1
|
Djokic S, Bakhrat A, Li M, Akbari OS, Abdu U. Scale-type-specific requirement for the mosquito Aedes aegypti Spindle-F homologue by regulating microtubule organization. INSECT MOLECULAR BIOLOGY 2022; 31:216-224. [PMID: 34919304 PMCID: PMC10537241 DOI: 10.1111/imb.12752] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 11/11/2021] [Accepted: 12/12/2021] [Indexed: 06/14/2023]
Abstract
Insect epithelial cells contain unique cellular extensions such as bristles, hairs, and scales. In contrast to bristle and hair, which are not divergent in their shape, scale morphology shows high diversity. In our attempt to characterize the role of the insect-specific gene, Spindle-F (spn-F), in mosquito development, we revealed a scale-type specific requirement for the mosquito Aedes aegypti spn-F homologue. Using CRISPR-Cas9, we generated Ae-spn-F mutants and found that Ae-spn-F is an essential gene, but we were able to recover a few adult escapers. These escapers could not fly nor move, and died after 3 to 4 days. We found that in Ae-spn-F mutants, only the tip part of the bristle was affected with bulbous with misoriented ribs. We also show that in Ae-spn-F mutants, only in falcate scales, which are curved with a sharp or narrowly rounded apex, and not in other scale types, the tip region is strongly affected. Our analysis also revealed that in contrast to Drosophila spn-F, which show strong defects in both the actin and microtubule (MT) network in the bristle, the Ae-spn-F gene is required only for MT organization in scales and bristles. In summary, our results reveal that Ae-spn-F is required for shaping tapered epithelial cellular extension structures, namely, the bristle and falcate scales by affecting MT organization.
Collapse
Affiliation(s)
- Sanja Djokic
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Anna Bakhrat
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| | - Ming Li
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, San Diego, CA, USA
| | - Omar S. Akbari
- Division of Biological Sciences, Section of Cell and Developmental Biology, University of California San Diego, San Diego, CA, USA
| | - Uri Abdu
- Department of Life Sciences, Ben-Gurion University of the Negev, Beer Sheva 84105, Israel
| |
Collapse
|
2
|
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
|
3
|
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
|
4
|
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
|
5
|
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
|
6
|
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
|
7
|
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
|
8
|
Huang Y, Mao X, van Jaarsveld RH, Shu L, Terhal PA, Jia Z, Xi H, Peng Y, Yan H, Yuan S, Li Q, Wang H, Bellen HJ. Variants in CAPZA2, a member of an F-actin capping complex, cause intellectual disability and developmental delay. Hum Mol Genet 2020; 29:1537-1546. [PMID: 32338762 PMCID: PMC7268783 DOI: 10.1093/hmg/ddaa078] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2020] [Revised: 03/29/2020] [Accepted: 04/20/2020] [Indexed: 11/13/2022] Open
Abstract
The actin cytoskeleton is regulated by many proteins including capping proteins that stabilize actin filaments (F-actin) by inhibiting actin polymerization and depolymerization. Here, we report two pediatric probands who carry damaging heterozygous de novo mutations in CAPZA2 (HGNC: 1490) and exhibit neurological symptoms with shared phenotypes including global motor development delay, speech delay, intellectual disability, hypotonia and a history of seizures. CAPZA2 encodes a subunit of an F-actin-capping protein complex (CapZ). CapZ is an obligate heterodimer consisting of α and β heterodimer conserved from yeast to human. Vertebrate genomes contain three α subunits encoded by three different genes and CAPZA2 encodes the α2 subunit. The single orthologue of CAPZA genes in Drosophila is cpa. Loss of cpa leads to lethality in early development and expression of the human reference; CAPZA2 rescues this lethality. However, the two CAPZA2 variants identified in the probands rescue this lethality at lower efficiency than the reference. Moreover, expression of the CAPZA2 variants affects bristle morphogenesis, a process that requires extensive actin polymerization and bundling during development. Taken together, our findings suggest that variants in CAPZA2 lead to a non-syndromic neurodevelopmental disorder in children.
Collapse
Affiliation(s)
- Yan Huang
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, Baylor College of Medicine, Houston, TX 77030, USA
| | - Xiao Mao
- National Health Commission Key Laboratory of Birth Defects Research, Prevention and Treatment, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410008, China
- Department of Medical Genetics, Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan 410008, China
| | | | - Li Shu
- National Health Commission Key Laboratory of Birth Defects Research, Prevention and Treatment, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410008, China
- Department of Medical Genetics, Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan 410008, China
| | - Paulien A Terhal
- Department of Genetics, University Medical Center Utrecht, Utrecht CX 3584, The Netherlands
| | - Zhengjun Jia
- National Health Commission Key Laboratory of Birth Defects Research, Prevention and Treatment, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410008, China
- Department of Medical Genetics, Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan 410008, China
| | - Hui Xi
- National Health Commission Key Laboratory of Birth Defects Research, Prevention and Treatment, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410008, China
- Department of Medical Genetics, Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan 410008, China
| | - Ying Peng
- National Health Commission Key Laboratory of Birth Defects Research, Prevention and Treatment, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410008, China
- Department of Medical Genetics, Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan 410008, China
| | - Huiming Yan
- National Health Commission Key Laboratory of Birth Defects Research, Prevention and Treatment, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410008, China
- Department of Medical Genetics, Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan 410008, China
| | - Shan Yuan
- Department of Medical Genetics, Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan 410008, China
| | - Qibin Li
- Clabee Genomics, Shenzhen, Guangdong 518000, China
- Center on Translational Neuroscience, College of Life and Environmental Sciences, Minzu University of China, Beijing 100081, China
| | - Hua Wang
- National Health Commission Key Laboratory of Birth Defects Research, Prevention and Treatment, Hunan Provincial Maternal and Child Health Care Hospital, Changsha, Hunan 410008, China
- Department of Medical Genetics, Maternal and Child Health Hospital of Hunan Province, Changsha, Hunan 410008, China
| | - Hugo J Bellen
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
- Jan and Dan Duncan Neurological Research Institute, Texas Children’s Hospital, 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
| |
Collapse
|
9
|
Cui Y, Liu P, Mooney BP, Franz AWE. Quantitative Proteomic Analysis of Chikungunya Virus-Infected Aedes aegypti Reveals Proteome Modulations Indicative of Persistent Infection. J Proteome Res 2020; 19:2443-2456. [PMID: 32375005 DOI: 10.1021/acs.jproteome.0c00173] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The mosquito-borne chikungunya virus (CHIKV) poses a threat to human health in tropical countries throughout the world. The molecular interactions of CHIKV with its mosquito vector Aedes aegypti are not fully understood. Following oral acquisition of CHIKV via salinemeals, we analyzed changes in the proteome of Ae. aegypti in 12 h intervals by label-free quantification using a timsTOF Pro mass spectrometer. For each of the seven time points, between 2647 and 3167 proteins were identified among CHIKV-infected and noninfected mosquito samples, and fewer than 6% of those identified proteins were affected by the virus. Functional enrichment analysis revealed that the three pathways, Endocytosis, Oxidative phosphorylation, and Ribosome biogenesis, were enriched during CHIKV infection. On the other hand, three pathways of the cellular RNA machinery and five metabolism related pathways were significantly attenuated in the CHIKV-infected samples. Furthermore, proteins associated with cytoskeleton and vesicular transport, as well as various serine-type endopeptidases and metallo-proteinases, were modulated in the presence of CHIKV. Our study reveals biological pathways and novel proteins interacting with CHIKV in the mosquito. Overall, CHIKV infection caused minor changes to the mosquito proteome demonstrating a high level of adaption between the vector and the virus, essentially coexisting in a nonpathogenic relationship. The mass spectrometry data have been deposited to the MassIVE repository (https://massive.ucsd.edu/ProteoSAFe/dataset.jsp?task=abfd14f7015243c69854731998d55df1) with the data set identifier MSV000085115.
Collapse
Affiliation(s)
- Yingjun Cui
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri 65211, United States
| | - Pei Liu
- Charles W. Gehrke Proteomics Center, University of Missouri, Columbia, Missouri 65211, United States
| | - Brian P Mooney
- Department of Biochemistry and Charles W. Gehrke Proteomics Center, University of Missouri, Columbia, Missouri 65211, United States
| | - Alexander W E Franz
- Department of Veterinary Pathobiology, University of Missouri, Columbia, Missouri 65211, United States
| |
Collapse
|
10
|
Skouloudaki K, Christodoulou I, Khalili D, Tsarouhas V, Samakovlis C, Tomancak P, Knust E, Papadopoulos DK. Yorkie controls tube length and apical barrier integrity during airway development. J Cell Biol 2019; 218:2762-2781. [PMID: 31315941 PMCID: PMC6683733 DOI: 10.1083/jcb.201809121] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2018] [Revised: 05/02/2019] [Accepted: 06/04/2019] [Indexed: 12/18/2022] Open
Abstract
Skouloudaki et al. identify an alternative role of the transcriptional coactivator Yorkie (Yki) in controlling water impermeability and tube size of developing Drosophila airways. Tracheal impermeability is triggered by Yki-mediated transcriptional regulation of δ-aminolevulinate synthase (Alas), whereas tube elongation is controlled by binding of Yki to the actin-severing factor Twinstar. Epithelial organ size and shape depend on cell shape changes, cell–matrix communication, and apical membrane growth. The Drosophila melanogaster embryonic tracheal network is an excellent model to study these processes. Here, we show that the transcriptional coactivator of the Hippo pathway, Yorkie (YAP/TAZ in vertebrates), plays distinct roles in the developing Drosophila airways. Yorkie exerts a cytoplasmic function by binding Drosophila Twinstar, the orthologue of the vertebrate actin-severing protein Cofilin, to regulate F-actin levels and apical cell membrane size, which are required for proper tracheal tube elongation. Second, Yorkie controls water tightness of tracheal tubes by transcriptional regulation of the δ-aminolevulinate synthase gene (Alas). We conclude that Yorkie has a dual role in tracheal development to ensure proper tracheal growth and functionality.
Collapse
Affiliation(s)
| | - Ioannis Christodoulou
- Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| | - Dilan Khalili
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Vasilios Tsarouhas
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Christos Samakovlis
- Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden.,Excellence Cluster Cardio-Pulmonary System, University of Giessen, Giessen, Germany
| | - Pavel Tomancak
- Max-Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
| | - Elisabeth Knust
- Max-Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany
| | - Dimitrios K Papadopoulos
- Max-Planck Institute for Molecular Cell Biology and Genetics, Dresden, Germany .,Medical Research Council Human Genetics Unit, Institute of Genetics and Molecular Medicine, University of Edinburgh, Edinburgh, UK
| |
Collapse
|
11
|
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
|
12
|
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]
|
13
|
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
|
14
|
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
|
15
|
Li L, Liu L, Qu B, Li X, Gao X, Zhang M. Twinfilin 1 enhances milk bio-synthesis and proliferation of bovine mammary epithelial cells via the mTOR signaling pathway. Biochem Biophys Res Commun 2017; 492:289-294. [DOI: 10.1016/j.bbrc.2017.08.130] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Accepted: 08/28/2017] [Indexed: 01/02/2023]
|
16
|
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
|
17
|
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
|
18
|
High-speed depolymerization at actin filament ends jointly catalysed by Twinfilin and Srv2/CAP. Nat Cell Biol 2015; 17:1504-11. [PMID: 26458246 PMCID: PMC4808055 DOI: 10.1038/ncb3252] [Citation(s) in RCA: 89] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2015] [Accepted: 09/11/2015] [Indexed: 12/16/2022]
Abstract
Purified actin filaments depolymerize slowly, and cytosolic conditions strongly favor actin assembly over disassembly, which has left our understanding of how actin filaments are rapidly turned over in vivo incomplete 1,2. One mechanism for driving filament disassembly is severing by factors such as Cofilin. However, even after severing, pointed end depolymerization remains slow and unable to fully account for observed rates of actin filament turnover in vivo. Here we describe a mechanism by which Twinfilin and Cyclase-associated protein work in concert to accelerate depolymerization of actin filaments by 3-fold and 17-fold at their barbed and pointed ends, respectively. This mechanism occurs even under assembly conditions, allowing reconstitution and direct visualization of individual filaments undergoing tunable, accelerated treadmilling. Further, we use specific mutations to demonstrate that this activity is critical for Twinfilin function in vivo. These findings fill a major gap in our knowledge of mechanisms, and suggest that depolymerization and severing may be deployed separately or together to control the dynamics and architecture of distinct actin networks.
Collapse
|
19
|
Ydenberg CA, Johnston A, Weinstein J, Bellavance D, Jansen S, Goode BL. Combinatorial genetic analysis of a network of actin disassembly-promoting factors. Cytoskeleton (Hoboken) 2015; 72:349-61. [PMID: 26147656 PMCID: PMC5014199 DOI: 10.1002/cm.21231] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2015] [Revised: 06/29/2015] [Accepted: 07/01/2015] [Indexed: 12/12/2022]
Abstract
The patterning of actin cytoskeleton structures in vivo is a product of spatially and temporally regulated polymer assembly balanced by polymer disassembly. While in recent years our understanding of actin assembly mechanisms has grown immensely, our knowledge of actin disassembly machinery and mechanisms has remained comparatively sparse. Saccharomyces cerevisiae is an ideal system to tackle this problem, both because of its amenabilities to genetic manipulation and live‐cell imaging and because only a single gene encodes each of the core disassembly factors: cofilin (COF1), Srv2/CAP (SRV2), Aip1 (AIP1), GMF (GMF1/AIM7), coronin (CRN1), and twinfilin (TWF1). Among these six factors, only the functions of cofilin are essential and have been well defined. Here, we investigated the functions of the nonessential actin disassembly factors by performing genetic and live‐cell imaging analyses on a combinatorial set of isogenic single, double, triple, and quadruple mutants in S. cerevisiae. Our results show that each disassembly factor makes an important contribution to cell viability, actin organization, and endocytosis. Further, our data reveal new relationships among these factors, providing insights into how they work together to orchestrate actin turnover. Finally, we observe specific combinations of mutations that are lethal, e.g., srv2Δ aip1Δ and srv2Δ crn1Δ twf1Δ, demonstrating that while cofilin is essential, it is not sufficient in vivo, and that combinations of the other disassembly factors perform vital functions. © 2015 The Authors. Cytoskeleton Published by Wiley Periodicals, Inc.
Collapse
Affiliation(s)
- Casey A Ydenberg
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, 02454
| | - Adam Johnston
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, 02454
| | - Jaclyn Weinstein
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, 02454
| | - Danielle Bellavance
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, 02454
| | - Silvia Jansen
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, 02454
| | - Bruce L Goode
- Department of Biology, Rosenstiel Basic Medical Science Research Center, Brandeis University, Waltham, Massachusetts, 02454
| |
Collapse
|
20
|
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
|
21
|
Stratoulias V, Heino TI. MANF silencing, immunity induction or autophagy trigger an unusual cell type in metamorphosing Drosophila brain. Cell Mol Life Sci 2014; 72:1989-2004. [PMID: 25511196 PMCID: PMC4412683 DOI: 10.1007/s00018-014-1789-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2014] [Revised: 11/17/2014] [Accepted: 11/20/2014] [Indexed: 12/31/2022]
Abstract
Glia are abundant cells in the brain of animals ranging from flies to humans. They perform conserved functions not only in neural development and wiring, but also in brain homeostasis. Here we show that by manipulating gene expression in glia, a previously unidentified cell type appears in the Drosophila brain during metamorphosis. More specifically, this cell type appears in three contexts: (1) after the induction of either immunity, or (2) autophagy, or (3) by silencing of neurotrophic factor DmMANF in glial cells. We call these cells MANF immunoreactive Cells (MiCs). MiCs are migratory based on their shape, appearance in brain areas where no cell bodies exist and the nuclear localization of dSTAT. They are labeled with a unique set of molecular markers including the conserved neurotrophic factor DmMANF and the transcription factor Zfh1. They possess the nuclearly localized protein Relish, which is the hallmark of immune response activation. They also express the conserved engulfment receptor Draper, therefore indicating that they are potentially phagocytic. Surprisingly, they do not express any of the common glial and neuronal markers. In addition, ultrastructural studies show that MiCs are extremely rich in lysosomes. Our findings reveal critical molecular and functional components of an unusual cell type in the Drosophila brain. We suggest that MiCs resemble macrophages/hemocytes and vertebrate microglia based on their appearance in the brain upon genetically challenged conditions and the expression of molecular markers. Interestingly, macrophages/hemocytes or microglia-like cells have not been reported in the fly nervous system before.
Collapse
Affiliation(s)
- Vassilis Stratoulias
- Department of Biosciences, University of Helsinki, P.O. Box 56, Viikinkaari 5, 00014, Helsinki, Finland,
| | | |
Collapse
|
22
|
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
|
23
|
Edwards M, Zwolak A, Schafer DA, Sept D, Dominguez R, Cooper JA. Capping protein regulators fine-tune actin assembly dynamics. Nat Rev Mol Cell Biol 2014; 15:677-89. [PMID: 25207437 DOI: 10.1038/nrm3869] [Citation(s) in RCA: 191] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Capping protein (CP) binds the fast growing barbed end of the actin filament and regulates actin assembly by blocking the addition and loss of actin subunits. Recent studies provide new insights into how CP and barbed-end capping are regulated. Filament elongation factors, such as formins and ENA/VASP (enabled/vasodilator-stimulated phosphoprotein), indirectly regulate CP by competing with CP for binding to the barbed end, whereas other molecules, including V-1 and phospholipids, directly bind to CP and sterically block its interaction with the filament. In addition, a diverse and unrelated group of proteins interact with CP through a conserved 'capping protein interaction' (CPI) motif. These proteins, including CARMIL (capping protein, ARP2/3 and myosin I linker), CD2AP (CD2-associated protein) and the WASH (WASP and SCAR homologue) complex subunit FAM21, recruit CP to specific subcellular locations and modulate its actin-capping activity via allosteric effects.
Collapse
Affiliation(s)
- Marc Edwards
- Department of Cell Biology and Physiology, Washington University, St. Louis, Missouri 63110, USA
| | - Adam Zwolak
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Dorothy A Schafer
- Departments of Biology and Cell Biology, University of Virginia, Charlottesville, Virginia 22904, USA
| | - David Sept
- Department of Biomedical Engineering and Center for Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, Michigan 48109, USA
| | - Roberto Dominguez
- Department of Physiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - John A Cooper
- Department of Cell Biology and Physiology, Washington University, St. Louis, Missouri 63110, USA
| |
Collapse
|
24
|
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
|
25
|
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
|
26
|
Stephan R, Gohl C, Fleige A, Klämbt C, Bogdan S. Membrane-targeted WAVE mediates photoreceptor axon targeting in the absence of the WAVE complex in Drosophila. Mol Biol Cell 2011; 22:4079-92. [PMID: 21900504 PMCID: PMC3204070 DOI: 10.1091/mbc.e11-02-0121] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
A tight spatial-temporal coordination of F-actin dynamics is crucial for a large variety of cellular processes that shape cells. The Abelson interactor (Abi) has a conserved role in Arp2/3-dependent actin polymerization, regulating Wiskott-Aldrich syndrome protein (WASP) and WASP family verprolin-homologous protein (WAVE). In this paper, we report that Abi exerts nonautonomous control of photoreceptor axon targeting in the Drosophila visual system through WAVE. In abi mutants, WAVE is unstable but restored by reexpression of Abi, confirming that Abi controls the integrity of the WAVE complex in vivo. Remarkably, expression of a membrane-tethered WAVE protein rescues the axonal projection defects of abi mutants in the absence of the other subunits of the WAVE complex, whereas cytoplasmic WAVE only slightly affects the abi mutant phenotype. Thus complex formation not only stabilizes WAVE, but also provides further membrane-recruiting signals, resulting in an activation of WAVE.
Collapse
Affiliation(s)
- Raiko Stephan
- Institut für Neurobiologie, Universität Münster, 48149 Münster, Germany
| | | | | | | | | |
Collapse
|
27
|
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
|
28
|
Hild G, Bugyi B, Nyitrai M. Conformational dynamics of actin: effectors and implications for biological function. Cytoskeleton (Hoboken) 2010; 67:609-29. [PMID: 20672362 PMCID: PMC3038201 DOI: 10.1002/cm.20473] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2010] [Accepted: 07/15/2010] [Indexed: 12/30/2022]
Abstract
Actin is a protein abundant in many cell types. Decades of investigations have provided evidence that it has many functions in living cells. The diverse morphology and dynamics of actin structures adapted to versatile cellular functions is established by a large repertoire of actin-binding proteins. The proper interactions with these proteins assume effective molecular adaptations from actin, in which its conformational transitions play essential role. This review attempts to summarise our current knowledge regarding the coupling between the conformational states of actin and its biological function.
Collapse
Affiliation(s)
- Gábor Hild
- Department of Biophysics, University of Pécs, Faculty of Medicine, Pécs, Szigeti str. 12, H-7624, Hungary
| | | | | |
Collapse
|
29
|
Wang D, Zhang L, Zhao G, Wahlström G, Heino TI, Chen J, Zhang YQ. Drosophila twinfilin is required for cell migration and synaptic endocytosis. J Cell Sci 2010; 123:1546-56. [PMID: 20410372 DOI: 10.1242/jcs.060251] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Precise actin regulation is essential for diverse cellular processes such as axonal growth, cell migration and endocytosis. twinfilin (twf) encodes a protein that sequesters actin monomers, but its in vivo functions are unclear. In this study, we characterized twf-null mutants in a metazoan for the first time and found that Drosophila twf negatively regulates F-actin formation in subcellular regions of rapid actin turnover in three different systems, namely postsynaptic neuromuscular junction (NMJ) synapses, migratory border cells and epithelial follicle cells. Loss of twf function results in defects in axonal growth in the brain and border cell migration in the ovary. Additionally, we found that the actin-dependent postsynaptic localization of glutamate receptor GluRIIA, but not GluRIIB, was specifically reduced in twf mutants. More importantly, we showed that twf mutations caused significantly reduced presynaptic endocytosis at NMJ synapses, as detected using the fluorescent dye FM1-43 uptake assay. Furthermore, electrophysiological analysis under high-frequency stimulation showed compromised neurotransmission in twf mutant synapses, confirming an insufficient replenishment of synaptic vesicles. Together, our results reveal that twinfilin promotes actin turnover in multiple cellular processes that are highly dependent on actin dynamics.
Collapse
Affiliation(s)
- Dan Wang
- Key Laboratory of Molecular and Developmental Biology, Institute of Genetics and Developmental Biology, and Graduate University, Chinese Academy of Sciences, Datun Road, Chao Yang District, Beijing 100101, China
| | | | | | | | | | | | | |
Collapse
|
30
|
Li Q, Song XW, Zou J, Wang GK, Kremneva E, Li XQ, Zhu N, Sun T, Lappalainen P, Yuan WJ, Qin YW, Jing Q. Attenuation of microRNA-1 derepresses the cytoskeleton regulatory protein twinfilin-1 to provoke cardiac hypertrophy. J Cell Sci 2010; 123:2444-52. [PMID: 20571053 DOI: 10.1242/jcs.067165] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
MicroRNAs are involved in several aspects of cardiac hypertrophy, including cardiac growth, conduction, and fibrosis. However, their effects on the regulation of the cardiomyocyte cytoskeleton in this pathological process are not known. Here, with microRNA microarray and small RNA library sequencing, we show that microRNA-1 (miR-1) is the most abundant microRNA in the human heart. By applying bioinformatic target prediction, a cytoskeleton regulatory protein twinfilin-1 was identified as a potential target of miR-1. Overexpression of miR-1 not only reduced the luciferase activity of the reporter containing the 3' untranslated region of twinfilin-1 mRNA, but also suppressed the endogenous protein expression of twinfilin-1, indicating that twinfilin-1 is a direct target of miR-1. miR-1 was substantially downregulated in the rat hypertrophic left ventricle and phenylephrine-induced hypertrophic cardiomyocytes, and accordingly, the protein level of twinfilin-1 was increased. Furthermore, overexpression of miR-1 in hypertrophic cardiomyocytes reduced the cell size and attenuated the expression of hypertrophic markers, whereas silencing of miR-1 in cardiomyocytes resulted in the hypertrophic phenotype. In accordance, twinfilin-1 overexpression promoted cardiomyocyte hypertrophy. Taken together, our results demonstrate that the cytoskeleton regulatory protein twinfilin-1 is a novel target of miR-1, and that reduction of miR-1 by hypertrophic stimuli induces the upregulation of twinfilin-1, which in turn evokes hypertrophy through the regulation of cardiac cytoskeleton.
Collapse
Affiliation(s)
- Qing Li
- Key Laboratory of Stem Cell Biology and Laboratory of Nucleic Acid and Molecular Medicine, Institute of Health Sciences, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences and Shanghai Jiao-Tong University School of Medicine, Shanghai 200025, China.
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Goroncy AK, Koshiba S, Tochio N, Tomizawa T, Sato M, Inoue M, Watanabe S, Hayashizaki Y, Tanaka A, Kigawa T, Yokoyama S. NMR solution structures of actin depolymerizing factor homology domains. Protein Sci 2010; 18:2384-92. [PMID: 19768801 DOI: 10.1002/pro.248] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Actin is one of the most conserved proteins in nature. Its assembly and disassembly are regulated by many proteins, including the family of actin-depolymerizing factor homology (ADF-H) domains. ADF-H domains can be divided into five classes: ADF/cofilin, glia maturation factor (GMF), coactosin, twinfilin, and Abp1/drebrin. The best-characterized class is ADF/cofilin. The other four classes have drawn much less attention and very few structures have been reported. This study presents the solution NMR structure of the ADF-H domain of human HIP-55-drebrin-like protein, the first published structure of a drebrin-like domain (mammalian), and the first published structure of GMF beta (mouse). We also determined the structures of mouse GMF gamma, the mouse coactosin-like domain and the C-terminal ADF-H domain of mouse twinfilin 1. Although the overall fold of the five domains is similar, some significant differences provide valuable insights into filamentous actin (F-actin) and globular actin (G-actin) binding, including the identification of binding residues on the long central helix. This long helix is stabilized by three or four residues. Notably, the F-actin binding sites of mouse GMF beta and GMF gamma contain two additional beta-strands not seen in other ADF-H structures. The G-actin binding site of the ADF-H domain of human HIP-55-drebrin-like protein is absent and distorted in mouse GMF beta and GMF gamma.
Collapse
Affiliation(s)
- Alexander K Goroncy
- RIKEN Systems and Structural Biology Center, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, Japan
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
32
|
MyosinVIIa interacts with Twinfilin-2 at the tips of mechanosensory stereocilia in the inner ear. PLoS One 2009; 4:e7097. [PMID: 19774077 PMCID: PMC2743196 DOI: 10.1371/journal.pone.0007097] [Citation(s) in RCA: 50] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2009] [Accepted: 08/14/2009] [Indexed: 11/19/2022] Open
Abstract
In vertebrates hearing is dependent upon the microvilli-like mechanosensory stereocilia and their length gradation. The staircase-like organization of the stereocilia bundle is dynamically maintained by variable actin turnover rates. Two unconventional myosins were previously implicated in stereocilia length regulation but the mechanisms of their action remain unknown. MyosinXVa is expressed in stereocilia tips at levels proportional to stereocilia length and its absence produces staircase-like bundles of very short stereocilia. MyosinVIIa localizes to the tips of the shorter stereocilia within bundles, and when absent, the stereocilia are abnormally long. We show here that myosinVIIa interacts with twinfilin-2, an actin binding protein, which inhibits actin polymerization at the barbed end of the filament, and that twinfilin localization in stereocilia overlaps with myosinVIIa. Exogenous expression of myosinVIIa in fibroblasts results in a reduced number of filopodia and promotes accumulation of twinfilin-2 at the filopodia tips. We hypothesize that the newly described interaction between myosinVIIa and twinfilin-2 is responsible for the establishment and maintenance of slower rates of actin turnover in shorter stereocilia, and that interplay between complexes of myosinVIIa/twinfilin-2 and myosinXVa/whirlin is responsible for stereocilia length gradation within the bundle staircase.
Collapse
|
33
|
Two biochemically distinct and tissue-specific twinfilin isoforms are generated from the mouse Twf2 gene by alternative promoter usage. Biochem J 2008; 417:593-600. [DOI: 10.1042/bj20080608] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Twf (twinfilin) is an evolutionarily conserved regulator of actin dynamics composed of two ADF-H (actin-depolymerizing factor homology) domains. Twf binds actin monomers and heterodimeric capping protein with high affinity. Previous studies have demonstrated that mammals express two Twf isoforms, Twf1 and Twf2, of which at least Twf1 also regulates cytoskeletal dynamics by capping actin filament barbed-ends. In the present study, we show that alternative promoter usage of the mouse Twf2 gene generates two isoforms, which differ from each other only at their very N-terminal region. Of these isoforms, Twf2a is predominantly expressed in non-muscle tissues, whereas expression of Twf2b is restricted to heart and skeletal muscle. Both proteins bind actin monomers and capping protein, as well as efficiently capping actin filament barbed-ends. However, the N-terminal ADF-H domain of Twf2b interacts with ADP-G-actin with a 5-fold higher affinity than with ATP-G-actin, whereas the corresponding domain of Twf2a binds ADP-G-actin and ATP-G-actin with equal affinities. Taken together, these results show that, like Twf1, mouse Twf2 is a filament barbed-end capping protein, and that two tissue-specific and biochemically distinct isoforms are generated from the Twf2 gene through alternative promoter usage.
Collapse
|
34
|
Tang H, Heeley T, Morlec R, Hubbard SJ. Characterising alternate splicing and tissue specific expression in the chicken from ESTs. Cytogenet Genome Res 2007; 117:268-77. [PMID: 17675868 PMCID: PMC2266501 DOI: 10.1159/000103188] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2006] [Accepted: 11/15/2006] [Indexed: 01/19/2023] Open
Abstract
Alternate splicing is believed to produce the greatest diversity in transcriptional complexity and function in eukaryotic species. In this study, we present an analysis of alternative splicing events that occur in the chicken, using the recently sequenced genomic sequence and over 580,000 EST sequences mapped back to the genome. A carefully controlled EST-to-genome mapping pipeline is presented, based around the EXONERATE program using the est2genome model, which also considers several quality control steps to filter out erroneous matches. The data is then used to estimate the level of alternate splicing events with respect to Ensembl predicted transcripts. The EST-genome mappings are characterised at the exon level, in order to classify individual splicing events and provide estimates of novel transcripts not currently annotated by the Ensembl genome database. This is the first large scale analysis of this kind in an avian species, and suggests that chicken displays a similar level of alternate splicing as that found in other higher vertebrates such as human and mouse, both in terms of the number of genes that undergo alternate splicing events, and the average number of transcripts produced per gene. The EST data suggests alternate splicing may occur in some 50-60% of the chicken gene set and with an average of around 2.3 transcripts per gene which undergo this process. The EST data is also used to look at gene and transcript usage in the tissues sequenced in embryonic and adult libraries. Genes which display notable biases were analysed in more detail, including twinfilin-2 and embryonic heavy chain myosin. This also highlights several as yet functionally un-annotated genes which appear to be important in embryonic tissues and also undergo alternate splicing events. The analysis also demonstrates some of the difficulties involved in using EST-based data to annotate transcriptional activity in eukaryotic genes, where a broad spectrum of tissues and a large number of sequenced transcripts are required in order to fully characterise alternate splicing and differential expression.
Collapse
Affiliation(s)
- H Tang
- Faculty of Life Sciences, The University of Manchester, Manchester, UK
| | | | | | | |
Collapse
|
35
|
Ren N, Charlton J, Adler PN. The flare gene, which encodes the AIP1 protein of Drosophila, functions to regulate F-actin disassembly in pupal epidermal cells. Genetics 2007; 176:2223-34. [PMID: 17565945 PMCID: PMC1950627 DOI: 10.1534/genetics.107.072959] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Adult Drosophila are decorated with several types of polarized cuticular structures, such as hairs and bristles. The morphogenesis of these takes place in pupal cells and is mediated by the actin and microtubule cytoskeletons. Mutations in flare (flr) result in grossly abnormal epidermal hairs. We report here that flr encodes the Drosophila actin interacting protein 1 (AIP1). In other systems this protein has been found to promote cofilin-mediated F-actin disassembly. In Drosophila cofilin is encoded by twinstar (tsr). We show that flr mutations result in increased levels of F-actin accumulation and increased F-actin stability in vivo. Further, flr is essential for cell proliferation and viability and for the function of the frizzled planar cell polarity system. All of these phenotypes are similar to those seen for tsr mutations. This differs from the situation in yeast where cofilin is essential while aip1 mutations result in only subtle defects in the actin cytoskeleton. Surprisingly, we found that mutations in flr and tsr also result in greatly increased tubulin staining, suggesting a tight linkage between the actin and microtubule cytoskeleton in these cells.
Collapse
Affiliation(s)
- Nan Ren
- Biology Department, Institute for Morphogenesis and Regenerative Medicine and Cancer Center, University of Virginia, Charlottesville, VA 22903, USA
| | | | | |
Collapse
|
36
|
Sánchez-Soriano N, Tear G, Whitington P, Prokop A. Drosophila as a genetic and cellular model for studies on axonal growth. Neural Dev 2007; 2:9. [PMID: 17475018 PMCID: PMC1876224 DOI: 10.1186/1749-8104-2-9] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2007] [Accepted: 05/02/2007] [Indexed: 11/10/2022] Open
Abstract
One of the most fascinating processes during nervous system development is the establishment of stereotypic neuronal networks. An essential step in this process is the outgrowth and precise navigation (pathfinding) of axons and dendrites towards their synaptic partner cells. This phenomenon was first described more than a century ago and, over the past decades, increasing insights have been gained into the cellular and molecular mechanisms regulating neuronal growth and navigation. Progress in this area has been greatly assisted by the use of simple and genetically tractable invertebrate model systems, such as the fruit fly Drosophila melanogaster. This review is dedicated to Drosophila as a genetic and cellular model to study axonal growth and demonstrates how it can and has been used for this research. We describe the various cellular systems of Drosophila used for such studies, insights into axonal growth cones and their cytoskeletal dynamics, and summarise identified molecular signalling pathways required for growth cone navigation, with particular focus on pathfinding decisions in the ventral nerve cord of Drosophila embryos. These Drosophila-specific aspects are viewed in the general context of our current knowledge about neuronal growth.
Collapse
Affiliation(s)
- Natalia Sánchez-Soriano
- The Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, UK
| | - Guy Tear
- MRC Centre for Developmental Neurobiology, Guy's Campus, King's College, London, UK
| | - Paul Whitington
- Department of Anatomy and Cell Biology, University of Melbourne, Victoria, Australia
| | - Andreas Prokop
- The Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, UK
| |
Collapse
|
37
|
Paavilainen VO, Hellman M, Helfer E, Bovellan M, Annila A, Carlier MF, Permi P, Lappalainen P. Structural basis and evolutionary origin of actin filament capping by twinfilin. Proc Natl Acad Sci U S A 2007; 104:3113-8. [PMID: 17360616 PMCID: PMC1805582 DOI: 10.1073/pnas.0608725104] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Dynamic reorganization of the actin cytoskeleton is essential for motile and morphological processes in all eukaryotic cells. One highly conserved protein that regulates actin dynamics is twinfilin, which both sequesters actin monomers and caps actin filament barbed ends. Twinfilin is composed of two ADF/cofilin-like domains, Twf-N and Twf-C. Here, we reveal by systematic domain-swapping/inactivation analysis that the two functional ADF-H domains of twinfilin are required for barbed-end capping and that Twf-C plays a critical role in this process. However, these domains are not functionally equivalent. NMR-structure and mutagenesis analyses, together with biochemical and motility assays showed that Twf-C, in addition to its binding to G-actin, interacts with the sides of actin filaments like ADF/cofilins, whereas Twf-N binds only G-actin. Our results indicate that during filament barbed-end capping, Twf-N interacts with the terminal actin subunit, whereas Twf-C binds between two adjacent subunits at the side of the filament. Thus, the domain requirement for actin filament capping by twinfilin is remarkably similar to that of gelsolin family proteins, suggesting the existence of a general barbed-end capping mechanism. Furthermore, we demonstrate that a synthetic protein consisting of duplicated ADF/cofilin domains caps actin filament barbed ends, providing evidence that the barbed-end capping activity of twinfilin arose through a duplication of an ancient ADF/cofilin-like domain.
Collapse
Affiliation(s)
- Ville O. Paavilainen
- Programs in *Cellular Biotechnology and
- Cytoskeleton Dynamics and Motility, Laboratoire d'Enzymologie et Biochimie Structurale, Centre National de la Recherche Scientifique, 91118 Gif-sur-Yvette, France
| | - Maarit Hellman
- Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, FI-00014, Finland; and
| | - Emmanuèle Helfer
- Cytoskeleton Dynamics and Motility, Laboratoire d'Enzymologie et Biochimie Structurale, Centre National de la Recherche Scientifique, 91118 Gif-sur-Yvette, France
| | | | - Arto Annila
- Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, FI-00014, Finland; and
| | - Marie-France Carlier
- Cytoskeleton Dynamics and Motility, Laboratoire d'Enzymologie et Biochimie Structurale, Centre National de la Recherche Scientifique, 91118 Gif-sur-Yvette, France
| | - Perttu Permi
- Structural Biology and Biophysics, Institute of Biotechnology, University of Helsinki, FI-00014, Finland; and
- To whom correspondence may be addressed at: Institute of Biotechnology, P.O. Box 56, University of Helsinki, FI-00014 Helsinki, Finland. E-mail: or
| | - Pekka Lappalainen
- Programs in *Cellular Biotechnology and
- To whom correspondence may be addressed at: Institute of Biotechnology, P.O. Box 56, University of Helsinki, FI-00014 Helsinki, Finland. E-mail: or
| |
Collapse
|
38
|
Frank DJ, Hopmann R, Lenartowska M, Miller KG. Capping protein and the Arp2/3 complex regulate nonbundle actin filament assembly to indirectly control actin bundle positioning during Drosophila melanogaster bristle development. Mol Biol Cell 2006; 17:3930-9. [PMID: 16822838 PMCID: PMC1593168 DOI: 10.1091/mbc.e06-06-0500] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Drosophila melanogaster bristle development is dependent on actin assembly, and prominent actin bundles form against the elongating cell membrane, giving the adult bristle its characteristic grooved pattern. Previous work has demonstrated that several actin-regulating proteins are required to generate normal actin bundles. Here we have addressed how two actin regulators, capping protein, a barbed end binding protein, and the Arp2/3 complex, a potent actin assembly nucleator, function to generate properly organized bundles. As predicted from studies in motile cells, we find that capping protein and the Arp2/3 complex act antagonistically to one another during bristle development. However, these proteins do not primarily act directly on bundles, but rather on a dynamic population of actin filaments that are not part of the bundles. These nonbundle filaments, termed snarls, play an important role in determining the number and spacing of the actin bundles. Reduction of capping protein leads to an increase in snarls, which prevents actin bundles from properly attaching to the membrane. Conversely, loss of an Arp2/3 complex component leads to a loss of snarls and accumulation of excess membrane-attached bundles. These results indicate that in nonmotile cells dynamic actin filaments can function to regulate the positioning of stable actin structures. In addition, our results suggest that the Arpc1 subunit may have an additional function, independent of the rest of the Arp2/3 complex.
Collapse
Affiliation(s)
- Deborah J. Frank
- *Department of Biology, Washington University, St. Louis, MO 63130; and
| | - Roberta Hopmann
- *Department of Biology, Washington University, St. Louis, MO 63130; and
| | - Marta Lenartowska
- *Department of Biology, Washington University, St. Louis, MO 63130; and
- Laboratory of Developmental Biology, Institute of General and Molecular Biology, Nicolaus Copernicus University, 87-100 Torun, Poland
| | - Kathryn G. Miller
- *Department of Biology, Washington University, St. Louis, MO 63130; and
| |
Collapse
|
39
|
Moseley JB, Okada K, Balcer HI, Kovar DR, Pollard TD, Goode BL. Twinfilin is an actin-filament-severing protein and promotes rapid turnover of actin structures in vivo. J Cell Sci 2006; 119:1547-57. [PMID: 16569665 DOI: 10.1242/jcs.02860] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Working in concert, multiple actin-binding proteins regulate the dynamic turnover of actin networks. Here, we define a novel function for the conserved actin-binding protein twinfilin, which until now was thought to function primarily as a monomer-sequestering protein. We show that purified budding yeast twinfilin (Twf1) binds to and severs actin filaments in vitro at pH below 6.0 in bulk kinetic and fluorescence microscopy assays. Further, we use total internal reflection fluorescence (TIRF) microscopy to demonstrate that Twf1 severs individual actin filaments in real time. It has been shown that capping protein directly binds to Twf1 and is required for Twf1 localization to cortical actin patches in vivo. We demonstrate that capping protein directly inhibits the severing activity of Twf1, the first biochemical function ascribed to this interaction. In addition, phosphatidylinositol (4,5)-bisphosphate [PtdIns(4,5)P2] inhibits Twf1 filament-severing activity. Consistent with these biochemical activities, a twf1Δ mutation causes reduced rates of cortical actin patch turnover in living cells. Together, our data suggest that twinfilin coordinates filament severing and monomer sequestering at sites of rapid actin turnover and is controlled by multiple regulatory inputs.
Collapse
Affiliation(s)
- James B Moseley
- Department of Biology and The Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454, USA
| | | | | | | | | | | |
Collapse
|
40
|
Helfer E, Nevalainen EM, Naumanen P, Romero S, Didry D, Pantaloni D, Lappalainen P, Carlier MF. Mammalian twinfilin sequesters ADP-G-actin and caps filament barbed ends: implications in motility. EMBO J 2006; 25:1184-95. [PMID: 16511569 PMCID: PMC1422163 DOI: 10.1038/sj.emboj.7601019] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2005] [Accepted: 02/02/2006] [Indexed: 11/09/2022] Open
Abstract
Twinfilins are conserved actin-binding proteins composed of two actin depolymerizing factor homology (ADF-H) domains. Twinfilins are involved in diverse morphological and motile processes, but their mechanism of action has not been elucidated. Here, we show that mammalian twinfilin both sequesters ADP-G-actin and caps filament barbed ends with preferential affinity for ADP-bound ends. Twinfilin replaces capping protein and promotes motility of N-WASP functionalized beads in a biomimetic motility assay, indicating that the capping activity supports twinfilin's function in motility. Consistently, in vivo twinfilin localizes to actin tails of propelling endosomes. The ADP-actin-sequestering activity cooperates with the filament capping activity of twinfilin to finely regulate motility due to processive filament assembly catalyzed by formin-functionalized beads. The isolated ADF-H domains do not cap barbed ends nor promote motility, but sequester ADP-actin, the C-terminal domain showing the highest affinity. A structural model for binding of twinfilin to barbed ends is proposed based on the similar foldings of twinfilin ADF-H domains and gelsolin segments.
Collapse
Affiliation(s)
- Emmanuèle Helfer
- Cytoskeleton Dynamics and Motility, LEBS, CNRS, Gif-sur-Yvette, France
| | | | | | - Stéphane Romero
- Cytoskeleton Dynamics and Motility, LEBS, CNRS, Gif-sur-Yvette, France
| | - Dominique Didry
- Cytoskeleton Dynamics and Motility, LEBS, CNRS, Gif-sur-Yvette, France
| | | | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, Finland
- Institute of Biotechnology, University of Helsinki, Finland. Tel.: +358 9 191 59499; E-mail:
| | - Marie-France Carlier
- Cytoskeleton Dynamics and Motility, LEBS, CNRS, Gif-sur-Yvette, France
- Dynamique du Cytosquelette, LEBS, CNRS, Gif-sur-Yvette F-91198, France. Tel.: +33 1 69 82 34 65; Fax: +33 1 69 82 341 29; E-mail:
| |
Collapse
|
41
|
Price MH, Roberts DM, McCartney BM, Jezuit E, Peifer M. Cytoskeletal dynamics and cell signaling during planar polarity establishment in theDrosophilaembryonic denticle. J Cell Sci 2006; 119:403-15. [PMID: 16418222 DOI: 10.1242/jcs.02761] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Many epithelial cells are polarized along the plane of the epithelium, a property termed planar cell polarity. The Drosophila wing and eye imaginal discs are the premier models of this process. Many proteins required for polarity establishment and its translation into cytoskeletal polarity were identified from studies of those tissues. More recently, several vertebrate tissues have been shown to exhibit planar cell polarity. Striking similarities and differences have been observed when different tissues exhibiting planar cell polarity are compared. Here we describe a new tissue exhibiting planar cell polarity – the denticles, hair-like projections of the Drosophila embryonic epidermis. We describe in real time the changes in the actin cytoskeleton that underlie denticle development, and compare this with the localization of microtubules, revealing new aspects of cytoskeletal dynamics that may have more general applicability. We present an initial characterization of the localization of several actin regulators during denticle development. We find that several core planar cell polarity proteins are asymmetrically localized during the process. Finally, we define roles for the canonical Wingless and Hedgehog pathways and for core planar cell polarity proteins in denticle polarity.
Collapse
Affiliation(s)
- Meredith H Price
- Department of Biology, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599-3280, USA
| | | | | | | | | |
Collapse
|
42
|
Tselykh TV, Roos C, Heino TI. The mitochondrial ribosome-specific MrpL55 protein is essential in Drosophila and dynamically required during development. Exp Cell Res 2005; 307:354-66. [PMID: 15894314 DOI: 10.1016/j.yexcr.2005.03.037] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2004] [Revised: 03/22/2005] [Accepted: 03/24/2005] [Indexed: 10/25/2022]
Abstract
We report on the essential Drosophila mRpL55 gene conserved exclusively in metazoans. Null mRpL55 mutants did not grow after hatching, moved slowly and died as first instar larvae. MrpL55 is similar to mammalian MRPL55, a protein that, in a large-scale mass spectrometry study, has been found as a mitoribosome-specific large subunit protein. We showed that MrpL55 was localised to the mitochondrion in S2 cells and tissues and was enriched in cells with a higher protein synthesis activity. The MrpL55 protein contains a KOW-like motif present in proteins with a role in transcriptional anti-termination and regulation of translation. Modulation of mRpL55 expression level is critical for development. Somatic clonal analysis showed that MrpL55 was not required in larval eye imaginal discs but required in pupal discs apparently during the second mitotic wave. Therefore, our results showed that the MrpL55 protein acts dynamically in the cell during development. We propose that MrpL55 is involved in Drosophila mitochondrial biogenesis and G2/M phase cell cycle progression.
Collapse
MESH Headings
- Amino Acid Motifs/genetics
- Amino Acid Sequence
- Animals
- Animals, Genetically Modified
- Cell Line
- Cloning, Molecular
- Drosophila Proteins/genetics
- Drosophila Proteins/metabolism
- Drosophila Proteins/physiology
- Drosophila melanogaster/embryology
- Drosophila melanogaster/growth & development
- Drosophila melanogaster/physiology
- Eye/cytology
- Eye/growth & development
- Female
- Gene Deletion
- Gene Expression/genetics
- Gene Expression Regulation, Developmental
- Humans
- Immunohistochemistry
- Larva/genetics
- Larva/growth & development
- Mitochondria/chemistry
- Mitochondria/metabolism
- Mitochondrial Proteins/genetics
- Mitochondrial Proteins/metabolism
- Mitochondrial Proteins/physiology
- Molecular Sequence Data
- Mutation
- Nematoda/genetics
- Oogenesis/physiology
- Phenotype
- Protein Structure, Secondary
- RNA, Messenger, Stored/analysis
- RNA, Messenger, Stored/physiology
- RNA-Binding Proteins/genetics
- RNA-Binding Proteins/metabolism
- RNA-Binding Proteins/physiology
- Recombination, Genetic/genetics
- Ribosomal Proteins/genetics
- Ribosomal Proteins/metabolism
- Ribosomal Proteins/physiology
- Salivary Glands/cytology
- Salivary Glands/metabolism
- Sequence Homology, Amino Acid
- Subcellular Fractions/chemistry
Collapse
Affiliation(s)
- Timofey V Tselykh
- Institute of Biotechnology, Developmental Biology Program, University of Helsinki, FIN-00014 Helsinki, Finland.
| | | | | |
Collapse
|
43
|
Falck S, Paavilainen VO, Wear MA, Grossmann JG, Cooper JA, Lappalainen P. Biological role and structural mechanism of twinfilin-capping protein interaction. EMBO J 2004; 23:3010-9. [PMID: 15282541 PMCID: PMC514927 DOI: 10.1038/sj.emboj.7600310] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2004] [Accepted: 06/14/2004] [Indexed: 11/08/2022] Open
Abstract
Twinfilin and capping protein (CP) are highly conserved actin-binding proteins that regulate cytoskeletal dynamics in organisms from yeast to mammals. Twinfilin binds actin monomer, while CP binds the barbed end of the actin filament. Remarkably, twinfilin and CP also bind directly to each other, but the mechanism and role of this interaction in actin dynamics are not defined. Here, we found that the binding of twinfilin to CP does not affect the binding of either protein to actin. Furthermore, site-directed mutagenesis studies revealed that the CP-binding site resides in the conserved C-terminal tail region of twinfilin. The solution structure of the twinfilin-CP complex supports these conclusions. In vivo, twinfilin's binding to both CP and actin monomer was found to be necessary for twinfilin's role in actin assembly dynamics, based on genetic studies with mutants that have defined biochemical functions. Our results support a novel model for how sequential interactions between actin monomers, twinfilin, CP, and actin filaments promote cytoskeletal dynamics.
Collapse
Affiliation(s)
- Sandra Falck
- Program in Cellular Biotechnology, Institute of Biotechnology, University of Helsinki, Finland
| | - Ville O Paavilainen
- Program in Cellular Biotechnology, Institute of Biotechnology, University of Helsinki, Finland
| | - Martin A Wear
- Department of Cell Biology and Physiology, Washington University, St Louis, MO, USA
| | - J Günter Grossmann
- CCLRC Daresbury Laboratory, Synchrotron Radiation Department, Daresbury, Warrington, UK
| | - John A Cooper
- Department of Cell Biology and Physiology, Washington University, St Louis, MO, USA
| | - Pekka Lappalainen
- Program in Cellular Biotechnology, Institute of Biotechnology, University of Helsinki, Finland
| |
Collapse
|
44
|
Paavilainen VO, Bertling E, Falck S, Lappalainen P. Regulation of cytoskeletal dynamics by actin-monomer-binding proteins. Trends Cell Biol 2004; 14:386-94. [PMID: 15246432 DOI: 10.1016/j.tcb.2004.05.002] [Citation(s) in RCA: 163] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
The actin cytoskeleton is a vital component of several key cellular and developmental processes in eukaryotes. Many proteins that interact with filamentous and/or monomeric actin regulate the structure and dynamics of the actin cytoskeleton. Actin-filament-binding proteins control the nucleation, assembly, disassembly and crosslinking of actin filaments, whereas actin-monomer-binding proteins regulate the size, localization and dynamics of the large pool of unpolymerized actin in cells. In this article, we focus on recent advances in understanding how the six evolutionarily conserved actin-monomer-binding proteins - profilin, ADF/cofilin, twinfilin, Srv2/CAP, WASP/WAVE and verprolin/WIP - interact with actin monomers and regulate their incorporation into filament ends. We also present a model of how, together, these ubiquitous actin-monomer-binding proteins contribute to cytoskeletal dynamics and actin-dependent cellular processes.
Collapse
Affiliation(s)
- Ville O Paavilainen
- Program in Cellular Biotechnology, Institute of Biotechnology, PO Box 56, University of Helsinki, Helsinki 00014, Finland
| | | | | | | |
Collapse
|
45
|
Hilpelä P, Vartiainen MK, Lappalainen P. Regulation of the Actin Cytoskeleton by PI(4,5)P2 and PI(3,4,5)P3. Curr Top Microbiol Immunol 2004; 282:117-63. [PMID: 14594216 DOI: 10.1007/978-3-642-18805-3_5] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The actin cytoskeleton is fundamental for various motile and morphogenetic processes in cells. The structure and dynamics of the actin cytoskeleton are regulated by a wide array of actin-binding proteins, whose activities are controlled by various signal transduction pathways. Recent studies have shown that certain membrane phospholipids, especially PI(4,5)P2 and PI(3,4,5)P3, regulate actin filament assembly in cells and in cell extracts. PI(4,5)P2 appears to be a general regulator of actin polymerization at the plasma membrane or at membrane microdomains, whereas PI(3,4,5)P3 promotes the assembly of specialized actin filament structures in response to some growth factors. Biochemical studies have demonstrated that the activities of many proteins promoting actin assembly are upregulated by PI(4,5)P2, whereas proteins that inhibit actin assembly or promote filament disassembly are down-regulated by PI(4,5)P2. PI(3,4,5)P3 promotes its effects on the actin cytoskeleton mainly through activation of the Rho family of small GTPases. In addition to their effects on actin dynamics, both PI(4,5)P2 and PI(3,4,5)P3 promote the formation of specific actin filament structures through activation/inactivation of actin filament cross-linking proteins and proteins that mediate cytoskeleton-plasma membrane interactions.
Collapse
Affiliation(s)
- P Hilpelä
- Program in Cellular Biotechnology, Institute of Biotechnology, University of Helsinki, P.O. Box 56, 00014 Helsinki, Finland
| | | | | |
Collapse
|
46
|
Affiliation(s)
- Antonio Jacinto
- Instituto Gulbenkian de Ciencia, Rua da Quinta Grande, 6, 2780-156 Oeiras, Portugal
| | | |
Collapse
|
47
|
Vartiainen MK, Sarkkinen EM, Matilainen T, Salminen M, Lappalainen P. Mammals have two twinfilin isoforms whose subcellular localizations and tissue distributions are differentially regulated. J Biol Chem 2003; 278:34347-55. [PMID: 12807912 DOI: 10.1074/jbc.m303642200] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Twinfilin is a highly conserved actin monomer-binding protein that regulates cytoskeletal dynamics in organisms from yeast to mammals. In addition to the previously characterized mammalian twinfilin-1, a second protein with approximately 65% sequence identity to twinfilin-1 exists in mouse and humans. However, previous studies failed to identify any actin binding activity in this protein (Rohwer, A., Kittstein, W., Marks, F., and Gschwendt, M. (1999) Eur. J. Biochem. 263, 518-525). Here we show that this protein, which we named twinfilin-2, is indeed an actin monomer-binding protein. Similar to twinfilin-1, mouse twinfilin-2 binds ADP-G-actin with a higher affinity (KD = 0.12 microM) than ATP-G-actin (KD = 1.96 microM) and efficiently inhibits actin filament assembly in vitro. Both mouse twinfilins inhibit the nucleotide exchange on actin monomers and directly interact with capping protein. Furthermore, the actin interactions of mouse twinfilin-1 and twinfilin-2 are inhibited by phosphatidylinositol (4,5)-bisphosphate. Although biochemically very similar, our Northern blots and in situ hybridizations show that these two proteins display distinct expression patterns. Twinfilin-1 is the major isoform in embryos and in most adult mouse non-muscle cell-types, whereas twinfilin-2 is the predominant isoform of adult heart and skeletal muscles. Studies with isoform-specific antibodies demonstrated that although the two proteins show similar localizations in unstimulated cells, they are regulated by different mechanisms. The small GTPases Rac1 and Cdc42 induce the redistribution of twinfilin-1 to membrane ruffles and cell-cell contacts, respectively, but do not affect the localization of twinfilin-2. Taken together, these data show that mammals have two twinfilin isoforms, which are differentially expressed and regulated through distinct cellular signaling pathways.
Collapse
MESH Headings
- 3T3 Cells
- Actins/chemistry
- Actins/metabolism
- Amino Acid Sequence
- Animals
- Blotting, Northern
- Blotting, Western
- Carrier Proteins
- Cell Communication
- Cells, Cultured
- Cytoskeleton/metabolism
- DNA, Complementary/metabolism
- Dose-Response Relationship, Drug
- Electrophoresis, Polyacrylamide Gel
- Gene Expression Regulation
- Glutathione Transferase/metabolism
- Humans
- In Situ Hybridization
- Kinetics
- Mice
- Microfilament Proteins/chemistry
- Microscopy, Fluorescence
- Molecular Sequence Data
- Phosphatidylinositol 4,5-Diphosphate/chemistry
- Plasmids/metabolism
- Protein Binding
- Protein Isoforms
- Protein Structure, Tertiary
- Protein-Tyrosine Kinases
- RNA/metabolism
- Saccharomyces cerevisiae/metabolism
- Saccharomyces cerevisiae Proteins
- Signal Transduction
- Time Factors
- Tissue Distribution
- Tumor Cells, Cultured
- cdc42 GTP-Binding Protein/chemistry
- rac1 GTP-Binding Protein/metabolism
Collapse
Affiliation(s)
- Maria K Vartiainen
- Program in Cellular Biotechnology, Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | | | | | | | | |
Collapse
|
48
|
Hopmann R, Miller KG. A balance of capping protein and profilin functions is required to regulate actin polymerization in Drosophila bristle. Mol Biol Cell 2003; 14:118-28. [PMID: 12529431 PMCID: PMC140232 DOI: 10.1091/mbc.e02-05-0300] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Profilin is a well-characterized protein known to be important for regulating actin filament assembly. Relatively few studies have addressed how profilin interacts with other actin-binding proteins in vivo to regulate assembly of complex actin structures. To investigate the function of profilin in the context of a differentiating cell, we have studied an instructive genetic interaction between mutations in profilin (chickadee) and capping protein (cpb). Capping protein is the principal protein in cells that caps actin filament barbed ends. When its function is reduced in the Drosophila bristle, F-actin levels increase and the actin cytoskeleton becomes disorganized, causing abnormal bristle morphology. chickadee mutations suppress the abnormal bristle phenotype and associated abnormalities of the actin cytoskeleton seen in cpb mutants. Furthermore, overexpression of profilin in the bristle mimics many features of the cpb loss-of-function phenotype. The interaction between cpb and chickadee suggests that profilin promotes actin assembly in the bristle and that a balance between capping protein and profilin activities is important for the proper regulation of F-actin levels. Furthermore, this balance of activities affects the association of actin structures with the membrane, suggesting a link between actin filament dynamics and localization of actin structures within the cell.
Collapse
Affiliation(s)
- Roberta Hopmann
- Department of Biology, Washington University, St Louis, Missouri 63130, USA
| | | |
Collapse
|
49
|
Paavilainen VO, Merckel MC, Falck S, Ojala PJ, Pohl E, Wilmanns M, Lappalainen P. Structural conservation between the actin monomer-binding sites of twinfilin and actin-depolymerizing factor (ADF)/cofilin. J Biol Chem 2002; 277:43089-95. [PMID: 12207032 DOI: 10.1074/jbc.m208225200] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Twinfilin is an evolutionarily conserved actin monomer-binding protein that regulates cytoskeletal dynamics in organisms from yeast to mammals. It is composed of two actin-depolymerization factor homology (ADF-H) domains that show approximately 20% sequence identity to ADF/cofilin proteins. In contrast to ADF/cofilins, which bind both G-actin and F-actin and promote filament depolymerization, twinfilin interacts only with G-actin. To elucidate the molecular mechanisms of twinfilin-actin monomer interaction, we determined the crystal structure of the N-terminal ADF-H domain of twinfilin and mapped its actin-binding site by site-directed mutagenesis. This domain has similar overall structure to ADF/cofilins, and the regions important for actin monomer binding in ADF/cofilins are especially well conserved in twinfilin. Mutagenesis studies show that the N-terminal ADF-H domain of twinfilin and ADF/cofilins also interact with actin monomers through similar interfaces, although the binding surface is slightly extended in twinfilin. In contrast, the regions important for actin-filament interactions in ADF/cofilins are structurally different in twinfilin. This explains the differences in actin-interactions (monomer versus filament binding) between twinfilin and ADF/cofilins. Taken together, our data show that the ADF-H domain is a structurally conserved actin-binding motif and that relatively small structural differences at the actin interfaces of this domain are responsible for the functional variation between the different classes of ADF-H domain proteins.
Collapse
Affiliation(s)
- Ville O Paavilainen
- Program in Cellular Biotechnology, Institute of Biotechnology, P.O. Box 56, University of Helsinki, 00014 Helsinki, Finland
| | | | | | | | | | | | | |
Collapse
|
50
|
Ojala PJ, Paavilainen VO, Vartiainen MK, Tuma R, Weeds AG, Lappalainen P. The two ADF-H domains of twinfilin play functionally distinct roles in interactions with actin monomers. Mol Biol Cell 2002; 13:3811-21. [PMID: 12429826 PMCID: PMC133594 DOI: 10.1091/mbc.e02-03-0157] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Twinfilin is a ubiquitous and abundant actin monomer-binding protein that is composed of two ADF-H domains. To elucidate the role of twinfilin in actin dynamics, we examined the interactions of mouse twinfilin and its isolated ADF-H domains with G-actin. Wild-type twinfilin binds ADP-G-actin with higher affinity (K(D) = 0.05 microM) than ATP-G-actin (K(D) = 0.47 microM) under physiological ionic conditions and forms a relatively stable (k(off) = 1.8 s(-1)) complex with ADP-G-actin. Data from native PAGE and size exclusion chromatography coupled with light scattering suggest that twinfilin competes with ADF/cofilin for the high-affinity binding site on actin monomers, although at higher concentrations, twinfilin, cofilin, and actin may also form a ternary complex. By systematic deletion analysis, we show that the actin-binding activity is located entirely in the two ADF-H domains of twinfilin. Individually, these domains compete for the same binding site on actin, but the C-terminal ADF-H domain, which has >10-fold higher affinity for ADP-G-actin, is almost entirely responsible for the ability of twinfilin to increase the amount of monomeric actin in cosedimentation assays. Isolated ADF-H domains associate with ADP-G-actin with rapid second-order kinetics, whereas the association of wild-type twinfilin with G-actin exhibits kinetics consistent with a two-step binding process. These data suggest that the association with an actin monomer induces a first-order conformational change within the twinfilin molecule. On the basis of these results, we propose a kinetic model for the role of twinfilin in actin dynamics and its possible function in cells.
Collapse
Affiliation(s)
- Pauli J Ojala
- Program of Cellular Biotechnology, Institute of Biotechnology, University of Helsinki, 00014, Helsinki, Finland
| | | | | | | | | | | |
Collapse
|