1
|
Christophers B, Leahy SN, Soffar DB, von Saucken VE, Broadie K, Baylies MK. Muscle cofilin alters neuromuscular junction postsynaptic development to strengthen functional neurotransmission. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.11.21.568166. [PMID: 38045306 PMCID: PMC10690168 DOI: 10.1101/2023.11.21.568166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/05/2023]
Abstract
Cofilin, an actin severing protein, plays critical roles in muscle sarcomere addition and maintenance. Our previous work has shown Drosophila cofilin (DmCFL) knockdown causes progressive deterioration of muscle structure and function and produces features seen in nemaline myopathy (NM) caused by cofilin mutations. We hypothesized that disruption of actin cytoskeleton dynamics by DmCFL knockdown would impact other aspects of muscle development, and, thus, conducted an RNA sequencing analysis which unexpectedly revealed upregulated expression of numerous neuromuscular junction (NMJ) genes. We found that DmCFL is enriched in the muscle postsynaptic compartment and that DmCFL deficiency causes F-actin disorganization in this subcellular domain prior to the sarcomere defects observed later in development. Despite NMJ gene expression changes, we found no significant changes in gross presynaptic Bruchpilot active zones or total postsynaptic glutamate receptor levels. However, DmCFL knockdown results in mislocalization of glutamate receptors containing the GluRIIA subunit in more deteriorated muscles and neurotransmission strength is strongly impaired. These findings expand our understanding of cofilin's roles in muscle to include NMJ structural development and suggest that NMJ defects may contribute to NM pathophysiology.
Collapse
Affiliation(s)
- Briana Christophers
- Weill Cornell–Rockefeller–Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY, 10065, USA
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Shannon N. Leahy
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - David B. Soffar
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Victoria E. von Saucken
- Weill Cornell–Rockefeller–Sloan Kettering Tri-Institutional MD-PhD Program, New York, NY, 10065, USA
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| | - Kendal Broadie
- Department of Biological Sciences, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
- Kennedy Center for Research on Human Development, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
- Vanderbilt Brain Institute, Vanderbilt University and Medical Center, Nashville, TN 37235, USA
| | - Mary K. Baylies
- Biochemistry, Cell & Developmental Biology, and Molecular Biology (BCMB) program, Weill Cornell Graduate School of Medical Sciences, New York, NY 10065, USA
- Developmental Biology Program, Sloan Kettering Institute, Memorial Sloan Kettering, Cancer Center, New York, NY 10065, USA
| |
Collapse
|
2
|
Vaikakkara Chithran A, Allan DW, O'Connor TP. Adult expression of Semaphorins and Plexins is essential for motor neuron survival. Sci Rep 2023; 13:5894. [PMID: 37041188 PMCID: PMC10090137 DOI: 10.1038/s41598-023-32943-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 04/05/2023] [Indexed: 04/13/2023] Open
Abstract
Axon guidance cues direct the growth and steering of neuronal growth cones, thus guiding the axons to their targets during development. Nonetheless, after axons have reached their targets and established functional circuits, many mature neurons continue to express these developmental cues. The role of axon guidance cues in the adult nervous system has not been fully elucidated. Using the expression pattern data available on FlyBase, we found that more than 96% of the guidance genes that are expressed in the Drosophila melanogaster embryo continue to be expressed in adults. We utilized the GeneSwitch and TARGET systems to spatiotemporally knockdown the expression of these guidance genes selectively in the adult neurons, once the development was completed. We performed an RNA interference (RNAi) screen against 44 guidance genes in the adult Drosophila nervous system and identified 14 genes that are required for adult survival and normal motility. Additionally, we show that adult expression of Semaphorins and Plexins in motor neurons is necessary for neuronal survival, indicating that guidance genes have critical functions in the mature nervous system.
Collapse
Affiliation(s)
- Aarya Vaikakkara Chithran
- Graduate Program in Neuroscience, University of British Columbia, 3402-2215 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada
- Department of Cellular and Physiological Sciences, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Douglas W Allan
- Department of Cellular and Physiological Sciences, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada
| | - Timothy P O'Connor
- Department of Cellular and Physiological Sciences, University of British Columbia, 2350 Health Sciences Mall, Vancouver, BC, V6T 1Z3, Canada.
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, 2215 Wesbrook Mall, Vancouver, BC, V6T 1Z3, Canada.
| |
Collapse
|
3
|
Myers KR, Fan Y, McConnell P, Cooper JA, Zheng JQ. Actin capping protein regulates postsynaptic spine development through CPI-motif interactions. Front Mol Neurosci 2022; 15:1020949. [PMID: 36245917 PMCID: PMC9557104 DOI: 10.3389/fnmol.2022.1020949] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Accepted: 09/12/2022] [Indexed: 12/02/2022] Open
Abstract
Dendritic spines are small actin-rich protrusions essential for the formation of functional circuits in the mammalian brain. During development, spines begin as dynamic filopodia-like protrusions that are then replaced by relatively stable spines containing an expanded head. Remodeling of the actin cytoskeleton plays a key role in the formation and modification of spine morphology, however many of the underlying regulatory mechanisms remain unclear. Capping protein (CP) is a major actin regulating protein that caps the barbed ends of actin filaments, and promotes the formation of dense branched actin networks. Knockdown of CP impairs the formation of mature spines, leading to an increase in the number of filopodia-like protrusions and defects in synaptic transmission. Here, we show that CP promotes the stabilization of dendritic protrusions, leading to the formation of stable mature spines. However, the localization and function of CP in dendritic spines requires interactions with proteins containing a capping protein interaction (CPI) motif. We found that the CPI motif-containing protein Twinfilin-1 (Twf1) also localizes to spines where it plays a role in CP spine enrichment. The knockdown of Twf1 leads to an increase in the density of filopodia-like protrusions and a decrease in the stability of dendritic protrusions, similar to CP knockdown. Finally, we show that CP directly interacts with Shank and regulates its spine accumulation. These results suggest that spatiotemporal regulation of CP in spines not only controls the actin dynamics underlying the formation of stable postsynaptic spine structures, but also plays an important role in the assembly of the postsynaptic apparatus underlying synaptic function.
Collapse
Affiliation(s)
- Kenneth R. Myers
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
| | - Yanjie Fan
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
| | - Patrick McConnell
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO, United States
| | - John A. Cooper
- Department of Biochemistry and Molecular Biophysics, Washington University in St. Louis, St. Louis, MO, United States
| | - James Q. Zheng
- Department of Cell Biology, Emory University School of Medicine, Atlanta, GA, United States
- Department of Neurology, Emory University School of Medicine, Atlanta, GA, United States
- Center for Neurodegenerative Diseases, Emory University School of Medicine, Atlanta, GA, United States
| |
Collapse
|
4
|
Xu R, Li Y, Liu C, Shen N, Zhang Q, Cao T, Qin M, Han L, Tang D. Twinfilin regulates actin assembly and Hexagonal peroxisome 1 (Hex1) localization in the pathogenesis of rice blast fungus Magnaporthe oryzae. MOLECULAR PLANT PATHOLOGY 2021; 22:1641-1655. [PMID: 34519407 PMCID: PMC8578832 DOI: 10.1111/mpp.13136] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 08/06/2021] [Accepted: 08/18/2021] [Indexed: 05/06/2023]
Abstract
Actin assembly at the hyphal tip is key for polar growth and pathogenesis of the rice blast fungus Magnaporthe oryzae. The mechanism of its precise assemblies and biological functions is not understood. Here, we characterized the role of M. oryzae Twinfilin (MoTwf) in M. oryzae infection through organizing the actin cables that connect to Spitzenkörper (Spk) at the hyphal tip. MoTwf could bind and bundle the actin filaments. It formed a complex with Myosin2 (MoMyo2) and the Woronin body protein Hexagonal peroxisome 1 (MoHex1). Enrichment of MoMyo2 and MoHex1 in the hyphal apical region was disrupted in a ΔMotwf loss-of-function mutant, which also showed a decrease in the number and width of actin cables. These findings indicate that MoTwf participates in the virulence of M. oryzae by organizing Spk-connected actin filaments and regulating MoHex1 distribution at the hyphal tip.
Collapse
Affiliation(s)
- Rui Xu
- State Key Laboratory of Ecological Control of Fujian‐Taiwan Crop PestsKey Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of CropsPlant Immunity CenterFujian Agriculture and Forestry UniversityFuzhouChina
- College of Crop ScienceFujian Agriculture and Forestry UniversityFuzhouChina
| | - Yuan‐Bao Li
- State Key Laboratory of Ecological Control of Fujian‐Taiwan Crop PestsKey Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of CropsPlant Immunity CenterFujian Agriculture and Forestry UniversityFuzhouChina
- College of Crop ScienceFujian Agriculture and Forestry UniversityFuzhouChina
| | - Chengyu Liu
- State Key Laboratory of Ecological Control of Fujian‐Taiwan Crop PestsKey Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of CropsPlant Immunity CenterFujian Agriculture and Forestry UniversityFuzhouChina
- College of Life SciencesFujian Agriculture and Forestry UniversityFuzhouChina
| | - Ningning Shen
- State Key Laboratory of Ecological Control of Fujian‐Taiwan Crop PestsKey Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of CropsPlant Immunity CenterFujian Agriculture and Forestry UniversityFuzhouChina
- College of Crop ScienceFujian Agriculture and Forestry UniversityFuzhouChina
| | - Qian Zhang
- State Key Laboratory of Ecological Control of Fujian‐Taiwan Crop PestsKey Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of CropsPlant Immunity CenterFujian Agriculture and Forestry UniversityFuzhouChina
- College of Crop ScienceFujian Agriculture and Forestry UniversityFuzhouChina
| | - Tingyan Cao
- State Key Laboratory of Ecological Control of Fujian‐Taiwan Crop PestsKey Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of CropsPlant Immunity CenterFujian Agriculture and Forestry UniversityFuzhouChina
- College of Life SciencesFujian Agriculture and Forestry UniversityFuzhouChina
| | - Minghui Qin
- State Key Laboratory of Ecological Control of Fujian‐Taiwan Crop PestsKey Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of CropsPlant Immunity CenterFujian Agriculture and Forestry UniversityFuzhouChina
- College of Crop ScienceFujian Agriculture and Forestry UniversityFuzhouChina
| | - Li‐Bo Han
- State Key Laboratory of Ecological Control of Fujian‐Taiwan Crop PestsKey Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of CropsPlant Immunity CenterFujian Agriculture and Forestry UniversityFuzhouChina
- College of Crop ScienceFujian Agriculture and Forestry UniversityFuzhouChina
| | - Dingzhong Tang
- State Key Laboratory of Ecological Control of Fujian‐Taiwan Crop PestsKey Laboratory of Ministry of Education for Genetics, Breeding and Multiple Utilization of CropsPlant Immunity CenterFujian Agriculture and Forestry UniversityFuzhouChina
- College of Crop ScienceFujian Agriculture and Forestry UniversityFuzhouChina
| |
Collapse
|
5
|
Alteration of twinfilin1 expression underlies opioid withdrawal-induced remodeling of actin cytoskeleton at synapses and formation of aversive memory. Mol Psychiatry 2021; 26:6218-6236. [PMID: 33963280 DOI: 10.1038/s41380-021-01111-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 03/26/2021] [Accepted: 04/09/2021] [Indexed: 11/08/2022]
Abstract
Exposure to drugs of abuse induces alterations of dendritic spine morphology and density that has been proposed to be a cellular basis of long-lasting addictive memory and heavily depend on remodeling of its underlying actin cytoskeleton by the actin cytoskeleton regulators. However, the actin cytoskeleton regulators involved and the specific mechanisms whereby drugs of abuse alter their expression or function are largely unknown. Twinfilin (Twf1) is a highly conserved actin-depolymerizing factor that regulates actin dynamics in organisms from yeast to mammals. Despite abundant expression of Twf1 in mammalian brain, little is known about its importance for brain functions such as experience-dependent synaptic and behavioral plasticity. Here we show that conditioned morphine withdrawal (CMW)-induced synaptic structure and behavior plasticity depends on downregulation of Twf1 in the amygdala of rats. Genetically manipulating Twf1 expression in the amygdala bidirectionally regulates CMW-induced changes in actin polymerization, spine density and behavior. We further demonstrate that downregulation of Twf1 is due to upregulation of miR101a expression via a previously unrecognized mechanism involving CMW-induced increases in miR101a nuclear processing via phosphorylation of MeCP2 at Ser421. Our findings establish the importance of Twf1 in regulating opioid-induced synaptic and behavioral plasticity and demonstrate its value as a potential therapeutic target for the treatment of opioid addiction.
Collapse
|
6
|
Robbins M, Clayton E, Kaminski Schierle GS. Synaptic tau: A pathological or physiological phenomenon? Acta Neuropathol Commun 2021; 9:149. [PMID: 34503576 PMCID: PMC8428049 DOI: 10.1186/s40478-021-01246-y] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 08/12/2021] [Indexed: 12/17/2022] Open
Abstract
In this review, we discuss the synaptic aspects of Tau pathology occurring during Alzheimer's disease (AD) and how this may relate to memory impairment, a major hallmark of AD. Whilst the clinical diagnosis of AD patients is a loss of working memory and long-term declarative memory, the histological diagnosis is the presence of neurofibrillary tangles of hyperphosphorylated Tau and Amyloid-beta plaques. Tau pathology spreads through synaptically connected neurons to impair synaptic function preceding the formation of neurofibrillary tangles, synaptic loss, axonal retraction and cell death. Alongside synaptic pathology, recent data suggest that Tau has physiological roles in the pre- or post- synaptic compartments. Thus, we have seen a shift in the research focus from Tau as a microtubule-stabilising protein in axons, to Tau as a synaptic protein with roles in accelerating spine formation, dendritic elongation, and in synaptic plasticity coordinating memory pathways. We collate here the myriad of emerging interactions and physiological roles of synaptic Tau, and discuss the current evidence that synaptic Tau contributes to pathology in AD.
Collapse
|
7
|
Del Signore SJ, Kelley CF, Messelaar EM, Lemos T, Marchan MF, Ermanoska B, Mund M, Fai TG, Kaksonen M, Rodal AA. An autoinhibitory clamp of actin assembly constrains and directs synaptic endocytosis. eLife 2021; 10:69597. [PMID: 34324418 PMCID: PMC8321554 DOI: 10.7554/elife.69597] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Accepted: 06/21/2021] [Indexed: 01/05/2023] Open
Abstract
Synaptic membrane-remodeling events such as endocytosis require force-generating actin assembly. The endocytic machinery that regulates these actin and membrane dynamics localizes at high concentrations to large areas of the presynaptic membrane, but actin assembly and productive endocytosis are far more restricted in space and time. Here we describe a mechanism whereby autoinhibition clamps the presynaptic endocytic machinery to limit actin assembly to discrete functional events. We found that collective interactions between the Drosophila endocytic proteins Nwk/FCHSD2, Dap160/intersectin, and WASp relieve Nwk autoinhibition and promote robust membrane-coupled actin assembly in vitro. Using automated particle tracking to quantify synaptic actin dynamics in vivo, we discovered that Nwk-Dap160 interactions constrain spurious assembly of WASp-dependent actin structures. These interactions also promote synaptic endocytosis, suggesting that autoinhibition both clamps and primes the synaptic endocytic machinery, thereby constraining actin assembly to drive productive membrane remodeling in response to physiological cues. Neurons constantly talk to each other by sending chemical signals across the tiny gap, or ‘synapse’, that separates two cells. While inside the emitting cell, these molecules are safely packaged into small, membrane-bound vessels. Upon the right signal, the vesicles fuse with the external membrane of the neuron and spill their contents outside, for the receiving cell to take up and decode. The emitting cell must then replenish its vesicle supply at the synapse through a recycling mechanism known as endocytosis. To do so, it uses dynamically assembling rod-like ‘actin’ filaments, which work in concert with many other proteins to pull in patches of membrane as new vesicles. The proteins that control endocytosis and actin assembly abound at neuronal synapses, and, when mutated, are linked to many neurological diseases. Unlike other cell types, neurons appear to ‘pre-deploy’ these actin-assembly proteins to synaptic membranes, but to keep them inactive under normal conditions. How neurons control the way this machinery is recruited and activated remains unknown. To investigate this question, Del Signore et al. conducted two sets of studies. First, they exposed actin to several different purified proteins in initial ‘test tube’ experiments. This revealed that, depending on the conditions, a group of endocytosis proteins could prevent or promote actin assembly: assembly occurred only if the proteins were associated with membranes. Next, Del Signore et al. mutated these proteins in fruit fly larvae, and performed live cell microscopy to determine their impact on actin assembly and endocytosis. Consistent with the test tube findings, endocytosis mutants had more actin assembly overall, implying that the proteins were required to prevent random actin assembly. However, the same mutants had reduced levels of endocytosis, suggesting that the proteins were also necessary for productive actin assembly. Together, these experiments suggest that, much like a mousetrap holds itself poised ready to spring, some endocytic proteins play a dual role to restrain actin assembly when and where it is not needed, and to promote it at sites of endocytosis. These results shed new light on how neurons might build and maintain effective, working synapses. Del Signore et al. hope that this knowledge may help to better understand and combat neurological diseases, such as Alzheimer’s, which are linked to impaired membrane traffic and cell signalling.
Collapse
Affiliation(s)
| | | | | | - Tania Lemos
- Department of Biology, Brandeis University, Walltham, United States
| | | | | | - Markus Mund
- Department of Biochemistry and NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
| | - Thomas G Fai
- Department of Mathematics, Brandeis University, Waltham, United States
| | - Marko Kaksonen
- Department of Biochemistry and NCCR Chemical Biology, University of Geneva, Geneva, Switzerland
| | | |
Collapse
|
8
|
Yang Y, Ye X, Dang C, Cao Y, Hong R, Sun YH, Xiao S, Mei Y, Xu L, Fang Q, Xiao H, Li F, Ye G. Genome of the pincer wasp Gonatopus flavifemur reveals unique venom evolution and a dual adaptation to parasitism and predation. BMC Biol 2021; 19:145. [PMID: 34315471 PMCID: PMC8314478 DOI: 10.1186/s12915-021-01081-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Accepted: 06/30/2021] [Indexed: 02/07/2023] Open
Abstract
Background Hymenoptera comprise extremely diverse insect species with extensive variation in their life histories. The Dryinidae, a family of solitary wasps of Hymenoptera, have evolved innovations that allow them to hunt using venom and a pair of chelae developed from the fore legs that can grasp prey. Dryinidae larvae are also parasitoids of Auchenorrhyncha, a group including common pests such as planthoppers and leafhoppers. Both of these traits make them effective and valuable for pest control, but little is yet known about the genetic basis of its dual adaptation to parasitism and predation. Results We sequenced and assembled a high-quality genome of the dryinid wasp Gonatopus flavifemur, which at 636.5 Mb is larger than most hymenopterans. The expansion of transposable elements, especially DNA transposons, is a major contributor to the genome size enlargement. Our genome-wide screens reveal a number of positively selected genes and rapidly evolving proteins involved in energy production and motor activity, which may contribute to the predatory adaptation of dryinid wasp. We further show that three female-biased, reproductive-associated yellow genes, in response to the prey feeding behavior, are significantly elevated in adult females, which may facilitate the egg production. Venom is a powerful weapon for dryinid wasp during parasitism and predation. We therefore analyze the transcriptomes of venom glands and describe specific expansions in venom Idgf-like genes and neprilysin-like genes. Furthermore, we find the LWS2-opsin gene is exclusively expressed in male G. flavifemur, which may contribute to partner searching and mating. Conclusions Our results provide new insights into the genome evolution, predatory adaptation, venom evolution, and sex-biased genes in G. flavifemur, and present genomic resources for future in-depth comparative analyses of hymenopterans that may benefit pest control. Supplementary Information The online version contains supplementary material available at 10.1186/s12915-021-01081-6.
Collapse
Affiliation(s)
- Yi Yang
- State Key Laboratory of Rice Biology and Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Xinhai Ye
- State Key Laboratory of Rice Biology and Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Cong Dang
- State Key Laboratory of Rice Biology and Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Yunshen Cao
- State Key Laboratory of Rice Biology and Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Rui Hong
- State Key Laboratory of Rice Biology and Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Yu H Sun
- Department of Biology, University of Rochester, Rochester, NY, USA
| | - Shan Xiao
- State Key Laboratory of Rice Biology and Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Yang Mei
- State Key Laboratory of Rice Biology and Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Le Xu
- State Key Laboratory of Rice Biology and Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Qi Fang
- State Key Laboratory of Rice Biology and Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Huamei Xiao
- State Key Laboratory of Rice Biology and Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China.,Key Laboratory of Crop Growth and Development Regulation of Jiangxi Province, College of Life Sciences and Resource Environment, Yichun University, Yichun, China
| | - Fei Li
- State Key Laboratory of Rice Biology and Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China
| | - Gongyin Ye
- State Key Laboratory of Rice Biology and Ministry of Agricultural and Rural Affairs Key Laboratory of Molecular Biology of Crop Pathogens and Insects, Zhejiang University, Hangzhou, China.
| |
Collapse
|
9
|
Devitt CC, Lee C, Cox RM, Papoulas O, Alvarado J, Shekhar S, Marcotte EM, Wallingford JB. Twinfilin1 controls lamellipodial protrusive activity and actin turnover during vertebrate gastrulation. J Cell Sci 2021; 134:jcs254011. [PMID: 34060614 PMCID: PMC8325956 DOI: 10.1242/jcs.254011] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 05/12/2021] [Indexed: 11/20/2022] Open
Abstract
The dynamic control of the actin cytoskeleton is a key aspect of essentially all animal cell movements. Experiments in single migrating cells and in vitro systems have provided an exceptionally deep understanding of actin dynamics. However, we still know relatively little of how these systems are tuned in cell-type-specific ways, for example in the context of collective cell movements that sculpt the early embryo. Here, we provide an analysis of the actin-severing and depolymerization machinery during vertebrate gastrulation, with a focus on Twinfilin1 (Twf1) in Xenopus. We find that Twf1 is essential for convergent extension, and loss of Twf1 results in a disruption of lamellipodial dynamics and polarity. Moreover, Twf1 loss results in a failure to assemble polarized cytoplasmic actin cables, which are essential for convergent extension. These data provide an in vivo complement to our more-extensive understanding of Twf1 action in vitro and provide new links between the core machinery of actin regulation and the specialized cell behaviors of embryonic morphogenesis.
Collapse
Affiliation(s)
- Caitlin C. Devitt
- Department of Molecular Biosciences, University of Texas, Austin, TX 78712, USA
| | - Chanjae Lee
- Department of Molecular Biosciences, University of Texas, Austin, TX 78712, USA
| | - Rachael M. Cox
- Department of Molecular Biosciences, University of Texas, Austin, TX 78712, USA
| | - Ophelia Papoulas
- Department of Molecular Biosciences, University of Texas, Austin, TX 78712, USA
| | - José Alvarado
- Department of Physics, University of Texas, Austin, TX 78712, USA
| | - Shashank Shekhar
- Department of Physics, Emory University, Atlanta, GA 30322, USA
- Department of Cell Biology, Emory University, Atlanta, GA 30322, USA
| | - Edward M. Marcotte
- Department of Molecular Biosciences, University of Texas, Austin, TX 78712, USA
| | - John B. Wallingford
- Department of Molecular Biosciences, University of Texas, Austin, TX 78712, USA
| |
Collapse
|
10
|
Twinfilin uncaps filament barbed ends to promote turnover of lamellipodial actin networks. Nat Cell Biol 2021; 23:147-159. [PMID: 33558729 DOI: 10.1038/s41556-020-00629-y] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 12/21/2020] [Indexed: 01/18/2023]
Abstract
Coordinated polymerization of actin filaments provides force for cell migration, morphogenesis and endocytosis. Capping protein (CP) is a central regulator of actin dynamics in all eukaryotes. It binds to actin filament (F-actin) barbed ends with high affinity and slow dissociation kinetics to prevent filament polymerization and depolymerization. However, in cells, CP displays remarkably rapid dynamics within F-actin networks, but the underlying mechanism remains unclear. Here, we report that the conserved cytoskeletal regulator twinfilin is responsible for CP's rapid dynamics and specific localization in cells. Depletion of twinfilin led to stable association between CP and cellular F-actin arrays, as well as to its retrograde movement throughout leading-edge lamellipodia. These were accompanied by diminished F-actin turnover rates. In vitro single-filament imaging approaches revealed that twinfilin directly promotes dissociation of CP from filament barbed ends, while enabling subsequent filament depolymerization. These results uncover a bipartite mechanism that controls how actin cytoskeleton-mediated forces are generated in cells.
Collapse
|
11
|
Mwangangi DM, Manser E, Robinson RC. The structure of the actin filament uncapping complex mediated by twinfilin. SCIENCE ADVANCES 2021; 7:eabd5271. [PMID: 33571120 PMCID: PMC7840138 DOI: 10.1126/sciadv.abd5271] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 12/08/2020] [Indexed: 05/25/2023]
Abstract
Uncapping of actin filaments is essential for driving polymerization and depolymerization dynamics from capping protein-associated filaments; however, the mechanisms of uncapping leading to rapid disassembly are unknown. Here, we elucidated the x-ray crystal structure of the actin/twinfilin/capping protein complex to address the mechanisms of twinfilin uncapping of actin filaments. The twinfilin/capping protein complex binds to two G-actin subunits in an orientation that resembles the actin filament barbed end. This suggests an unanticipated mechanism by which twinfilin disrupts the stable capping of actin filaments by inducing a G-actin conformation in the two terminal actin subunits. Furthermore, twinfilin disorders critical actin-capping protein interactions, which will assist in the dissociation of capping protein, and may promote filament uncapping through a second mechanism involving V-1 competition for an actin-binding surface on capping protein. The extensive interactions with capping protein indicate that the evolutionary conserved role of twinfilin is to uncap actin filaments.
Collapse
Affiliation(s)
- Dennis M Mwangangi
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis, Singapore 138673, Singapore
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Edward Manser
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis, Singapore 138673, Singapore
- Department of Pharmacology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117597, Singapore
| | - Robert C Robinson
- Institute of Molecular and Cell Biology, A*STAR (Agency for Science, Technology and Research), Biopolis, Singapore 138673, Singapore.
- School of Biomolecular Science and Engineering (BSE), Vidyasirimedhi Institute of Science and Technology (VISTEC), Rayong 21210, Thailand
- Research Institute for Interdisciplinary Science (RIIS), Okayama University, Okayama 700-8530, Japan
| |
Collapse
|
12
|
Yoo DY, Jung HY, Kim W, Hahn KR, Kwon HJ, Nam SM, Chung JY, Yoon YS, Kim DW, Hwang IK. Entacapone Treatment Modulates Hippocampal Proteins Related to Synaptic Vehicle Trafficking. Cells 2020; 9:cells9122712. [PMID: 33352833 PMCID: PMC7765944 DOI: 10.3390/cells9122712] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/09/2020] [Accepted: 12/10/2020] [Indexed: 11/29/2022] Open
Abstract
Entacapone, a reversible inhibitor of catechol-O-methyl transferase, is used for patients in Parkinson’s disease because it increases the bioavailability and effectiveness of levodopa. In the present study, we observed that entacapone increases novel object recognition and neuroblasts in the hippocampus. In the present study, two-dimensional electrophoresis (2-DE) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry were performed to compare the abundance profiles of proteins expressed in the hippocampus after entacapone treatment in mice. Results of 2-DE, MALDI-TOF mass spectrometry, and subsequent proteomic analysis revealed an altered protein expression profile in the hippocampus after entacapone treatment. Based on proteomic analysis, 556 spots were paired during the image analysis of 2-DE gels and 76 proteins were significantly changed more than two-fold among identified proteins. Proteomic analysis indicated that treatment with entacapone induced expressional changes in proteins involved in synaptic transmission, cellular processes, cellular signaling, the regulation of cytoskeletal structure, energy metabolism, and various subcellular enzymatic reactions. In particular, entacapone significantly increased proteins related to synaptic trafficking and plasticity, such as dynamin 1, synapsin I, and Munc18-1. Immunohistochemical staining showed the localization of the proteins, and western blot confirmed the significant increases in dynamin I (203.5% of control) in the hippocampus as well as synapsin I (254.0% of control) and Munc18-1 (167.1% of control) in the synaptic vesicle fraction of hippocampus after entacapone treatment. These results suggest that entacapone can enhance hippocampal synaptic trafficking and plasticity against various neurological diseases related to hippocampal dysfunction.
Collapse
Affiliation(s)
- Dae Young Yoo
- Department of Anatomy and Cell Biology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (D.Y.Y.); (H.Y.J.); (W.K.); (K.R.H.); (Y.S.Y.)
- Department of Anatomy, College of Medicine, Soonchunhyang University, Cheonan 31151, Korea
| | - Hyo Young Jung
- Department of Anatomy and Cell Biology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (D.Y.Y.); (H.Y.J.); (W.K.); (K.R.H.); (Y.S.Y.)
| | - Woosuk Kim
- Department of Anatomy and Cell Biology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (D.Y.Y.); (H.Y.J.); (W.K.); (K.R.H.); (Y.S.Y.)
- Department of Biomedical Sciences, Research Institute for Bioscience and Biotechnology, Hallym University, Chuncheon 24252, Korea
| | - Kyu Ri Hahn
- Department of Anatomy and Cell Biology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (D.Y.Y.); (H.Y.J.); (W.K.); (K.R.H.); (Y.S.Y.)
| | - Hyun Jung Kwon
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University, Gangneung 25457, Korea;
| | - Sung Min Nam
- Department of Anatomy, School of Medicine and Institute for Environmental Science, Wonkwang University, Iksan 54538, Korea;
| | - Jin Young Chung
- Department of Veterinary Internal Medicine and Geriatrics, College of Veterinary Medicine, Kangwon National University, Chuncheon 24341, Korea;
| | - Yeo Sung Yoon
- Department of Anatomy and Cell Biology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (D.Y.Y.); (H.Y.J.); (W.K.); (K.R.H.); (Y.S.Y.)
| | - Dae Won Kim
- Department of Biochemistry and Molecular Biology, Research Institute of Oral Sciences, College of Dentistry, Gangneung-Wonju National University, Gangneung 25457, Korea;
- Correspondence: (D.W.K.); (I.K.H.)
| | - In Koo Hwang
- Department of Anatomy and Cell Biology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University, Seoul 08826, Korea; (D.Y.Y.); (H.Y.J.); (W.K.); (K.R.H.); (Y.S.Y.)
- Correspondence: (D.W.K.); (I.K.H.)
| |
Collapse
|
13
|
Zhao K, Hong H, Zhao L, Huang S, Gao Y, Metwally E, Jiang Y, Sigrist SJ, Zhang YQ. Postsynaptic cAMP signalling regulates the antagonistic balance of Drosophila glutamate receptor subtypes. Development 2020; 147:226061. [PMID: 33234716 PMCID: PMC7758632 DOI: 10.1242/dev.191874] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Accepted: 11/13/2020] [Indexed: 12/19/2022]
Abstract
The balance among different subtypes of glutamate receptors (GluRs) is crucial for synaptic function and plasticity at excitatory synapses. However, the mechanisms balancing synaptic GluR subtypes remain unclear. Herein, we show that the two subtypes of GluRs (A and B) expressed at Drosophila neuromuscular junction synapses mutually antagonize each other in terms of their relative synaptic levels and affect subsynaptic localization of each other, as shown by super-resolution microscopy. Upon temperature shift-induced neuromuscular junction plasticity, GluR subtype A increased but subtype B decreased with a timecourse of hours. Inhibition of the activity of GluR subtype A led to imbalance of GluR subtypes towards more GluRIIA. To gain a better understanding of the signalling pathways underlying the balance of GluR subtypes, we performed an RNA interference screen of candidate genes and found that postsynaptic-specific knockdown of dunce, which encodes cAMP phosphodiesterase, increased levels of GluR subtype A but decreased subtype B. Furthermore, bidirectional alterations of postsynaptic cAMP signalling resulted in the same antagonistic regulation of the two GluR subtypes. Our findings thus identify a direct role of postsynaptic cAMP signalling in control of the plasticity-related balance of GluRs. Summary: The antagonistic balance of GluR subtypes, which is associated with synaptic plasticity, is regulated by cAMP signalling in postsynaptic muscles of Drosophila NMJ synapses.
Collapse
Affiliation(s)
- Kai Zhao
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Huilin Hong
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Lu Zhao
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Sheng Huang
- Freie Universität Berlin, Institute for Biology/Genetics, Takustrasse 6, 14195 Berlin, Germany
| | - Ying Gao
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Elsayed Metwally
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yuqiang Jiang
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Stephan J Sigrist
- Freie Universität Berlin, Institute for Biology/Genetics, Takustrasse 6, 14195 Berlin, Germany.,NeuroCure, Charite, Chariteplatz 1, 10117 Berlin, Germany
| | - Yong Q Zhang
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| |
Collapse
|
14
|
Ojelade SA, Lee TV, Giagtzoglou N, Yu L, Ugur B, Li Y, Duraine L, Zuo Z, Petyuk V, De Jager PL, Bennett DA, Arenkiel BR, Bellen HJ, Shulman JM. cindr, the Drosophila Homolog of the CD2AP Alzheimer's Disease Risk Gene, Is Required for Synaptic Transmission and Proteostasis. Cell Rep 2019; 28:1799-1813.e5. [PMID: 31412248 PMCID: PMC6703184 DOI: 10.1016/j.celrep.2019.07.041] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Revised: 05/30/2019] [Accepted: 07/15/2019] [Indexed: 12/11/2022] Open
Abstract
The Alzheimer's disease (AD) susceptibility gene, CD2-associated protein (CD2AP), encodes an actin binding adaptor protein, but its function in the nervous system is largely unknown. Loss of the Drosophila ortholog cindr enhances neurotoxicity of human Tau, which forms neurofibrillary tangle pathology in AD. We show that Cindr is expressed in neurons and present at synaptic terminals. cindr mutants show impairments in synapse maturation and both synaptic vesicle recycling and release. Cindr associates and genetically interacts with 14-3-3ζ, regulates the ubiquitin-proteasome system, and affects turnover of Synapsin and the plasma membrane calcium ATPase (PMCA). Loss of cindr elevates PMCA levels and reduces cytosolic calcium. Studies of Cd2ap null mice support a conserved role in synaptic proteostasis, and CD2AP protein levels are inversely related to Synapsin abundance in human postmortem brains. Our results reveal CD2AP neuronal requirements with relevance to AD susceptibility, including for proteostasis, calcium handling, and synaptic structure and function.
Collapse
Affiliation(s)
- Shamsideen A Ojelade
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Tom V Lee
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Nikolaos Giagtzoglou
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Lei Yu
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
| | - Berrak Ugur
- Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Yarong Li
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA
| | - Lita Duraine
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Zhongyuan Zuo
- Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Vlad Petyuk
- Pacific Northwest National Laboratory, Richland, WA 99354, USA
| | - Philip L De Jager
- Center for Translational & Computational Neuroimmunology, Department of Neurology and the Taub Institute, Columbia University Medical Center, New York, NY 10032, USA; Cell Circuits Program, Broad Institute, Cambridge, MA 02142, USA
| | - David A Bennett
- Rush Alzheimer's Disease Center, Rush University Medical Center, Chicago, IL 60612, USA
| | - Benjamin R Arenkiel
- Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hugo J Bellen
- Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA; Howard Hughes Medical Institute, Baylor College of Medicine, Houston, TX 77030, USA
| | - Joshua M Shulman
- Department of Neurology, Baylor College of Medicine, Houston, TX 77030, USA; Jan and Dan Duncan Neurologic Research Institute, Texas Children's Hospital, Houston, TX 77030, USA; Program in Developmental Biology, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular & Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA; Department of Neuroscience, Baylor College of Medicine, Houston, TX 77030, USA.
| |
Collapse
|
15
|
Ou M, Wang S, Sun M, An J, Lv H, Zeng X, Hou SX, Xie W. The PDZ-GEF Gef26 regulates synapse development and function via FasII and Rap1 at the Drosophila neuromuscular junction. Exp Cell Res 2018; 374:342-352. [PMID: 30553967 DOI: 10.1016/j.yexcr.2018.12.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Revised: 12/09/2018] [Accepted: 12/12/2018] [Indexed: 12/29/2022]
Abstract
Guanine nucleotide exchange factors (GEFs) are essential for small G proteins to activate their downstream signaling pathways, which are involved in morphogenesis, cell adhesion, and migration. Mutants of Gef26, a PDZ-GEF (PDZ domain-containing guanine nucleotide exchange factor) in Drosophila, exhibit strong defects in wings, eyes, and the reproductive and nervous systems. However, the precise roles of Gef26 in development remain unclear. In the present study, we analyzed the role of Gef26 in synaptic development and function. We identified significant decreases in bouton number and branch length at larval neuromuscular junctions (NMJs) in Gef26 mutants, and these defects were fully rescued by restoring Gef26 expression, indicating that Gef26 plays an important role in NMJ morphogenesis. In addition to the observed defects in NMJ morphology, electrophysiological analyses revealed functional defects at NMJs, and locomotor deficiency appeared in Gef26 mutant larvae. Furthermore, Gef26 regulated NMJ morphogenesis by regulating the level of synaptic Fasciclin II (FasII), a well-studied cell adhesion molecule that functions in NMJ development and remodeling. Finally, our data demonstrate that Gef26-specific small G protein Rap1 worked downstream of Gef26 to regulate the level of FasII at NMJs, possibly through a βPS integrin-mediated signaling pathway. Taken together, our findings define a novel role of Gef26 in regulating NMJ development and function.
Collapse
Affiliation(s)
- Mengzhu Ou
- The Key Laboratory of Development Genes and Human Diseases, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Su Wang
- The Key Laboratory of Development Genes and Human Diseases, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Mingkuan Sun
- The Key Laboratory of Development Genes and Human Diseases, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Jinsong An
- The Key Laboratory of Development Genes and Human Diseases, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Huihui Lv
- The Key Laboratory of Development Genes and Human Diseases, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Xiankun Zeng
- Basic Research Laboratory, National Cancer Institute at Frederick, NIH, Frederick, MD 21702, USA
| | - Steven X Hou
- Basic Research Laboratory, National Cancer Institute at Frederick, NIH, Frederick, MD 21702, USA.
| | - Wei Xie
- The Key Laboratory of Development Genes and Human Diseases, Ministry of Education, Institute of Life Sciences, Southeast University, Nanjing 210096, China.
| |
Collapse
|
16
|
Johnston AB, Hilton DM, McConnell P, Johnson B, Harris MT, Simone A, Amarasinghe GK, Cooper JA, Goode BL. A novel mode of capping protein-regulation by twinfilin. eLife 2018; 7:41313. [PMID: 30351272 PMCID: PMC6249002 DOI: 10.7554/elife.41313] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2018] [Accepted: 10/22/2018] [Indexed: 12/29/2022] Open
Abstract
Cellular actin assembly is controlled at the barbed ends of actin filaments, where capping protein (CP) limits polymerization. Twinfilin is a conserved in vivo binding partner of CP, yet the significance of this interaction has remained a mystery. Here, we discover that the C-terminal tail of Twinfilin harbors a CP-interacting (CPI) motif, identifying it as a novel CPI-motif protein. Twinfilin and the CPI-motif protein CARMIL have overlapping binding sites on CP. Further, Twinfilin binds competitively with CARMIL to CP, protecting CP from barbed-end displacement by CARMIL. Twinfilin also accelerates dissociation of the CP inhibitor V-1, restoring CP to an active capping state. Knockdowns of Twinfilin and CP each cause similar defects in cell morphology, and elevated Twinfilin expression rescues defects caused by CARMIL hyperactivity. Together, these observations define Twinfilin as the first ‘pro-capping’ ligand of CP and lead us to propose important revisions to our understanding of the CP regulatory cycle. Plant and animal cells are supported by skeleton-like structures that can grow and shrink beneath the cell membrane, pushing and pulling on the edges of the cell. This scaffolding network – known as the cytoskeleton – contains long strands, or filaments, made from many identical copies of a protein called actin. The shape of the actin proteins allows them to slot together, end-to-end, and allows the strands to grow and shrink on-demand. When the strands are the correct length, the cell caps the growing ends with a protein known as Capping Protein. This helps to stabilize the cell’s skeleton, preventing the strands from getting any longer, or any shorter. Proteins that interfere with the activity of Capping Protein allow the actin strands to grow or shrink. Some, like a protein called V-1, attach to Capping Protein and get in the way so that it cannot sit on the ends of the actin strands. Others, like CARMIL, bind to Capping Protein and change its shape, making it more likely to fall off the strands. So far, no one had found a partner that helps Capping Protein limit the growth of the actin cytoskeleton. A protein called Twinfilin often appears alongside Capping Protein, but the two proteins seemed to have no influence on each other, and had what appeared to be different roles. Whilst Capping Protein blocks growth and stabilizes actin strands, Twinfilin speeds up their disassembly at their ends. But Johnston, Hilton et al. now reveal that the two proteins actually work together. Twinfilin helps Capping Protein resist the effects of CARMIL and V-1, and Capping Protein puts Twinfilin at the end of the strand. Thus, when Capping Protein is finally removed by CARMIL, Twinfilin carries on with disassembling the actin strands. The tail of the Twinfilin protein looks like part of the CARMIL protein, suggesting that they might interact with Capping Protein in the same way. Attaching a fluorescent tag to the Twinfilin tail revealed that the two proteins compete to attach to the same part of the Capping Protein. When mouse cells produced extra Twinfilin, it blocked the effects of CARMIL, helping to grow the actin strands. V-1 attaches to Capping Protein in a different place, but Twinfilin was also able to interfere with its activity. When Twinfilin attached to the CARMIL binding site, it did not directly block V-1 binding, but it made the protein more likely to fall off. Understanding how the actin cytoskeleton moves is a key question in cell biology, but it also has applications in medicine. Twinfilin plays a role in the spread of certain blood cancer cells, and in the formation of elaborate structures in the inner ear that help us hear. Understanding how Twinfilin and Capping Protein interact could open paths to new therapies for a range of medical conditions.
Collapse
Affiliation(s)
- Adam B Johnston
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, United States
| | - Denise M Hilton
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, United States
| | - Patrick McConnell
- Department of Biochemistry and Molecular Biophysics, Washington University, St Louis, United states
| | - Britney Johnson
- Department of Pathology and Immunology, Washington University, St Louis, United States
| | - Meghan T Harris
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, United States
| | - Avital Simone
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, United States
| | - Gaya K Amarasinghe
- Department of Pathology and Immunology, Washington University, St Louis, United States
| | - John A Cooper
- Department of Biochemistry and Molecular Biophysics, Washington University, St Louis, United states
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, United States
| |
Collapse
|
17
|
Ogienko AA, Yarinich LA, Fedorova EV, Lebedev MO, Andreyeva EN, Pindyurin AV, Baricheva EM. New slbo-Gal4 driver lines for the analysis of border cell migration during Drosophila oogenesis. Chromosoma 2018; 127:475-487. [DOI: 10.1007/s00412-018-0676-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Revised: 06/09/2018] [Accepted: 06/28/2018] [Indexed: 12/23/2022]
|
18
|
Hilton DM, Aguilar RM, Johnston AB, Goode BL. Species-Specific Functions of Twinfilin in Actin Filament Depolymerization. J Mol Biol 2018; 430:3323-3336. [PMID: 29928893 DOI: 10.1016/j.jmb.2018.06.025] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Revised: 05/28/2018] [Accepted: 06/12/2018] [Indexed: 11/16/2022]
Abstract
Twinfilin is a highly conserved member of the actin depolymerization factor homology (ADF-H) protein superfamily, which also includes ADF/Cofilin, Abp1/Drebrin, GMF, and Coactosin. Twinfilin has a unique molecular architecture consisting of two ADF-H domains joined by a linker and followed by a C-terminal tail. Yeast Twinfilin, in conjunction with yeast cyclase-associated protein (Srv2/CAP), increases the rate of depolymerization at both the barbed and pointed ends of actin filaments. However, it has remained unclear whether these activities extend to Twinfilin homologs in other species. To address this, we purified the three mouse Twinfilin isoforms (mTwf1, mTwf2a, mTwf2b) and mouse CAP1, and used total internal reflection fluorescence microscopy assays to study their effects on filament disassembly. Our results show that all three mouse Twinfilin isoforms accelerate barbed end depolymerization similar to yeast Twinfilin, suggesting that this activity is evolutionarily conserved. In striking contrast, mouse Twinfilin isoforms and CAP1 failed to induce rapid pointed end depolymerization. Using chimeras, we show that the yeast-specific pointed end depolymerization activity is specified by the C-terminal ADF-H domain of yeast Twinfilin. In addition, Tropomyosin decoration of filaments failed to impede depolymerization by yeast and mouse Twinfilin and Srv2/CAP, but inhibited Cofilin severing. Together, our results indicate that Twinfilin has conserved functions in regulating barbed end dynamics, although its ability to drive rapid pointed end depolymerization appears to be species-specific. We discuss the implications of this work, including that pointed end depolymerization may be catalyzed by different ADF-H family members in different species.
Collapse
Affiliation(s)
- Denise M Hilton
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Rey M Aguilar
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Adam B Johnston
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, MA 02454, USA.
| |
Collapse
|
19
|
Structure, dynamics, and biochemical characterization of ADF/cofilin Twinstar from Drosophilamelanogaster. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2018; 1866:885-898. [PMID: 29709602 DOI: 10.1016/j.bbapap.2018.04.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 04/25/2018] [Accepted: 04/25/2018] [Indexed: 11/22/2022]
Abstract
BACKGROUND Twinstar is an ADF/cofilin family protein, which is expressed by the tsr gene in Drosophila melanogaster. Twinstar is one of the main regulators of actin cytoskeleton remodelling and is essential for vital cellular processes like cytokinesis and endocytosis. METHODS We have characterized the structure and dynamics of Twinstar by solution NMR spectroscopy, the interaction of Twinstar with rabbit muscle actin by ITC, and biochemical activities of Twinstar through different biochemical assays using fluorescence spectroscopy and ultra-centrifugation. RESULTS The solution structure of Twinstar shows characteristic ADF-H fold with well-formed G/F-site and F-site for interaction with actin. The structure possesses an extended F-loop, which is rigid at the base, but flexible towards its apical region. Twinstar shares similar dynamics for the G/F-site with C. elegans homologs, UNC-60A and UNC-60B. However, the dynamics of its F-loop are different from its C. elegans homologs. Twinstar shows strong affinity for ADP-G-Actin and ATP-G-Actin with Kds of ~7.6 nM and ~0.4 μM, respectively. It shows mild F-actin depolymerizing activity and stable interaction with F-actin with a Kd of ~5.0 μM. It inhibits the rate of the nucleotide exchange in a dose dependent manner. CONCLUSION On the basis of structure, dynamics, and biochemical activity, Twinstar can be taken to execute its biochemical role by facilitating directional growth and maintenance of length of actin filaments. GENERAL SIGNIFICANCE This study characterizes the structure, backbone dynamics, and biochemical activities of Twinstar of Drosophila, which provides an insight into the regulation of actin dynamics in the member of phylum insecta.
Collapse
|
20
|
Hakala M, Kalimeri M, Enkavi G, Vattulainen I, Lappalainen P. Molecular mechanism for inhibition of twinfilin by phosphoinositides. J Biol Chem 2018; 293:4818-4829. [PMID: 29425097 DOI: 10.1074/jbc.ra117.000484] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2017] [Revised: 01/30/2018] [Indexed: 12/22/2022] Open
Abstract
Membrane phosphoinositides control organization and dynamics of the actin cytoskeleton by regulating the activities of several key actin-binding proteins. Twinfilin is an evolutionarily conserved protein that contributes to cytoskeletal dynamics by interacting with actin monomers, filaments, and the heterodimeric capping protein. Twinfilin also binds phosphoinositides, which inhibit its interactions with actin, but the underlying mechanism has remained unknown. Here, we show that the high-affinity binding site of twinfilin for phosphoinositides is located at the C-terminal tail region, whereas the two actin-depolymerizing factor (ADF)/cofilin-like ADF homology domains of twinfilin bind phosphoinositides only with low affinity. Mutagenesis and biochemical experiments combined with atomistic molecular dynamics simulations reveal that the C-terminal tail of twinfilin interacts with membranes through a multivalent electrostatic interaction with a preference toward phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2), PI(4,5)P2, and PI(3,4,5)P3 This initial interaction places the actin-binding ADF homology domains of twinfilin in close proximity to the membrane and subsequently promotes their association with the membrane, thus leading to inhibition of the actin interactions. In support of this model, a twinfilin mutant lacking the C-terminal tail inhibits actin filament assembly in a phosphoinositide-insensitive manner. Our mutagenesis data also reveal that the phosphoinositide- and capping protein-binding sites overlap in the C-terminal tail of twinfilin, suggesting that phosphoinositide binding additionally inhibits the interactions of twinfilin with the heterodimeric capping protein. The results demonstrate that the conserved C-terminal tail of twinfilin is a multifunctional binding motif, which is crucial for interaction with the heterodimeric capping protein and for tethering twinfilin to phosphoinositide-rich membranes.
Collapse
Affiliation(s)
- Markku Hakala
- Institute of Biotechnology, FI-00014 Helsinki, Finland
| | - Maria Kalimeri
- Laboratory of Physics, Tampere University of Technology, FI-33101 Tampere, Finland
| | - Giray Enkavi
- Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland
| | - Ilpo Vattulainen
- Laboratory of Physics, Tampere University of Technology, FI-33101 Tampere, Finland; Department of Physics, University of Helsinki, FI-00014 Helsinki, Finland; MEMPHYS Center for Biomembrane Physics, University of Southern Denmark, DK-5230 Odense, Denmark
| | | |
Collapse
|
21
|
Wu CH, Giampetruzzi A, Tran H, Fallini C, Gao FB, Landers JE. A Drosophila model of ALS reveals a partial loss of function of causative human PFN1 mutants. Hum Mol Genet 2017; 26:2146-2155. [PMID: 28379367 DOI: 10.1093/hmg/ddx112] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Accepted: 03/16/2017] [Indexed: 01/04/2023] Open
Abstract
Mutations in the profilin 1 (PFN1) gene are causative for familial amyotrophic lateral sclerosis (fALS). However, it is still not fully understood how these mutations lead to neurodegeneration. To address this question, we generated a novel Drosophila model expressing human wild-type and ALS-causative PFN1 mutants. We show that at larval neuromuscular junctions (NMJ), motor neuron expression of wild-type human PFN1 increases the number of ghost boutons, active zone density, F-actin content, and the formation of filopodia. In contrast, the expression of ALS-causative human PFN1 mutants causes a less pronounced phenotype, suggesting a loss of function of these mutants in promoting NMJ remodeling. Importantly, expression of human PFN1 in motor neurons results in progressive locomotion defects and shorter lifespan in adult flies, while ALS-causative PFN1 mutants display a less toxic effect. In summary, our study provides evidence that PFN1 is important in regulating NMJ morphology and influences survival and locomotion in Drosophila. Furthermore, our results suggest ALS-causative human PFN1 mutants display a partial loss of function relative to wild-type hPFN1 that may contribute to human disease pathogenesis.
Collapse
Affiliation(s)
- Chi-Hong Wu
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Anthony Giampetruzzi
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Helene Tran
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Claudia Fallini
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - Fen-Biao Gao
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| | - John E Landers
- Department of Neurology, University of Massachusetts Medical School, Worcester, MA 01605, USA
| |
Collapse
|
22
|
Zardi-Bergaoui A, Ben Nejma A, Harzallah-Skhiri F, Flamini G, Ascrizzi R, Ben Jannet H. Chemical Composition and Biological Studies of the Essential Oil from Aerial Parts of Beta vulgaris subsp. maritima (L.) Arcang. Growing in Tunisia. Chem Biodivers 2017; 14. [PMID: 28613450 DOI: 10.1002/cbdv.201700234] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Accepted: 06/09/2017] [Indexed: 12/12/2022]
Abstract
The chemical composition, antioxidant, cytotoxic, anticholinesterase and anti-tyrosinase activities of the hydrodistilled essential oil of the aerial parts of Beta vulgaris subsp. maritime (L.) Arcang. from Tunisia have been evaluated. The chemical composition of the oil (yield 0.037% [w/w]), determined by GC-FID and GC/MS is reported for the first time. Twenty five components, accounting for 98.1% of the total oil have been identified. The oil was characterized by a high proportion of oxygenated sesquiterpenes (39.2%), followed by sesquiterpene hydrocarbons (30.3%) and one apocarotenoids (26.3%). The main compounds were γ-irone (26.3%), α-cadinol (12.1%), T-cadinol (10.6%), bicyclogermacrene (10.4%) and δ-cadinene (6.0%). The isolated oil was tested for its antioxidant activity using the DPPH· , ABTS+· , catalase, and paraoxonase assays and also for its cytotoxic, anticholinesterase, and anti-tyrosinase activities. The essential oil exhibited high antioxidant activity (IC50 = 0.055 ± 0.006 mg/ml) and important result oncatalase (524.447 ± 2.58 Units/mg protein). Furthermore, it exerted a significant cytotoxic effect against A549 cell line, with IC50 = 42.44 ± 1.40 μg/ml. The results indicate that the essential oil of B. vulgaris subsp. maritima (L.) Arcang. aerial parts may be used in future as an alternative to synthetic antioxidant agents, with potential application in the food and pharmaceutical industries.
Collapse
Affiliation(s)
- Afifa Zardi-Bergaoui
- Laboratory of Heterocyclic Chemistry, Natural Products and Reactivity (LR11ES39), Team: Medicinal Chemistry and Natural Products, Faculty of Science of Monastir, University of Monastir, Avenue of Environment, 5019, Monastir, Tunisia
| | - Aymen Ben Nejma
- Laboratory of Heterocyclic Chemistry, Natural Products and Reactivity (LR11ES39), Team: Medicinal Chemistry and Natural Products, Faculty of Science of Monastir, University of Monastir, Avenue of Environment, 5019, Monastir, Tunisia
| | - Fethia Harzallah-Skhiri
- Laboratory of Genetics Biodiversity and Valorisation of Bioressources (LR11ES41), Higher Institute of Biotechnology of Monastir, University of Monastir, Rue Tahar Haddad, 5000, Monastir, Tunisia
| | - Guido Flamini
- Dipartimento di Farmacia, Università di Pisa, Via Bonanno 33, 56126, Pisa, Italy.,Centro Interdipartimentale di Ricerca 'Nutraceutica e Alimentazione per la Salute' Nutrafood, University of Pisa, Via del Borghetto 80, 56124 Pisa, Italy
| | - Roberta Ascrizzi
- Dipartimento di Farmacia, Università di Pisa, Via Bonanno 33, 56126, Pisa, Italy
| | - Hichem Ben Jannet
- Laboratory of Heterocyclic Chemistry, Natural Products and Reactivity (LR11ES39), Team: Medicinal Chemistry and Natural Products, Faculty of Science of Monastir, University of Monastir, Avenue of Environment, 5019, Monastir, Tunisia
| |
Collapse
|
23
|
Twinfilin 2a regulates platelet reactivity and turnover in mice. Blood 2017; 130:1746-1756. [PMID: 28743718 DOI: 10.1182/blood-2017-02-770768] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Accepted: 07/21/2017] [Indexed: 01/22/2023] Open
Abstract
Regulated reorganization of the actin cytoskeleton is a prerequisite for proper platelet production and function. Consequently, defects in proteins controlling actin dynamics have been associated with platelet disorders in humans and mice. Twinfilin 2a (Twf2a) is a small actin-binding protein that inhibits actin filament assembly by sequestering actin monomers and capping filament barbed ends. Moreover, Twf2a binds heterodimeric capping proteins, but the role of this interaction in cytoskeletal dynamics has remained elusive. Even though Twf2a has pronounced effects on actin dynamics in vitro, only little is known about its function in vivo. Here, we report that constitutive Twf2a-deficient mice (Twf2a-/-) display mild macrothrombocytopenia due to a markedly accelerated platelet clearance in the spleen. Twf2a-/- platelets showed enhanced integrin activation and α-granule release in response to stimulation of (hem) immunoreceptor tyrosine-based activation motif (ITAM) and G-protein-coupled receptors, increased adhesion and aggregate formation on collagen I under flow, and accelerated clot retraction and spreading on fibrinogen. In vivo, Twf2a deficiency resulted in shortened tail bleeding times and faster occlusive arterial thrombus formation. The hyperreactivity of Twf2a-/- platelets was attributed to enhanced actin dynamics, characterized by an increased activity of n-cofilin and profilin 1, leading to a thickened cortical cytoskeleton and hence sustained integrin activation by limiting calpain-mediated integrin inactivation. In summary, our results reveal the first in vivo functions of mammalian Twf2a and demonstrate that Twf2a-controlled actin rearrangements dampen platelet activation responses in a n-cofilin- and profilin 1-dependent manner, thereby indirectly regulating platelet reactivity and half-life in mice.
Collapse
|
24
|
Roland BP, Zeccola AM, Larsen SB, Amrich CG, Talsma AD, Stuchul KA, Heroux A, Levitan ES, VanDemark AP, Palladino MJ. Structural and Genetic Studies Demonstrate Neurologic Dysfunction in Triosephosphate Isomerase Deficiency Is Associated with Impaired Synaptic Vesicle Dynamics. PLoS Genet 2016; 12:e1005941. [PMID: 27031109 PMCID: PMC4816394 DOI: 10.1371/journal.pgen.1005941] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 02/24/2016] [Indexed: 01/05/2023] Open
Abstract
Triosephosphate isomerase (TPI) deficiency is a poorly understood disease characterized by hemolytic anemia, cardiomyopathy, neurologic dysfunction, and early death. TPI deficiency is one of a group of diseases known as glycolytic enzymopathies, but is unique for its severe patient neuropathology and early mortality. The disease is caused by missense mutations and dysfunction in the glycolytic enzyme, TPI. Previous studies have detailed structural and catalytic changes elicited by disease-associated TPI substitutions, and samples of patient erythrocytes have yielded insight into patient hemolytic anemia; however, the neuropathophysiology of this disease remains a mystery. This study combines structural, biochemical, and genetic approaches to demonstrate that perturbations of the TPI dimer interface are sufficient to elicit TPI deficiency neuropathogenesis. The present study demonstrates that neurologic dysfunction resulting from TPI deficiency is characterized by synaptic vesicle dysfunction, and can be attenuated with catalytically inactive TPI. Collectively, our findings are the first to identify, to our knowledge, a functional synaptic defect in TPI deficiency derived from molecular changes in the TPI dimer interface.
Collapse
Affiliation(s)
- Bartholomew P. Roland
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- The Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Alison M. Zeccola
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- The Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Samantha B. Larsen
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- The Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Christopher G. Amrich
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Aaron D. Talsma
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- The Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Kimberly A. Stuchul
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- The Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Annie Heroux
- Energy Sciences Directorate/Photon Science Division, Brookhaven National Laboratory, Upton, New York, United States of America
| | - Edwin S. Levitan
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
| | - Andrew P. VanDemark
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Michael J. Palladino
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- The Pittsburgh Institute for Neurodegenerative Diseases (PIND), University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
| |
Collapse
|
25
|
Kumar G, Kajuluri LP, Gupta CM, Sahasrabuddhe AA. A twinfilin-like protein coordinates karyokinesis by influencing mitotic spindle elongation and DNA replication in Leishmania. Mol Microbiol 2016; 100:173-87. [PMID: 26713845 DOI: 10.1111/mmi.13310] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/13/2015] [Indexed: 11/30/2022]
Abstract
Twinfilin is an evolutionarily conserved actin-binding protein, which regulates actin-dynamics in eukaryotic cells. Homologs of this protein have been detected in the genome of various protozoan parasites causing diseases in human. However, very little is known about their core functions in these organisms. We show here that a twinfilin homolog in a human pathogen Leishmania, primarily localizes to the nucleolus and, to some extent, also in the basal body region. In the dividing cells, nucleolar twinfilin redistributes to the mitotic spindle and remains there partly associated with the spindle microtubules. We further show that approximately 50% depletion of this protein significantly retards the cell growth due to sluggish progression of S phase of the cell division cycle, owing to the delayed nuclear DNA synthesis. Interestingly, overexpression of this protein results in significantly increased length of the mitotic spindle in the dividing Leishmania cells, whereas, its depletion adversely affects spindle elongation and architecture. Our results indicate that twinfilin controls on one hand, the DNA synthesis and on the other, the mitotic spindle elongation, thus contributing to karyokinesis in Leishmania.
Collapse
Affiliation(s)
- Gaurav Kumar
- CSIR-Central Drug Research Institute, Jankipuram Extension-10, Sitapur Road, Lucknow, PIN-226 031, India
| | - Lova P Kajuluri
- CSIR-Central Drug Research Institute, Jankipuram Extension-10, Sitapur Road, Lucknow, PIN-226 031, India
| | - Chhitar M Gupta
- Department of Biosciences, Institute of Bioinformatics and Applied Biotechnology, Biotech Park, Electronics City, Phase-I, Bangaluru, PIN-560 100, India
| | - Amogh A Sahasrabuddhe
- CSIR-Central Drug Research Institute, Jankipuram Extension-10, Sitapur Road, Lucknow, PIN-226 031, India
| |
Collapse
|
26
|
Chang CL, Villalun M, Geib SM, Goodman CL, Ringbauer J, Stanley D. Pupal X-ray irradiation influences protein expression in adults of the oriental fruit fly, Bactrocera dorsalis. JOURNAL OF INSECT PHYSIOLOGY 2015; 76:7-16. [PMID: 25772096 DOI: 10.1016/j.jinsphys.2015.03.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Revised: 03/04/2015] [Accepted: 03/04/2015] [Indexed: 06/04/2023]
Abstract
The oriental fruit fly, Bactrocera dorsalis, is a pest of fruit in the Asia-Pacific region and also, due to quarantine restrictions, a threat to California fruit production. Area-wide suppression of B. dorsalis integrated several approaches including the sterile insect technique (SIT). SIT involves exposing juveniles to gamma radiation and releasing sterile males in substantial numbers, where they successfully compete for wild females. The resulting infertile eggs lead to reduction of the pest populations. Although these protocols are well documented, arising issues about the international transport and distribution of radioactive products is creating difficulties in use of radioactive sources for sterilizing radiation. This led to a shift toward use of X-ray irradiation, which also sterilizes male and female insects. However, use of X-ray technologies is in its infancy and there is virtually no information on the effects of irradiation, other than sterilization, at the physiological and molecular levels of fruit fly biology. We posed the hypothesis that sterilizing male oriental fruit flies via radiation treatment also influences protein expression in the flies. We found that exposing pupae to X-ray irradiation impacted expression of 26 proteins in adult females and 31 proteins in adult males. Seven proteins (glyceraldehyde-3-phosphate dehydrogenase, fructose-bisphosphate aldolase, larval cuticle protein 2, sarcoplasmic calcium-binding protein alpha-B and A chains, general odorant-binding protein 99b, polyubiquitin, and protein disulfide-isomerase) were impacted in both sexes. Some of the proteins act in central energy-generating and in pheromone-signal processing pathways; we infer that males sterilized by X-ray irradiation may be enfeebled in their ability to compete with wild males for females in nature.
Collapse
Affiliation(s)
- Chiou Ling Chang
- USDA/Agricultural Research Service, Daniel K. Iouye U.S. Pacific Basin Agricultural Research Center, 64 Nowelo Street, Hilo, HI 96720, USA.
| | - MaryAnn Villalun
- USDA/Agricultural Research Service, Daniel K. Iouye U.S. Pacific Basin Agricultural Research Center, 64 Nowelo Street, Hilo, HI 96720, USA
| | - Scott M Geib
- USDA/Agricultural Research Service, Daniel K. Iouye U.S. Pacific Basin Agricultural Research Center, 64 Nowelo Street, Hilo, HI 96720, USA
| | - Cynthia L Goodman
- USDA/Agricultural Research Service, Biological Control of Insects Research Laboratory, 1503 South Providence Road, Columbia, MO 65203, USA
| | - Joseph Ringbauer
- USDA/Agricultural Research Service, Biological Control of Insects Research Laboratory, 1503 South Providence Road, Columbia, MO 65203, USA
| | - David Stanley
- USDA/Agricultural Research Service, Biological Control of Insects Research Laboratory, 1503 South Providence Road, Columbia, MO 65203, USA
| |
Collapse
|
27
|
Abstract
Endocytosis, the process whereby the plasma membrane invaginates to form vesicles, is essential for bringing many substances into the cell and for membrane turnover. The mechanism driving clathrin-mediated endocytosis (CME) involves > 50 different protein components assembling at a single location on the plasma membrane in a temporally ordered and hierarchal pathway. These proteins perform precisely choreographed steps that promote receptor recognition and clustering, membrane remodeling, and force-generating actin-filament assembly and turnover to drive membrane invagination and vesicle scission. Many critical aspects of the CME mechanism are conserved from yeast to mammals and were first elucidated in yeast, demonstrating that it is a powerful system for studying endocytosis. In this review, we describe our current mechanistic understanding of each step in the process of yeast CME, and the essential roles played by actin polymerization at these sites, while providing a historical perspective of how the landscape has changed since the preceding version of the YeastBook was published 17 years ago (1997). Finally, we discuss the key unresolved issues and where future studies might be headed.
Collapse
Affiliation(s)
- Bruce L Goode
- Brandeis University, Department of Biology, Rosenstiel Center, Waltham, Massachusetts 02454
| | - Julian A Eskin
- Brandeis University, Department of Biology, Rosenstiel Center, Waltham, Massachusetts 02454
| | - Beverly Wendland
- The Johns Hopkins University, Department of Biology, Baltimore, Maryland 21218
| |
Collapse
|
28
|
Farkaš R, Beňová-Liszeková D, Mentelová L, Mahmood S, Ďatková Z, Beňo M, Pečeňová L, Raška O, Šmigová J, Chase BA, Raška I, Mechler BM. Vacuole dynamics in the salivary glands ofDrosophila melanogasterduring prepupal development. Dev Growth Differ 2015; 57:74-96. [DOI: 10.1111/dgd.12193] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2014] [Revised: 10/21/2014] [Accepted: 11/28/2014] [Indexed: 01/29/2023]
Affiliation(s)
- Robert Farkaš
- Laboratory of Developmental Genetics; Institute of Experimental Endocrinology; Slovak Academy of Sciences; Vlárska 3 83306 Bratislava Slovakia
| | - Denisa Beňová-Liszeková
- Laboratory of Developmental Genetics; Institute of Experimental Endocrinology; Slovak Academy of Sciences; Vlárska 3 83306 Bratislava Slovakia
| | - Lucia Mentelová
- Laboratory of Developmental Genetics; Institute of Experimental Endocrinology; Slovak Academy of Sciences; Vlárska 3 83306 Bratislava Slovakia
- Department of Genetics; Comenius University; Mlynská dolina, B-1 84215 Bratislava Slovakia
| | - Silvia Mahmood
- Laboratory of Developmental Genetics; Institute of Experimental Endocrinology; Slovak Academy of Sciences; Vlárska 3 83306 Bratislava Slovakia
- Department of Medical Biochemistry; Jessenius Faculty of Medicine; Comenius University; Mala Hora 4 03601 Martin Slovakia
| | - Zuzana Ďatková
- Laboratory of Developmental Genetics; Institute of Experimental Endocrinology; Slovak Academy of Sciences; Vlárska 3 83306 Bratislava Slovakia
- Department of Genetics; Comenius University; Mlynská dolina, B-1 84215 Bratislava Slovakia
| | - Milan Beňo
- Laboratory of Developmental Genetics; Institute of Experimental Endocrinology; Slovak Academy of Sciences; Vlárska 3 83306 Bratislava Slovakia
| | - Ludmila Pečeňová
- Laboratory of Developmental Genetics; Institute of Experimental Endocrinology; Slovak Academy of Sciences; Vlárska 3 83306 Bratislava Slovakia
- Department of Genetics; Comenius University; Mlynská dolina, B-1 84215 Bratislava Slovakia
| | - Otakar Raška
- Institute of Cellular Biology and Pathology; 1st Faculty of Medicine; Charles University in Prague; Albertov 4 12800 Prague Czech Republic
| | - Jana Šmigová
- Institute of Cellular Biology and Pathology; 1st Faculty of Medicine; Charles University in Prague; Albertov 4 12800 Prague Czech Republic
| | - Bruce A. Chase
- Department of Biology; University of Nebraska at Omaha; 6001 Dodge Street Omaha NE 68182-0040 USA
| | - Ivan Raška
- Institute of Cellular Biology and Pathology; 1st Faculty of Medicine; Charles University in Prague; Albertov 4 12800 Prague Czech Republic
| | - Bernard M. Mechler
- Institute of Cellular Biology and Pathology; 1st Faculty of Medicine; Charles University in Prague; Albertov 4 12800 Prague Czech Republic
- German Cancer Research Centre; Neuenheimer Feld 581 D-69120 Heidelberg Germany
- VIT-University; Vellore Tamil Nadu India
| |
Collapse
|
29
|
Phosphoproteomic profiling of selenate-treated Alzheimer's disease model cells. PLoS One 2014; 9:e113307. [PMID: 25485856 PMCID: PMC4259334 DOI: 10.1371/journal.pone.0113307] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Accepted: 10/21/2014] [Indexed: 11/19/2022] Open
Abstract
The reversible phosphorylation of proteins regulates most biological processes, while abnormal phosphorylation is a cause or consequence of many diseases including Alzheimer's disease (AD). One of the hallmarks of AD is the formation of neurofibrillary tangles (NFTs), which is composed of hyperphosphorylated tau proteins. Sodium selenate has been recently found to reduce tau hyperphosphorylation and NFTs formation, and to improve spatial learning and motor performance in AD mice. In the current study, the phosphoproteomics of N2aSW cells treated with selenate were investigated. To avoid missing low-abundance phosphoproteins, both the total proteins of cells and the phosphor-enriched proteins were extracted and subjected to the two-dimensional gel electrophoresis with Pro-Q diamond staining and then LC-MS/MS analysis. A total of 65 proteins were altered in phosphorylation level, of which 39 were up-regulated and 26 were down-regulated. All identified phosphoproteins were bioinformatically annotated according to their physiochemical features, subcellular location, and biological function. Most of these significantly changed phosphoproteins are involved in crucial neural processes such as protesome activity, oxidative stress, cysteine and methionine metabolism, and energy metabolism. Furthermore, decreases were found in homocysteine, phosphor-tau and amyloid β upon selenate treatment. Our results suggest that selenate may intervene in the pathological process of AD by altering the phosphorylation of some key proteins involved in oxidative stress, energy metabolism and protein degradation, thus play important roles in maintaining redox homeostasis, generating ATP, and clearing misfolded proteins and aggregates. The present paper provides some new clues to the mechanism of selenate in AD prevention.
Collapse
|
30
|
Ghosh R, Vegesna S, Safi R, Bao H, Zhang B, Marenda DR, Liebl FLW. Kismet positively regulates glutamate receptor localization and synaptic transmission at the Drosophila neuromuscular junction. PLoS One 2014; 9:e113494. [PMID: 25412171 PMCID: PMC4239079 DOI: 10.1371/journal.pone.0113494] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Accepted: 10/24/2014] [Indexed: 12/20/2022] Open
Abstract
The Drosophila neuromuscular junction (NMJ) is a glutamatergic synapse that is structurally and functionally similar to mammalian glutamatergic synapses. These synapses can, as a result of changes in activity, alter the strength of their connections via processes that require chromatin remodeling and changes in gene expression. The chromodomain helicase DNA binding (CHD) protein, Kismet (Kis), is expressed in both motor neuron nuclei and postsynaptic muscle nuclei of the Drosophila larvae. Here, we show that Kis is important for motor neuron synaptic morphology, the localization and clustering of postsynaptic glutamate receptors, larval motor behavior, and synaptic transmission. Our data suggest that Kis is part of the machinery that modulates the development and function of the NMJ. Kis is the homolog to human CHD7, which is mutated in CHARGE syndrome. Thus, our data suggest novel avenues of investigation for synaptic defects associated with CHARGE syndrome.
Collapse
Affiliation(s)
- Rupa Ghosh
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Srikar Vegesna
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
| | - Ramia Safi
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
| | - Hong Bao
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States of America
| | - Bing Zhang
- Division of Biological Sciences, University of Missouri, Columbia, Missouri, United States of America
| | - Daniel R. Marenda
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, United States of America
- Department of Neurobiology and Anatomy, Drexel University College of Medicine, Philadelphia, Pennsylvania, United States of America
- * E-mail: (FLWL); (DRM)
| | - Faith L. W. Liebl
- Department of Biological Sciences, Southern Illinois University Edwardsville, Edwardsville, Illinois, United States of America
- * E-mail: (FLWL); (DRM)
| |
Collapse
|
31
|
Xing G, Gan G, Chen D, Sun M, Yi J, Lv H, Han J, Xie W. Drosophila neuroligin3 regulates neuromuscular junction development and synaptic differentiation. J Biol Chem 2014; 289:31867-31877. [PMID: 25228693 DOI: 10.1074/jbc.m114.574897] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Neuroligins (Nlgs) are a family of cell adhesion molecules thought to be important for synapse maturation and function. Mammalian studies have shown that different Nlgs have different roles in synaptic maturation and function. In Drosophila melanogaster, the roles of Drosophila neuroligin1 (DNlg1), neuroligin2, and neuroligin4 have been examined. However, the roles of neuroligin3 (dnlg3) in synaptic development and function have not been determined. In this study, we used the Drosophila neuromuscular junctions (NMJs) as a model system to investigate the in vivo role of dnlg3. We showed that DNlg3 was expressed in both the CNS and NMJs where it was largely restricted to the postsynaptic site. We generated dnlg3 mutants and showed that these mutants exhibited an increased bouton number and reduced bouton size compared with the wild-type (WT) controls. Consistent with alterations in bouton properties, pre- and postsynaptic differentiations were affected in dnlg3 mutants. This included abnormal synaptic vesicle endocytosis, increased postsynaptic density length, and reduced GluRIIA recruitment. In addition to impaired synaptic development and differentiation, we found that synaptic transmission was reduced in dnlg3 mutants. Altogether, our data showed that DNlg3 was required for NMJ development, synaptic differentiation, and function.
Collapse
Affiliation(s)
- Guanglin Xing
- Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Guangming Gan
- Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Dandan Chen
- Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Mingkuan Sun
- Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Jukang Yi
- Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Huihui Lv
- Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Junhai Han
- Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China
| | - Wei Xie
- Key Laboratory of Developmental Genes and Human Disease, Institute of Life Sciences, Southeast University, Nanjing 210096, China.
| |
Collapse
|
32
|
Brain tumor regulates neuromuscular synapse growth and endocytosis in Drosophila by suppressing mad expression. J Neurosci 2013; 33:12352-63. [PMID: 23884941 DOI: 10.1523/jneurosci.0386-13.2013] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The precise regulation of synaptic growth is critical for the proper formation and plasticity of functional neural circuits. Identification and characterization of factors that regulate synaptic growth and function have been under intensive investigation. Here we report that brain tumor (brat), which was identified as a translational repressor in multiple biological processes, plays a crucial role at Drosophila neuromuscular junction (NMJ) synapses. Immunohistochemical analysis demonstrated that brat mutants exhibited synaptic overgrowth characterized by excess satellite boutons at NMJ terminals, whereas electron microscopy revealed increased synaptic vesicle size but reduced density at active zones compared with wild-types. Spontaneous miniature excitatory junctional potential amplitudes were larger and evoked quantal content was lower at brat mutant NMJs. In agreement with the morphological and physiological phenotypes, loss of Brat resulted in reduced FM1-43 uptake at the NMJ terminals, indicating that brat regulates synaptic endocytosis. Genetic analysis revealed that the actions of Brat at synapses are mediated through mothers against decapentaplegic (Mad), the signal transduction effector of the bone morphogenetic protein (BMP) signaling pathway. Furthermore, biochemical analyses showed upregulated levels of Mad protein but normal mRNA levels in the larval brains of brat mutants, suggesting that Brat suppresses Mad translation. Consistently, knockdown of brat by RNA interference in Drosophila S2 cells also increased Mad protein level. These results together reveal an important and previously unidentified role for Brat in synaptic development and endocytosis mediated by suppression of BMP signaling.
Collapse
|
33
|
Zhao L, Wang D, Wang Q, Rodal AA, Zhang YQ. Drosophila cyfip regulates synaptic development and endocytosis by suppressing filamentous actin assembly. PLoS Genet 2013; 9:e1003450. [PMID: 23593037 PMCID: PMC3616907 DOI: 10.1371/journal.pgen.1003450] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2012] [Accepted: 02/28/2013] [Indexed: 01/06/2023] Open
Abstract
The formation of synapses and the proper construction of neural circuits depend on signaling pathways that regulate cytoskeletal structure and dynamics. After the mutual recognition of a growing axon and its target, multiple signaling pathways are activated that regulate cytoskeletal dynamics to determine the morphology and strength of the connection. By analyzing Drosophila mutations in the cytoplasmic FMRP interacting protein Cyfip, we demonstrate that this component of the WAVE complex inhibits the assembly of filamentous actin (F-actin) and thereby regulates key aspects of synaptogenesis. Cyfip regulates the distribution of F-actin filaments in presynaptic neuromuscular junction (NMJ) terminals. At cyfip mutant NMJs, F-actin assembly was accelerated, resulting in shorter NMJs, more numerous satellite boutons, and reduced quantal content. Increased synaptic vesicle size and failure to maintain excitatory junctional potential amplitudes under high-frequency stimulation in cyfip mutants indicated an endocytic defect. cyfip mutants exhibited upregulated bone morphogenetic protein (BMP) signaling, a major growth-promoting pathway known to be attenuated by endocytosis at the Drosophila NMJ. We propose that Cyfip regulates synapse development and endocytosis by inhibiting actin assembly. Synapses are specialized junctions at which neurons communicate with target cells. To establish properly wired neuronal circuits, synapses must grow in size and strength with a high degree of accuracy. The actin cytoskeleton plays a crucial role in the formation and function of synapses, but the underlying mechanisms remain poorly understood. The Drosophila neuromuscular junction (NMJ) is an excellent model for studying synaptic development and function. By analyzing Drosophila mutants of the cytoplasmic FMRP interacting protein Cyfip, we establish that this protein inhibits the assembly of filamentous actin (F-actin). At cyfip mutant NMJ synapses, F-actin assembly was accelerated and NMJ terminals were shorter and grew supernumerary buds. Furthermore, neurotransmission was not sustained under high-frequency stimulation. These changes could be caused by defects in synaptic endocytosis, which would compromise the endocytic attenuation of signaling pathways such as the NMJ growth-promoting bone morphogenetic protein (BMP) pathway. Indeed, BMP signaling was upregulated in cyfip mutants. We propose that Cyfip regulates synaptic development and function by inhibiting F-actin assembly, which in turn downregulates BMP signaling via endocytosis. This study establishes a novel role for Cyfip-mediated regulation of the actin cytoskeleton at the Drosophila NMJ.
Collapse
Affiliation(s)
- Lu Zhao
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
| | | | | | | | | |
Collapse
|
34
|
Group choreography: mechanisms orchestrating the collective movement of border cells. Nat Rev Mol Cell Biol 2012; 13:631-45. [PMID: 23000794 DOI: 10.1038/nrm3433] [Citation(s) in RCA: 170] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Cell movements are essential for animal development and homeostasis but also contribute to disease. Moving cells typically extend protrusions towards a chemoattractant, adhere to the substrate, contract and detach at the rear. It is less clear how cells that migrate in interconnected groups in vivo coordinate their behaviour and navigate through natural environments. The border cells of the Drosophila melanogaster ovary have emerged as an excellent model for the study of collective cell movement, aided by innovative genetic, live imaging, and photomanipulation techniques. Here we provide an overview of the molecular choreography of border cells and its more general implications.
Collapse
|
35
|
Lin CM, Lin PY, Li YC, Hsu JC. Capulet and Slingshot share overlapping functions during Drosophila eye morphogenesis. J Biomed Sci 2012; 19:46. [PMID: 22545588 PMCID: PMC3411472 DOI: 10.1186/1423-0127-19-46] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 04/30/2012] [Indexed: 02/05/2023] Open
Abstract
Background CAP/Capulet (Capt), Slingshot (Ssh) and Cofilin/Twinstar (Tsr) are actin-binding proteins that restrict actin polymerization. Previously, it was shown that low resolution analyses of loss-of-function mutations in capt, ssh and tsr all show ectopic F-actin accumulation in various Drosophila tissues. In contrast, RNAi depletion of capt, tsr and ssh in Drosophila S2 cells all affect actin-based lamella formation differently. Whether loss of these three related genes might cause the same effect in the same tissue remains unclear. Methods Loss-of-function mutant clones were generated using the MARCM or EGUF system whereas overexpression clones were generated using the Flip-out system. Immunostaining were then performed in eye imaginal discs with clones. FRAP was performed in cultured eye discs. Results Here, we compared their loss-of-function phenotype at single-cell resolution, using a sheet of epithelial cells in the Drosophila eye imaginal disc as a model system. Surprisingly, we found that capt and ssh, but not tsr, mutant cells within and posterior to the morphogenetic furrow (MF) shared similar phenotypes. The capt/ssh mutant cells possessed: (1) hexagonal cell packing with discontinuous adherens junctions; and (2) largely complementary accumulation of excessive phosphorylated myosin light chain (p-MLC) and F-actin rings at the apical cortex. We further showed that the capt/ssh mutant phenotypes depended on the inactivation of protein kinase A (PKA) and activation of Rho. Conclusions Although Capt, Ssh and Tsr were reported to negatively regulate actin polymerization, we found that Capt and Ssh, but not Tsr, share overlapping functions during eye morphogenesis.
Collapse
Affiliation(s)
- Chiao-Ming Lin
- Institute of Molecular Medicine, Department of Life Science, National Tsing Hua University, Hsinchu, Taiwan 30034, Republic of China
| | | | | | | |
Collapse
|
36
|
Poukkula M, Kremneva E, Serlachius M, Lappalainen P. Actin-depolymerizing factor homology domain: a conserved fold performing diverse roles in cytoskeletal dynamics. Cytoskeleton (Hoboken) 2011; 68:471-90. [PMID: 21850706 DOI: 10.1002/cm.20530] [Citation(s) in RCA: 110] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2011] [Revised: 06/29/2011] [Accepted: 08/05/2011] [Indexed: 11/09/2022]
Abstract
Actin filaments form contractile and protrusive structures that play central roles in many processes such as cell migration, morphogenesis, endocytosis, and cytokinesis. During these processes, the dynamics of the actin filaments are precisely regulated by a large array of actin-binding proteins. The actin-depolymerizing factor homology (ADF-H) domain is a structurally conserved protein motif, which promotes cytoskeletal dynamics by interacting with monomeric and/or filamentous actin, and with the Arp2/3 complex. Despite their structural homology, the five classes of ADF-H domain proteins display distinct biochemical activities and cellular roles, only parts of which are currently understood. ADF/cofilin promotes disassembly of aged actin filaments, whereas twinfilin inhibits actin filament assembly via sequestering actin monomers and interacting with filament barbed ends. GMF does not interact with actin, but instead binds Arp2/3 complex and promotes dissociation of Arp2/3-mediated filament branches. Abp1 and drebrin are multidomain proteins that interact with actin filaments and regulate the activities of other proteins during various actin-dependent processes. The exact function of coactosin is currently incompletely understood. In this review article, we discuss the biochemical functions, cellular roles, and regulation of the five groups of ADF-H domain proteins.
Collapse
Affiliation(s)
- Minna Poukkula
- Program in Cell and Molecular Biology, Institute of Biotechnology, University of Helsinki, Finland
| | | | | | | |
Collapse
|
37
|
Abstract
Twinfilins are evolutionarily conserved regulators of cytoskeletal dynamics. They inhibit actin polymerization by binding both actin monomers and filament barbed ends. Inactivation of the single twinfilin gene from budding yeast and fruit fly results in defects in endocytosis, cell migration, and organization of the cortical actin filament structures. Mammals express three twinfilin isoforms, of which twinfilin-1 and twinfilin-2a display largely overlapping expression patterns in non-muscle tissues of developing and adult mice. The expression of twinfilin-2b, which is generated through alternative promoter usage of the twinfilin-2 gene, is restricted to heart and skeletal muscles. However, the physiological functions of mammalian twinfilins have not been reported. As a first step towards understanding the function of twinfilin in vertebrates, we generated twinfilin-2a deficient mice by deleting exon 1 of the twinfilin-2 gene. Twinfilin-2a knockout mice developed normally to adulthood, were fertile, and did not display obvious morphological or behavioural abnormalities. Tissue anatomy and morphology in twinfilin-2a deficient mice was similar to that of wild-type littermates. These data suggest that twinfilin-2a plays a redundant role in cytoskeletal dynamics with the biochemically similar twinfilin-1, which is typically co-expressed in same tissues with twinfilin-2a.
Collapse
|
38
|
Liu Z, Huang Y, Zhang Y, Chen D, Zhang YQ. Drosophila Acyl-CoA synthetase long-chain family member 4 regulates axonal transport of synaptic vesicles and is required for synaptic development and transmission. J Neurosci 2011; 31:2052-63. [PMID: 21307243 PMCID: PMC6633061 DOI: 10.1523/jneurosci.3278-10.2011] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 11/22/2010] [Accepted: 12/02/2010] [Indexed: 11/21/2022] Open
Abstract
Acyl-CoA synthetase long-chain family member 4 (ACSL4) converts long-chain fatty acids to acyl-CoAs that are indispensable for lipid metabolism and cell signaling. Mutations in ACSL4 cause nonsyndromic X-linked mental retardation. We previously demonstrated that Drosophila dAcsl is functionally homologous to human ACSL4, and is required for axonal targeting in the brain. Here, we report that Drosophila dAcsl mutants exhibited distally biased axonal aggregates that were immunopositive for the synaptic-vesicle proteins synaptotagmin (Syt) and cysteine-string protein, the late endosome/lysosome marker lysosome-associated membrane protein 1, the autophagosomal marker Atg8, and the multivesicular body marker Hrs (hepatocyte growth factor-regulated tyrosine kinase substrate). In contrast, the axonal distribution of mitochondria and the cell adhesion molecule Fas II (fasciclin II) was normal. Electron microscopy revealed accumulation of prelysomes and multivesicle bodies. These aggregates appear as retrograde instead of anterograde cargos. Live imaging analysis revealed that dAcsl mutations increased the velocity of anterograde transport but reduced the flux, velocity, and processivity of retrograde transport of Syt-enhanced green fluorescent protein-labeled vesicles. Immunohistochemical and electrophysiological analyses showed significantly reduced growth and stability of neuromuscular synapses, and impaired glutamatergic neurotransmission in dAcsl mutants. The axonal aggregates and synaptic defects in dAcsl mutants were fully rescued by neuronal expression of human ACSL4, supporting a functional conservation of ACSL4 across species in the nervous system. Together, our findings demonstrate that dAcsl regulates axonal transport of synaptic vesicles and is required for synaptic development and function. Defects in axonal transport and synaptic function may account, at least in part, for the pathogenesis of ACSL4-related mental retardation.
Collapse
Affiliation(s)
- Zhihua Liu
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yan Huang
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yi Zhang
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Di Chen
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| | - Yong Q. Zhang
- Key Laboratory for Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing 100101, China
| |
Collapse
|