HJURP is a CENP-A chromatin assembly factor sufficient to form a functional de novo kinetochore

Barnhart et al. 194 (2): 229 Abstract Centromeres of higher eukaryotes are epigenetically marked by the centromere-specific CENP-A nucleosome. New CENP-A recruitment requires the CENP-A histone chaperone HJURP. In this paper, we show that a LacI (Lac repressor) fusion of HJURP drove the stable recruitment of CENP-A to a LacO (Lac operon) array at a noncentromeric locus. Ectopically targeted CENP-A … Continue reading

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APC/CCdh1-dependent proteolysis of USP1 regulates the response to UV-mediated DNA damage

Cotto-Rios et al. 194 (2): 17 Abstract Targeted protein destruction of critical cellular regulators during the G1 phase of the cell cycle is achieved by anaphase-promoting complex/cyclosomeCdh1 (APC/CCdh1), a multisubunit E3 ubiquitin ligase. Cells lacking Cdh1 have been shown to accumulate deoxyribonucleic acid (DNA) damage, suggesting that it may play a previously unrecognized role in maintaining genomic stability. The ubiquitin-specific … Continue reading

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The mitochondrial import protein Mim1 promotes biogenesis of multispanning outer membrane proteins

Abstract The mitochondrial outer membrane contains translocase complexes for the import of precursor proteins. The translocase of the outer membrane complex functions as a general preprotein entry gate, whereas the sorting and assembly machinery complex mediates membrane insertion of β-barrel proteins of the outer membrane. Several α-helical outer membrane proteins are known to carry multiple transmembrane segments; however, only limited … Continue reading

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Nuclear envelope starts with a clean sheet

After mitosis, nuclear membranes form directly from ER cisternae before nuclear pore complex reassembly. At the start of mitosis, the nuclear envelope breaks down and merges with the endoplasmic reticulum (ER). At the same time, the nuclear pore complexes that mediate transport across the inner and outer membranes of the envelope also disassemble. Transmembrane pore proteins move into the ER, … Continue reading

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Multispan mitochondrial outer membrane protein Ugo1 follows a unique Mim1-dependent import pathway

Papić et al. 194 (3): 397 Abstract The mitochondrial outer membrane (MOM) harbors several multispan proteins that execute various functions. Despite their importance, the mechanisms by which these proteins are recognized and inserted into the outer membrane remain largely unclear. In this paper, we address this issue using yeast mitochondria and the multispan protein Ugo1. Using a specific insertion assay … Continue reading

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Formation of the postmitotic nuclear envelope from extended ER cisternae precedes nuclear pore assembly

Abstract During mitosis, the nuclear envelope merges with the endoplasmic reticulum (ER), and nuclear pore complexes are disassembled. In a current model for reassembly after mitosis, the nuclear envelope forms by a reshaping of ER tubules. For the assembly of pores, two major models have been proposed. In the insertion model, nuclear pore complexes are embedded in the nuclear envelope … Continue reading

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Tracing the origins of centrioles, cilia, and flagella

Abstract Centrioles/basal bodies (CBBs) are microtubule-based cylindrical organelles that nucleate the formation of centrosomes, cilia, and flagella. CBBs, cilia, and flagella are ancestral structures; they are present in all major eukaryotic groups. Despite the conservation of their core structure, there is variability in their architecture, function, and biogenesis. Recent genomic and functional studies have provided insight into the evolution of … Continue reading

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Nuclear translocation of AMPK-α1 potentiates striatal neurodegeneration in Huntington’s disease

Abstract Adenosine monophosphate–activated protein kinase (AMPK) is a major energy sensor that maintains cellular energy homeostasis. Huntington’s disease (HD) is a neurodegenerative disorder caused by the expansion of CAG repeats in the huntingtin (Htt) gene. In this paper, we report that activation of the α1 isoform of AMPK (AMPK-α1) occurred in striatal neurons of humans and mice with HD. Overactivation … Continue reading

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Visualization of dynein-dependent microtubule gliding at the cell cortex: implications for spindle positioning

Gusnowski and Srayko 194 (3): 377 Abstract Dynein motors move along the microtubule (MT) lattice in a processive “walking” manner. In the one-cell Caenorhabditis elegans embryo, dynein is required for spindle-pulling forces during mitosis. Posteriorly directed spindle-pulling forces are higher than anteriorly directed forces, and this imbalance results in posterior spindle displacement during anaphase and an asymmetric division. To address … Continue reading

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