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161.
Dharmendra Puri Keerthana Ponniah Kasturi Biswas Atrayee Basu Swagata Dey Erik A. Lundquist Anindya Ghosh-Roy 《The Journal of cell biology》2021,220(9)
Neuronal polarization is facilitated by the formation of axons with parallel arrays of plus-end-out and dendrites with the nonuniform orientation of microtubules. In C. elegans, the posterior lateral microtubule (PLM) neuron is bipolar with its two processes growing along the anterior–posterior axis under the guidance of Wnt signaling. Here we found that loss of the Kinesin-13 family microtubule-depolymerizing enzyme KLP-7 led to the ectopic extension of axon-like processes from the PLM cell body. Live imaging of the microtubules and axonal transport revealed mixed polarity of the microtubules in the short posterior process, which is dependent on both KLP-7 and the minus-end binding protein PTRN-1. KLP-7 is positively regulated in the posterior process by planar cell polarity components of Wnt involving rho-1/rock to induce mixed polarity of microtubules, whereas it is negatively regulated in the anterior process by the unc-73/ced-10 cascade to establish a uniform microtubule polarity. Our work elucidates how evolutionarily conserved Wnt signaling establishes the microtubule polarity in neurons through Kinesin-13. 相似文献
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We analyzed the global genetic variation pattern of Capsella bursa‐pastoris (Brassicaceae) as expressed in allozymic (within‐locus) diversity and isozymic (between‐locus) diversity. Results are based on a global sampling of more than 20,000 C. bursa‐pastoris individuals randomly taken from 1,469 natural provenances in the native and introduced range, covering a broad spectrum of the species’ geographic distribution. We evaluated data for population genetic parameters and F‐statistics, and Mantel tests and AMOVA were performed. Geographical distribution patterns of alleles and multilocus genotypes are shown in maps and tables. Genetic diversity of introduced populations is only moderately reduced in comparison with native populations. Global population structure was analyzed with structure, and the obtained cluster affiliation was tested independently with classification approaches and macroclimatic data using species distribution modeling. Analyses revealed two main clusters: one distributed predominantly in warm arid to semiarid climate regions and the other predominantly in more temperate humid to semihumid climate regions. We observed admixture between the two lineages predominantly in regions with intermediate humidity in both the native and non‐native ranges. The genetically derived clusters are strongly supported in macroclimatic data space. The worldwide distribution patterns of genetic variation in the range of C. bursa‐pastoris can be explained by intensive intra‐ and intercontinental migration, but environmental filtering due to climate preadaption seems also involved. Multiple independent introductions of genotypes from different source regions are obvious. “Endemic” genotypes might be the outcome of admixture or of de novo mutation. We conclude that today's successfully established Capsella genotypes were preadapted and found matching niche conditions in the colonized range parts. 相似文献
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Ute Armbruster Mathias Labs Mathias Pribil Stefania Viola Wenteng Xu Michael Scharfenberg Alexander P. Hertle Ulrike Rojahn Poul Erik Jensen Fabrice Rappaport Pierre Joliot Peter D?rmann Gerhard Wanner Dario Leister 《The Plant cell》2013,25(7):2661-2678
Chloroplasts of land plants characteristically contain grana, cylindrical stacks of thylakoid membranes. A granum consists of a core of appressed membranes, two stroma-exposed end membranes, and margins, which connect pairs of grana membranes at their lumenal sides. Multiple forces contribute to grana stacking, but it is not known how the extreme curvature at margins is generated and maintained. We report the identification of the CURVATURE THYLAKOID1 (CURT1) protein family, conserved in plants and cyanobacteria. The four Arabidopsis thaliana CURT1 proteins (CURT1A, B, C, and D) oligomerize and are highly enriched at grana margins. Grana architecture is correlated with the CURT1 protein level, ranging from flat lobe-like thylakoids with considerably fewer grana margins in plants without CURT1 proteins to an increased number of membrane layers (and margins) in grana at the expense of grana diameter in overexpressors of CURT1A. The endogenous CURT1 protein in the cyanobacterium Synechocystis sp PCC6803 can be partially replaced by its Arabidopsis counterpart, indicating that the function of CURT1 proteins is evolutionary conserved. In vitro, Arabidopsis CURT1A proteins oligomerize and induce tubulation of liposomes, implying that CURT1 proteins suffice to induce membrane curvature. We therefore propose that CURT1 proteins modify thylakoid architecture by inducing membrane curvature at grana margins. 相似文献
168.
The ichnogenus Tonganoxichnus, produced by one or more monuran insect taxa, is now recorded from the Middle Pennsylvanian Mansfield Formation of Indiana. Tonganoxichnus is a resting trace that has three important implications. First, it represents a recurrent behavioral pattern in Upper Carboniferous to Lower Permian marginal marine environments of North America. Second, it provides finely resolved anatomical information for axial and appendicular body structures and behaviors that are difficult to determine from body‐fossil material alone. Third, integrated sedimentologic and ichnologic observations indicate that the Tonganoxichnus assemblage, inclusive of other ichnotaxa, is common in tidal rhythmites that were developed under freshwater conditions, probably in the innermost part of estuarine systems, close to or at the fluvioestuarine transition. 相似文献
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Angela Oppelt Viola H Lobert Kaisa Haglund Ashley M Mackey Lucia E Rameh Knut Liestøl Kay Oliver Schink Nina Marie Pedersen Eva M Wenzel Ellen M Haugsten Andreas Brech Tor Erik Rusten Harald Stenmark Jørgen Wesche 《EMBO reports》2013,14(1):57-64
Although phosphatidylinositol 5‐phosphate (PtdIns5P) is present in many cell types and its biogenesis is increased by diverse stimuli, its precise cellular function remains elusive. Here we show that PtdIns5P levels increase when cells are stimulated to move and we find PtdIns5P to promote cell migration in tissue culture and in a Drosophila in vivo model. First, class III phosphatidylinositol 3‐kinase, which produces PtdIns3P, was shown to be involved in migration of fibroblasts. In a cell migration screen for proteins containing PtdIns3P‐binding motifs, we identified the phosphoinositide 5‐kinase PIKfyve and the phosphoinositide 3‐phosphatase MTMR3, which together constitute a phosphoinositide loop that produces PtdIns5P via PtdIns(3,5)P2. The ability of PtdIns5P to stimulate cell migration was demonstrated directly with exogenous PtdIns5P and a PtdIns5P‐producing bacterial enzyme. Thus, the identified phosphoinositide loop defines a new role for PtdIns5P in cell migration. 相似文献
170.
Meina Wang Erik R Sampson Hongting Jin Jia Li Qiao H Ke Hee-Jeong Im Di Chen 《Arthritis research & therapy》2013,15(1):R5