Main Menu (Mobile)- Block

Main Menu - Block

janelia7_blocks-janelia7_fake_breadcrumb | block
Koyama Lab / Publications
custom | custom

Filter

facetapi-Q2b17qCsTdECvJIqZJgYMaGsr8vANl1n | block

Associated Lab

facetapi-W9JlIB1X0bjs93n1Alu3wHJQTTgDCBGe | block
facetapi-PV5lg7xuz68EAY8eakJzrcmwtdGEnxR0 | block
facetapi-021SKYQnqXW6ODq5W5dPAFEDBaEJubhN | block
general_search_page-panel_pane_1 | views_panes

192 Publications

Showing 51-60 of 192 results
Your Criteria:
    09/30/21 | Cellular bases of olfactory circuit assembly revealed by systematic time-lapse imaging.
    Li T, Fu T, Wong KK, Li H, Xie Q, Luginbuhl DJ, Wagner MJ, Betzig E, Luo L
    Cell. 2021 Sep 30;184(20):5107. doi: 10.1016/j.cell.2021.08.030

    Neural circuit assembly features simultaneous targeting of numerous neuronal processes from constituent neuron types, yet the dynamics is poorly understood. Here, we use the Drosophila olfactory circuit to investigate dynamic cellular processes by which olfactory receptor neurons (ORNs) target axons precisely to specific glomeruli in the ipsi- and contralateral antennal lobes. Time-lapse imaging of individual axons from 30 ORN types revealed a rich diversity in extension speed, innervation timing, and ipsilateral branch locations and identified that ipsilateral targeting occurs via stabilization of transient interstitial branches. Fast imaging using adaptive optics-corrected lattice light-sheet microscopy showed that upon approaching target, many ORN types exhibiting "exploring branches" consisted of parallel microtubule-based terminal branches emanating from an F-actin-rich hub. Antennal nerve ablations uncovered essential roles for bilateral axons in contralateral target selection and for ORN axons to facilitate dendritic refinement of postsynaptic partner neurons. Altogether, these observations provide cellular bases for wiring specificity establishment.

    View Publication Page
    09/30/21 | The LRRK2 G2019S mutation alters astrocyte-to-neuron communication via extracellular vesicles and induces neuron atrophy in a human iPSC-derived model of Parkinson’s disease
    Aurelie de Rus Jacquet , Jenna L. Tancredi , Andrew L. Lemire , Michael C. DeSantis , Wei-Ping Li , Erin K. O’Shea
    eLife. 2021 Sep 30:. doi: https://doi.org/10.7554/eLife.73062

    Astrocytes are essential cells of the central nervous system, characterized by dynamic relationships with neurons that range from functional metabolic interactions and regulation of neuronal firing activities, to the release of neurotrophic and neuroprotective factors. In Parkinson’s disease (PD), dopaminergic neurons are progressively lost during the course of the disease, but the effects of PD on astrocytes and astrocyte-to-neuron communication remains largely unknown. This study focuses on the effects of the PD-related mutation LRRK2 G2019S in astrocytes generated from patient-derived induced pluripotent stem cells. We report the alteration of extracellular vesicle (EV) biogenesis in astrocytes, and we identify the abnormal accumulation of key PD-related proteins within multi vesicular bodies (MVBs). We found that dopaminergic neurons internalize astrocyte-secreted EVs and that LRRK2 G2019S EVs are abnormally enriched in neurites and fail to provide full neurotrophic support to dopaminergic neurons. Thus, dysfunctional astrocyte-to-neuron communication via altered EV biological properties may participate in the progression of PD.

    View Publication Page
    09/27/21 | A dominant-negative SOX18 mutant disrupts multiple regulatory layers essential to transcription factor activity.
    McCann AJ, Lou J, Moustaqil M, Graus MS, Blum A, Fontaine F, Liu H, Luu W, Rudolffi-Soto P, Koopman P, Sierecki E, Gambin Y, Meunier FA, Liu Z, Hinde E, Francois M
    Nucleic Acids Research. 2021 Sep 27:. doi: 10.1093/nar/gkab820

    Few genetically dominant mutations involved in human disease have been fully explained at the molecular level. In cases where the mutant gene encodes a transcription factor, the dominant-negative mode of action of the mutant protein is particularly poorly understood. Here, we studied the genome-wide mechanism underlying a dominant-negative form of the SOX18 transcription factor (SOX18RaOp) responsible for both the classical mouse mutant Ragged Opossum and the human genetic disorder Hypotrichosis-lymphedema-telangiectasia-renal defect syndrome. Combining three single-molecule imaging assays in living cells together with genomics and proteomics analysis, we found that SOX18RaOp disrupts the system through an accumulation of molecular interferences which impair several functional properties of the wild-type SOX18 protein, including its target gene selection process. The dominant-negative effect is further amplified by poisoning the interactome of its wild-type counterpart, which perturbs regulatory nodes such as SOX7 and MEF2C. Our findings explain in unprecedented detail the multi-layered process that underpins the molecular aetiology of dominant-negative transcription factor function.

    View Publication Page
    09/27/21 | A dominant-negative SOX18 mutant disrupts multiple regulatory layers essential to transcription factor activity.
    McCann AJ, Lou J, Moustaqil M, Graus MS, Blum A, Fontaine F, Liu H, Luu W, Rudolffi-Soto P, Koopman P, Sierecki E, Gambin Y, Meunier FA, Liu Z, Hinde E, Francois M
    Nucleic Acids Research. 2021 Sep 27:. doi: 10.1093/nar/gkab820

    Few genetically dominant mutations involved in human disease have been fully explained at the molecular level. In cases where the mutant gene encodes a transcription factor, the dominant-negative mode of action of the mutant protein is particularly poorly understood. Here, we studied the genome-wide mechanism underlying a dominant-negative form of the SOX18 transcription factor (SOX18RaOp) responsible for both the classical mouse mutant Ragged Opossum and the human genetic disorder Hypotrichosis-lymphedema-telangiectasia-renal defect syndrome. Combining three single-molecule imaging assays in living cells together with genomics and proteomics analysis, we found that SOX18RaOp disrupts the system through an accumulation of molecular interferences which impair several functional properties of the wild-type SOX18 protein, including its target gene selection process. The dominant-negative effect is further amplified by poisoning the interactome of its wild-type counterpart, which perturbs regulatory nodes such as SOX7 and MEF2C. Our findings explain in unprecedented detail the multi-layered process that underpins the molecular aetiology of dominant-negative transcription factor function.

    View Publication Page
    09/25/21 | Coding sequence-independent homology search identifies highly divergent homopteran putative effector gene family
    Stern D, Han C
    bioRxiv. 2021 Sep 25:. doi: https://doi.org/10.1101/2021.09.24.461719

    Many genomes contain rapidly evolving and highly divergent genes whose homology to genes of known function often cannot be determined from sequence similarity alone. However, coding sequence-independent features of genes, such as intron-exon boundaries, often evolve more slowly than coding sequences and can provide complementary evidence for homology. We found that a linear logistic regression classifier using only structural features of rapidly evolving bicycle aphid effector genes identified many putative bicycle homologs in aphids, phylloxerids, and scale insects, whereas sequence similarity search methods yielded few homologs in most aphids and no homologs in phylloxerids and scale insects. Subsequent examination of sequence features and intron locations supported homology assignments. Differential expression studies of newly-identified bicycle homologs, together with prior proteomic studies, support the hypothesis that BICYCLE proteins act as plant effector proteins in many aphid species and perhaps also in phylloxerids and scale insects.

    View Publication Page
    09/21/21 | Activity-dependent Golgi satellite formation in dendrites reshapes the neuronal surface glycoproteome.
    Govind AP, Jeyifous O, Russell TA, Yi Z, Weigel AV, Ramaprasad A, Newell L, Ramos W, Valbuena FM, Casler JC, Yan J, Glick BS, Swanson GT, Lippincott-Schwartz J, Green WN
    eLife. 2021 Sep 21;10:. doi: 10.7554/eLife.68910

    Activity-driven changes in the neuronal surface glycoproteome are known to occur with synapse formation, plasticity and related diseases, but their mechanistic basis and significance are unclear. Here, we observed that -glycans on surface glycoproteins of dendrites shift from immature to mature forms containing sialic acid in response to increased neuronal activation. In exploring the basis of these -glycosylation alterations, we discovered they result from the growth and proliferation of Golgi satellites scattered throughout the dendrite. Golgi satellites that formed during neuronal excitation were in close association with ER exit sites and early endosomes and contained glycosylation machinery without the Golgi structural protein, GM130. They functioned as distal glycosylation stations in dendrites, terminally modifying sugars either on newly synthesized glycoproteins passing through the secretory pathway, or on surface glycoproteins taken up from the endocytic pathway. These activities led to major changes in the dendritic surface of excited neurons, impacting binding and uptake of lectins, as well as causing functional changes in neurotransmitter receptors such as nicotinic acetylcholine receptors. Neural activity thus boosts the activity of the dendrite's satellite micro-secretory system by redistributing Golgi enzymes involved in glycan modifications into peripheral Golgi satellites. This remodeling of the neuronal surface has potential significance for synaptic plasticity, addiction and disease.

    View Publication Page
    09/11/21 | Erratum: Label-free imaging of fibroblast membrane interfaces and protein signatures with vibrational infrared photothermal and phase signals: publisher's note.
    Samolis PD, Langley D, O'Reilly BM, Oo Z, Hilzenrat G, Erramilli S, Sgro AE, McArthur S, Sander MY
    Biomed Opt Express. 09/2021;12(9):5400. doi: 10.1364/BOE.438946

    [This corrects the article on p. 303 in vol. 12, PMID: 33520386.].

    View Publication Page
    09/07/21 | Dissociable contributions of phasic dopamine activity to reward and prediction.
    Pan W, Coddington LT, Dudman JT
    Cell Reports. 2021 Sep 07;36(10):109684. doi: 10.1016/j.celrep.2021.109684

    Sensory cues that precede reward acquire predictive (expected value) and incentive (drive reward-seeking action) properties. Mesolimbic dopamine neurons' responses to sensory cues correlate with both expected value and reward-seeking action. This has led to the proposal that phasic dopamine responses may be sufficient to inform value-based decisions, elicit actions, and/or induce motivational states; however, causal tests are incomplete. Here, we show that direct dopamine neuron stimulation, both calibrated to physiological and greater intensities, at the time of reward can be sufficient to induce and maintain reward seeking (reinforcing) although replacement of a cue with stimulation is insufficient to induce reward seeking or act as an informative cue. Stimulation of descending cortical inputs, one synapse upstream, are sufficient for reinforcement and cues to future reward. Thus, physiological activation of mesolimbic dopamine neurons can be sufficient for reinforcing properties of reward without being sufficient for the predictive and incentive properties of cues.

    View Publication Page
    09/06/21 | Nitrite reductase activity within an antiparallel de novo scaffold.
    Koebke KJ, Tebo AG, Manickas EC, Deb A, Penner-Hahn JE, Pecoraro VL
    JBIC Journal of Biological Inorganic Chemistry. 09/2021;26(7):855 - 862. doi: 10.1007/s00775-021-01889-1

    Copper nitrite reductase (CuNiR) is a copper enzyme that converts nitrite to nitric oxide and is an important part of the global nitrogen cycle in bacteria. The relatively simple CuHis3 binding site of the CuNiR active site has made it an enticing target for small molecule modeling and de novo protein design studies. We have previously reported symmetric CuNiR models within parallel three stranded coiled coil systems, with activities that span a range of three orders of magnitude. In this report, we investigate the same CuHis3 binding site within an antiparallel three helical bundle scaffold, which allows the design of asymmetric constructs. We determine that a simple CuHis3 binding site can be designed within this scaffold with enhanced activity relative to the comparable construct in parallel coiled coils. Incorporating more complex designs or repositioning this binding site can decrease this activity as much as 15 times. Comparing these constructs, we reaffirm a previous result in which a blue shift in the 1s to 4p transition energy determined by Cu(I) X-ray absorption spectroscopy is correlated with an enhanced activity within imidazole-based constructs. With this step and recent successful electron transfer site designs within this scaffold, we are one step closer to a fully functional de novo designed nitrite reductase.

    View Publication Page
    09/06/21 | Visualizing the Invisible: Advanced Optical Microscopy as a Tool to Measure Biomechanical Forces.
    Hobson CM, Aaron JS, Heddleston JM, Chew T
    Frontiers in Cell and Developmental Biology. 2021 Sep 06;9:706126. doi: 10.3389/fcell.2021.706126

    The importance of mechanical force in biology is evident across diverse length scales, ranging from tissue morphogenesis during embryo development to mechanotransduction across single adhesion proteins at the cell surface. Consequently, many force measurement techniques rely on optical microscopy to measure forces being applied by cells on their environment, to visualize specimen deformations due to external forces, or even to directly apply a physical perturbation to the sample via photoablation or optogenetic tools. Recent developments in advanced microscopy offer improved approaches to enhance spatiotemporal resolution, imaging depth, and sample viability. These advances can be coupled with already existing force measurement methods to improve sensitivity, duration and speed, amongst other parameters. However, gaining access to advanced microscopy instrumentation and the expertise necessary to extract meaningful insights from these techniques is an unavoidable hurdle. In this Live Cell Imaging special issue Review, we survey common microscopy-based force measurement techniques and examine how they can be bolstered by emerging microscopy methods. We further explore challenges related to the accompanying data analysis in biomechanical studies and discuss the various resources available to tackle the global issue of technology dissemination, an important avenue for biologists to gain access to pre-commercial instruments that can be leveraged for biomechanical studies.

    View Publication Page