PXA Domain-Containing Protein Pxa1 Is Required for Normal Vacuole Function and Morphology in Schizosaccharomyces pombe

PhoX homology (PX) domain-containing proteins play critical roles in vesicular trafficking, protein sorting, and lipid modification in eukaryotic cells. Several proteins with PX domains contain an associated domain termed PXA (PX-associated). Although PXA domain-containing proteins are required for some important cellular processes, the function of the PXA domain is unknown. We identified three PXA domain-containing proteins in Schizosaccharomyces pombe. S. pombe Pxa1p (SPAC5D6.07c) contained only the PXA domain, not the PX domain. To elucidate the role of the PXA domain in eukaryotic cells, we constructed and characterized a disruption mutant, pxa1. The pxa1 disruptant contained enlarged vacuoles and exhibited mislocalization of vacuolar carboxypeptidase Y (CPY). The conversion rate from pro- to mature-CPY was greatly impaired in pxa1 cells, and fluorescence microscopy indicated that a sorting receptor for CPY, Vps10p, mislocalized to the vacuolar membrane. The mutants were also deficient in vacuolar sorting of a multivesicular body (MVB) marker, a ubiquitin–GFP–carboxypeptidase S (Ub–GFP–CPS) fusion protein. Taken together, these results indicate that Pxa1 protein is required for normal vacuole function and morphology in S. pombe.     

Dexamethasone Inhibits Mitogen-dependent Synthesis of Histamine Due to Histidine Decarboxylase Induced in Cultured Mouse Spleen Cells

Schizosaccharomyces pombe has four α-amylase homologs (Aah1p-Aah4p) with a glycosylphosphatidylinositol (GPI) modification site at the C-terminal end. Disruption mutants of aah genes were tested for mislocalization of vacuolar carboxypeptidase Y (CPY), and aah3Δ was found to secrete CPY. The conversion rate from pro- to mature CPY was greatly impaired in aah3Δ, and fluorescence microscopy inidicated that a sorting receptor for CPY, Vps10p, mislocalized to the vacuolar membrane. These results indicate that aah3Δ had a defect in the retrograde transport of Vps10p, and that Aah3p is the first S. pombe specific protein required for vacuolar protein sorting.     

Environmental heterogeneity among lakes promotes hyper β‐diversity across phytoplankton communities

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Variations in nitrogen use efficiency reflect the biochemical subtype while variations in water use efficiency reflect the evolutionary lineage of C4 grasses at inter‐glacial CO2

C₄ photosynthesis evolved multiple times in diverse lineages. Most physiological studies comparing C₄ plants were not conducted at the low atmospheric CO₂ prevailing during their evolution. Here, 24 C₄ grasses belonging to three biochemical subtypes [nicotinamide adenine dinucleotide malic enzyme (NAD‐ME), phosphoenolpyruvate carboxykinase (PCK) and nicotinamide adenine dinucleotide phosphate malic enzyme (NADP‐ME)] and six major evolutionary lineages were grown under ambient (400 μL L^?1) and inter‐glacial (280 μL L^?1) CO₂. We hypothesized that nitrogen‐related and water‐related physiological traits are associated with subtypes and lineages, respectively. Photosynthetic rate and stomatal conductance were constrained by the shared lineage, while variation in leaf mass per area (LMA), leaf N per area, plant dry mass and plant water use efficiency were influenced by the subtype. Subtype and lineage were equally important for explaining variations in photosynthetic nitrogen use efficiency (PNUE) and photosynthetic water use efficiency (PWUE). CO₂ treatment impacted most parameters. Overall, higher LMA and leaf N distinguished the Chloridoideae/NAD‐ME group, while NADP‐ME and PCK grasses were distinguished by higher PNUE regardless of lineage. Plants were characterized by high photosynthesis and PWUE when grown at ambient CO₂ and by high conductance at inter‐glacial CO₂. In conclusion, the evolutionary and biochemical diversity among C₄ grasses was aligned with discernible leaf physiology, but it remains unknown whether these traits represent ecophysiological adaptation.     

Landscape‐scale spatial abundance distributions discriminate core from random components of boreal lake bacterioplankton

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MYC-induced apoptosis in mammary epithelial cells is associated with repression of lineage-specific gene signatures

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CD138免疫磁珠细胞分选的FISH技术在多发性骨髓瘤诊断中的应用

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The New Face of the Lipid Droplet: Lipid Droplet Proteins

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