rsob.150008. Macroautophagy is a highly conserved intracellular bulk degradation system of all eukaryotic cells. It is governed by a large number of autophagy proteins (ATGs) and is crucial for many cellular processes. Here, we describe the phenotypes of Dictyostelium discoideum ATG16(-) and ATG9(-)/16(-) cells and compare them to the previously reported ATG9(-) mutant. ATG16 deficiency caused an increase in the expression of several core autophagy genes, among them atg9 and the two atg8 paralogues. The single and double ATG9 and ATG16 knock-out mutants had complex phenotypes and displayed severe and comparable defects in pinocytosis and phagocytosis. Uptake of Legionella pneumophila was reduced. In addition, ATG9(-) and ATG16(-) cells had dramatic defects in autophagy, development and proteasomal activity which were much more severe in the ATG9(-)/16(-) double mutant. Mutant cells showed an increase in poly-ubiquitinated proteins and contained large ubiquitin-positive protein aggregates which partially co-localized with ATG16-GFP in ATG9(-)/16(-) cells. The more severe autophagic, developmental and proteasomal phenotypes of ATG9(-)/16(-) cells imply that ATG9 and ATG16 probably function in parallel in autophagy and have in addition autophagy-independent functions in further cellular processes. Submitted by Ludwig Eichinger [ludwig.eichinger@uni-koeln.de] ---------------------------------------------------------------------- Evolution of centrosomes and the nuclear lamina: Amoebozoan assets Ralph GrŠf, Petros Batsios and Irene Meyer UniversitŠt Potsdam, Institut fźr Biochemie und Biologie, Potsdam-Golm, Germany. Eur. J. Cell Biol., in press The current eukaryotic tree of life groups most eukaryotes into one of five supergroups, the Opisthokonta, Amoebozoa, Archaeplastida, Excavata and SAR (Stramenopile, Alveolata, Rhizaria). Molecular and comparative morphological analyses revealed that the last eukaryotic common ancestor (LECA) already contained a rather sophisticated equipment of organelles including a mitochondrion, an endomembrane system, a nucleus with a lamina, a microtubule-organizing center (MTOC), and a flagellar apparatus. Recent studies of MTOCs, basal bodies/centrioles, and nuclear envelope organization of organisms in different supergroups have clarified our picture of how the nucleus and MTOCs co-evolved from LECA to extant eukaryotes. In this review we summarize these findings with special emphasis on valuable contributions of research on a lamin-like protein, nuclear envelope proteins, and the MTOC in the amoebozoan model organism Dictyostelium discoideum. Submitted by Ralph GrŠf [rgraef@uni-potsdam.de] ============================================================== [End dictyNews, volume 41, number 8]