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Suchowerska AK, Fok S, Stefen H, Gunning PW, Hardeman EC, Power J, Fath T. Developmental Profiling of Tropomyosin Expression in Mouse Brain Reveals Tpm4.2 as the Major Post-synaptic Tropomyosin in the Mature Brain. Front Cell Neurosci 2017; 11:421. [PMID: 29311841 PMCID: PMC5743921 DOI: 10.3389/fncel.2017.00421] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2017] [Accepted: 12/14/2017] [Indexed: 12/14/2022] Open
Abstract
Nerve cell connections, formed in the developing brain of mammals, undergo a well-programmed process of maturation with changes in their molecular composition over time. The major structural element at the post-synaptic specialization is the actin cytoskeleton, which is composed of different populations of functionally distinct actin filaments. Previous studies, using ultrastructural and light imaging techniques have established the presence of different actin filament populations at the post-synaptic site. However, it remains unknown, how these different actin filament populations are defined and how their molecular composition changes over time. In the present study, we have characterized changes in a core component of actin filaments, the tropomyosin (Tpm) family of actin-associated proteins from embryonal stage to the adult stage. Using biochemical fractionation of mouse brain tissue, we identified the tropomyosin Tpm4.2 as the major post-synaptic Tpm. Furthermore, we found age-related differences in the composition of Tpms at the post-synaptic compartment. Our findings will help to guide future studies that aim to define the functional properties of actin filaments at different developmental stages in the mammalian brain.
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Affiliation(s)
- Alexandra K Suchowerska
- Neurodegeneration and Repair Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Sandra Fok
- Neurodegeneration and Repair Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Holly Stefen
- Neurodegeneration and Repair Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia.,Neuron Culture Core Facility, University of New South Wales, SydneyNSW, Australia
| | - Peter W Gunning
- Cellular and Genetic Medicine Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Edna C Hardeman
- Cellular and Genetic Medicine Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - John Power
- Translational Neuroscience Facility, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia
| | - Thomas Fath
- Neurodegeneration and Repair Unit, School of Medical Sciences, University of New South Wales, Sydney, NSW, Australia.,Neuron Culture Core Facility, University of New South Wales, SydneyNSW, Australia
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Bobkov DE, Kropacheva IV. The effect of lysophosphatidic acid on the composition of cytoplasmic protein complexes that contain myosin-9 and tropomyosin. ACTA ACUST UNITED AC 2017. [DOI: 10.1134/s1990519x17030026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Gunning PW, Hardeman EC, Lappalainen P, Mulvihill DP. Tropomyosin - master regulator of actin filament function in the cytoskeleton. J Cell Sci 2015; 128:2965-74. [PMID: 26240174 DOI: 10.1242/jcs.172502] [Citation(s) in RCA: 169] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Tropomyosin (Tpm) isoforms are the master regulators of the functions of individual actin filaments in fungi and metazoans. Tpms are coiled-coil parallel dimers that form a head-to-tail polymer along the length of actin filaments. Yeast only has two Tpm isoforms, whereas mammals have over 40. Each cytoskeletal actin filament contains a homopolymer of Tpm homodimers, resulting in a filament of uniform Tpm composition along its length. Evidence for this 'master regulator' role is based on four core sets of observation. First, spatially and functionally distinct actin filaments contain different Tpm isoforms, and recent data suggest that members of the formin family of actin filament nucleators can specify which Tpm isoform is added to the growing actin filament. Second, Tpms regulate whole-organism physiology in terms of morphogenesis, cell proliferation, vesicle trafficking, biomechanics, glucose metabolism and organ size in an isoform-specific manner. Third, Tpms achieve these functional outputs by regulating the interaction of actin filaments with myosin motors and actin-binding proteins in an isoform-specific manner. Last, the assembly of complex structures, such as stress fibers and podosomes involves the collaboration of multiple types of actin filament specified by their Tpm composition. This allows the cell to specify actin filament function in time and space by simply specifying their Tpm isoform composition.
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Affiliation(s)
- Peter W Gunning
- School of Medical Sciences, UNSW Australia, Sydney 2052, Australia
| | - Edna C Hardeman
- School of Medical Sciences, UNSW Australia, Sydney 2052, Australia
| | - Pekka Lappalainen
- Institute of Biotechnology, University of Helsinki, Helsinki, 00014, Finland
| | - Daniel P Mulvihill
- School of Biosciences, Stacey Building, University of Kent, Canterbury, Kent CT2 7NJ, UK
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Desouza M, Gunning PW, Stehn JR. The actin cytoskeleton as a sensor and mediator of apoptosis. BIOARCHITECTURE 2014; 2:75-87. [PMID: 22880146 PMCID: PMC3414384 DOI: 10.4161/bioa.20975] [Citation(s) in RCA: 173] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Apoptosis is an important biological process required for the removal of unwanted or damaged cells. Mounting evidence implicates the actin cytoskeleton as both a sensor and mediator of apoptosis. Studies also suggest that actin binding proteins (ABPs) significantly contribute to apoptosis and that actin dynamics play a key role in regulating apoptosis signaling. Changes in the organization of the actin cytoskeleton has been attributed to the process of malignant transformation and it is hypothesized that remodeling of the actin cytoskeleton may enable tumor cells to evade normal apoptotic signaling. This review aims to illuminate the role of the actin cytoskeleton in apoptosis by systematically analyzing how actin and ABPs regulate different apoptosis pathways and to also highlight the potential for developing novel compounds that target tumor-specific actin filaments.
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Affiliation(s)
- Melissa Desouza
- Oncology Research Unit; School of Medical Sciences; The University of New South Wales; Sydney, Australia
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Arseneault R, Chien A, Newington JT, Rappon T, Harris R, Cumming RC. Attenuation of LDHA expression in cancer cells leads to redox-dependent alterations in cytoskeletal structure and cell migration. Cancer Lett 2013; 338:255-66. [DOI: 10.1016/j.canlet.2013.03.034] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2012] [Revised: 03/28/2013] [Accepted: 03/30/2013] [Indexed: 01/22/2023]
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Savill SA, Leitch HF, Harvey JN, Thomas TH. Functional structure of the promoter regions for the predominant low molecular weight isoforms of tropomyosin in human kidney cells. J Cell Biochem 2013; 113:3576-86. [PMID: 22740512 DOI: 10.1002/jcb.24236] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
High and low molecular weight (LMW) tropomyosin isoforms, by regulation of actin filaments, have a major role in the regulation of cell behaviour. They affect malignant transformation, motility, differentiation, metastasis and cell membrane protein presentation. Expression of LMW isoforms from the TPM1 and TPM3 genes have an important role in these effects but the regulation of their expression is unknown. Luciferase assays on a progressively truncated 1.7 kb fragment upstream of the exon 1b translation start site in the TPM1 and TPM3 genes in HEK-293 cells showed upstream activation sequences in TPM1 between -152 and -139 bp and in TPM3 between -154 and -102 bp. The effect of mutating candidate transcription factor binding sites identified an AML1-like transcription factor binding site in TPM1 and a cAMP response element in TPM3. Downstream from the primary activation sequence in TPM1 was a repressor region corresponding to two Sp/KLF family binding GC boxes. Band shift assays confirmed that deletion of these sites altered transcription factor binding and ChIP assays confirmed the presence of AML1 and CREB at the TPM1 and TPM3 activation sequences in the respective promoters. Expression of LMW isoforms from TPM1 and TPM3 genes is regulated very differently. This facilitates regulation of the many cell processes involving these proteins. In situations where these proteins have a critical role, such as cancer metastasis, it also facilitates specific intervention.
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Affiliation(s)
- Stuart A Savill
- Diabetes and Endocrinology Research Group, College of Health and Behavioural Sciences, Wrexham Academic Unit, Bangor University, Bangor, UK.
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Bobkov DE, Aizenshtadt AA, Kropacheva IV, Pinaev GP. Isolation of tropomyosin particles from cultured cell cytosol and their protein composition assay. ACTA ACUST UNITED AC 2012. [DOI: 10.1134/s1990519x12020046] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Lees JG, Bach CTT, O'Neill GM. Interior decoration: tropomyosin in actin dynamics and cell migration. Cell Adh Migr 2011; 5:181-6. [PMID: 21173575 DOI: 10.4161/cam.5.2.14438] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Cell migration and invasion requires the precise temporal and spatial orchestration of a variety of biological processes. Filaments of polymerized actin are critical players in these diverse processes, including the regulation of cell anchorage points (both cell-cell and cell-extracellular matrix), the uptake and delivery of molecules via endocytic pathways and the generation of force for both membrane protrusion and retraction. How the actin filaments are specialized for each of these discrete functions is yet to be comprehensively elucidated. The cytoskeletal tropomyosins are a family of actin associating proteins that form head-to-tail polymers which lay in the major groove of polymerized actin filaments. In the present review we summarize the emerging isoform-specific functions of tropomyosins in cell migration and invasion and discuss their potential roles in the specialization of actin filaments for the diverse cellular processes that together regulate cell migration and invasion.
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Affiliation(s)
- Justin G Lees
- Children's Cancer Research Unit, Kids Research Institute, The Children's Hospital at Westmead, Westmead, New South Wales, Australia
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Cao S, Ho GH, Lin VCL. Tetratricopeptide repeat domain 9A is an interacting protein for tropomyosin Tm5NM-1. BMC Cancer 2008; 8:231. [PMID: 18699990 PMCID: PMC2538545 DOI: 10.1186/1471-2407-8-231] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2008] [Accepted: 08/12/2008] [Indexed: 02/07/2023] Open
Abstract
Background Tetratricopeptide repeat domain 9A (TTC9A) protein is a recently identified protein which contains three tetratricopeptide repeats (TPRs) on its C-terminus. In our previous studies, we have shown that TTC9A was a hormonally-regulated gene in breast cancer cells. In this study, we found that TTC9A was over-expressed in breast cancer tissues compared with the adjacent controls (P < 0.00001), suggesting it might be involved in the breast cancer development process. The aim of the current study was to further elucidate the function of TTC9A. Methods Breast samples from 25 patients including the malignant breast tissues and the adjacent normal tissues were processed for Southern blot analysis. Yeast-two-hybrid assay, GST pull-down assay and co-immunoprecipitation were used to identify and verify the interaction between TTC9A and other proteins. Results Tropomyosin Tm5NM-1 was identified as one of the TTC9A partner proteins. The interaction between TTC9A and Tm5NM-1 was further confirmed by GST pull-down assay and co-immunoprecipitation in mammalian cells. TTC9A domains required for the interaction were also characterized in this study. The results suggested that the first TPR domain and the linker fragment between the first two TPR domains of TTC9A were important for the interaction with Tm5NM-1 and the second and the third TPR might play an inhibitory role. Conclusion Since the primary function of tropomyosin is to stabilize actin filament, its interaction with TTC9A may play a role in cell shape and motility. In our previous results, we have found that progesterone-induced TTC9A expression was associated with increased cell motility and cell spreading. We speculate that TTC9A acts as a chaperone protein to facilitate the function of tropomyosins in stabilizing microfilament and it may play a role in cancer cell invasion and metastasis.
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Affiliation(s)
- Shenglan Cao
- School of Biological Sciences, Nanyang Technological University, Singapore.
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Gunning P, O'Neill G, Hardeman E. Tropomyosin-based regulation of the actin cytoskeleton in time and space. Physiol Rev 2008; 88:1-35. [PMID: 18195081 DOI: 10.1152/physrev.00001.2007] [Citation(s) in RCA: 352] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Tropomyosins are rodlike coiled coil dimers that form continuous polymers along the major groove of most actin filaments. In striated muscle, tropomyosin regulates the actin-myosin interaction and, hence, contraction of muscle. Tropomyosin also contributes to most, if not all, functions of the actin cytoskeleton, and its role is essential for the viability of a wide range of organisms. The ability of tropomyosin to contribute to the many functions of the actin cytoskeleton is related to the temporal and spatial regulation of expression of tropomyosin isoforms. Qualitative and quantitative changes in tropomyosin isoform expression accompany morphogenesis in a range of cell types. The isoforms are segregated to different intracellular pools of actin filaments and confer different properties to these filaments. Mutations in tropomyosins are directly involved in cardiac and skeletal muscle diseases. Alterations in tropomyosin expression directly contribute to the growth and spread of cancer. The functional specificity of tropomyosins is related to the collaborative interactions of the isoforms with different actin binding proteins such as cofilin, gelsolin, Arp 2/3, myosin, caldesmon, and tropomodulin. It is proposed that local changes in signaling activity may be sufficient to drive the assembly of isoform-specific complexes at different intracellular sites.
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Affiliation(s)
- Peter Gunning
- Oncology Research Unit, The Children's Hospital at Westmead, and Muscle Development Unit, Children's Medical Research Institute, Westmead; New South Wales, Australia.
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Kaneko M, Takeoka M, Oguchi M, Koganehira Y, Murata H, Ehara T, Tozuka M, Saida T, Taniguchi S. Calponin h1 suppresses tumor growth of Src-induced transformed 3Y1 cells in association with a decrease in angiogenesis. Jpn J Cancer Res 2002; 93:935-43. [PMID: 12716472 PMCID: PMC5927104 DOI: 10.1111/j.1349-7006.2002.tb01340.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Calponin h1 (CNh1) is a basic actin-binding protein that is abundantly expressed in smooth muscle cells and involved in smooth muscle contraction by inhibiting actomyosin MgATPase. In recent studies, CNh1 was noted to suppress cell proliferation and tumorigenicity in leiomyosarcoma and tumor growth in fibrosarcoma cell lines. To further investigate the function of CNh1 as a tumor suppressor, we transfected the human CNh1 gene into a v-src-transformed rat fibroblast cell line SR-3Y1. The volume of the tumors derived from one randomly selected CNh1-transfectant (C1) in nude mice was reduced to 34.1% of that from a randomly selected vector transfectant (V1). A similar tendency was observed in another independent pair (C2, V2). Pathological analysis showed a significant decrease in the number of mitotic cells in the CNh1-transfectants. Further, a marked reduction in the number of vessels in the CNh1-transfectant was observed. DNA synthesis under conditions without serum was significantly reduced in the CNh1-transfectant (C1) compared with the control transfectant (V1), while no significant difference was seen in the cellular growth in the presence of 10% serum. A slight but significant reduction in in vitro cellular motility in the CNh1-transfectant was also observed. While the suppression of growth potential and cell motility by CNh1 transfer was significant but partial, a marked reduction in vascular endothelial growth factor (VEGF) mRNA and the secretion of VEGF protein was observed in the CNh1-transfectant. These results suggest that CNh1 plays a role as tumor suppressor in SR-3Y1 mainly by decreasing VEGF expression and angiogenesis in vivo and partially through reducing cellular proliferative potential and cell motility.
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Affiliation(s)
- Miwako Kaneko
- Department of Dermatology, Shinshu University School of Medicine, Matsumoto 390-8621, Japan
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