1
|
De Felice B, De Luca P, Montanino C, Mallardo M, Babino G, Mattera E, Sorbo R, Ragozzino G, Argenziano G, Daniele A, Nigro E. LncRNA microarray profiling identifies novel circulating lncRNAs in hidradenitis suppurativa. Mol Med Rep 2024; 30:112. [PMID: 38757342 PMCID: PMC11094584 DOI: 10.3892/mmr.2024.13236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Accepted: 02/13/2024] [Indexed: 05/18/2024] Open
Abstract
Long noncoding RNAs (lncRNAs) have been demonstrated to be involved in biological processes, both physiological and pathological, including cancer, cardiovascular diseases, multiple sclerosis, autoimmune hepatitis and types I and II diabetes. LncRNAs are also known to have a critical role in the physiology of skin, and in the pathology of cutaneous diseases. LncRNAs are involved in a wide range of biological activities, including transcriptional post‑transcriptional processes, epigenetics, RNA splicing, gene activation and or silencing, modifications and/or editing; therefore, lncRNAs may be useful as potential targets for disease treatment. Hidradenitis suppurativa (HS), also termed acne inversa, is a major skin disease, being an inflammatory disorder that affects ~1% of global population in a chronic manner. Its pathogenesis, however, is only partly understood, although immune dysregulation is known to have an important role. To investigate the biological relevance of lncRNAs with HS, the most differentially expressed lncRNAs and mRNAs were first compared. Furthermore, the lncRNA‑microRNA regulatory network was also defined via reverse transcription‑quantitative PCR analysis, whereby a trio of lncRNA expression signatures, lncRNA‑TINCR, lncRNA‑RBM5‑ASI1 and lncRNA‑MRPL23‑AS1, were found to be significantly overexpressed in patients with HS compared with healthy controls. In conclusion, the three lncRNAs isolated in the present study may be useful for improving the prognostic prediction of HS, as well as contributing towards an improved understanding of the underlying pathogenic mechanisms, thereby potentially providing new therapeutic targets.
Collapse
Affiliation(s)
- Bruna De Felice
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania Luigi Vanvitelli, I-81100 Caserta, Italy
| | | | - Concetta Montanino
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania Luigi Vanvitelli, I-81100 Caserta, Italy
| | - Marta Mallardo
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania Luigi Vanvitelli, I-81100 Caserta, Italy
- CEINGE-Franco Salvatore Advanced Biotechnology, I-80145 Naples, Italy
| | - Graziella Babino
- Dermatology Unit, University of Campania Luigi Vanvitelli, I-80131 Naples, Italy
| | - Edi Mattera
- Department of Internal and Experimental Medicine and Surgery Unit of Internal Medicine, University of Campania Luigi Vanvitelli, I-80131 Naples, Italy
| | - Raffaele Sorbo
- Department of Internal and Experimental Medicine and Surgery Unit of Internal Medicine, University of Campania Luigi Vanvitelli, I-80131 Naples, Italy
| | - Giovanni Ragozzino
- Department of Internal and Experimental Medicine and Surgery Unit of Internal Medicine, University of Campania Luigi Vanvitelli, I-80131 Naples, Italy
| | - Giuseppe Argenziano
- Dermatology Unit, University of Campania Luigi Vanvitelli, I-80131 Naples, Italy
| | - Aurora Daniele
- CEINGE-Franco Salvatore Advanced Biotechnology, I-80145 Naples, Italy
- Department of Molecular Medicine and Medical Biotechnology, University of Naples Federico II, I-80131 Naples, Italy
| | - Ersilia Nigro
- Department of Environmental, Biological and Pharmaceutical Sciences and Technologies, University of Campania Luigi Vanvitelli, I-81100 Caserta, Italy
- CEINGE-Franco Salvatore Advanced Biotechnology, I-80145 Naples, Italy
| |
Collapse
|
2
|
Weiler SME, Bissinger M, Rose F, von Bubnoff F, Lutz T, Ori A, Schirmacher P, Breuhahn K. SEPTIN10-mediated crosstalk between cytoskeletal networks controls mechanotransduction and oncogenic YAP/TAZ signaling. Cancer Lett 2024; 584:216637. [PMID: 38242197 DOI: 10.1016/j.canlet.2024.216637] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2023] [Revised: 12/19/2023] [Accepted: 01/09/2024] [Indexed: 01/21/2024]
Abstract
The transcriptional co-activators of the Hippo pathway, YAP and TAZ, are regulated by mechanotransduction, which depends on dynamic actin cytoskeleton remodeling. Here, we identified SEPTIN10 as a novel cytoskeletal protein, which is transcriptionally regulated by YAP/TAZ and whose overexpression correlates with poor survival and vascular invasion in hepatocellular carcinoma (HCC) patients. Functional characterization demonstrated that SEPTIN10 promotes YAP/TAZ-dependent cell viability, migration and invasion of liver cancer cells. Mechanistically, SEPTIN10 interacts with actin and microtubule filaments supporting actin stress fiber formation and intracellular tension through binding to CAPZA2 while concurrently inhibiting microtubule polymerization through the blockage of MAP4 function. This functional antagonism is important for cytoskeleton-dependent feedback activation of YAP/TAZ, as microtubule depolymerization induces actin stress fiber formation and subsequently YAP/TAZ activity. Importantly, the crosstalk between microfilaments and microtubules is mediated by SEPTIN10 as its loss abrogates actin stress fiber formation after microtubule disruption. Together, the YAP/TAZ target gene SEPTIN10 controls the dynamic interplay between actin and microtubule filaments, which feeds back on Hippo pathway activity in HCC cells and thus acts as molecular switch with impact on oncogenic signaling and cancer cell biology.
Collapse
Affiliation(s)
- Sofia M E Weiler
- Institute of Pathology, University Hospital Heidelberg, 69120, Heidelberg, Germany.
| | - Michaela Bissinger
- Institute of Pathology, University Hospital Heidelberg, 69120, Heidelberg, Germany
| | - Fabian Rose
- Institute of Pathology, University Hospital Heidelberg, 69120, Heidelberg, Germany
| | - Fabian von Bubnoff
- Institute of Pathology, University Hospital Heidelberg, 69120, Heidelberg, Germany
| | - Teresa Lutz
- Institute of Pathology, University Hospital Heidelberg, 69120, Heidelberg, Germany
| | - Alessandro Ori
- Leibniz Institute on Aging - Fritz Lipmann Institute (FLI), 07745, Jena, Germany
| | - Peter Schirmacher
- Institute of Pathology, University Hospital Heidelberg, 69120, Heidelberg, Germany
| | - Kai Breuhahn
- Institute of Pathology, University Hospital Heidelberg, 69120, Heidelberg, Germany.
| |
Collapse
|
3
|
Sharma K, Menon MB. Decoding post-translational modifications of mammalian septins. Cytoskeleton (Hoboken) 2023; 80:169-181. [PMID: 36797225 DOI: 10.1002/cm.21747] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Revised: 01/21/2023] [Accepted: 02/10/2023] [Indexed: 02/18/2023]
Abstract
Septins are cytoskeletal GTPases that form nonpolar filaments and higher-ordered structures and they take part in a wide range of cellular processes. Septins are conserved from yeast to mammals but absent from higher plants. The number of septin genes vary between organisms and they usually form complex heteropolymeric networks. Most septins are known to be capable of GTP hydrolysis which may regulate septin dynamics. Knowledge on regulation of septin function by post-translational modifications is still in its infancy. In this review article, we highlight the post-translational modifications reported for the 13 human septins and discuss their implications on septin functions. In addition to the functionally investigated modifications, we also try to make sense of the complex septin post-translational modification code revealed from large-scale phospho-proteomic datasets. Future studies may determine how these isoform-specific and homology group specific modifications affect septin structure and function.
Collapse
Affiliation(s)
- Khushboo Sharma
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India
| | - Manoj B Menon
- Kusuma School of Biological Sciences, Indian Institute of Technology Delhi, New Delhi, India
| |
Collapse
|
4
|
Werner B, Yadav S. Phosphoregulation of the septin cytoskeleton in neuronal development and disease. Cytoskeleton (Hoboken) 2023; 80:275-289. [PMID: 36127729 PMCID: PMC10025170 DOI: 10.1002/cm.21728] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 08/13/2022] [Accepted: 09/12/2022] [Indexed: 11/06/2022]
Abstract
Septins are highly conserved GTP-binding proteins that oligomerize and form higher order structures. The septin cytoskeleton plays an important role in cellular organization, intracellular transport, and cytokinesis. Kinase-mediated phosphorylation of septins regulates various aspects of their function, localization, and dynamics. Septins are enriched in the mammalian nervous system where they contribute to neurodevelopment and neuronal function. Emerging research has implicated aberrant changes in septin cytoskeleton in several human diseases. The mechanisms through which aberrant phosphorylation by kinases contributes to septin dysfunction in neurological disorders are poorly understood and represent an important question for future research with therapeutic implications. This review summarizes the current state of knowledge of the diversity of kinases that interact with and phosphorylate mammalian septins, delineates how phosphoregulation impacts septin dynamics, and describes how aberrant septin phosphorylation contributes to neurological disorders.
Collapse
Affiliation(s)
- Bailey Werner
- Department of Pharmacology, University of Washington, Seattle, WA, United States
| | - Smita Yadav
- Department of Pharmacology, University of Washington, Seattle, WA, United States
| |
Collapse
|
5
|
Neuronal-specific septin-3 binds Atg8/LC3B, accumulates and localizes to autophagosomes during induced autophagy. Cell Mol Life Sci 2022; 79:471. [PMID: 35932293 PMCID: PMC9356936 DOI: 10.1007/s00018-022-04488-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 06/27/2022] [Accepted: 07/13/2022] [Indexed: 11/03/2022]
Abstract
In synapses that show signs of local apoptosis and mitochondrial stress and undergo neuro-immunological synapse pruning, an increase in the levels of the presynaptic protein, neuronal-specific septin-3 can be observed. Septin-3 is a member of the septin GTPase family with the ability to form multimers and contribute to the cytoskeleton. However, the function of septin-3 remains elusive. Here, we provide evidence that septin-3 is capable of binding the most-studied autophagy protein Atg8 homolog microtubule-associated protein 1 light chain 3B (LC3B), besides another homolog, GABA receptor-associated protein-like 2 (GABARAPL2). Moreover, we demonstrate that colocalization of septin-3 and LC3B increases upon chemical autophagy induction in primary neuronal cells. Septin-3 is accumulated in primary neurons upon autophagy enhancement or blockade, similar to autophagy proteins. Using electron microscopy, we also show that septin-3 localizes to LC3B positive membranes and can be found at mitochondria. However, colocalization results of septin-3 and the early mitophagy marker PTEN-induced kinase 1 (PINK1) do not support that binding of septin-3 to mitochondria is mitophagy related. We conclude that septin-3 correlates with synaptic/neuronal autophagy, binds Atg8 and localizes to autophagic membranes that can be enhanced with chemical autophagy induction. Based on our results, elevated septin-3 levels might indicate enhanced or impeded autophagy in neurons.
Collapse
|
6
|
Kim OV, Litvinov RI, Mordakhanova ER, Bi E, Vagin O, Weisel JW. Contribution of septins to human platelet structure and function. iScience 2022; 25:104654. [PMID: 35832887 PMCID: PMC9272382 DOI: 10.1016/j.isci.2022.104654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2021] [Revised: 04/23/2022] [Accepted: 06/17/2022] [Indexed: 11/29/2022] Open
Abstract
Although septins have been well-studied in nucleated cells, their role in anucleate blood platelets remains obscure. Here, we elucidate the contribution of septins to human platelet structure and functionality. We show that Septin-2 and Septin-9 are predominantly distributed at the periphery of resting platelets and co-localize strongly with microtubules. Activation of platelets by thrombin causes clustering of septins and impairs their association with microtubules. Inhibition of septin dynamics with forchlorfenuron (FCF) reduces thrombin-induced densification of septins and lessens their colocalization with microtubules in resting and activated platelets. Exposure to FCF alters platelet shape, suggesting that septins stabilize platelet cytoskeleton. FCF suppresses platelet integrin αIIbβ3 activation, promotes phosphatidylserine exposure on activated platelets, and induces P-selectin expression on resting platelets, suggesting septin involvement in these processes. Inhibition of septin dynamics substantially reduces platelet contractility and abrogates their spreading on fibrinogen-coated surfaces. Overall, septins strongly contribute to platelet structure, activation and biomechanics.
Collapse
Affiliation(s)
- Oleg V. Kim
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Rustem I. Litvinov
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Elmira R. Mordakhanova
- Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russian Federation
| | - Erfei Bi
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Olga Vagin
- Department of Pediatrics, Geffen School of Medicine at UCLA, Los Angeles, CA, USA
- Veterans Affairs Greater Los Angeles Health Care System, Los Angeles, CA, USA
| | - John W. Weisel
- Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| |
Collapse
|
7
|
Cavini IA, Leonardo DA, Rosa HVD, Castro DKSV, D'Muniz Pereira H, Valadares NF, Araujo APU, Garratt RC. The Structural Biology of Septins and Their Filaments: An Update. Front Cell Dev Biol 2021; 9:765085. [PMID: 34869357 PMCID: PMC8640212 DOI: 10.3389/fcell.2021.765085] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2021] [Accepted: 10/27/2021] [Indexed: 01/22/2023] Open
Abstract
In order to fully understand any complex biochemical system from a mechanistic point of view, it is necessary to have access to the three-dimensional structures of the molecular components involved. Septins and their oligomers, filaments and higher-order complexes are no exception. Indeed, the spontaneous recruitment of different septin monomers to specific positions along a filament represents a fascinating example of subtle molecular recognition. Over the last few years, the amount of structural information available about these important cytoskeletal proteins has increased dramatically. This has allowed for a more detailed description of their individual domains and the different interfaces formed between them, which are the basis for stabilizing higher-order structures such as hexamers, octamers and fully formed filaments. The flexibility of these structures and the plasticity of the individual interfaces have also begun to be understood. Furthermore, recently, light has been shed on how filaments may bundle into higher-order structures by the formation of antiparallel coiled coils involving the C-terminal domains. Nevertheless, even with these advances, there is still some way to go before we fully understand how the structure and dynamics of septin assemblies are related to their physiological roles, including their interactions with biological membranes and other cytoskeletal components. In this review, we aim to bring together the various strands of structural evidence currently available into a more coherent picture. Although it would be an exaggeration to say that this is complete, recent progress seems to suggest that headway is being made in that direction.
Collapse
Affiliation(s)
- Italo A Cavini
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Diego A Leonardo
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Higor V D Rosa
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Danielle K S V Castro
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil.,São Carlos Institute of Chemistry, University of São Paulo, São Carlos, Brazil
| | | | | | - Ana P U Araujo
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| | - Richard C Garratt
- São Carlos Institute of Physics, University of São Paulo, São Carlos, Brazil
| |
Collapse
|
8
|
Devlin L, Okletey J, Perkins G, Bowen JR, Nakos K, Montagna C, Spiliotis ET. Proteomic profiling of the oncogenic septin 9 reveals isoform-specific interactions in breast cancer cells. Proteomics 2021; 21:e2100155. [PMID: 34409731 DOI: 10.1002/pmic.202100155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Accepted: 08/05/2021] [Indexed: 02/06/2023]
Abstract
Septins are a family of multimeric GTP-binding proteins, which are abnormally expressed in cancer. Septin 9 (SEPT9) is an essential and ubiquitously expressed septin with multiple isoforms, which have differential expression patterns and effects in breast cancer cells. It is unknown, however, if SEPT9 isoforms associate with different molecular networks and functions. Here, we performed a proteomic screen in MCF-7 breast cancer cells to identify the interactome of GFP-SEPT9 isoforms 1, 4 and 5, which vary significantly in their N-terminal extensions. While all three isoforms associated with SEPT2 and SEPT7, the truncated SEPT9_i4 and SEPT9_i5 interacted with septins of the SEPT6 group more promiscuously than SEPT9_i1, which bound predominately SEPT8. Spatial mapping and functional clustering of non-septin partners showed isoform-specific differences in interactions with proteins of distinct subcellular organelles (e.g., nuclei, centrosomes, cilia) and functions such as cell signalling and ubiquitination. The interactome of the full length SEPT9_i1 was more enriched in cytoskeletal regulators, while the truncated SEPT9_i4 and SEPT9_i5 exhibited preferential and isoform-specific interactions with nuclear, signalling, and ubiquitinating proteins. These data provide evidence for isoform-specific interactions, which arise from truncations in the N-terminal extensions of SEPT9, and point to novel roles in the pathogenesis of breast cancer.
Collapse
Affiliation(s)
- Louis Devlin
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA.,Sanofi Pasteur, Swiftwater, Pennsylvania, USA
| | - Joshua Okletey
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | | | - Jonathan R Bowen
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Konstantinos Nakos
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA
| | - Cristina Montagna
- Department of Radiology & Oncology, Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey, USA
| | - Elias T Spiliotis
- Department of Biology, Drexel University, Philadelphia, Pennsylvania, USA
| |
Collapse
|
9
|
Spiliotis ET, Kesisova IA. Spatial regulation of microtubule-dependent transport by septin GTPases. Trends Cell Biol 2021; 31:979-993. [PMID: 34253430 DOI: 10.1016/j.tcb.2021.06.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 06/10/2021] [Accepted: 06/14/2021] [Indexed: 01/21/2023]
Abstract
The intracellular long-range transport of membrane vesicles and organelles is mediated by microtubule motors (kinesins, dynein) which move cargo with spatiotemporal accuracy and efficiency. How motors navigate the microtubule network and coordinate their activity on membrane cargo are fundamental but poorly understood questions. New studies show that microtubule-dependent membrane traffic is spatially controlled by septins - a unique family of multimerizing GTPases that associate with microtubules and membrane organelles. We review how septins selectively regulate motor interactions with microtubules and membrane cargo. We posit that septins provide a novel traffic code that specifies the movement and directionality of select motor-cargo complexes on distinct microtubule tracks.
Collapse
Affiliation(s)
- Elias T Spiliotis
- Department of Biology, Drexel University, Philadelphia, PA 19104, USA.
| | - Ilona A Kesisova
- Department of Biology, Drexel University, Philadelphia, PA 19104, USA
| |
Collapse
|
10
|
Huang M, Wang Y. GLOBAL AND TARGETED PROFILING OF GTP-BINDING PROTEINS IN BIOLOGICAL SAMPLES BY MASS SPECTROMETRY. MASS SPECTROMETRY REVIEWS 2021; 40:215-235. [PMID: 32519381 PMCID: PMC7725852 DOI: 10.1002/mas.21637] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 05/04/2020] [Accepted: 05/15/2020] [Indexed: 05/05/2023]
Abstract
GTP-binding proteins are among the most important enzyme families that are involved in a plethora of biological processes. However, owing to the enormous diversity of the nucleotide-binding protein family, comprehensive analyses of the expression level, structure, activity, and regulatory mechanisms of GTP-binding proteins remain challenging with the use of conventional approaches. The many advances in mass spectrometry (MS) instrumentation and data acquisition methods, together with a variety of enrichment approaches in sample preparation, render MS a powerful tool for the comprehensive characterizations of the activities and expression levels of various GTP-binding proteins. We review herein the recent developments in the application of MS-based techniques, together with general and widely used affinity enrichment approaches, for the proteome-wide and targeted capture, identification, and quantification of GTP-binding proteins. The working principles, advantages, and limitations of various strategies for profiling the expression level, activity, posttranslational modifications, and interactome of GTP-binding proteins are discussed. It can be envisaged that future applications of MS-based proteomics will lead to a better understanding about the roles of GTP-binding proteins in different biological processes and human diseases. © 2020 John Wiley & Sons Ltd. Mass Spec Rev.
Collapse
Affiliation(s)
- Ming Huang
- Environmental Toxicology Graduate Program, University of California Riverside, Riverside, CA 92521, USA
| | - Yinsheng Wang
- Environmental Toxicology Graduate Program, University of California Riverside, Riverside, CA 92521, USA
- Department of Chemistry, University of California Riverside, Riverside, CA 92521, USA
- Correspondence author: Yinsheng Wang. Telephone: (951)827-2700;
| |
Collapse
|
11
|
Septins in Infections: Focus on Viruses. Pathogens 2021; 10:pathogens10030278. [PMID: 33801245 PMCID: PMC8001386 DOI: 10.3390/pathogens10030278] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 02/17/2021] [Accepted: 02/25/2021] [Indexed: 11/17/2022] Open
Abstract
Human septins comprise a family of 13 genes that encode conserved GTP-binding proteins. They form nonpolar complexes, which assemble into higher-order structures, such as bundles, scaffolding structures, or rings. Septins are counted among the cytoskeletal elements. They interact with the actin and microtubule networks and can bind to membranes. Many cellular functions with septin participation have been described in the literature, including cytokinesis, motility, forming of scaffolding platforms or lateral diffusion barriers, vesicle transport, exocytosis, and recognition of micron-scale curvature. Septin dysfunction has been implicated in diverse human pathologies, including neurodegeneration and tumorigenesis. Moreover, septins are thought to affect the outcome of host–microbe interactions. Implication of septins has been demonstrated in fungal, bacterial, and viral infections. Knowledge on the precise function of a particular septin in the different steps of the virus infection and replication cycle is still limited. Published data for vaccinia virus (VACV), hepatitis C virus (HCV), influenza A virus (H1N1 and H5N1), human herpesvirus 8 (HHV-8), and Zika virus (ZIKV), all of major concern for public health, will be discussed here.
Collapse
|
12
|
Martinez Barrera S, Byrum S, Mackintosh SG, Kozubowski L. Registered report protocol: Quantitative analysis of septin Cdc10-associated proteome in Cryptococcus neoformans. PLoS One 2020; 15:e0242381. [PMID: 33315917 PMCID: PMC7735571 DOI: 10.1371/journal.pone.0242381] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 10/29/2020] [Indexed: 11/19/2022] Open
Abstract
Cryptococcus neoformans is a pathogenic basidiomycetous yeast that primarily infects immunocompromised individuals. C. neoformans can thrive during infections due to its three main virulence-related characteristics: the ability to grow at host temperature (37°C), formation of carbohydrate capsule, and its ability to produce melanin. C. neoformans strains lacking septin proteins Cdc3 or Cdc12 are viable at 25°C; however, they fail to proliferate at 37°C and are avirulent in the murine model of infection. The basis of septin contribution to growth at host temperature remains unknown. Septins are a family of conserved filament-forming GTPases with roles in cytokinesis and morphogenesis. In the model organism Saccharomyces cerevisiae septins are essential. S. cerevisiae septins form a higher order complex at the mother-bud neck to scaffold over 80 proteins, including those involved in cell wall organization, cell polarity, and cell cycle control. In C. neoformans, septins also form a complex at the mother-bud neck but the septin interacting proteome in this species remains largely unknown. Moreover, it remains possible that septins play other roles important for high temperature stress that are independent of their established role in cytokinesis. Therefore, we propose to perform a global analysis of septin Cdc10 binding partners in C. neoformans, including those that are specific to high temperature stress. This analysis will shed light on the underlying mechanism of survival of this pathogenic yeast during infection and can potentially lead to the discovery of novel drug targets.
Collapse
Affiliation(s)
- Stephani Martinez Barrera
- Department of Genetics and Biochemistry, Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, SC, United States of America
| | - Stephanie Byrum
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States of America
| | - Samuel G. Mackintosh
- Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States of America
| | - Lukasz Kozubowski
- Department of Genetics and Biochemistry, Eukaryotic Pathogens Innovation Center, Clemson University, Clemson, SC, United States of America
- * E-mail:
| |
Collapse
|
13
|
Woods BL, Gladfelter AS. The state of the septin cytoskeleton from assembly to function. Curr Opin Cell Biol 2020; 68:105-112. [PMID: 33188984 DOI: 10.1016/j.ceb.2020.10.007] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/01/2020] [Accepted: 10/08/2020] [Indexed: 01/09/2023]
Abstract
Septins are conserved guanine nucleotide-binding proteins that polymerize into filaments at the cell cortex or in association with other cytoskeletal proteins, such as actin or microtubules. As integral players in many morphogenic and signaling events, septins form scaffolds important for the recruitment of the cytokinetic machinery, organization of the plasma membrane, and orientation of cell polarity. Mutations in septins or their misregulation are associated with numerous diseases. Despite growing appreciation for the importance of septins in different aspects of cell biology and disease, septins remain relatively poorly understood compared with other cytoskeletal proteins. Here in this review, we highlight some of the recent developments of the last two years in the field of septin cell biology.
Collapse
Affiliation(s)
- Benjamin L Woods
- Biology Department, University of North Carolina, Chapel Hill, NC, 27599, USA
| | - Amy S Gladfelter
- Biology Department, University of North Carolina, Chapel Hill, NC, 27599, USA; Marine Biological Laboratory, Woods Hole, MA, 02543, USA.
| |
Collapse
|
14
|
Johnson CR, Steingesser MG, Weems AD, Khan A, Gladfelter A, Bertin A, McMurray MA. Guanidine hydrochloride reactivates an ancient septin hetero-oligomer assembly pathway in budding yeast. eLife 2020; 9:e54355. [PMID: 31990274 PMCID: PMC7056273 DOI: 10.7554/elife.54355] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 01/25/2020] [Indexed: 01/22/2023] Open
Abstract
Septin proteins evolved from ancestral GTPases and co-assemble into hetero-oligomers and cytoskeletal filaments. In Saccharomyces cerevisiae, five septins comprise two species of hetero-octamers, Cdc11/Shs1-Cdc12-Cdc3-Cdc10-Cdc10-Cdc3-Cdc12-Cdc11/Shs1. Slow GTPase activity by Cdc12 directs the choice of incorporation of Cdc11 vs Shs1, but many septins, including Cdc3, lack GTPase activity. We serendipitously discovered that guanidine hydrochloride rescues septin function in cdc10 mutants by promoting assembly of non-native Cdc11/Shs1-Cdc12-Cdc3-Cdc3-Cdc12-Cdc11/Shs1 hexamers. We provide evidence that in S. cerevisiae Cdc3 guanidinium occupies the site of a 'missing' Arg side chain found in other fungal species where (i) the Cdc3 subunit is an active GTPase and (ii) Cdc10-less hexamers natively co-exist with octamers. We propose that guanidinium reactivates a latent septin assembly pathway that was suppressed during fungal evolution in order to restrict assembly to octamers. Since homodimerization by a GTPase-active human septin also creates hexamers that exclude Cdc10-like central subunits, our new mechanistic insights likely apply throughout phylogeny.
Collapse
Affiliation(s)
- Courtney R Johnson
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Marc G Steingesser
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Andrew D Weems
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical CampusAuroraUnited States
| | - Anum Khan
- Department of Biology, University of North Carolina at Chapel HillChapel HillUnited States
| | - Amy Gladfelter
- Department of Biology, University of North Carolina at Chapel HillChapel HillUnited States
| | - Aurélie Bertin
- Laboratoire Physico Chimie Curie, Institut Curie, PSL Research University, CNRS UMR 168ParisFrance
- Sorbonne Université UPMC Univ Paris 06ParisFrance
| | - Michael A McMurray
- Department of Cell and Developmental Biology, University of Colorado Anschutz Medical CampusAuroraUnited States
| |
Collapse
|
15
|
Gönczi M, Dienes B, Dobrosi N, Fodor J, Balogh N, Oláh T, Csernoch L. Septins, a cytoskeletal protein family, with emerging role in striated muscle. J Muscle Res Cell Motil 2020; 42:251-265. [PMID: 31955380 PMCID: PMC8332580 DOI: 10.1007/s10974-020-09573-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 01/06/2020] [Indexed: 12/15/2022]
Abstract
Appropriate organization of cytoskeletal components are required for normal distribution and intracellular localization of different ion channels and proteins involved in calcium homeostasis, signal transduction, and contractile function of striated muscle. Proteins of the contractile system are in direct or indirect connection with the extrasarcomeric cytoskeleton. A number of other molecules which have essential role in regulating stretch-, voltage-, and chemical signal transduction from the surface into the cytoplasm or other intracellular compartments are already well characterized. Sarcomere, the basic contractile unit, is comprised of a precisely organized system of thin (actin), and thick (myosin) filaments. Intermediate filaments connect the sarcomeres and other organelles (mitochondria and nucleus), and are responsible for the cellular integrity. Interacting proteins have a very diverse function in coupling of the intracellular assembly components and regulating the normal physiological function. Despite the more and more intense investigations of a new cytoskeletal protein family, the septins, only limited information is available regarding their expression and role in striated, especially in skeletal muscles. In this review we collected basic and specified knowledge regarding this protein group and emphasize the importance of this emerging field in skeletal muscle biology.
Collapse
Affiliation(s)
- Mónika Gönczi
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, 4012, Hungary
| | - Beatrix Dienes
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, 4012, Hungary
| | - Nóra Dobrosi
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, 4012, Hungary
| | - János Fodor
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, 4012, Hungary
| | - Norbert Balogh
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, 4012, Hungary.,Doctoral School of Molecular Medicine, University of Debrecen, Debrecen, 4012, Hungary
| | - Tamás Oláh
- Center of Experimental Orthopaedics, Saarland University, 66421, Homburg, Saar, Germany
| | - László Csernoch
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, 4012, Hungary.
| |
Collapse
|
16
|
Mendonça DC, Macedo JN, Guimarães SL, Barroso da Silva FL, Cassago A, Garratt RC, Portugal RV, Araujo APU. A revised order of subunits in mammalian septin complexes. Cytoskeleton (Hoboken) 2019; 76:457-466. [PMID: 31608568 DOI: 10.1002/cm.21569] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2019] [Revised: 09/18/2019] [Accepted: 09/19/2019] [Indexed: 12/15/2022]
Abstract
Septins are GTP binding proteins considered to be novel components of the cytoskeleton. They polymerize into filaments based on hexameric or octameric core particles in which two copies of either three or four different septins, respectively, assemble into a specific sequence. Viable combinations of the 13 human septins are believed to obey substitution rules in which the different septins involved must come from distinct subgroups. The hexameric assembly, for example, has been reported to be SEPT7-SEPT6-SEPT2-SEPT2-SEPT6-SEPT7. Here, we have replaced SEPT2 by SEPT5 according to the substitution rules and used transmission electron microscopy to demonstrate that the resulting recombinant complex assembles into hexameric particles which are inverted with respect that predicted previously. MBP-SEPT5 constructs and immunostaining show that SEPT5 occupies the terminal positions of the hexamer. We further show that this is also true for the assembly including SEPT2, in direct contradiction with that reported previously. Consequently, both complexes expose an NC interface, as reported for yeast, which we show to be more susceptible to high salt concentrations. The correct assembly for the canonical combination of septins 2-6-7 is therefore established to be SEPT2-SEPT6-SEPT7-SEPT7-SEPT6-SEPT2, implying the need for revision of the mechanisms involved in filament assembly.
Collapse
Affiliation(s)
| | - Joci N Macedo
- São Carlos Institute of Physics, USP, São Carlos, SP, Brazil
- Federal Institute of Education, Science and Technology of Rondonia
| | | | - Fernando L Barroso da Silva
- Faculty of Pharmaceutical Sciences, USP, Ribeirão Preto, SP, Brazil
- UMR_S 1134, Université Paris Diderot, Paris, France
| | - Alexandre Cassago
- Brazilian Nanotechnology National Laboratory, CNPEM, Campinas, SP, Brazil
| | | | - Rodrigo V Portugal
- Brazilian Nanotechnology National Laboratory, CNPEM, Campinas, SP, Brazil
| | - Ana P U Araujo
- São Carlos Institute of Physics, USP, São Carlos, SP, Brazil
| |
Collapse
|
17
|
Kumagai PS, Martins CS, Sales EM, Rosa HV, Mendonça DC, Damalio JCP, Spinozzi F, Itri R, Araujo APU. Correct partner makes the difference: Septin G-interface plays a critical role in amyloid formation. Int J Biol Macromol 2019; 133:428-435. [DOI: 10.1016/j.ijbiomac.2019.04.105] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2019] [Revised: 04/12/2019] [Accepted: 04/15/2019] [Indexed: 01/04/2023]
|
18
|
An Interaction Network of the Human SEPT9 Established by Quantitative Mass Spectrometry. G3-GENES GENOMES GENETICS 2019; 9:1869-1880. [PMID: 30975701 PMCID: PMC6553528 DOI: 10.1534/g3.119.400197] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Septins regulate the organization of the actin cytoskeleton, vesicle transport and fusion, chromosome alignment and segregation, and cytokinesis in mammalian cells. SEPT9 is part of the core septin hetero-octamer in human cells which is composed of SEPT2, SEPT6, SEPT7, and SEPT9. SEPT9 has been linked to a variety of intracellular functions as well as to diseases and diverse types of cancer. A targeted high-throughput approach to systematically identify the interaction partners of SEPT9 has not yet been performed. We applied a quantitative proteomics approach to establish an interactome of SEPT9 in human fibroblast cells. Among the newly identified interaction partners were members of the myosin family and LIM domain containing proteins. Fluorescence microscopy of SEPT9 and its interaction partners provides additional evidence that SEPT9 might participate in vesicle transport from and to the plasma membrane as well as in the attachment of actin stress fibers to cellular adhesions.
Collapse
|
19
|
A blueprint of septin expression in human tissues. Funct Integr Genomics 2019; 19:787-797. [PMID: 31089837 DOI: 10.1007/s10142-019-00690-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Revised: 05/03/2019] [Accepted: 05/06/2019] [Indexed: 12/29/2022]
Abstract
Septins are GTP-binding proteins that polymerize to form filaments involved in several important biological processes. In human, 13 distinct septins genes are classified in four groups. Filaments formed by septins are complex and usually involve members of each group in specific positions. Expression data from GTEx database, a publicly available expression database with thousands of samples derived from multiple human tissues, was used to evaluate the expression of septins. The brain is noticeably a hotspot for septin expression where few genes contribute to a large portion of septin transcript pool. Co-expression data between septins suggests two predominant specific complexes in brain tissues and one filament in other tissues. SEPT3 and SEPT5 are two genes highly expressed in the brain and with a strong co-expression in all brain tissues. Additional analysis shows that the expression of these two genes is highly variable between individuals, but significantly dependent on the individual's age. Age-dependent decrease of expression from those two septins involved in synapses reinforces their possible link with cognitive decay and neurodegenerative diseases associated with aging. Analysis of enrichment of Gene Ontology terms from lists of genes consistently co-expressed with septins suggests participation in diverse biological processes, pointing out some novel roles for septins. Interestingly, we observed strong consistency of some of these terms with experimentally described roles of septins. Coordination of septins expression with genes involved in DNA repair and cell cycle control may provide insights for previously described links between septins and cancer.
Collapse
|
20
|
Abstract
Septins are widely recognized as a component of the cytoskeleton that is essential for cell division, and new work has shown that septins can recognise cell shape by assembling into filaments on membrane regions that display micrometer-scale curvature (e.g. at the cytokinetic furrow). Moreover, infection biology studies have illuminated important roles for septins in mediating the outcome of host-microbe interactions. In this Review, we discuss a selection of mechanistic insights recently gained from studying three infection paradigms: the rice blast fungus Magnaporthe oryzae, the poxvirus family member vaccinia virus and the Gram-negative bacterium Shigella flexneri These studies have respectively discovered that higher-order septin assemblies enable fungal invasion into plant cells, entrap viral particles at the plasma membrane and recognize dividing bacterial cells for delivery to lysosomes. Collectively, these insights illustrate how studying septin biology during microbial infection can provide fundamental advances in both cell and infection biology, and suggest new concepts underlying infection control.
Collapse
Affiliation(s)
- Hoan Van Ngo
- Department of Immunology & Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| | - Serge Mostowy
- Department of Immunology & Infection, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, London WC1E 7HT, UK
| |
Collapse
|
21
|
James NE, Cantillo E, Yano N, Chichester CO, DiSilvestro PA, Hovanesian V, Rao RSP, Kim KK, Moore RG, Ahsan N, Ribeiro JR. Septin-2 is overexpressed in epithelial ovarian cancer and mediates proliferation via regulation of cellular metabolic proteins. Oncotarget 2019; 10:2959-2972. [PMID: 31105878 PMCID: PMC6508204 DOI: 10.18632/oncotarget.26836] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 03/23/2019] [Indexed: 02/06/2023] Open
Abstract
Epithelial Ovarian Cancer (EOC) is associated with dismal survival rates due to the fact that patients are frequently diagnosed at an advanced stage and eventually become resistant to traditional chemotherapeutics. Hence, there is a crucial need for new and innovative therapies. Septin-2, a member of the septin family of GTP binding proteins, has been characterized in EOC for the first time and represents a potential future target. Septin-2 was found to be overexpressed in serous and clear cell human patient tissue compared to benign disease. Stable septin-2 knockdown clones developed in an ovarian cancer cell line exhibited a significant decrease in proliferation rates. Comparative label-free proteomic analysis of septin-2 knockdown cells revealed differential protein expression of pathways associated with the TCA cycle, acetyl CoA, proteasome and spliceosome. Further validation of target proteins indicated that septin-2 plays a predominant role in post-transcriptional and translational modifications as well as cellular metabolism, and suggested the potential novel role of septin-2 in promoting EOC tumorigenesis through these mechanisms.
Collapse
Affiliation(s)
- Nicole E. James
- Division of Gynecologic Oncology, Program in Women’s Oncology, Department of Obstetrics and Gynecology, Women and Infants Hospital, Providence, RI, USA
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA
| | - Evelyn Cantillo
- Division of Gynecologic Oncology, Program in Women’s Oncology, Department of Obstetrics and Gynecology, Women and Infants Hospital, Providence, RI, USA
| | - Naohiro Yano
- Department of Surgery, Roger Williams Medical Center, Boston University Medical School, Providence, RI, USA
| | - Clinton O. Chichester
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, RI, USA
| | - Paul A. DiSilvestro
- Division of Gynecologic Oncology, Program in Women’s Oncology, Department of Obstetrics and Gynecology, Women and Infants Hospital, Providence, RI, USA
- Division of Biology and Medicine, Warren Alpert Medical School, Brown University, Providence, RI, USA
| | | | - R. Shyama Prasad Rao
- Biostatistics and Bioinformatics Division, Yenepoya Research Center, Yenepoya University, Mangalore, India
| | - Kyukwang K. Kim
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY, USA
| | - Richard G. Moore
- Division of Gynecologic Oncology, Department of Obstetrics and Gynecology, Wilmot Cancer Institute, University of Rochester Medical Center, Rochester, NY, USA
| | - Nagib Ahsan
- Center for Cancer Research Development, Proteomics Core Facility, Rhode Island Hospital, Providence, RI, USA
- Division of Biology and Medicine, Warren Alpert Medical School, Brown University, Providence, RI, USA
| | - Jennifer R. Ribeiro
- Division of Gynecologic Oncology, Program in Women’s Oncology, Department of Obstetrics and Gynecology, Women and Infants Hospital, Providence, RI, USA
- Division of Biology and Medicine, Warren Alpert Medical School, Brown University, Providence, RI, USA
| |
Collapse
|
22
|
In Vitro Analyses Reveal the Effect of Synthetic Cytokinin Forchlorfenuron (FCF) on a Septin-Like Protein of Taeniid Cysticerci. J Parasitol Res 2019; 2019:8578936. [PMID: 30941206 PMCID: PMC6420996 DOI: 10.1155/2019/8578936] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Revised: 01/08/2019] [Accepted: 01/23/2019] [Indexed: 11/18/2022] Open
Abstract
Cytokinin forchlorfenuron (FCF), a synthetic cytokinin, has been used specifically for the characterization of septins. In spite of genomic evidence of their existence, nothing is known about septin filaments in taeniid cestodes. The aim of this work was to determine the presence of a septin-like protein in cysticerci of Taenia crassiceps and Taenia solium using the deduced amino acid sequence of T. solium septin 4 (SEPT4_Tsm), to design and synthesize a derived immunogenic peptide (residues 88 to 103), to prepare a specific rabbit polyclonal antibody, and to examine the effects of FCF at different concentrations and exposure times on an in vitro culture of T. crassiceps cysticerci. In vitro, FCF altered the morphology and motility of T. crassiceps cysticerci, and its effects were reversible under specific concentrations. In addition, we observed by ultrastructural observation that FCF alters the cellular subunit of the protonephridial system of cestodes, where disruption of the axoneme pattern of flame cells was observed. The rabbit polyclonal antibody prepared against the synthetic peptide recognized a major band of 41 kDa in both parasites. Our results establish the importance of SEPT4_Tsm in the dynamics and survival of taeniid cysticerci, as well as their susceptibility to FCF. This is also the first report that a septin is present in the cytoskeleton of taeniids.
Collapse
|
23
|
Lobato‐Márquez D, Krokowski S, Sirianni A, Larrouy‐Maumus G, Mostowy S. A requirement for septins and the autophagy receptor p62 in the proliferation of intracellular Shigella. Cytoskeleton (Hoboken) 2019; 76:163-172. [PMID: 29752866 PMCID: PMC6519264 DOI: 10.1002/cm.21453] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2018] [Revised: 04/11/2018] [Accepted: 05/09/2018] [Indexed: 12/28/2022]
Abstract
Shigella flexneri, a Gram-negative enteroinvasive pathogen, causes inflammatory destruction of the human intestinal epithelium. During infection of epithelial cells, Shigella escape from the phagosome to the cytosol, where they reroute host cell glycolysis to obtain nutrients for proliferation. Septins, a poorly understood component of the cytoskeleton, can entrap cytosolic Shigella targeted to autophagy in cage-like structures to restrict bacterial proliferation. Although bacterial entrapment by septin caging has been the subject of intense investigation, the role of septins and the autophagy machinery in the proliferation of noncaged Shigella is mostly unknown. Here, we found that intracellular Shigella fail to efficiently proliferate in SEPT2-, SEPT7-, or p62/SQSTM1-depleted cells. Consistent with a failure to proliferate, single cell analysis of bacteria not entrapped in septin cages showed that the number of metabolically active Shigella in septin- or p62-depleted cells is reduced. Targeted metabolomic analysis revealed that host cell glycolysis is dysregulated in septin-depleted cells, suggesting a key role for septins in modulation of glycolysis. Together, these results suggest that septins and the autophagy machinery may regulate metabolic pathways that promote the proliferation of intracellular Shigella not entrapped in septin cages.
Collapse
Affiliation(s)
- Damián Lobato‐Márquez
- MRC Centre for Molecular Bacteriology and Infection, Department of MedicineSection of Microbiology, Imperial College LondonLondonUnited Kingdom
- Department of Immunology and InfectionLondon School of Hygiene and Tropical Medicine, Keppel StreetLondonUnited Kingdom
| | - Sina Krokowski
- MRC Centre for Molecular Bacteriology and Infection, Department of MedicineSection of Microbiology, Imperial College LondonLondonUnited Kingdom
- Department of Immunology and InfectionLondon School of Hygiene and Tropical Medicine, Keppel StreetLondonUnited Kingdom
| | - Andrea Sirianni
- MRC Centre for Molecular Bacteriology and Infection, Department of MedicineSection of Microbiology, Imperial College LondonLondonUnited Kingdom
| | - Gerald Larrouy‐Maumus
- MRC Centre for Molecular Bacteriology and Infection, Department of Life Sciences, Faculty of Natural SciencesImperial College LondonLondonUnited Kingdom
| | - Serge Mostowy
- MRC Centre for Molecular Bacteriology and Infection, Department of MedicineSection of Microbiology, Imperial College LondonLondonUnited Kingdom
- Department of Immunology and InfectionLondon School of Hygiene and Tropical Medicine, Keppel StreetLondonUnited Kingdom
| |
Collapse
|
24
|
Upadia J, Gonzales PR, Atkinson TP, Schroeder HW, Robin NH, Rudy NL, Mikhail FM. A previously unrecognized 22q13.2 microdeletion syndrome that encompasses TCF20 and TNFRSF13C. Am J Med Genet A 2018; 176:2791-2797. [PMID: 30216695 DOI: 10.1002/ajmg.a.40492] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 05/01/2018] [Accepted: 07/03/2018] [Indexed: 12/23/2022]
Abstract
Phelan-McDermid syndrome (PMS, OMIM 606232) is a heterozygous contiguous gene microdeletion syndrome occurring at the distal region of chromosome 22q13. This deletion encompasses the SHANK3 gene at 22q13.33, which is thought to be the critical gene for the neurodevelopmental features seen in this syndrome. PMS is typically characterized by intellectual disability, autism spectrum disorder, absent to severely delayed speech, neonatal hypotonia, and dysmorphic features. Two patients presenting with classic clinical features of PMS have been reported to have interstitial microdeletions in the 22q13.2 region that map proximal to the SHANK3 gene (0.54 and 0.72 Mb, respectively). Here, we describe a 13-month-old girl with a de novo 1.16 Mb interstitial deletion in the 22q13.2 region who presented with global developmental delay, subtle dysmorphic features, and immunodeficiency. This deletion overlaps with the two previously published cases and five cases from the DECIPHER database. All eight patients share features common to patients with PMS including developmental delay and language delay, which suggests that this represents a previously unrecognized microdeletion syndrome in the 22q13.2 region. Our patient's deletion encompasses the TCF20 and TNFRSF13C genes, which are thought to play causative roles in the patient's neurodevelopmental and immunological features, respectively.
Collapse
Affiliation(s)
- Jariya Upadia
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Patrick R Gonzales
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| | - T Prescott Atkinson
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Harry W Schroeder
- Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Nathaniel H Robin
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama.,Department of Pediatrics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Natasha L Rudy
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| | - Fady M Mikhail
- Department of Genetics, University of Alabama at Birmingham, Birmingham, Alabama
| |
Collapse
|
25
|
Spiliotis ET. Spatial effects - site-specific regulation of actin and microtubule organization by septin GTPases. J Cell Sci 2018; 131:jcs207555. [PMID: 29326311 PMCID: PMC5818061 DOI: 10.1242/jcs.207555] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The actin and microtubule cytoskeletons comprise a variety of networks with distinct architectures, dynamics and protein composition. A fundamental question in eukaryotic cell biology is how these networks are spatially and temporally controlled, so they are positioned in the right intracellular places at the right time. While significant progress has been made in understanding the self-assembly of actin and microtubule networks, less is known about how they are patterned and regulated in a site-specific manner. In mammalian systems, septins are a large family of GTP-binding proteins that multimerize into higher-order structures, which associate with distinct subsets of actin filaments and microtubules, as well as membranes of specific curvature and lipid composition. Recent studies have shed more light on how septins interact with actin and microtubules, and raised the possibility that the cytoskeletal topology of septins is determined by their membrane specificity. Importantly, new functions have emerged for septins regarding the generation, maintenance and positioning of cytoskeletal networks with distinct organization and biochemical makeup. This Review presents new and past findings, and discusses septins as a unique regulatory module that instructs the local differentiation and positioning of distinct actin and microtubule networks.
Collapse
Affiliation(s)
- Elias T Spiliotis
- Drexel University, Department of Biology, Drexel University, Philadelphia, PA 19104, USA
| |
Collapse
|
26
|
Campos JLO, Doratioto TR, Videira NB, Ribeiro Filho HV, Batista FAH, Fattori J, Indolfo NDC, Nakahira M, Bajgelman MC, Cvoro A, Laurindo FRM, Webb P, Figueira ACM. Protein Disulfide Isomerase Modulates the Activation of Thyroid Hormone Receptors. Front Endocrinol (Lausanne) 2018; 9:784. [PMID: 30671024 PMCID: PMC6331412 DOI: 10.3389/fendo.2018.00784] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Accepted: 12/12/2018] [Indexed: 12/30/2022] Open
Abstract
Thyroid hormone receptors (TRs) are responsible for mediating thyroid hormone (T3 and T4) actions at a cellular level. They belong to the nuclear receptor (NR) superfamily and execute their main functions inside the cell nuclei as hormone-regulated transcription factors. These receptors also exhibit so-called "non-classic" actions, for which other cellular proteins, apart from coregulators inside nuclei, regulate their activity. Aiming to find alternative pathways of TR modulation, we searched for interacting proteins and found that PDIA1 interacts with TRβ in a yeast two-hybrid screening assay. The functional implications of PDIA1-TR interactions are still unclear; however, our co-immunoprecipitation (co-IP) and fluorescence assay results showed that PDI was able to bind both TR isoforms in vitro. Moreover, T3 appears to have no important role in these interactions in cellular assays, where PDIA1 was able to regulate transcription of TRα and TRβ-mediated genes in different ways depending on the promoter region and on the TR isoform involved. Although PDIA1 appears to act as a coregulator, it binds to a TR surface that does not interfere with coactivator binding. However, the TR:PDIA1 complex affinity and activation are different depending on the TR isoform. Such differences may reflect the structural organization of the PDIA1:TR complex, as shown by models depicting an interaction interface with exposed cysteines from both proteins, suggesting that PDIA1 might modulate TR by its thiol reductase/isomerase activity.
Collapse
Affiliation(s)
- Jessica L. O. Campos
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research Energy and Materials (CNPEM), São Paulo, Brazil
- Graduation Program of Biosciences and Bioactive Products Technology, Institute of Biology, State University of Campinas (Unicamp), São Paulo, Brazil
| | - Tabata R. Doratioto
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research Energy and Materials (CNPEM), São Paulo, Brazil
- Graduation Program of Biosciences and Bioactive Products Technology, Institute of Biology, State University of Campinas (Unicamp), São Paulo, Brazil
| | - Natalia B. Videira
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research Energy and Materials (CNPEM), São Paulo, Brazil
- Graduation Program of Biosciences and Bioactive Products Technology, Institute of Biology, State University of Campinas (Unicamp), São Paulo, Brazil
| | - Helder V. Ribeiro Filho
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research Energy and Materials (CNPEM), São Paulo, Brazil
- Graduation Program of Biosciences and Bioactive Products Technology, Institute of Biology, State University of Campinas (Unicamp), São Paulo, Brazil
| | - Fernanda A. H. Batista
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research Energy and Materials (CNPEM), São Paulo, Brazil
| | - Juliana Fattori
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research Energy and Materials (CNPEM), São Paulo, Brazil
| | - Nathalia de C. Indolfo
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research Energy and Materials (CNPEM), São Paulo, Brazil
- Graduation Program of Biosciences and Bioactive Products Technology, Institute of Biology, State University of Campinas (Unicamp), São Paulo, Brazil
| | - Marcel Nakahira
- Institute of Chemistry (IQ), State University of Campinas (Unicamp), São Paulo, Brazil
| | - Marcio C. Bajgelman
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research Energy and Materials (CNPEM), São Paulo, Brazil
| | - Aleksandra Cvoro
- Genomic Medicine, The Methodist Hospital Research Institute, Houston, TX, United States
| | - Francisco R. M. Laurindo
- Vascular Biology Laboratory, Heart Institute (InCor), School of Medicine, University of São Paulo, São Paulo, Brazil
| | - Paul Webb
- California Institute for Regenerative Medicine, Oakland, CA, United States
| | - Ana Carolina M. Figueira
- Brazilian Biosciences National Laboratory (LNBio), Brazilian Center for Research Energy and Materials (CNPEM), São Paulo, Brazil
- *Correspondence: Ana Carolina M. Figueira
| |
Collapse
|
27
|
Ribet D, Boscaini S, Cauvin C, Siguier M, Mostowy S, Echard A, Cossart P. SUMOylation of human septins is critical for septin filament bundling and cytokinesis. J Cell Biol 2017; 216:4041-4052. [PMID: 29051266 PMCID: PMC5716278 DOI: 10.1083/jcb.201703096] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2017] [Revised: 07/25/2017] [Accepted: 08/23/2017] [Indexed: 01/22/2023] Open
Abstract
Septins are cytoskeletal proteins that assemble into nonpolar filaments. They are critical in diverse cellular functions, acting as scaffolds for protein recruitment and as diffusion barriers for subcellular compartmentalization. Human septins are encoded by 13 different genes and are classified into four groups based on sequence homology (SEPT2, SEPT3, SEPT6, and SEPT7 groups). In yeast, septins were among the first proteins reported to be modified by SUMOylation, a ubiquitin-like posttranslational modification. However, whether human septins could be modified by small ubiquitin-like modifiers (SUMOs) and what roles this modification may have in septin function remains unknown. In this study, we first show that septins from all four human septin groups can be covalently modified by SUMOs. We show in particular that endogenous SEPT7 is constitutively SUMOylated during the cell cycle. We then map SUMOylation sites to the C-terminal domain of septins belonging to the SEPT6 and SEPT7 groups and to the N-terminal domain of septins from the SEPT3 group. We finally demonstrate that expression of non-SUMOylatable septin variants from the SEPT6 and SEPT7 groups leads to aberrant septin bundle formation and defects in cytokinesis after furrow ingression. Altogether, our results demonstrate a pivotal role for SUMOylation in septin filament bundling and cell division.
Collapse
Affiliation(s)
- David Ribet
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, Institut National de la Santé et de la Recherche Médicale, Institut National de la Recherche Agronomique, Paris, France
| | - Serena Boscaini
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, Institut National de la Santé et de la Recherche Médicale, Institut National de la Recherche Agronomique, Paris, France
| | - Clothilde Cauvin
- Unité de Trafic Membranaire et Division Cellulaire, Département de Biologie Cellulaire et Infection, Institut Pasteur, Paris, France
- Centre National de la Recherche Scientifique UMR3691, Paris, France
- Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 06, Institut de Formation Doctorale, Paris, France
| | - Martin Siguier
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, Institut National de la Santé et de la Recherche Médicale, Institut National de la Recherche Agronomique, Paris, France
| | - Serge Mostowy
- Medical Research Council Centre for Molecular Bacteriology and Infection, Imperial College London, London, England, UK
| | - Arnaud Echard
- Unité de Trafic Membranaire et Division Cellulaire, Département de Biologie Cellulaire et Infection, Institut Pasteur, Paris, France
- Centre National de la Recherche Scientifique UMR3691, Paris, France
- Sorbonne Universités, Université Pierre et Marie Curie, Université Paris 06, Institut de Formation Doctorale, Paris, France
| | - Pascale Cossart
- Unité des Interactions Bactéries-Cellules, Institut Pasteur, Institut National de la Santé et de la Recherche Médicale, Institut National de la Recherche Agronomique, Paris, France
| |
Collapse
|
28
|
Senger K, Marka G, Soller K, Sakk V, Florian MC, Geiger H. Septin 6 regulates engraftment and lymphoid differentiation potential of murine long-term hematopoietic stem cells. Exp Hematol 2017; 55:45-55. [DOI: 10.1016/j.exphem.2017.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 07/06/2017] [Accepted: 07/19/2017] [Indexed: 01/22/2023]
|
29
|
Valadares NF, d' Muniz Pereira H, Ulian Araujo AP, Garratt RC. Septin structure and filament assembly. Biophys Rev 2017; 9:481-500. [PMID: 28905266 DOI: 10.1007/s12551-017-0320-4] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2017] [Accepted: 08/17/2017] [Indexed: 12/13/2022] Open
Abstract
Septins are able to polymerize into long apolar filaments and have long been considered to be a component of the cytoskeleton alongside intermediate filaments (which are also apolar in nature), microtubules and actin filaments (which are not). Their central guanosine triphosphate (GTP)-binding domain, which is essential for stabilizing the filament itself, is flanked by N- and C-terminal domains for which no direct structural information is yet available. In most cases, physiological filaments are built from a number of different septin monomers, and in the case of mammalian septins this is most commonly either three or four. Comprehending the structural basis for the spontaneous assembly of such filaments requires a deeper understanding of the interfaces between individual GTP-binding domains than is currently available. Nevertheless, in this review we will summarize the considerable progress which has been made over the course of the last 10 years. We will provide a brief description of each structure determined to date and comment on how it has added to the body of knowledge which is rapidly growing. Rather than simply repeat data which have already been described in the literature, as far as is possible we will try to take advantage of the full set of information now available (mostly derived from human septins) and draw the reader's attention to some of the details of the structures themselves and the filaments they form which have not be commented on previously. An additional aim is to clarify some misconceptions.
Collapse
Affiliation(s)
| | - Humberto d' Muniz Pereira
- Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador Sancarlense, 400, São Carlos, SP, 13560-590, Brazil
| | - Ana Paula Ulian Araujo
- Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador Sancarlense, 400, São Carlos, SP, 13560-590, Brazil
| | - Richard Charles Garratt
- Instituto de Física de São Carlos, Universidade de São Paulo, Av. Trabalhador Sancarlense, 400, São Carlos, SP, 13560-590, Brazil.
| |
Collapse
|
30
|
Interaction of Recombinant Gallus gallus SEPT5 and Brain Proteins of H5N1-Avian Influenza Virus-Infected Chickens. Proteomes 2017; 5:proteomes5030023. [PMID: 28895884 PMCID: PMC5620540 DOI: 10.3390/proteomes5030023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Revised: 09/05/2017] [Accepted: 09/07/2017] [Indexed: 11/16/2022] Open
Abstract
Septin forms a conserved family of cytoskeletal guanosine triphosphate (GTP) binding proteins that have diverse roles in protein scaffolding, vesicle trafficking, and cytokinesis. The involvement of septins in infectious viral disease pathogenesis has been demonstrated by the upregulation of SEPT5 protein and its mRNA in brain tissues of H5N1-infected chickens, thus, providing evidence for the potential importance of this protein in the pathogenesis of neurovirulence caused by the avian influenza virus. In this study, cloning, expression, and purification of Gallus gallus SEPT5 protein was performed in Escherichia coli. The SEPT5 gene was inserted into the pRSETB expression vector, transformed in the E. coli BL21 (DE3) strain and the expression of SEPT5 protein was induced by IPTG. The SEPT5 protein was shown to be authentic as it was able to be pulled down by a commercial anti-SEPT5 antibody in a co-immunoprecipitation assay. In vivo aggregation of the recombinant protein was limited by cultivation at a reduced temperature of 16 °C. Using co-immunoprecipitation techniques, the purified recombinant SEPT5 protein was used to pull down host’s interacting or binding proteins, i.e., proteins of brains of chickens infected with the H5N1 influenza virus. Interacting proteins, such as CRMP2, tubulin proteins, heat-shock proteins and other classes of septins were identified using LCMS/MS. Results from this study suggest that the codon-optimized SEPT5 gene can be efficiently expressed in the E. coli bacterial system producing authentic SEPT5 protein, thus, enabling multiple host’s proteins to interact with the SEPT5 protein.
Collapse
|
31
|
The Borg family of Cdc42 effector proteins Cdc42EP1-5. Biochem Soc Trans 2017; 44:1709-1716. [PMID: 27913681 PMCID: PMC5134998 DOI: 10.1042/bst20160219] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 09/15/2016] [Accepted: 09/19/2016] [Indexed: 02/06/2023]
Abstract
Despite being discovered more than 15 years ago, the Borg (binder of Rho GTPases) family of Cdc42 effector proteins (Cdc42EP1-5) remains largely uncharacterised and relatively little is known about their structure, regulation and role in development and disease. Recent studies are starting to unravel some of the key functional and mechanistic aspects of the Borg proteins, including their role in cytoskeletal remodelling and signalling. In addition, the participation of Borg proteins in important cellular processes such as cell shape, directed migration and differentiation is slowly emerging, directly linking Borgs with important physiological and pathological processes such as angiogenesis, neurotransmission and cancer-associated desmoplasia. Here, we review some of these findings and discuss future prospects.
Collapse
|
32
|
Armijo-Weingart L, Gallo G. It takes a village to raise a branch: Cellular mechanisms of the initiation of axon collateral branches. Mol Cell Neurosci 2017; 84:36-47. [PMID: 28359843 DOI: 10.1016/j.mcn.2017.03.007] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2016] [Revised: 01/03/2017] [Accepted: 03/01/2017] [Indexed: 12/14/2022] Open
Abstract
The formation of axon collateral branches from the pre-existing shafts of axons is an important aspect of neurodevelopment and the response of the nervous system to injury. This article provides an overview of the role of the cytoskeleton and signaling mechanisms in the formation of axon collateral branches. Both the actin filament and microtubule components of the cytoskeleton are required for the formation of axon branches. Recent work has begun to shed light on how these two elements of the cytoskeleton are integrated by proteins that functionally or physically link the cytoskeleton. While a number of signaling pathways have been determined as having a role in the formation of axon branches, the complexity of the downstream mechanisms and links to specific signaling pathways remain to be fully determined. The regulation of intra-axonal protein synthesis and organelle function are also emerging as components of signal-induced axon branching. Although much has been learned in the last couple of decades about the mechanistic basis of axon branching we can look forward to continue elucidating this complex biological phenomenon with the aim of understanding how multiple signaling pathways, cytoskeletal regulators and organelles are coordinated locally along the axon to give rise to a branch.
Collapse
Affiliation(s)
- Lorena Armijo-Weingart
- Shriners Pediatric Research Center, Temple University, Department of Anatomy and Cell Biology, 3500 North Broad St, Philadelphia, PA 19140, United States
| | - Gianluca Gallo
- Shriners Pediatric Research Center, Temple University, Department of Anatomy and Cell Biology, 3500 North Broad St, Philadelphia, PA 19140, United States.
| |
Collapse
|
33
|
Kaplan C, Steinmann M, Zapiorkowska NA, Ewers H. Functional Redundancy of Septin Homologs in Dendritic Branching. Front Cell Dev Biol 2017; 5:11. [PMID: 28265560 PMCID: PMC5316521 DOI: 10.3389/fcell.2017.00011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2016] [Accepted: 02/06/2017] [Indexed: 01/02/2023] Open
Abstract
Septins are cytoskeletal GTPases present in nonpolar heteromeric complexes that assemble in a palindromic fashion from two to eight subunits. Mammalian septins function in several fundamental cellular processes at the membrane-cytoskeleton interface including dendritic branching in neurons. Sequence homology divides the 13 mammalian septin genes into four homology groups. Experimental findings suggest that septin function is redundant among septins from one homology group. This is best understood for the isoforms of the SEPT2 group, which form a homodimer at the center of septin complexes. In vitro, all SEPT2-group septins form recombinant hexameric complexes with two copies of SEPT6 and SEPT7. However, it remains unclear to what extent homologs septins can substitute for each other in specific cellular processes. Here, we use the experimental paradigm of dendritic branching in hippocampal rat neurons to ask, to what extent septins of the SEPT2-group are functionally redundant. Dendritic branching is significantly reduced when SEPT5 is downregulated. In neurons expressing SEPT5-shRNA, simultaneously expressed SEPT2-GFP, and SEPT4-GFP colocalize with SEPT7 at dendritic spine necks and rescue dendritic branching. In contrast, SEPT1-GFP is diffusely distributed in the cytoplasm in SEPT5 downregulated neurons and cannot rescue dendritic branching. Our findings provide a basis for the study of septin-specific functions in cells.
Collapse
Affiliation(s)
- Charlotte Kaplan
- Department of Biology, Institute of Biochemistry, University of ZurichZurich, Switzerland; Laboratory of Physical Chemistry, University of ZurichZurich, Switzerland
| | - Mayra Steinmann
- Department of Biology, Institute of Biochemistry, University of ZurichZurich, Switzerland; Laboratory of Physical Chemistry, University of ZurichZurich, Switzerland
| | - Natalia A Zapiorkowska
- Department of Biology, Institute of Biochemistry, University of ZurichZurich, Switzerland; Laboratory of Physical Chemistry, University of ZurichZurich, Switzerland
| | - Helge Ewers
- Department of Biology, Institute of Biochemistry, University of ZurichZurich, Switzerland; Laboratory of Physical Chemistry, University of ZurichZurich, Switzerland
| |
Collapse
|
34
|
Abstract
Septins are GTP-binding and membrane-interacting proteins with a highly conserved domain structure involved in various cellular processes, including cytoskeleton organization, cytokinesis, and membrane dynamics. To date, 13 different septin genes have been identified in mammals (SEPT1 to SEPT12 and SEPT14), which can be classified into four distinct subgroups based on the sequence homology of their domain structure (SEPT2, SEPT3, SEPT6, and SEPT7 subgroup). The family members of these subgroups have a strong affinity for other septins and form apolar tri-, hexa-, or octameric complexes consisting of multiple septin polypeptides. The first characterized core complex is the hetero-trimer SEPT2-6-7. Within these complexes single septins can be exchanged in a subgroup-specific manner. Hexamers contain SEPT2 and SEPT6 subgroup members and SEPT7 in two copies each whereas the octamers additionally comprise two SEPT9 subgroup septins. The various isoforms seem to determine the function and regulation of the septin complex. Septins self-assemble into higher-order structures, including filaments and rings in orders, which are typical for different cell types. Misregulation of septins leads to human diseases such as neurodegenerative and bleeding disorders. In non-dividing cells such as neuronal tissue and platelets septins have been associated with exocytosis. However, many mechanistic details and roles attributed to septins are poorly understood. We describe here some important mammalian septin interactions with a special focus on the clinically relevant septin interactions.
Collapse
Affiliation(s)
- Katharina Neubauer
- Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, Faculty of Medicine, Medical Center-University of Freiburg Freiburg, Germany
| | - Barbara Zieger
- Division of Pediatric Hematology and Oncology, Department of Pediatrics and Adolescent Medicine, Faculty of Medicine, Medical Center-University of Freiburg Freiburg, Germany
| |
Collapse
|
35
|
Vagin O, Beenhouwer DO. Septins: Regulators of Protein Stability. Front Cell Dev Biol 2016; 4:143. [PMID: 28066764 PMCID: PMC5168428 DOI: 10.3389/fcell.2016.00143] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2016] [Accepted: 12/02/2016] [Indexed: 12/31/2022] Open
Abstract
Septins are small GTPases that play a role in several important cellular processes. In this review, we focus on the roles of septins in protein stabilization. Septins may regulate protein stability by: (1) interacting with proteins involved in degradation pathways, (2) regulating the interaction between transmembrane proteins and cytoskeletal proteins, (3) affecting the mobility of transmembrane proteins in lipid bilayers, and (4) modulating the interaction of proteins with their adaptor or signaling proteins. In this context, we discuss the role of septins in protecting four different proteins from degradation. First we consider botulinum neurotoxin serotype A (BoNT/A) and the contribution of septins to its extraordinarily long intracellular persistence. Next, we discuss the role of septins in stabilizing the receptor tyrosine kinases EGFR and ErbB2. Finally, we consider the contribution of septins in protecting hypoxia-inducible factor 1α (HIF-1α) from degradation.
Collapse
Affiliation(s)
- Olga Vagin
- Department of Physiology, Geffen School of Medicine at UCLALos Angeles, CA, USA; VA Greater Los Angeles Healthcare SystemLos Angeles, CA, USA
| | - David O Beenhouwer
- Department of Medicine, Geffen School of Medicine at UCLALos Angeles, CA, USA; Division of Infectious Diseases, VA Greater Los Angeles Health Care SystemLos Angeles, CA, USA
| |
Collapse
|
36
|
Angelis D, Spiliotis ET. Septin Mutations in Human Cancers. Front Cell Dev Biol 2016; 4:122. [PMID: 27882315 PMCID: PMC5101219 DOI: 10.3389/fcell.2016.00122] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2016] [Accepted: 10/17/2016] [Indexed: 12/22/2022] Open
Abstract
Septins are GTP-binding proteins that are evolutionarily and structurally related to the RAS oncogenes. Septin expression levels are altered in many cancers and new advances point to how abnormal septin expression may contribute to the progression of cancer. In contrast to the RAS GTPases, which are frequently mutated and actively promote tumorigenesis, little is known about the occurrence and role of septin mutations in human cancers. Here, we review septin missense mutations that are currently in the Catalog of Somatic Mutations in Cancer (COSMIC) database. The majority of septin mutations occur in tumors of the large intestine, skin, endometrium and stomach. Over 25% of the annotated mutations in SEPT2, SEPT4, and SEPT9 belong to large intestine tumors. From all septins, SEPT9 and SEPT14 exhibit the highest mutation frequencies in skin, stomach and large intestine cancers. While septin mutations occur with frequencies lower than 3%, recurring mutations in several invariant and highly conserved amino acids are found across different septin paralogs and tumor types. Interestingly, a significant number of these mutations occur in the GTP-binding pocket and septin dimerization interfaces. Future studies may determine how these somatic mutations affect septin structure and function, whether they contribute to the progression of specific cancers and if they could serve as tumor-specific biomarkers.
Collapse
|
37
|
Song K, Russo G, Krauss M. Septins As Modulators of Endo-Lysosomal Membrane Traffic. Front Cell Dev Biol 2016; 4:124. [PMID: 27857942 PMCID: PMC5093113 DOI: 10.3389/fcell.2016.00124] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 10/19/2016] [Indexed: 11/13/2022] Open
Abstract
Septins constitute a family of GTP-binding proteins, which assemble into non-polar filaments in a nucleotide-dependent manner. These filaments can be recruited to negatively charged membrane surfaces. When associated with membranes septin filaments can act as diffusion barriers, which confine subdomains of distinct biological functions. In addition, they serve scaffolding roles by recruiting cytosolic proteins and other cytoskeletal elements. Septins have been implicated in a large variety of membrane-dependent processes, including cytokinesis, signaling, cell migration, and membrane traffic, and several family members have been implicated in disease. However, surprisingly little is known about the molecular mechanisms underlying their biological functions. This review summarizes evidence in support of regulatory roles of septins during endo-lysosomal sorting, with a particular focus on phosphoinositides, which serve as spatial landmarks guiding septin recruitment to distinct subcellular localizations.
Collapse
Affiliation(s)
- Kyungyeun Song
- Leibniz-Institut für Molekulare Pharmakologie Berlin, Germany
| | - Giulia Russo
- Leibniz-Institut für Molekulare Pharmakologie Berlin, Germany
| | - Michael Krauss
- Leibniz-Institut für Molekulare Pharmakologie Berlin, Germany
| |
Collapse
|
38
|
Partial Functional Diversification of Drosophila melanogaster Septin Genes Sep2 and Sep5. G3-GENES GENOMES GENETICS 2016; 6:1947-57. [PMID: 27172205 PMCID: PMC4938648 DOI: 10.1534/g3.116.028886] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The septin family of hetero-oligomeric complex-forming proteins can be divided into subgroups, and subgroup members are interchangeable at specific positions in the septin complex. Drosophila melanogaster has five septin genes, including the two SEPT6 subgroup members Sep2 and Sep5. We previously found that Sep2 has a unique function in oogenesis, which is not performed by Sep5. Here, we find that Sep2 is uniquely required for follicle cell encapsulation of female germline cysts, and that Sep2 and Sep5 are redundant for follicle cell proliferation. The five D. melanogaster septins localize similarly in oogenesis, including as rings flanking the germline ring canals. Pnut fails to localize in Sep5; Sep2 double mutant follicle cells, indicating that septin complexes fail to form in the absence of both Sep2 and Sep5. We also find that mutations in septins enhance the mutant phenotype of bazooka, a key component in the establishment of cell polarity, suggesting a link between septin function and cell polarity. Overall, this work suggests that Sep5 has undergone partial loss of ancestral protein function, and demonstrates redundant and unique functions of septins.
Collapse
|
39
|
Abstract
Rho family GTPases such as Cdc42 are key regulators of essential cellular processes through their effects on cytoskeletal dynamics, signaling and gene expression. Rho GTPases modulate these functions by engaging a wide variety of downstream effectors. Among these effectors is the largely understudied Cdc42EP/BORG family of Cdc42 effectors. BORG proteins have been linked to actin and septin regulation, but their role in development and disease is only starting to emerge. Recently, Cdc42EP3/BORG2 was shown to coordinate actin and septin cytoskeleton rearrangements in cancer-associated fibroblasts (CAFs). Interestingly, Cdc42EP3 expression potentiated cellular responses to mechanical stimulation leading to signaling and transcriptional adaptations required for the emergence of a fully activated CAF phenotype. These findings uncover a novel role for the BORG/septin network in cancer. Here, we demonstrate that Cdc42EP3 function in CAFs relies on tight regulation by Cdc42.
Collapse
Affiliation(s)
- Aaron J Farrugia
- a Tumour Microenvironment Team, Division of Cancer Biology , Institute of Cancer Research , London , UK
| | - Fernando Calvo
- a Tumour Microenvironment Team, Division of Cancer Biology , Institute of Cancer Research , London , UK
| |
Collapse
|
40
|
McMurray MA. Assays for genetic dissection of septin filament assembly in yeast, from de novo folding through polymerization. Methods Cell Biol 2016; 136:99-116. [PMID: 27473905 DOI: 10.1016/bs.mcb.2016.03.012] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023]
Abstract
In Saccharomyces cerevisiae, septin mutations have severe effects on colony-forming ability, particularly at high temperatures, allowing the full variety of genetic tools available in this model organism to be applied to the study of septin biology. Although many details of septin function remain unknown, one can exploit a small number of easily scored phenotypes-proliferation capacity, cell morphology, septin localization, and septin ring integrity-as sensitive readouts of properly assembled septin filaments. Accordingly, this chapter focuses on genetic approaches targeted toward understanding the molecular mechanisms of de novo septin folding, heterooligomerization, and polymerization into filaments. The same general methods can be used to interrogate septin function, although interpretation of results can be more complicated. As genetic-based methodologies are technically simple but particularly dependent on interpretation, here I focus on the logic underlying the most common interpretations of results using septin mutants.
Collapse
Affiliation(s)
- M A McMurray
- University of Colorado Anschutz Medical Campus, Aurora, CO, United States.
| |
Collapse
|
41
|
Septin oligomerization regulates persistent expression of ErbB2/HER2 in gastric cancer cells. Biochem J 2016; 473:1703-18. [PMID: 27048593 DOI: 10.1042/bcj20160203] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 04/05/2016] [Indexed: 12/19/2022]
Abstract
Septins are a family of cytoskeletal GTP-binding proteins that assemble into membrane-associated hetero-oligomers and organize scaffolds for recruitment of cytosolic proteins or stabilization of membrane proteins. Septins have been implicated in a diverse range of cancers, including gastric cancer, but the underlying mechanisms remain unclear. The hypothesis tested here is that septins contribute to cancer by stabilizing the receptor tyrosine kinase ErbB2, an important target for cancer treatment. Septins and ErbB2 were highly over-expressed in gastric cancer cells. Immunoprecipitation followed by MS analysis identified ErbB2 as a septin-interacting protein. Knockdown of septin-2 or cell exposure to forchlorfenuron (FCF), a well-established inhibitor of septin oligomerization, decreased surface and total levels of ErbB2. These treatments had no effect on epidermal growth factor receptor (EGFR), emphasizing the specificity and functionality of the septin-ErbB2 interaction. The level of ubiquitylated ErbB2 at the plasma membrane was elevated in cells treated with FCF, which was accompanied by a decrease in co-localization of ErbB2 with septins at the membrane. Cathepsin B inhibitor, but not bafilomycin or lactacystin, prevented FCF-induced decrease in total ErbB2 by increasing accumulation of ubiquitylated ErbB2 in lysosomes. Therefore, septins protect ErbB2 from ubiquitylation, endocytosis and lysosomal degradation. The FCF-induced degradation pathway is distinct from and additive with the degradation induced by inhibiting ErbB2 chaperone Hsp90. These results identify septins as novel regulators of ErbB2 expression that contribute to the remarkable stabilization of the receptor at the plasma membrane of cancer cells and may provide a basis for the development of new ErbB2-targeting anti-cancer therapies.
Collapse
|
42
|
Ortore MG, Macedo JNA, Araujo APU, Ferrero C, Mariani P, Spinozzi F, Itri R. Structural and Thermodynamic Properties of Septin 3 Investigated by Small-Angle X-Ray Scattering. Biophys J 2016; 108:2896-902. [PMID: 26083929 DOI: 10.1016/j.bpj.2015.05.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2014] [Revised: 04/30/2015] [Accepted: 05/11/2015] [Indexed: 01/22/2023] Open
Abstract
Septins comprise a family of proteins involved in a variety of cellular processes and related to several human pathologies. They are constituted by three structural domains: the N- and C-terminal domains, highly variable in length and composition, and the central domain, involved in the guanine nucleotide (GTP) binding. Thirteen different human septins are known to form heterogeneous complexes or homofilaments, which are stabilized by specific interactions between the different interfaces present in the domains. In this work, we have investigated by in-solution small-angle x-ray scattering the structural and thermodynamic properties of a human septin 3 construct, SEPT3-GC, which contains both of both interfaces (G and NC) responsible for septin-septin interactions. In order to shed light on the role of these interactions, small-angle x-ray scattering measurements were performed in a wide range of temperatures, from 2 up to 56°C, both with and without a nonhydrolysable form of GTP (GTPγS). The acquired data show a temperature-dependent coexistence of monomers, dimers, and higher-order aggregates that were analyzed using a global fitting approach, taking into account the crystallographic structure of the recently reported SEPT3 dimer, PDB:3SOP. As a result, the enthalpy, entropy, and heat capacity variations that control the dimer-monomer dissociation equilibrium in solution were derived and GTPγS was detected to increase the enthalpic stability of the dimeric species. Moreover, a temperature increase was observed to induce dissociation of SEPT3-GC dimers into monomers just preceding their reassembling into amyloid aggregates, as revealed by the Thioflavin-T fluorescence assays.
Collapse
Affiliation(s)
- Maria Grazia Ortore
- Dipartimento di Scienze della Vita e dell'Ambiente and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Università Politecnica delle Marche, Ancona, Italy
| | - Joci N A Macedo
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | - Ana Paula U Araujo
- Instituto de Física de São Carlos, Universidade de São Paulo, São Carlos, Brazil
| | | | - Paolo Mariani
- Dipartimento di Scienze della Vita e dell'Ambiente and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Università Politecnica delle Marche, Ancona, Italy
| | - Francesco Spinozzi
- Dipartimento di Scienze della Vita e dell'Ambiente and Consorzio Nazionale Interuniversitario per le Scienze Fisiche della Materia, Università Politecnica delle Marche, Ancona, Italy.
| | - Rosangela Itri
- Instituto de Física da Universidade de São Paulo, São Paulo, Brazil.
| |
Collapse
|
43
|
Interaction of Ca(2+)-dependent activator protein for secretion 1 (CAPS1) with septin family proteins in mouse brain. Neurosci Lett 2016; 617:232-5. [PMID: 26917099 DOI: 10.1016/j.neulet.2016.02.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2015] [Revised: 02/18/2016] [Accepted: 02/19/2016] [Indexed: 01/22/2023]
Abstract
The Ca(2+)-dependent activator protein for secretion 1 (CAPS1) protein plays a regulatory role in the dense-core vesicle exocytosis pathway. To clarify the functions of this protein in the brain, we searched for novel interaction partners of CAPS1 by mass spectrometry. We identified a specific interaction of CAPS1 with septin family proteins. We also demonstrated that the C-terminal region of the CAPS1 protein binds to part of the deduced GTP-binding domain of septin proteins. It is possible that a tertiary complex of septin, CAPS, and syntaxin contributes to dense-core vesicle trafficking and exocytosis in neurons.
Collapse
|
44
|
Renz C, Oeljeklaus S, Grinhagens S, Warscheid B, Johnsson N, Gronemeyer T. Identification of Cell Cycle Dependent Interaction Partners of the Septins by Quantitative Mass Spectrometry. PLoS One 2016; 11:e0148340. [PMID: 26871441 PMCID: PMC4752459 DOI: 10.1371/journal.pone.0148340] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Accepted: 01/15/2016] [Indexed: 01/21/2023] Open
Abstract
The septins are a conserved family of GTP-binding proteins that, in the baker's yeast, assemble into a highly ordered array of filaments at the mother bud neck. These filaments undergo significant structural rearrangements during the cell cycle. We aimed at identifying key components that are involved in or regulate the transitions of the septins. By combining cell synchronization and quantitative affinity-purification mass-spectrometry, we performed a screen for specific interaction partners of the septins at three distinct stages of the cell cycle. A total of 83 interaction partners of the septins were assigned. Surprisingly, we detected DNA-interacting/nuclear proteins and proteins involved in ribosome biogenesis and protein synthesis predominantly present in alpha-factor arrested that do not display an assembled septin structure. Furthermore, two distinct sets of regulatory proteins that are specific for cells at S-phase with a stable septin collar or at mitosis with split septin rings were identified. Complementary methods like SPLIFF and immunoprecipitation allowed us to more exactly define the spatial and temporal characteristics of selected hits of the AP-MS screen.
Collapse
Affiliation(s)
- Christian Renz
- Ulm University, Department of Molecular Genetics and Cell Biology, Ulm, Germany
| | - Silke Oeljeklaus
- University of Freiburg, Department of Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, Freiburg, Germany
| | - Sören Grinhagens
- Ulm University, Department of Molecular Genetics and Cell Biology, Ulm, Germany
| | - Bettina Warscheid
- University of Freiburg, Department of Biochemistry and Functional Proteomics, Institute of Biology II, Faculty of Biology and BIOSS Centre for Biological Signalling Studies, Freiburg, Germany
| | - Nils Johnsson
- Ulm University, Department of Molecular Genetics and Cell Biology, Ulm, Germany
| | - Thomas Gronemeyer
- Ulm University, Department of Molecular Genetics and Cell Biology, Ulm, Germany
- * E-mail:
| |
Collapse
|
45
|
|
46
|
Scholz R, Imami K, Scott NE, Trimble WS, Foster LJ, Finlay BB. Novel Host Proteins and Signaling Pathways in Enteropathogenic E. coli Pathogenesis Identified by Global Phosphoproteome Analysis. Mol Cell Proteomics 2015; 14:1927-45. [PMID: 25944883 DOI: 10.1074/mcp.m114.046847] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2014] [Indexed: 12/21/2022] Open
Abstract
Enteropathogenic Escherichia coli (EPEC) uses a type III secretion system (T3SS) to directly translocate effector proteins into host cells where they play a pivotal role in subverting host cell signaling needed for disease. However, our knowledge of how EPEC affects host protein phosphorylation is limited to a few individual protein studies. We employed a quantitative proteomics approach to globally map alterations in the host phosphoproteome during EPEC infection. By characterizing host phosphorylation events at various time points throughout infection, we examined how EPEC dynamically impacts the host phosphoproteome over time. This experimental setup also enabled identification of T3SS-dependent and -independent changes in host phosphorylation. Specifically, T3SS-regulated events affected various cellular processes that are known EPEC targets, including cytoskeletal organization, immune signaling, and intracellular trafficking. However, the involvement of phosphorylation in these events has thus far been poorly studied. We confirmed the MAPK family as an established key host player, showed its central role in signal transduction during EPEC infection, and extended the repertoire of known signaling hubs with previously unrecognized proteins, including TPD52, CIN85, EPHA2, and HSP27. We identified altered phosphorylation of known EPEC targets, such as cofilin, where the involvement of phosphorylation has so far been undefined, thus providing novel mechanistic insights into the roles of these proteins in EPEC infection. An overlap of regulated proteins, especially those that are cytoskeleton-associated, was observed when compared with the phosphoproteome of Shigella-infected cells. We determined the biological relevance of the phosphorylation of a novel protein in EPEC pathogenesis, septin-9 (SEPT9). Both siRNA knockdown and a phosphorylation-impaired SEPT9 mutant decreased bacterial adherence and EPEC-mediated cell death. In contrast, a phosphorylation-mimicking SEPT9 mutant rescued these effects. Collectively, this study provides the first global analysis of phosphorylation-mediated processes during infection with an extracellular, diarrheagenic bacterial pathogen.
Collapse
Affiliation(s)
| | - Koshi Imami
- §Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Nichollas E Scott
- §Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - William S Trimble
- ¶Cell Biology Program, Hospital for Sick Children and ‖Department of Biochemistry, University of Toronto, Toronto, Ontario M5G 1X8, Canada
| | - Leonard J Foster
- §Centre for High-Throughput Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada, **Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada, and
| | - B Brett Finlay
- From the ‡Michael Smith Laboratories and **Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada, and ¶¶Department of Microbiology and Immunology, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| |
Collapse
|
47
|
Menon MB, Gaestel M. Sep(t)arate or not – how some cells take septin-independent routes through cytokinesis. J Cell Sci 2015; 128:1877-86. [PMID: 25690008 DOI: 10.1242/jcs.164830] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Cytokinesis is the final step of cell division, and is a process that requires a precisely coordinated molecular machinery to fully separate the cytoplasm of the parent cell and to establish the intact outer cell barrier of the daughter cells. Among various cytoskeletal proteins involved, septins are known to be essential mediators of cytokinesis. In this Commentary, we present recent observations that specific cell divisions can proceed in the absence of the core mammalian septin SEPT7 and its Drosophila homolog Peanut (Pnut) and that thus challenge the view that septins have an essential role in cytokinesis. In the pnut mutant neuroepithelium, orthogonal cell divisions are successfully completed. Similarly, in the mouse, Sept7-null mutant early embryonic cells and, more importantly, planktonically growing adult hematopoietic cells undergo productive proliferation. Hence, as discussed here, mechanisms must exist that compensate for the lack of SEPT7 and the other core septins in a cell-type-specific manner. Despite there being crucial non-canonical immune-relevant functions of septins, septin depletion is well tolerated by the hematopoietic system. Thus differential targeting of cytokinesis could form the basis for more specific anti-proliferative therapies to combat malignancies arising from cell types that require septins for cytokinesis, such as carcinomas and sarcomas, without impairing hematopoiesis that is less dependent on septin.
Collapse
Affiliation(s)
- Manoj B Menon
- Institute of Physiological Chemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| | - Matthias Gaestel
- Institute of Physiological Chemistry, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany
| |
Collapse
|
48
|
The Ordospora colligata genome: Evolution of extreme reduction in microsporidia and host-to-parasite horizontal gene transfer. mBio 2015; 6:mBio.02400-14. [PMID: 25587016 PMCID: PMC4313915 DOI: 10.1128/mbio.02400-14] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
UNLABELLED Microsporidia are a group of obligate intracellular parasites that are best known for their unique infection mechanism and their unparalleled levels of genomic reduction and compaction. We sequenced the genome of Ordospora colligata, a gut parasite of the microcrustacean Daphnia sp. and the closest known relative to the microsporidia characterized by the most extreme genomic reduction, the model genus Encephalitozoon. We found that the O. colligata genome is as compact as those of Encephalitozoon spp., featuring few introns and a similar complement of about 2,000 genes, altogether showing that the extreme reduction took place before the origin of Encephalitozoon spp. and their adaptation to vertebrate hosts. We also found that the O. colligata genome has acquired by horizontal transfer from its animal host a septin that is structurally analogous to septin 7, a protein that plays a major role in the endocytosis-based invasion mechanism of the fungal pathogen Candida albicans. Microsporidian invasion is most often characterized by injection through a projectile tube, but microsporidia are also known to invade cells by inducing endocytosis. Given the function of septins in other systems, we hypothesize that the acquired septin could help O. colligata induce its uptake by mimicking host receptors. IMPORTANCE The smallest known eukaryotic genomes are found in members of the Encephalitozoon genus of microsporidian parasites. Their extreme compaction, however, is not characteristic of the group, whose genomes can differ by an order of magnitude. The processes and evolutionary forces that led the Encephalitozoon genomes to shed so much of their ancestral baggage are unclear. We sequenced the genome of Ordospora colligata, a parasite of the water flea Daphnia sp. and the closest known relative of Encephalitozoon species, and show that this extreme reduction predated the split between the two lineages. We also found that O. colligata has acquired a septin gene by host-to-parasite horizontal transfer and predicted that the encoded protein folds like a septin 7, which plays a major role in endocytosis. We hypothesize that this acquisition could help O. colligata parasitize its hosts by facilitating endocytic infection, a mechanism that occurs in microsporidia but that is not yet well understood.
Collapse
|
49
|
Tokhtaeva E, Capri J, Marcus EA, Whitelegge JP, Khuzakhmetova V, Bukharaeva E, Deiss-Yehiely N, Dada LA, Sachs G, Fernandez-Salas E, Vagin O. Septin dynamics are essential for exocytosis. J Biol Chem 2015; 290:5280-97. [PMID: 25575596 DOI: 10.1074/jbc.m114.616201] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Septins are a family of 14 cytoskeletal proteins that dynamically form hetero-oligomers and organize membrane microdomains for protein complexes. The previously reported interactions with SNARE proteins suggested the involvement of septins in exocytosis. However, the contradictory results of up- or down-regulation of septin-5 in various cells and mouse models or septin-4 in mice suggested either an inhibitory or a stimulatory role for these septins in exocytosis. The involvement of the ubiquitously expressed septin-2 or general septin polymerization in exocytosis has not been explored to date. Here, by nano-LC with tandem MS and immunoblot analyses of the septin-2 interactome in mouse brain, we identified not only SNARE proteins but also Munc-18-1 (stabilizes assembled SNARE complexes), N-ethylmaleimide-sensitive factor (NSF) (disassembles SNARE complexes after each membrane fusion event), and the chaperones Hsc70 and synucleins (maintain functional conformation of SNARE proteins after complex disassembly). Importantly, α-soluble NSF attachment protein (SNAP), the adaptor protein that mediates NSF binding to the SNARE complex, did not interact with septin-2, indicating that septins undergo reorganization during each exocytosis cycle. Partial depletion of septin-2 by siRNA or impairment of septin dynamics by forchlorfenuron inhibited constitutive and stimulated exocytosis of secreted and transmembrane proteins in various cell types. Forchlorfenuron impaired the interaction between SNAP-25 and its chaperone Hsc70, decreasing SNAP-25 levels in cultured neuroendocrine cells, and inhibited both spontaneous and stimulated acetylcholine secretion in mouse motor neurons. The results demonstrate a stimulatory role of septin-2 and the dynamic reorganization of septin oligomers in exocytosis.
Collapse
Affiliation(s)
- Elmira Tokhtaeva
- From the Departments of Physiology and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073
| | - Joe Capri
- The Neuropsychiatric Institute-Semel Institute, Pasarow Mass Spectrometry Laboratory, UCLA, Los Angeles, California 90024
| | - Elizabeth A Marcus
- Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073, Pediatrics, David Geffen School of Medicine at UCLA, Los Angeles, California 90095
| | - Julian P Whitelegge
- The Neuropsychiatric Institute-Semel Institute, Pasarow Mass Spectrometry Laboratory, UCLA, Los Angeles, California 90024
| | - Venera Khuzakhmetova
- Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center of the Russian Academy of Sciences, Kazan 420111, Russia, Kazan Federal University, Kazan 420008, Russia
| | - Ellya Bukharaeva
- Kazan Institute of Biochemistry and Biophysics, Kazan Scientific Center of the Russian Academy of Sciences, Kazan 420111, Russia, Kazan Federal University, Kazan 420008, Russia
| | - Nimrod Deiss-Yehiely
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, and
| | - Laura A Dada
- Division of Pulmonary and Critical Care Medicine, Feinberg School of Medicine, Northwestern University, Chicago, Illinois 60611, and
| | - George Sachs
- From the Departments of Physiology and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073
| | - Ester Fernandez-Salas
- Department of Pathology, School of Medicine, University of Michigan, Ann Arbor, Michigan 48109
| | - Olga Vagin
- From the Departments of Physiology and Veterans Affairs Greater Los Angeles Healthcare System, Los Angeles, California 90073,
| |
Collapse
|
50
|
Dolat L, Hu Q, Spiliotis ET. Septin functions in organ system physiology and pathology. Biol Chem 2014; 395:123-41. [PMID: 24114910 DOI: 10.1515/hsz-2013-0233] [Citation(s) in RCA: 116] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2013] [Accepted: 10/08/2013] [Indexed: 02/07/2023]
Abstract
Human septins comprise a family of 13 genes that encode for >30 protein isoforms with ubiquitous and tissue-specific expressions. Septins are GTP-binding proteins that assemble into higher-order oligomers and filamentous polymers, which associate with cell membranes and the cytoskeleton. In the last decade, much progress has been made in understanding the biochemical properties and cell biological functions of septins. In parallel, a growing number of studies show that septins play important roles for the development and physiology of specific tissues and organs. Here, we review the expression and function of septins in the cardiovascular, immune, nervous, urinary, digestive, respiratory, endocrine, reproductive, and integumentary organ systems. Furthermore, we discuss how the tissue-specific functions of septins relate to the pathology of human diseases that arise from aberrations in septin expression.
Collapse
|