TY - JOUR A1 - Hartel, Andreas J.W. A1 - Glogger, Marius A1 - Jones, Nicola G. A1 - Abuillan, Wasim A1 - Batram, Christopher A1 - Hermann, Anne A1 - Fenz, Susanne F. A1 - Tanaka, Motomu A1 - Engstler, Markus T1 - N-glycosylation enables high lateral mobility of GPI-anchored proteins at a molecular crowding threshold JF - Nature Communications N2 - The protein density in biological membranes can be extraordinarily high, but the impact of molecular crowding on the diffusion of membrane proteins has not been studied systematically in a natural system. The diversity of the membrane proteome of most cells may preclude systematic studies. African trypanosomes, however, feature a uniform surface coat that is dominated by a single type of variant surface glycoprotein (VSG). Here we study the density-dependence of the diffusion of different glycosylphosphatidylinositol-anchored VSG-types on living cells and in artificial membranes. Our results suggest that a specific molecular crowding threshold (MCT) limits diffusion and hence affects protein function. Obstacles in the form of heterologous proteins compromise the diffusion coefficient and the MCT. The trypanosome VSG-coat operates very close to its MCT. Importantly, our experiments show that N-linked glycans act as molecular insulators that reduce retarding intermolecular interactions allowing membrane proteins to function correctly even when densely packed. KW - parasitology KW - cellular imaging KW - membrane biophysics KW - single-molecule biophysics Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-171368 VL - 7 ER - TY - JOUR A1 - Dejung, Mario A1 - Subota, Ines A1 - Bucerius, Ferdinand A1 - Dindar, Gülcin A1 - Freiwald, Anja A1 - Engstler, Markus A1 - Boshart, Michael A1 - Butter, Falk A1 - Janzen, Chistian J. T1 - Quantitative proteomics uncovers novel factors involved in developmental differentiation of Trypanosoma brucei JF - PLoS Pathogens N2 - Developmental differentiation is a universal biological process that allows cells to adapt to different environments to perform specific functions. African trypanosomes progress through a tightly regulated life cycle in order to survive in different host environments when they shuttle between an insect vector and a vertebrate host. Transcriptomics has been useful to gain insight into RNA changes during stage transitions; however, RNA levels are only a moderate proxy for protein abundance in trypanosomes. We quantified 4270 protein groups during stage differentiation from the mammalian-infective to the insect form and provide classification for their expression profiles during development. Our label-free quantitative proteomics study revealed previously unknown components of the differentiation machinery that are involved in essential biological processes such as signaling, posttranslational protein modifications, trafficking and nuclear transport. Furthermore, guided by our proteomic survey, we identified the cause of the previously observed differentiation impairment in the histone methyltransferase DOT1B knock-out strain as it is required for accurate karyokinesis in the first cell division during differentiation. This epigenetic regulator is likely involved in essential chromatin restructuring during developmental differentiation, which might also be important for differentiation in higher eukaryotic cells. Our proteome dataset will serve as a resource for detailed investigations of cell differentiation to shed more light on the molecular mechanisms of this process in trypanosomes and other eukaryotes. KW - cell differentiation KW - cell cycle and cell division KW - parasitic cell cycles KW - proteomes KW - chromatin KW - parasitic life cycles KW - transcriptome analysis KW - host-pathogen interactions Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146362 VL - 12 IS - 2 ER - TY - JOUR A1 - Bargul, Joel L. A1 - Jung, Jamin A1 - McOdimba, Francis A. A1 - Omogo, Collins O. A1 - Adung'a, Vincent O. A1 - Krüger, Timothy A1 - Masiga, Daniel K. A1 - Engstler, Markus T1 - Species-Specific Adaptations of Trypanosome Morphology and Motility to the Mammalian Host JF - PLoS Pathogens N2 - African trypanosomes thrive in the bloodstream and tissue spaces of a wide range of mammalian hosts. Infections of cattle cause an enormous socio-economic burden in sub-Saharan Africa. A hallmark of the trypanosome lifestyle is the flagellate’s incessant motion. This work details the cell motility behavior of the four livestock-parasites Trypanosoma vivax, T. brucei, T. evansi and T. congolense. The trypanosomes feature distinct swimming patterns, speeds and flagellar wave frequencies, although the basic mechanism of flagellar propulsion is conserved, as is shown by extended single flagellar beat analyses. Three-dimensional analyses of the trypanosomes expose a high degree of dynamic pleomorphism, typified by the ‘cellular waveform’. This is a product of the flagellar oscillation, the chirality of the flagellum attachment and the stiffness of the trypanosome cell body. The waveforms are characteristic for each trypanosome species and are influenced by changes of the microenvironment, such as differences in viscosity and the presence of confining obstacles. The distinct cellular waveforms may be reflective of the actual anatomical niches the parasites populate within their mammalian host. T. vivax displays waveforms optimally aligned to the topology of the bloodstream, while the two subspecies T. brucei and T. evansi feature distinct cellular waveforms, both additionally adapted to motion in more confined environments such as tissue spaces. T. congolense reveals a small and stiff waveform, which makes these parasites weak swimmers and destined for cell adherence in low flow areas of the circulation. Thus, our experiments show that the differential dissemination and annidation of trypanosomes in their mammalian hosts may depend on the distinct swimming capabilities of the parasites. KW - swimming KW - viscosity KW - flagella KW - host-pathogen interactions KW - cell motility KW - blood KW - parasitic diseases KW - trypanosoma brucei gambiense Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-146513 VL - 12 IS - 2 ER -