1
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Umer N, Phadke S, Shakeri F, Arévalo L, Lohanadan K, Kirfel G, Sylvester M, Buness A, Schorle H. PFN4 is required for manchette development and acrosome biogenesis during mouse spermiogenesis. Development 2022; 149:276289. [PMID: 35950913 PMCID: PMC9481974 DOI: 10.1242/dev.200499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Accepted: 07/14/2022] [Indexed: 11/26/2022]
Abstract
Profilin 4 (Pfn4) is expressed during spermiogenesis and localizes to the acrosome-acroplaxome-manchette complex. Here, we generated PFN4-deficient mice, with sperm displaying severe impairment in manchette formation. Interestingly, HOOK1 staining suggests that the perinuclear ring is established; however, ARL3 staining is disrupted, suggesting that lack of PFN4 does not interfere with the formation of the perinuclear ring and initial localization of HOOK1, but impedes microtubular organization of the manchette. Furthermore, amorphous head shape and flagellar defects were detected, resulting in reduced sperm motility. Disrupted cis- and trans-Golgi networks and aberrant production of proacrosomal vesicles caused impaired acrosome biogenesis. Proteomic analysis showed that the proteins ARF3, SPECC1L and FKBP1, which are involved in Golgi membrane trafficking and PI3K/AKT pathway, are more abundant in Pfn4−/− testes. Levels of PI3K, AKT and mTOR were elevated, whereas AMPK level was reduced, consistent with inhibition of autophagy. This seems to result in blockage of autophagic flux, which could explain the failure in acrosome formation. In vitro fertilization demonstrated that PFN4-deficient sperm is capable of fertilizing zona-free oocytes, suggesting a potential treatment for PFN4-related human infertility. Summary: PFN4-deficient male mice exhibit impaired acrosome formation and malformation of the manchette, leading to amorphous sperm head shape, flagellar abnormalities and sterility.
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Affiliation(s)
- Naila Umer
- Institute of Pathology, University Hospital Bonn 1 Department of Developmental Pathology , , 53127 Bonn , Germany
| | - Sharang Phadke
- Institute of Pathology, University Hospital Bonn 1 Department of Developmental Pathology , , 53127 Bonn , Germany
| | - Farhad Shakeri
- Institute for Medical Biometry, Informatics and Epidemiology 2 , Medical Faculty , , 53127 Bonn , Germany
- University of Bonn 2 , Medical Faculty , , 53127 Bonn , Germany
- Institute for Genomic Statistics and Bioinformatics 3 , Medical Faculty , , 53127 Bonn , Germany
- University of Bonn 3 , Medical Faculty , , 53127 Bonn , Germany
| | - Lena Arévalo
- Institute of Pathology, University Hospital Bonn 1 Department of Developmental Pathology , , 53127 Bonn , Germany
| | | | - Gregor Kirfel
- Institute for Cell Biology, University of Bonn 4 , 53121 Bonn , Germany
| | - Marc Sylvester
- Institute of Biochemistry and Molecular Biology 5 Core Facility Mass Spectrometry , , Medical Faculty , , 53115 Bonn , Germany
- University of Bonn 5 Core Facility Mass Spectrometry , , Medical Faculty , , 53115 Bonn , Germany
| | - Andreas Buness
- Institute for Medical Biometry, Informatics and Epidemiology 2 , Medical Faculty , , 53127 Bonn , Germany
- University of Bonn 2 , Medical Faculty , , 53127 Bonn , Germany
- Institute for Genomic Statistics and Bioinformatics 3 , Medical Faculty , , 53127 Bonn , Germany
- University of Bonn 3 , Medical Faculty , , 53127 Bonn , Germany
| | - Hubert Schorle
- Institute of Pathology, University Hospital Bonn 1 Department of Developmental Pathology , , 53127 Bonn , Germany
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2
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Pimm ML, Liu X, Tuli F, Heritz J, Lojko A, Henty-Ridilla JL. Visualizing molecules of functional human profilin. eLife 2022; 11:e76485. [PMID: 35666129 PMCID: PMC9249392 DOI: 10.7554/elife.76485] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Accepted: 06/06/2022] [Indexed: 11/20/2022] Open
Abstract
Profilin-1 (PFN1) is a cytoskeletal protein that regulates the dynamics of actin and microtubule assembly. Thus, PFN1 is essential for the normal division, motility, and morphology of cells. Unfortunately, conventional fusion and direct labeling strategies compromise different facets of PFN1 function. As a consequence, the only methods used to determine known PFN1 functions have been indirect and often deduced in cell-free biochemical assays. We engineered and characterized two genetically encoded versions of tagged PFN1 that behave identical to each other and the tag-free protein. In biochemical assays purified proteins bind to phosphoinositide lipids, catalyze nucleotide exchange on actin monomers, stimulate formin-mediated actin filament assembly, and bound tubulin dimers (kD = 1.89 µM) to impact microtubule dynamics. In PFN1-deficient mammalian cells, Halo-PFN1 or mApple-PFN1 (mAp-PEN1) restored morphological and cytoskeletal functions. Titrations of self-labeling Halo-ligands were used to visualize molecules of PFN1. This approach combined with specific function-disrupting point-mutants (Y6D and R88E) revealed PFN1 bound to microtubules in live cells. Cells expressing the ALS-associated G118V disease variant did not associate with actin filaments or microtubules. Thus, these tagged PFN1s are reliable tools for studying the dynamic interactions of PFN1 with actin or microtubules in vitro as well as in important cell processes or disease-states.
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Affiliation(s)
- Morgan L Pimm
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Xinbei Liu
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Farzana Tuli
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Jennifer Heritz
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Ashley Lojko
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
| | - Jessica L Henty-Ridilla
- Department of Biochemistry and Molecular Biology, SUNY Upstate Medical UniversitySyracuseUnited States
- Department of Neuroscience and Physiology, SUNY Upstate Medical UniversitySyracuseUnited States
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3
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Wang Y, Lu Y, Wan R, Wang Y, Zhang C, Li M, Deng P, Cao L, Hu C. Profilin 1 Induces Tumor Metastasis by Promoting Microvesicle Secretion Through the ROCK 1/p-MLC Pathway in Non-Small Cell Lung Cancer. Front Pharmacol 2022; 13:890891. [PMID: 35586060 PMCID: PMC9108340 DOI: 10.3389/fphar.2022.890891] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2022] [Accepted: 04/12/2022] [Indexed: 11/13/2022] Open
Abstract
Profilin 1 (PFN1), an actin-binding protein, plays contrasting roles in the metastasis of several cancers; however, its role in non-small cell lung cancer (NSCLC) metastasis remains unclear. Here, PFN1 expression was upregulated in metastatic NSCLC tissues. PFN1 overexpression significantly promotes NSCLC metastasis in vitro and in vivo. Proteomics analysis revealed PFN1 involvment in microvesicles (MVs) secretion. In vitro experiments confirmed that PFN1 overexpression increased secretion of MVs. MVs are important mediators of metastasis. Here, we show an increased abundance of MVs in the sera of patients with metastatic NSCLC compared to that in the sera of patients with non-metastatic NSCLC. Both in vitro and in vivo experiments revealed that PFN1 could increase MV secretion, and MVs derived from PFN1-overexpressing cells markedly promoted NSCLC metastasis. We then elucidated the mechanisms underlying PFN1-mediated regulation of MVs and found that PFN1 could interact with ROCK1 and enhance its kinase activity to promote myosin light chain (MLC) phosphorylation for MV secretion. Inhibition of ROCK1 decreased MV secretion and partially reversed the PFN1-induced promotion of NSCLC metastasis. Collectively, these findings show that PFN1 regulates MV secretion to promote NSCLC metastasis. PFN1 and MVs represent potential predictors or therapeutic targets for NSCLC metastasis.
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Affiliation(s)
- Ya Wang
- Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Yichen Lu
- Department of Oncology, Hunan Provincial People’s Hospital/The First Affiliated Hospital of Hunan Normal University, Changsha, China
| | - Rongjun Wan
- Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Yang Wang
- Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Chunfang Zhang
- Department of Thoracic Surgery, Xiangya Hospital, Central South University, Changsha, China
| | - Min Li
- Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Pengbo Deng
- Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Liming Cao
- Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, China
| | - Chengping Hu
- Department of Respiratory Medicine, Xiangya Hospital, Central South University, Changsha, China
- *Correspondence: Chengping Hu,
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Umer N, Arévalo L, Phadke S, Lohanadan K, Kirfel G, Sons D, Sofia D, Witke W, Schorle H. Loss of Profilin3 Impairs Spermiogenesis by Affecting Acrosome Biogenesis, Autophagy, Manchette Development and Mitochondrial Organization. Front Cell Dev Biol 2021; 9:749559. [PMID: 34869336 PMCID: PMC8632698 DOI: 10.3389/fcell.2021.749559] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Accepted: 09/28/2021] [Indexed: 11/28/2022] Open
Abstract
Profilins (PFNs) are key regulatory proteins for the actin polymerization in cells and are encoded in mouse and humans by four Pfn genes. PFNs are involved in cell mobility, cell growth, neurogenesis, and metastasis of tumor cells. The testes-specific PFN3 is localized in the acroplaxome-manchette complex of developing spermatozoa. We demonstrate that PFN3 further localizes in the Golgi complex and proacrosomal vesicles during spermiogenesis, suggesting a role in vesicle transport for acrosome formation. Using CRISPR/Cas9 genome editing, we generated mice deficient for Pfn3. Pfn3-/- males are subfertile, displaying a type II globozoospermia. We revealed that Pfn3-/- sperm display abnormal manchette development leading to an amorphous sperm head shape. Additionally, Pfn3-/- sperm showed reduced sperm motility resulting from flagellum deformities. We show that acrosome biogenesis is impaired starting from the Golgi phase, and mature sperm seems to suffer from a cytoplasm removal defect. An RNA-seq analysis revealed an upregulation of Trim27 and downregulation of Atg2a. As a consequence, mTOR was activated and AMPK was suppressed, resulting in the inhibition of autophagy. This dysregulation of AMPK/mTOR affected the autophagic flux, which is hallmarked by LC3B accumulation and increased SQSTM1 protein levels. Autophagy is involved in proacrosomal vesicle fusion and transport to form the acrosome. We conclude that this disruption leads to the observed malformation of the acrosome. TRIM27 is associated with PFN3 as determined by co-immunoprecipitation from testis extracts. Further, actin-related protein ARPM1 was absent in the nuclear fraction of Pfn3-/- testes and sperm. This suggests that lack of PFN3 leads to destabilization of the PFN3-ARPM1 complex, resulting in the degradation of ARPM1. Interestingly, in the Pfn3-/- testes, we detected increased protein levels of essential actin regulatory proteins, cofilin-1 (CFL1), cofilin-2 (CFL2), and actin depolymerizing factor (ADF). Taken together, our results reveal the importance for PFN3 in male fertility and implicate this protein as a candidate for male factor infertility in humans.
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Affiliation(s)
- Naila Umer
- Department of Developmental Pathology, Institute of Pathology, University Hospital Bonn, Bonn, Germany
| | - Lena Arévalo
- Department of Developmental Pathology, Institute of Pathology, University Hospital Bonn, Bonn, Germany
| | - Sharang Phadke
- Department of Developmental Pathology, Institute of Pathology, University Hospital Bonn, Bonn, Germany
| | | | - Gregor Kirfel
- Institute for Cell Biology, University of Bonn, Bonn, Germany
| | - Dominik Sons
- Department of Membrane Biochemistry, Life and Medical Sciences (LIMES) Institute, University of Bonn, Bonn, Germany
| | - Denise Sofia
- Institute of Genetics, University of Bonn, Bonn, Germany
| | - Walter Witke
- Institute of Genetics, University of Bonn, Bonn, Germany
| | - Hubert Schorle
- Department of Developmental Pathology, Institute of Pathology, University Hospital Bonn, Bonn, Germany
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5
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Karlsson R, Dráber P. Profilin-A master coordinator of actin and microtubule organization in mammalian cells. J Cell Physiol 2021; 236:7256-7265. [PMID: 33821475 DOI: 10.1002/jcp.30379] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 03/08/2021] [Accepted: 03/12/2021] [Indexed: 12/17/2022]
Abstract
The last two decades have witnessed a tremendous increase in cell biology data. Not least is this true for studies of the dynamic organization of the microfilament and microtubule systems in animal cells where analyses of the molecular components and their interaction patterns have deepened our understanding of these complex force-generating machineries. Previous observations of a molecular cross-talk between the two systems have now led to the realization of the existence of several intricate mechanisms operating to maintain their coordinated cellular organization. In this short review, we relate to this development by discussing new results concerning the function of the actin regulator profilin 1 as a control component of microfilament-microtubule cross-talk.
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Affiliation(s)
- Roger Karlsson
- Department of Molecular Biosciences, WGI, Stockholm University, Stockholm, Sweden
| | - Pavel Dráber
- Department of Biology of Cytoskeleton, Institute of Molecular Genetics of the Czech Academy of Sciences, Prague, Czech Republic
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6
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Lu Y, Wang Y, Xu H, Shi C, Jin F, Li W. Profilin 1 induces drug resistance through Beclin1 complex-mediated autophagy in multiple myeloma. Cancer Sci 2018; 109:2706-2716. [PMID: 29945297 PMCID: PMC6125445 DOI: 10.1111/cas.13711] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2018] [Accepted: 06/19/2018] [Indexed: 01/01/2023] Open
Abstract
Autophagy plays an important role in multiple myeloma (MM) for homeostasis, survival and drug resistance, but which genes participate in this process is unclear. We identified several cytoskeleton genes upregulated in MM patients by gene expression profiling (GEP) datasets; in particular, patients with high profilin 1 (PFN1) expression had poor prognosis in MM. In vitro, overexpressed PFN1 promotes proliferation and bortezomib (BTZ) resistance in MM cells. Further study indicated overexpression of PFN1 significantly promoted the process of autophagy and induced BTZ resistance in MM. Otherwise, knockdown of PFN1 blocked autophagy and sensitized MM to BTZ. Co‐immunoprecipitation in MM cells indicated that PFN1 could bind Beclin1 complex and promote the initiation of autophagy. Inhibition of autophagy by blocking the formation of Beclin1 complex could reverse the phenotype of BTZ resistance in MM. Our findings suggested that PFN1 could promote autophagy through taking part in Beclin1 complex and contribute to BTZ resistance, which may become a novel molecular target in the therapy of MM.
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Affiliation(s)
- Yichen Lu
- Cancer Center, the First Bethune Hospital of Jilin University, Jilin, China
| | - Ya Wang
- Department of Respiratory Medicine (Department of Respiratory and Critical Care Medicine), National Key Clinical Specialty, Xiangya Hospital, Central South University, Hunan, China
| | - He Xu
- Cancer Center, the First Bethune Hospital of Jilin University, Jilin, China
| | - Chen Shi
- Cancer Center, the First Bethune Hospital of Jilin University, Jilin, China
| | - Fengyan Jin
- Cancer Center, the First Bethune Hospital of Jilin University, Jilin, China
| | - Wei Li
- Cancer Center, the First Bethune Hospital of Jilin University, Jilin, China
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7
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Nejedla M, Sadi S, Sulimenko V, de Almeida FN, Blom H, Draber P, Aspenström P, Karlsson R. Profilin connects actin assembly with microtubule dynamics. Mol Biol Cell 2016; 27:2381-93. [PMID: 27307590 PMCID: PMC4966980 DOI: 10.1091/mbc.e15-11-0799] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Accepted: 06/09/2016] [Indexed: 12/29/2022] Open
Abstract
Profilin is a well-known regulator of actin filament formation. It indirectly associates with microtubules and influences their growth rate. Formins are the linker molecules, and the turnover of the actin microfilament system balances profilin association with the microtubules. Profilin controls actin nucleation and assembly processes in eukaryotic cells. Actin nucleation and elongation promoting factors (NEPFs) such as Ena/VASP, formins, and WASP-family proteins recruit profilin:actin for filament formation. Some of these are found to be microtubule associated, making actin polymerization from microtubule-associated platforms possible. Microtubules are implicated in focal adhesion turnover, cell polarity establishment, and migration, illustrating the coupling between actin and microtubule systems. Here we demonstrate that profilin is functionally linked to microtubules with formins and point to formins as major mediators of this association. To reach this conclusion, we combined different fluorescence microscopy techniques, including superresolution microscopy, with siRNA modulation of profilin expression and drug treatments to interfere with actin dynamics. Our studies show that profilin dynamically associates with microtubules and this fraction of profilin contributes to balance actin assembly during homeostatic cell growth and affects microtubule dynamics. Hence profilin functions as a regulator of microtubule (+)-end turnover in addition to being an actin control element.
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Affiliation(s)
- Michaela Nejedla
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Sara Sadi
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Vadym Sulimenko
- Institute of Molecular Genetics, ASCR, 142 20 Prague 4, Czech Republic
| | | | - Hans Blom
- Science for Life Laboratory, SE-171 21 Solna, Sweden
| | - Pavel Draber
- Institute of Molecular Genetics, ASCR, 142 20 Prague 4, Czech Republic
| | - Pontus Aspenström
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, SE-171 77 Stockholm, Sweden
| | - Roger Karlsson
- Department of Molecular Biosciences, Wenner-Gren Institute, Stockholm University, SE-106 91 Stockholm, Sweden
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8
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Yu J, Roy SK, Kamal AHM, Cho K, Kwon SJ, Cho SW, So YS, Holland JB, Woo SH. Protein Profiling Reveals Novel Proteins in Pollen and Pistil of W22 (ga1; Ga1) in Maize. Proteomes 2014; 2:258-271. [PMID: 28250381 PMCID: PMC5302736 DOI: 10.3390/proteomes2020258] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2014] [Revised: 04/08/2014] [Accepted: 04/21/2014] [Indexed: 12/31/2022] Open
Abstract
Gametophytic factors mediate pollen-pistil interactions in maize (Zea mays L.) and play active roles in limiting gene flow among maize populations and between maize and teosinte. This study was carried out to identify proteins and investigate the mechanism of gametophytic factors using protein analysis. W22 (ga1); which did not carry a gametophytic factor and W22 (Ga1), a near iso-genic line, were used for the proteome investigation. SDS-PAGE was executed to investigate proteins in the pollen and pistil of W22 (ga1) and W22 (Ga1). A total of 44 differentially expressed proteins were identified in the pollen and pistil on SDS-PAGE using LTQ-FTICR MS. Among the 44 proteins, a total of 24 proteins were identified in the pollen of W22 (ga1) and W22 (Ga1) whereas 20 differentially expressed proteins were identified from the pistil of W22 (ga1) and W22 (Ga1). However, in pollen, 2 proteins were identified only in the W22 (ga1) and 12 proteins only in the W22 (Ga1) whereas 10 proteins were confirmed from the both of W22 (ga1) and W22 (Ga1). In contrary, 10 proteins were appeared only in the pistil of W22 (ga1) and 7 proteins from W22 (Ga1) while 3 proteins confirmed in the both of W22 (ga1) and W22 (Ga1). Moreover, the identified proteins were generally involved in hydrolase activity, nucleic acid binding and nucleotide binding. These results help to reveal the mechanism of gametophytic factors and provide a valuable clue for the pollen and pistil research in maize.
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Affiliation(s)
- Jin Yu
- Department of Crop Science, Chungbuk National University, Cheong-ju 361-763, Korea.
| | - Swapan Kumar Roy
- Department of Crop Science, Chungbuk National University, Cheong-ju 361-763, Korea.
| | | | - Kun Cho
- Division of Mass Spectrometry Research, Korea Basic Science Institute, Chungbuk 863-883, Korea.
| | - Soo-Jeong Kwon
- Department of Crop Science, Chungbuk National University, Cheong-ju 361-763, Korea.
| | - Seong-Woo Cho
- Lab of Molecular Breeding, Arid land Research Center, Tottori University, Tottori 680-8550, Japan.
| | - Yoon-Sup So
- Department of Crop Science, Chungbuk National University, Cheong-ju 361-763, Korea.
| | - James B Holland
- USDA-ARS Plant Science Research Unit, Department of Crop Science, Box 7620, North Carolina State University, Raleigh, NC 27695, USA.
| | - Sun Hee Woo
- Department of Crop Science, Chungbuk National University, Cheong-ju 361-763, Korea.
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9
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Sun T, Li S, Ren H. Profilin as a regulator of the membrane-actin cytoskeleton interface in plant cells. FRONTIERS IN PLANT SCIENCE 2013; 4:512. [PMID: 24391654 PMCID: PMC3867660 DOI: 10.3389/fpls.2013.00512] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 11/30/2013] [Indexed: 05/04/2023]
Abstract
Membrane structures and cytoskeleton dynamics are intimately inter-connected in the eukaryotic cell. Recently, the molecular mechanisms operating at this interface have been progressively addressed. Many experiments have revealed that the actin cytoskeleton can interact with membranes through various discrete membrane domains. The actin-binding protein, profilin has been proven to inhibit actin polymerization and to promote F-actin elongation. This is dependent on many factors, such as the profilin/G-actin ratio and the ionic environment of the cell. Additionally, profilin has specific domains that interact with phosphoinositides and poly-L-proline rich proteins; theoretically, this gives profilin the opportunity to interact with membranes, and a large number of experiments have confirmed this possibility. In this article, we summarize recent findings in plant cells, and discuss the evidence of the connections among actin cytoskeleton, profilin and biomembranes through direct or indirect relationships.
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Affiliation(s)
| | | | - Haiyun Ren
- *Correspondence: Haiyun Ren, Key Laboratory of Cell Proliferation and Regulation Biology of Ministry of Education, College of Life Science, Beijing Normal University, No. 19, Xin Jie Kou Wai Street, Beijing 100875, China e-mail:
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10
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Zandi F, Eslami N, Torkashvand F, Fayaz A, Khalaj V, Vaziri B. Expression changes of cytoskeletal associated proteins in proteomic profiling of neuroblastoma cells infected with different strains of rabies virus. J Med Virol 2012; 85:336-47. [PMID: 23168799 DOI: 10.1002/jmv.23458] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/01/2012] [Indexed: 12/17/2022]
Abstract
Rabies virus invades the nervous system, induces neuronal dysfunction and causes death of the host. The disruption of the cytoskeletal integrity and synaptic structures of the neurons by rabies virus has been postulated as a possible basis for neuronal dysfunction. In the present study, a two-dimensional electrophoresis/mass spectrometry proteomics analysis of neuroblastoma cells revealed a significant effect of a virulent strain of rabies virus on the host cytoskeleton related proteins which was quite different from that of an attenuated strain. Vimentin, actin cytoplasmic 1 isoform, profilin I, and Rho-GDP dissociation inhibitor were host cell cytoskeletal related proteins changed by the virulent strain. The proteomics data indicated that the virulent strain of rabies virus induces significant expression changes in the vimentin and actin cytoskeleton networks of neurons which could be a strong clue for the relation of cytoskeletal integrity distraction and rabies virus pathogenesis. In addition, the expression alteration of other host proteins, particularly some structural and regulatory proteins may have potential roles in rabies virus pathogenesis.
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Affiliation(s)
- Fatemeh Zandi
- Protein Chemistry Unit, Biotechnology Research Center, Pasteur Institute of Iran, Tehran, Iran
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11
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Söderberg E, Hessle V, von Euler A, Visa N. Profilin is associated with transcriptionally active genes. Nucleus 2012; 3:290-9. [PMID: 22572953 PMCID: PMC3414406 DOI: 10.4161/nucl.20327] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
We have raised antibodies against the profilin of Chironomus tentans to study the location of profilin relative to chromatin and to active genes in salivary gland polytene chromosomes. We show that a fraction of profilin is located in the nucleus, where profilin is highly concentrated in the nucleoplasm and at the nuclear periphery. Moreover, profilin is associated with multiple bands in the polytene chromosomes. By staining salivary glands with propidium iodide, we show that profilin does not co-localize with dense chromatin. Profilin associates instead with protein-coding genes that are transcriptionally active, as revealed by co-localization with hnRNP and snRNP proteins. We have performed experiments of transcription inhibition with actinomycin D and we show that the association of profilin with the chromosomes requires ongoing transcription. However, the interaction of profilin with the gene loci does not depend on RNA. Our results are compatible with profilin regulating actin polymerization in the cell nucleus. However, the association of actin with the polytene chromosomes of C. tentans is sensitive to RNase, whereas the association of profilin is not, and we propose therefore that the chromosomal location of profilin is independent of actin.
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Affiliation(s)
- Emilia Söderberg
- Department of Molecular Biology & Functional Genomics, Stockholm University, Stockholm, Sweden
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12
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Krishnan K, Moens PDJ. Structure and functions of profilins. Biophys Rev 2009; 1:71-81. [PMID: 28509986 PMCID: PMC5425664 DOI: 10.1007/s12551-009-0010-y] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2009] [Revised: 05/07/2009] [Accepted: 05/13/2009] [Indexed: 10/20/2022] Open
Abstract
Profilins are small actin-binding proteins found in eukaryotes and certain viruses that are involved in cell development, cytokinesis, membrane trafficking, and cell motility. Originally identified as an actin sequestering/binding protein, profilin has been involved in actin polymerization dynamics. It catalyzes the exchange of ADP/ATP in actin and increases the rate of polymerization. Profilins also interact with polyphosphoinositides (PPI) and proline-rich domains containing proteins. Through its interaction with PPIs, profilin has been linked to signaling pathways between the cell membrane and the cytoskeleton, while its role in membrane trafficking has been associated with its interaction with proline-rich domain-containing proteins. Depending on the organism, profilin is present in a various number of isoforms. Four isoforms of profilin have been reported in higher organisms, while only one or two isoforms are expressed in single-cell organisms. The affinity of these isoforms for their ligands varies between isoforms and should therefore modulate their functions. However, the significance and the functions of the different isoforms are not yet fully understood. The structures of many profilin isoforms have been solved both in the presence and the absence of actin and poly-L-proline. These structural studies will greatly improve our understanding of the differences and similarities between the different profilins. Structural stability studies of different profilins are also shedding some light on our understanding of the profilin/ligand interactions. Profilin is a multifaceted protein for which a dramatic increase in potential functions has been found in recent years; as such, it has been implicated in a variety of physiological and pathological processes.
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Affiliation(s)
- Kannan Krishnan
- Centre for Bioactive Discovery in Health and Ageing, School of Science and Technology, University of New England, McClymont Bldg, Armidale, NSW, 2351, Australia
| | - Pierre D J Moens
- Centre for Bioactive Discovery in Health and Ageing, School of Science and Technology, University of New England, McClymont Bldg, Armidale, NSW, 2351, Australia.
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13
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Behnen M, Murk K, Kursula P, Cappallo-Obermann H, Rothkegel M, Kierszenbaum AL, Kirchhoff C. Testis-expressed profilins 3 and 4 show distinct functional characteristics and localize in the acroplaxome-manchette complex in spermatids. BMC Cell Biol 2009; 10:34. [PMID: 19419568 PMCID: PMC2694148 DOI: 10.1186/1471-2121-10-34] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2009] [Accepted: 05/06/2009] [Indexed: 12/03/2022] Open
Abstract
Background Multiple profilin isoforms exist in mammals; at least four are expressed in the mammalian testis. The testis-specific isoforms profilin-3 (PFN3) and profilin-4 (PFN4) may have specialized roles in spermatogenic cells which are distinct from known functions fulfilled by the "somatic" profilins, profilin-1 (PFN1) and profilin-2 (PFN2). Results Ligand interactions and spatial distributions of PFN3 and PFN4 were compared by biochemical, molecular and immunological methods; PFN1 and PFN2 were employed as controls. β-actin, phosphoinositides, poly-L-proline and mDia3, but not VASP, were confirmed as in vitro interaction partners of PFN3. In parallel experiments, PFN4 bound to selected phosphoinositides but not to poly-L-proline, proline-rich proteins, or actin. Immunofluorescence microscopy of PFN3 and PFN4 revealed distinct subcellular locations in differentiating spermatids. Both were associated first with the acroplaxome and later with the transient manchette. Predicted 3D structures indicated that PFN3 has the actin-binding site conserved, but retains only approximately half of the common poly-L-proline binding site. PFN4, in comparison, has lost both, polyproline and actin binding sites completely, which is well in line with the experimental data. Conclusion The testis-specific isoform PFN3 showed major hallmarks of the well characterized "somatic" profilin isoforms, albeit with distinct binding affinities. PFN4, on the other hand, did not interact with actin or polyproline in vitro. Rather, it seemed to be specialized for phospholipid binding, possibly providing cellular functions which are distinct from actin dynamics regulation.
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Affiliation(s)
- Martina Behnen
- Department of Andrology, University Hospital Hamburg-Eppendorf, Germany.
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14
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Wang F, Jing Y, Wang Z, Mao T, Samaj J, Yuan M, Ren H. Arabidopsis profilin isoforms, PRF1 and PRF2 show distinctive binding activities and subcellular distributions. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2009; 51:113-21. [PMID: 19200149 DOI: 10.1111/j.1744-7909.2008.00781.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Profilin is an actin-binding protein that shows complex effects on the dynamics of the actin cytoskeleton. There are five profilin isoforms in Arabidopsis thaliana L. However, it is still an open question whether these isoforms are functionally different. In the present study, two profilin isoforms from Arabidopsis, PRF1 and PRF2 were fused with green fluorescent protein (GFP) tag and expressed in Escherichia coli and A. thaliana in order to compare their biochemical properties in vitro and their cellular distributions in vivo. Biochemical analysis revealed that fusion proteins of GFP-PRF1 and GFP-PRF2 can bind to poly-L-proline and G-actin showing remarkable differences. GFP-PRF1 has much higher affinities for both poly-L-proline and G-actin compared with GFP-PRF2. Observations of living cells in stable transgenic A. thaliana lines revealed that 35S::GFP-PRF1 formed a filamentous network, while 35S::GFP-PRF2 formed polygonal meshes. Results from the treatment with latrunculin A and a subsequent recovery experiment indicated that filamentous alignment of GFP-PRF1 was likely associated with actin filaments. However, GFP-PRF2 localized to polygonal meshes resembling the endoplasmic reticulum. Our results provide evidence that Arabidopsis profilin isoforms PRF1 and PRF2 have different biochemical affinities for poly-L-proline and G-actin, and show distinctive localizations in living cells. These data suggest that PRF1 and PRF2 are functionally different isoforms.
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Affiliation(s)
- Feng Wang
- State Key Laboratory of Plant Physiology and Biochemistry, China Agricultural University, Beijing 100094, China
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15
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Syriani E, Gomez-Cabrero A, Bosch M, Moya A, Abad E, Gual A, Gasull X, Morales M. Profilin induces lamellipodia by growth factor-independent mechanism. FASEB J 2008; 22:1581-96. [PMID: 18184720 DOI: 10.1096/fj.06-7654com] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Profilin has been implicated in cell motility and in a variety of cellular processes, such as membrane extension, endocytosis, and formation of focal complexes. In vivo, profilin replenish the pool of ATP-actin monomers by increasing the rate of nucleotide exchange of ADP-actin for ATP-actin, promoting the incorporation of new actin monomers at the barbed end of actin filaments. For this report, we generated a membrane-permeable version of profilin I (PTD4-PfnI) for the alteration of intracellular profilin levels taking advantage of the protein transduction technique. We show that profilin I induces lamellipodia formation independently of growth factor presence in primary bovine trabecular meshwork (BTM) cells. The effects are time- and concentration-dependent and specific to the profilin I isoform. Profilin II, the neuronal isoform, failed to extend lamellipodia in the same degree as profilin I. H133S, a mutation in the polyproline binding domain, showed a reduced ability to induce lamellipodia. H199E, mutation in the actin binding domain failed to induce membrane spreading and inhibit fetal bovine serum (FBS) -induced lamellipodia extension. Incubation with a synthetic polyproline domain peptide (GP5)3, fused to a transduction domain, abolished lamellipodia induction by profilin or FBS. Time-lapse microscopy confirmed the effects of profilin on lamellipodia extension with a higher spreading velocity than FBS. PTD4-Pfn I was found in the inner lamellipodia domain, at the membrane leading edge where it colocalizes with endogenous profilin. While FBS-induced lamellipodia formation activates Rac1, PTD4-Pfn I stimulation did not induce Rac1 activation. We propose a role of profilin I favoring lamellipodia formation by a mechanism downstream of growth factor.
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Affiliation(s)
- Enrique Syriani
- IDIBAPS-Department of Physiological Sciences I, Facultad de Medicina-University of Barcelona, Barcelona, Spain
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16
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Kadiu I, Ricardo-Dukelow M, Ciborowski P, Gendelman HE. Cytoskeletal protein transformation in HIV-1-infected macrophage giant cells. THE JOURNAL OF IMMUNOLOGY 2007; 178:6404-15. [PMID: 17475870 DOI: 10.4049/jimmunol.178.10.6404] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The mechanisms linking HIV-1 replication, macrophage biology, and multinucleated giant cell formation are incompletely understood. With the advent of functional proteomics, the characterization, regulation, and transformation of HIV-1-infected macrophage-secreted proteins can be ascertained. To these ends, we performed proteomic analyses of culture fluids derived from HIV-1 infected monocyte-derived macrophages. Robust reorganization, phosphorylation, and exosomal secretion of the cytoskeletal proteins profilin 1 and actin were observed in conjunction with productive viral replication and giant cell formation. Actin and profilin 1 recruitment to the macrophage plasma membrane paralleled virus-induced cytopathicity, podosome formation, and cellular fusion. Poly-l-proline, an inhibitor of profilin 1-mediated actin polymerization, inhibited cytoskeletal transformations and suppressed, in part, progeny virion production. These data support the idea that actin and profilin 1 rearrangement along with exosomal secretion affect viral replication and cytopathicity. Such events favor the virus over the host cell and provide insights into macrophage defense mechanisms used to contain viral growth and how they may be affected during progressive HIV-1 infection.
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Affiliation(s)
- Irena Kadiu
- Laboratory of Neuroregeneration, Department of Pharmacology and Experimental Neuroscience, Center for Neurovirology and Neurodegenerative Disorders, University of Nebraska Medical Center, Omaha 68198, USA
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17
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Heck JN, Mellman DL, Ling K, Sun Y, Wagoner MP, Schill NJ, Anderson RA. A conspicuous connection: structure defines function for the phosphatidylinositol-phosphate kinase family. Crit Rev Biochem Mol Biol 2007; 42:15-39. [PMID: 17364683 DOI: 10.1080/10409230601162752] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
The phosphatidylinositol phosphate (PIP) kinases are a unique family of enzymes that generate an assortment of lipid messengers, including the pivotal second messenger phosphatidylinositol 4,5-bisphosphate (PI4,5P2). While members of the PIP kinase family function by catalyzing a similar phosphorylation reaction, the specificity loop of each PIP kinase subfamily determines substrate preference and partially influences distinct subcellular targeting. Specific protein-protein interactions that are unique to particular isoforms or splice variants play a key role in targeting PIP kinases to appropriate subcellular compartments to facilitate the localized generation of PI4,5P2 proximal to effectors, a mechanism key for the function of PI4,5P2 as a second messenger. This review documents the discovery of the PIP kinases and their signaling products, and summarizes our current understanding of the mechanisms underlying the localized generation of PI4,5P2 by PIP kinases for the regulation of cellular events including actin cytoskeleton dynamics, vesicular trafficking, cell migration, and an assortment of nuclear events.
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Affiliation(s)
- Jessica N Heck
- Program in Molecular and Cellular Pharmacology, Department of Pharmacology, University of Wisconsin-Madison, University of Wisconsin Medical School, Madison, WI 53706, USA
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18
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Abstract
Profilins are small proteins involved in actin dynamics. In accordance with this function, they are found in all eukaryotes and are structurally highly conserved. However, their precise role in regulating actin-related functions is just beginning to emerge. This article recapitulates the wealth of information on structure, expression and functions accumulated on profilins from many different organisms in the 30 years after their discovery as actin-binding proteins. Emphasis is given to their interaction with a plethora of many different ligands in the cytoplasm as well as in the nucleus, which is considered the basis for their various activities and the significance of the tissue-specific expression of profilin isoforms.
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Affiliation(s)
- B M Jockusch
- Cell Biology, Zoological Institute, Technical University of Braunschweig, 38092 Braunschweig, Germany.
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19
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Kessels MM, Dong J, Leibig W, Westermann P, Qualmann B. Complexes of syndapin II with dynamin II promote vesicle formation at the trans-Golgi network. J Cell Sci 2006; 119:1504-16. [PMID: 16551695 DOI: 10.1242/jcs.02877] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The role of dynamin and so-called accessory proteins in endocytosis is well established. However, molecular details of the function(s) of dynamin II at the Golgi are largely unclear. We demonstrate that the ubiquitously expressed syndapin II isoform interacts with the proline-rich domain (PRD) of dynamin II through its Src-homology 3 (SH3) domain. Co-immunoprecipitation of endogenous syndapin II and dynamin II, and successful reconstitutions of such complexes at membranes in COS-7 cells, show the in vivo relevance of the interaction. Syndapin II can associate with Golgi membranes and this association increases upon Golgi exit block. Brefeldin A treatment clearly shows that the observed perinuclear localization of syndapin II co-localizing with syntaxin 6 reflects the Golgi complex and that it requires functional integrity of the Golgi. Syndapins are crucial for Golgi vesicle formation because anti-syndapin antibodies, used either in in vitro reconstitutions or in living cells, inhibited this process. Both types of assays additionally revealed the essential role of syndapin II SH3 interactions with the dynamin II PRD in vesicle formation. An excess of the syndapin SH3 domain strongly inhibited budding from Golgi membranes in vitro. Likewise, overexpression of the syndapin SH3 domain or of a dynamin II variant incapable of associating with syndapin II (dynamin IIΔPRD) impaired trafficking of vesicular stomatitis virus glycoprotein (VSVG)-GFP in vivo. By contrast, full-length syndapin II-l had no negative effect, and instead promoted VSVG-GFP export from the Golgi. Importantly, a cytosolic fraction containing endogenous syndapin-dynamin complexes was sufficient to promote vesicle formation from Golgi membranes in a syndapin-dependent manner. Thus, syndapin-dynamin complexes are crucial and sufficient to promote vesicle formation from the trans-Golgi network.
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Affiliation(s)
- Michael M Kessels
- Department of Neurochemistry and Molecular Biology, AG Membrane Trafficking and Cytoskeleton, Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany
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20
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Gareus R, Di Nardo A, Rybin V, Witke W. Mouse profilin 2 regulates endocytosis and competes with SH3 ligand binding to dynamin 1. J Biol Chem 2005; 281:2803-11. [PMID: 16319076 DOI: 10.1074/jbc.m503528200] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Mammalian profilins are abundantly expressed actin monomer-binding proteins, highly conserved with respect to their affinities for G-actin, poly-L-proline, and phosphoinositides. Profilins associate with a large number of proline-rich proteins; the physiological significance and regulation of which is poorly understood. Here we show that profilin 2 associates with dynamin 1 via the C-terminal proline-rich domain of dynamin and thereby competes with the binding of SH3 ligands such as endophilin, amphiphysin, and Grb2, thus interfering with the assembly of the endocytic machinery. We also present a novel role for the brain-specific mouse profilin 2 as a regulator of membrane trafficking. Overexpression of profilin 2 inhibits endocytosis, whereas lack of profilin 2 in neurons results in an increase in endocytosis and membrane recycling. Phosphatidylinositol 4,5-bisphosphate releases profilin 2 from the profilin 2-dynamin 1 complex as well as from the profilin 2-actin complex, suggesting that profilin 2 is diverging the phosphoinositide signaling pathway to actin polymerization as well as endocytosis.
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Affiliation(s)
- Ralph Gareus
- Mouse Biology Unit, European Molecular Biology Laboratory (EMBL), Campus Adriano Buzzati-Traverso, 00016 Monterotondo, Italy
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21
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Kessels MM, Qualmann B. Extending the court for cortactin: from the cortex to the Golgi. Nat Cell Biol 2005; 7:448-9. [PMID: 15867926 DOI: 10.1038/ncb0505-448] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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22
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Abstract
Profilins are small actin-binding proteins that are essential in all organisms that have been examined to date. In vitro, profilins regulate the dynamics of actin polymerization, which is their key role in vivo during cell motility. However, there is growing evidence that, apart from actin binding, profilins function as hubs that control a complex network of molecular interactions. Profilins interact with a plethora of proteins and the importance of this aspect of their function is just beginning to be understood. In this article, I will summarize recent findings in mammalian cells and mice, and discuss the evidence of a role for profilins in cellular processes such as membrane trafficking, small-GTPase signaling and nuclear activities, in addition to neurological diseases and tumor formation.
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Affiliation(s)
- Walter Witke
- EMBL, Program for Mouse Biology, Campus Adriano Buzzati-Traverso, 00016 Monterotondo, Italy.
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23
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Drøbak BK, Franklin-Tong VE, Staiger CJ. The role of the actin cytoskeleton in plant cell signaling. THE NEW PHYTOLOGIST 2004; 163:13-30. [PMID: 33873778 DOI: 10.1111/j.1469-8137.2004.01076.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
The plant actin cytoskeleton provides a dynamic cellular component which is involved in the maintenance of cell shape and structure. It has been demonstrated recently that the actin cytoskeleton and its associated elements provide a key target in many signaling events. In addition to acting as a target, the actin cytoskeleton can also act as a transducer of signal information. In this review we describe some newly discovered aspects of the roles of the actin cytoskeleton in plant cell signaling. In addition to a summary of the roles played by actin-binding proteins, we also briefly review the progress made in understanding how the actin cytoskeleton participates in the self-incompatibility response in pollen tubes. Finally, the emerging importance of the actin cytoskeleton in the perception and responses to stimuli such as gravity, touch and cold stress exposure are discussed. Contents I. Introduction - the actin cytoskeleton 13 II. Actin-binding proteins 14 III. The actin cytoskeleton as a target and mediator of plant cell signaling 20 IV. Summary and conclusion 25 References 25 Acknowledgements 25.
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Affiliation(s)
- B K Drøbak
- Cell Signaling Group, Department of Disease and Stress Biology, John Innes Centre, Norwich Research Park, Colney Lane, Norwich NR4 7UH, UK
| | - V E Franklin-Tong
- School of Biosciences, The University of Birmingham, Edgbaston, Birmingham, B15 2TT, UK
| | - C J Staiger
- Purdue Motility Group, Department of Biological Sciences, Purdue University, 333 Hansen Life Sciences Building, 201 S. University Street, West Lafayette, IN 47907-2064, USA
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24
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Wittenmayer N, Jandrig B, Rothkegel M, Schlüter K, Arnold W, Haensch W, Scherneck S, Jockusch BM. Tumor suppressor activity of profilin requires a functional actin binding site. Mol Biol Cell 2004; 15:1600-8. [PMID: 14767055 PMCID: PMC379259 DOI: 10.1091/mbc.e03-12-0873] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Profilin 1 (PFN1) is a regulator of the microfilament system and is involved in various signaling pathways. It interacts with many cytoplasmic and nuclear ligands. The importance of PFN1 for human tissue differentiation has been demonstrated by the findings that human cancer cells, expressing conspicuously low PFN1 levels, adopt a nontumorigenic phenotype upon raising their PFN1 level. In the present study, we characterize the ligand binding site crucial for profilin's tumor suppressor activity. Starting with CAL51, a human breast cancer cell line highly tumorigenic in nude mice, we established stable clones that express PFN1 mutants differentially defective in ligand binding. Clones expressing PFN1 mutants with reduced binding to either poly-proline-stretch ligands or phosphatidyl-inositol-4,5-bisphosphate, but with a functional actin binding site, were normal in growth, adhesion, and anchorage dependence, with only a weak tendency to elicit tumors in nude mice, similar to controls expressing wild-type PFN1. In contrast, clones expressing a mutant with severely reduced capacity to bind actin still behaved like the parental CAL51 and were highly tumorigenic. We conclude that the actin binding site on profilin is instrumental for normal differentiation of human epithelia and the tumor suppressor function of PFN1.
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Affiliation(s)
- Nina Wittenmayer
- Cell Biology, Zoological Institute, Technical University of Braunschweig, D-38092 Braunschweig, Germany
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25
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Grenklo S, Johansson T, Bertilson L, Karlsson R. Anti-actin antibodies generated against profilin:actin distinguish between non-filamentous and filamentous actin, and label cultured cells in a dotted pattern. Eur J Cell Biol 2004; 83:413-23. [PMID: 15506565 DOI: 10.1078/0171-9335-00400] [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] [Indexed: 12/14/2022] Open
Abstract
Actin polymerization is a prominent feature of migrating cells, where it powers the protrusion of the leading edge. Many studies have characterized the well-ordered and dynamic arrangement of filamentous actin in this submembraneous space. However, less is known about the organization of unpolymerized actin. Previously, we reported on the use of covalently coupled profilin:actin to study actin dynamics and presented evidence that profilin-bound actin is a major source of actin for filament growth. To locate profilin:actin in the cell we have now used this non-dissociable complex for antibody generation, and obtained monospecific anti-actin and anti-profilin antibodies from two separate immunizations. Fluorescence microscopy revealed drastic differences in the staining pattern generated by the anti-actin antibody preparations. With one, distinct puncta appeared at the actin-rich leading edge and sometimes aligned with microtubules in the interior of the lamella, while the other displayed typical actin filament staining. Labelling experiments in vitro demonstrated failure of the first antibody to recognize filamentous actin and none of the two bound microtubules. The two anti-profilin antibodies purified in parallel generated a punctated pattern similar to that seen with the first anti-actin antibody. All antibody preparations labelled the nuclei.
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Affiliation(s)
- Staffan Grenklo
- Department of Cell Biology, WGI, Stockholm University, S-10691 Stockholm, Sweden
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26
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Percival JM, Hughes JAI, Brown DL, Schevzov G, Heimann K, Vrhovski B, Bryce N, Stow JL, Gunning PW. Targeting of a tropomyosin isoform to short microfilaments associated with the Golgi complex. Mol Biol Cell 2003; 15:268-80. [PMID: 14528022 PMCID: PMC307546 DOI: 10.1091/mbc.e03-03-0176] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
A growing body of evidence suggests that the Golgi complex contains an actin-based filament system. We have previously reported that one or more isoforms from the tropomyosin gene Tm5NM (also known as gamma-Tm), but not from either the alpha- or beta-Tm genes, are associated with Golgi-derived vesicles (Heimann et al., (1999). J. Biol. Chem. 274, 10743-10750). We now show that Tm5NM-2 is sorted specifically to the Golgi complex, whereas Tm5NM-1, which differs by a single alternatively spliced internal exon, is incorporated into stress fibers. Tm5NM-2 is localized to the Golgi complex consistently throughout the G1 phase of the cell cycle and it associates with Golgi membranes in a brefeldin A-sensitive and cytochalasin D-resistant manner. An actin antibody, which preferentially reacts with the ends of microfilaments, newly reveals a population of short actin filaments associated with the Golgi complex and particularly with Golgi-derived vesicles. Tm5NM-2 is also found on these short microfilaments. We conclude that an alternative splice choice can restrict the sorting of a tropomyosin isoform to short actin filaments associated with Golgi-derived vesicles. Our evidence points to a role for these Golgi-associated microfilaments in vesicle budding at the level of the Golgi complex.
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Affiliation(s)
- Justin M Percival
- Oncology Research Unit, The Children's Hospital at Westmead, Westmead, NSW 2145, Australia
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27
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Wilkes DE, Otto JJ. Profilin Functions in Cytokinesis, Nuclear Positioning, and Stomatogenesis in Tetrahymena thermophila. J Eukaryot Microbiol 2003; 50:252-62. [PMID: 15132168 DOI: 10.1111/j.1550-7408.2003.tb00130.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Expression of the actin-binding protein profilin was disrupted in the ciliate Tetrahymena thermophila by an antisense ribosome method. In cells with the antisense disruption no profilin protein was detected. Cultures of cells with the antisense disruption could be maintained, indicating that profilin was not essential for cytokinesis or vegetative growth. Disruption of the expression of profilin resulted in many cells that were large and abnormally shaped. Formation of multiple micronuclei, which divide mitotically, was observed in cells with a single macronucleus, indicating a defect in early cytokinesis. Some cells with the antisense disruption contained multiple macronuclei, which in Tetrahymena may indicate a function late in cytokinesis. The lack of profilin also affected cytokinesis in the cells that could divide. Normal-sized and normal-shaped cells with the antisense disruption took significantly longer to divide than control cell types. The profilin disruption revealed two new processes in which profilin functions. In cells lacking profilin, micronuclei were not positioned at their normal site on the surface of the macronucleus and phagocytosis was defective. The defect in phagocytosis appeared to be due to disruption of the formation of oral apparatuses (stomatogenesis) and a possible failure in the internalization of phagocytic vacuoles.
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Affiliation(s)
- David E Wilkes
- Department of Biological Sciences, Purdue University, West Lafayette, Indiana 47907-1392, USA
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28
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Abstract
Phosphoinositides act as precursors of second messengers and membrane ligands for protein modules. Specific lipid kinases and phosphatases are located and differentially regulated in cell organelles, generating a non-uniform distribution of phosphoinositides. Although it is not clear whether and how the phosphoinositide pools are integrated, it is certain that they locally control fundamental processes, including membrane trafficking. This applies to the Golgi complex, where a direct, central role of the phosphatidylinositol 4,5-bisphosphate precursor phosphatidylinositol 4-phosphate has recently been reported.
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Affiliation(s)
- Maria De Matteis
- Department of Cell Biology and Oncology, Istituto di Ricerche Farmacologiche Mario Negri, Consorzio Mario Negri Sud, 66030, Santa Maria Imbaro, Chieti, Italy.
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29
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Li Y, Yen LF. Plant Golgi-associated vesicles contain a novel alpha-actinin-like protein. Eur J Cell Biol 2001; 80:703-10. [PMID: 11824789 DOI: 10.1078/0171-9335-00205] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
By using Western blotting, immunofluorescence and immunogold labeling, a novel alpha-actinin-like protein was found in pollen and pollen tubes of Lilium davidii, a model system for cytoskeleton and Golgi apparatus study of plant. As measured by Western blotting, the molecular mass of the a-actinin-like protein was about 80 kDa. Under confocal laser scanning microscopy after immunofluorescence labeling, the distribution of the alpha-actinin-like protein appeared punctated in the cytoplasm of the pollen and pollen tubes. When double labeled, the protein was co-localized with Golgi 58K protein. In addition, some fraction of the alpha-actinin-like protein was found to co-distribute with F-actin bundles in the pollen tubes. Additional studies with immuno-gold labeling and transmission electron microscopy revealed that the alpha-actinin-like protein bound mainly to the membranes of Golgi-associated vesicles. When the pollen tubes were treated with Brefeldin A (BFA), the a-actinin-like proteins were dispersed into the cytoplasm, and the growth of pollen tubes was inhibited. After BFA was removed, the protein was reversibly recovered on the Golgi apparatus. These results suggest that the novel alpha-actinin-like protein is a BFA-sensitive protein on the membranes of Golgi-associated vesicles, and may participate in Golgi-associated vesicles budding and/or sorting, together with actin microfilaments.
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Affiliation(s)
- Y Li
- Key Laboratory of Plant Physiology and Biochemistry, College of Biological Sciences, China Agricultural University, Beijing/PR China.
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30
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Verma DPS. CYTOKINESIS AND BUILDING OF THE CELL PLATE IN PLANTS. ANNUAL REVIEW OF PLANT PHYSIOLOGY AND PLANT MOLECULAR BIOLOGY 2001; 52:751-784. [PMID: 11337415 DOI: 10.1146/annurev.arplant.52.1.751] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cytokinesis in plant cells is more complex than in animals, as it involves building a cell plate as the final step in generating two cells. The cell plate is built in the center of phragmoplast by fusion of Golgi-derived vesicles. This step imposes an architectural problem where ballooning of the fused structures has to be avoided to create a plate instead. This is apparently achieved by squeezing the vesicles into dumbbell-shaped vesicle-tubule-vesicle (VTV) structures with the help of phragmoplastin, a homolog of dynamin. These structures are fused at their ends in a star-shaped body creating a tubulovesicular "honeycomb-like" structure sandwiched between the positive ends of the phragmoplast microtubules. This review summarizes our current understanding of various mechanisms involved in budding-off of Golgi vesicles, delivery and fusion of vesicles to initiate cell plate, and the synthesis of polysaccharides at the forming cell plate. Little is known about the molecular mechanisms involved in determining the site, direction, and the point of attachment of the growing cell plate with the parental cell wall. These gaps may be filled soon, as many genes that have been identified by mutations are analyzed and functions of their products are deciphered.
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Affiliation(s)
- Desh Pal S Verma
- Department of Molecular Genetics and Plant Biotechnology Center, Ohio State University, Columbus, Ohio 43210-1002; e-mail:
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Linder S, Hüfner K, Wintergerst U, Aepfelbacher M. Microtubule-dependent formation of podosomal adhesion structures in primary human macrophages. J Cell Sci 2000; 113 Pt 23:4165-76. [PMID: 11069762 DOI: 10.1242/jcs.113.23.4165] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Podosomes are unique actin-rich adhesion structures of monocyte-derived cells such as macrophages and osteoclasts. They clearly differ from other substratum-contacting organelles like focal adhesions in morphological and functional regards. Formation of podosomes has been shown to be dependent on the small GTPase CDC42Hs and its effector Wiskott-Aldrich syndrome protein (WASp). In this study, we investigated the functional relation between podosomes and the microtubule system in primary human macrophages. We demonstrate that, in contrast to focal adhesions, assembly of podosomes in macrophages and their monocytic precursors is dependent on an intact microtubule system. In contrast, experiments using Wiskott-Aldrich syndrome (WAS) macrophages indicate that the microtubule system is not reciprocally dependent on podosomes. A potential linker between podosomes and microtubules may be WASp itself, considering that microinjection of the WASp polyproline domain prevents podosome reassembly. This polyproline domain is thought to link WASp to microtubules via CDC42 interacting protein 4 (CIP4). Consistently, macrophages microinjected with CIP4 constructs deficient in either the microtubule- or the WASp-binding domain also fail to reassemble podosomes. In sum, our findings show that microtubules are essential for podosome formation in primary human macrophages and that WASp and CIP4 may be involved in this phenomenon.
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Affiliation(s)
- S Linder
- Institut für Prophylaxe und Epidemiologie der Kreislaufkrankheiten, Pettenkoferstr. 9, Germany.
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Dong J, Misselwitz R, Welfle H, Westermann P. Expression and purification of dynamin II domains and initial studies on structure and function. Protein Expr Purif 2000; 20:314-23. [PMID: 11049755 DOI: 10.1006/prep.2000.1305] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Dynamin II, a large GTP-binding protein, is involved in endocytosis and in vesicle formation at the trans-Golgi network. To further elucidate functions of dynamin II, the pleckstrin homology domain (PHD), the proline-rich domain (PRD), and the C-terminal part of dynamin II (dynamin(500-870)) were expressed in Escherichia coli. The PHD, tagged C-terminally by a (His)(6) peptide, was expressed to 15% of cellular proteins and could be purified on nickel-chelating agarose. On the contrary, the PRD and dynamin(500-870) had to be tagged with a (His)(6) peptide at the N-terminus to bind to nickel-chelating agarose. Additional tagging with the S-peptide, which forms a stable complex with immobilized S-protein, allowed removal of strongly interacting E. coli proteins. Circular dichroic spectra indicate a structured recombinant PHD with a secondary structure content similar to that of the known PHD from dynamin I. The N-terminally tagged, recombinant PRD is unfolded but nevertheless binds specifically to the SH3 domain of amphiphysin II as well as to proteins extracted from rat brain. The described methods are suitable to isolate functionally active domains of dynamin II in sufficient amount and purity for further studies.
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Affiliation(s)
- J Dong
- Max-Delbrück-Centre for Molecular Medicine, Berlin, D-13092, Federal Republic of Germany
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