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Putar D, Čizmar A, Chao X, Šimić M, Šoštar M, Ćutić T, Mijanović L, Smolko A, Tu H, Cosson P, Weber I, Cai H, Filić V. IqgC is a potent regulator of macropinocytosis in the presence of NF1 and its loading to macropinosomes is dependent on RasG. Open Biol 2024; 14:230372. [PMID: 38263885 PMCID: PMC10806400 DOI: 10.1098/rsob.230372] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Accepted: 11/26/2023] [Indexed: 01/25/2024] Open
Abstract
RasG is a major regulator of macropinocytosis in Dictyostelium discoideum. Its activity is under the control of an IQGAP-related protein, IqgC, which acts as a RasG-specific GAP (GTPase activating protein). IqgC colocalizes with the active Ras at the macropinosome membrane during its formation and for some time after the cup closure. However, the loss of IqgC induces only a minor enhancement of fluid uptake in axenic cells that already lack another RasGAP, NF1. Here, we show that IqgC plays an important role in the regulation of macropinocytosis in the presence of NF1 by restricting the size of macropinosomes. We further provide evidence that interaction with RasG is indispensable for the recruitment of IqgC to forming macropinocytic cups. We also demonstrate that IqgC interacts with another small GTPase from the Ras superfamily, Rab5A, but is not a GAP for Rab5A. Since mammalian Rab5 plays a key role in early endosome maturation, we hypothesized that IqgC could be involved in macropinosome maturation via its interaction with Rab5A. Although an excessive amount of Rab5A reduces the RasGAP activity of IqgC in vitro and correlates with IqgC dissociation from endosomes in vivo, the physiological significance of the Rab5A-IqgC interaction remains elusive.
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Affiliation(s)
- Darija Putar
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Anja Čizmar
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Xiaoting Chao
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China
- College of Life Sciences, University of Chinese Academy of Sciences, 100049 Beijing, People's Republic of China
| | - Marija Šimić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Marko Šoštar
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Tamara Ćutić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Lucija Mijanović
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Ana Smolko
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Hui Tu
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China
- College of Life Sciences, University of Chinese Academy of Sciences, 100049 Beijing, People's Republic of China
| | - Pierre Cosson
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Igor Weber
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
| | - Huaqing Cai
- National Laboratory of Biomacromolecules, Institute of Biophysics, Chinese Academy of Sciences, 100101 Beijing, People's Republic of China
- College of Life Sciences, University of Chinese Academy of Sciences, 100049 Beijing, People's Republic of China
| | - Vedrana Filić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia
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Matovina M, Tomašić Paić A, Tomić S, Brkić H, Horvat L, Barbarić L, Filić V, Pinterić M, Jurić S, Kussayeva A. Identification of SH2 Domain-Containing Protein 3C as a Novel, Putative Interactor of Dipeptidyl Peptidase 3. Int J Mol Sci 2023; 24:14178. [PMID: 37762480 PMCID: PMC10532290 DOI: 10.3390/ijms241814178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 09/11/2023] [Accepted: 09/12/2023] [Indexed: 09/29/2023] Open
Abstract
Dipeptidyl peptidase 3 (DPP3) is a zinc-dependent exopeptidase with broad specificity for four to eight amino acid residue substrates. It has a role in the regulation of oxidative stress response NRF2-KEAP1 pathway through the interaction with KEAP1. We have conducted stable isotope labeling by amino acids in a cell culture coupled to mass spectrometry (SILAC-MS) interactome analysis of TRex HEK293T cells using DPP3 as bait and identified SH2 Domain-Containing Protein 3C (SH2D3C) as prey. SH2D3C is one of three members of a family of proteins that contain both the SH2 domain and a domain similar to guanine nucleotide exchange factor domains of Ras family GTPases (Ras GEF-like domain), named novel SH2-containing proteins (NSP). NSPs, including SH2D3C (NSP3), are adaptor proteins involved in the regulation of adhesion, migration, tissue organization, and immune response. We have shown that SH2D3C binds to DPP3 through its C-terminal Ras GEF-like domain, detected the colocalization of the proteins in living cells, and confirmed direct interaction in the cytosol and membrane ruffles. Computational analysis also confirmed the binding of the C-terminal domain of SH2D3C to DPP3, but the exact model could not be discerned. This is the first indication that DPP3 and SH2D3C are interacting partners, and further studies to elucidate the physiological significance of this interaction are on the way.
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Affiliation(s)
- Mihaela Matovina
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (A.T.P.); (S.T.); (L.B.); (S.J.); (A.K.)
| | - Ana Tomašić Paić
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (A.T.P.); (S.T.); (L.B.); (S.J.); (A.K.)
| | - Sanja Tomić
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (A.T.P.); (S.T.); (L.B.); (S.J.); (A.K.)
| | - Hrvoje Brkić
- Faculty of Medicine, Josip Juraj Strossmayer University of Osijek, 31000 Osijek, Croatia;
| | - Lucija Horvat
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (L.H.); (V.F.)
| | - Lea Barbarić
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (A.T.P.); (S.T.); (L.B.); (S.J.); (A.K.)
| | - Vedrana Filić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (L.H.); (V.F.)
| | - Marija Pinterić
- Division of Molecular Medicine, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia;
| | - Snježana Jurić
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (A.T.P.); (S.T.); (L.B.); (S.J.); (A.K.)
| | - Akmaral Kussayeva
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička Cesta 54, 10000 Zagreb, Croatia; (A.T.P.); (S.T.); (L.B.); (S.J.); (A.K.)
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Filić V, Weber I. Rho GTPases in Model Systems. Cells 2023; 12:cells12050779. [PMID: 36899915 PMCID: PMC10000384 DOI: 10.3390/cells12050779] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 02/27/2023] [Indexed: 03/05/2023] Open
Abstract
Since the discovery of their role in the regulation of actin cytoskeleton 30 years ago, Rho GTPases have taken center stage in cell motility research [...].
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Skelin J, Đukić A, Filić V, Hufbauer M, Akgül B, Thomas M, Banks L, Tomaić V. MAML1-induced HPV E6 oncoprotein stability is required for cellular proliferation and migration of cervical tumor-derived cells. J Med Virol 2023; 95:e28624. [PMID: 36852660 DOI: 10.1002/jmv.28624] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 02/17/2023] [Accepted: 02/24/2023] [Indexed: 03/01/2023]
Abstract
While a small proportion of high-risk (HR) alpha (α) Human Papillomaviruses (HPVs) is associated with numerous human malignancies, of which cervical cancer is the most prevalent, beta (β) HPVs predominantly act as co-factors in skin carcinogenesis. A characteristic feature of both α- and β-E6 oncoproteins is the presence of the LXXLL binding motif, which α-E6s utilize to form a complex with E6AP and which enables β-E6s to interact with MAML1. Here we show that multiple α-E6 oncoproteins bind to MAML1 via the LXXLL binding motif and that this results in increased protein stability. Moreover, β-E6 oncoprotein stability is also dependent on the interaction with MAML1. Additionally, in the absence of MAML1, endogenous HPV-8 E6 and HPV-18 E6 are rapidly degraded at the proteasome. Ablation of both E6AP and MAML1 leads to an even more profound down-regulation of α-E6 protein expression, whereas this is not observed with β-E6. This highly suggests that there is one cellular pool for most of β-E6 that interacts solely with MAML1, whereas there are two cellular pools of HR α-E6, one forming a complex with MAML1 and the other interacting with E6AP. Furthermore, MAML1 induces HPV-8 E6 shuttling from the nucleus to the cytosolic fraction, while MAML1 interaction with HR E6 induces a drastic nuclear and membrane upregulation of E6. Interestingly, the HR α-E6 /MAML1 complex does not affect targeting of some of the known HR E6 cellular substrates such as p53 and DLG1. However, MAML1 and E6AP joint co-expression with HR α-E6 leads to a significant increase in cellular proliferation, whereas silencing MAML1 decreases wound closure in HeLa cells. These results demonstrate that HR α-E6 interaction with MAML1 results in a stable form of E6, which likely modulates MAML1's normal cellular activities, one consequence of which being an increased proliferative capacity of HPV-transformed cancer cells. Thus, this study shows a novel function of the α-E6 oncoprotein and how it's activity might affect HPV-induced pathogenesis. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Josipa Skelin
- Division of Molecular Medicine, Ruđer Bošković Institute, Bijenička cesta 54, 10000, Zagreb, Croatia
| | - Anamaria Đukić
- Division of Molecular Medicine, Ruđer Bošković Institute, Bijenička cesta 54, 10000, Zagreb, Croatia
| | - Vedrana Filić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička cesta 54, 10000, Zagreb, Croatia
| | - Martin Hufbauer
- Institute of Virology, University of Cologne, Medical Faculty and University Hospital Cologne, Fürst-Pückler-Str. 56, 50935, Cologne, Germany
| | - Baki Akgül
- Institute of Virology, University of Cologne, Medical Faculty and University Hospital Cologne, Fürst-Pückler-Str. 56, 50935, Cologne, Germany
| | - Miranda Thomas
- International Centre for Genetic Engineering and Biotechnology, AREA Science Park, Padriciano 99, I-34149, Trieste, Italy
| | - Lawrence Banks
- International Centre for Genetic Engineering and Biotechnology, AREA Science Park, Padriciano 99, I-34149, Trieste, Italy
| | - Vjekoslav Tomaić
- Division of Molecular Medicine, Ruđer Bošković Institute, Bijenička cesta 54, 10000, Zagreb, Croatia
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Filić V, Mijanović L, Putar D, Talajić A, Ćetković H, Weber I. Regulation of the Actin Cytoskeleton via Rho GTPase Signalling in Dictyostelium and Mammalian Cells: A Parallel Slalom. Cells 2021; 10:1592. [PMID: 34202767 PMCID: PMC8305917 DOI: 10.3390/cells10071592] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/16/2021] [Accepted: 06/16/2021] [Indexed: 01/15/2023] Open
Abstract
Both Dictyostelium amoebae and mammalian cells are endowed with an elaborate actin cytoskeleton that enables them to perform a multitude of tasks essential for survival. Although these organisms diverged more than a billion years ago, their cells share the capability of chemotactic migration, large-scale endocytosis, binary division effected by actomyosin contraction, and various types of adhesions to other cells and to the extracellular environment. The composition and dynamics of the transient actin-based structures that are engaged in these processes are also astonishingly similar in these evolutionary distant organisms. The question arises whether this remarkable resemblance in the cellular motility hardware is accompanied by a similar correspondence in matching software, the signalling networks that govern the assembly of the actin cytoskeleton. Small GTPases from the Rho family play pivotal roles in the control of the actin cytoskeleton dynamics. Indicatively, Dictyostelium matches mammals in the number of these proteins. We give an overview of the Rho signalling pathways that regulate the actin dynamics in Dictyostelium and compare them with similar signalling networks in mammals. We also provide a phylogeny of Rho GTPases in Amoebozoa, which shows a variability of the Rho inventories across different clades found also in Metazoa.
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Affiliation(s)
- Vedrana Filić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia; (L.M.); (D.P.); (A.T.); (H.Ć.)
| | | | | | | | | | - Igor Weber
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia; (L.M.); (D.P.); (A.T.); (H.Ć.)
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Bodinier R, Sabra A, Leiba J, Marchetti A, Lamrabet O, Ayadi I, Filić V, Kawata T, Weber I, Cosson P. Role of LrrkA in the Control of Phagocytosis and Cell Motility in Dictyostelium discoideum. Front Cell Dev Biol 2021; 9:629200. [PMID: 33763419 PMCID: PMC7982419 DOI: 10.3389/fcell.2021.629200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2020] [Accepted: 02/15/2021] [Indexed: 11/21/2022] Open
Abstract
LrrkA is a Dictyostelium discoideum kinase with leucine-rich repeats. LrrkA stimulates Kil2 and intra-phagosomal killing of ingested bacteria in response to folate. In this study, we show that genetic inactivation of lrrkA also causes a previously unnoticed phenotype: lrrkA KO cells exhibit enhanced phagocytosis and cell motility compared to parental cells. This phenotype is cell autonomous, is reversible upon re-expression of LrrkA, and is not due to an abnormal response to inhibitory quorum-sensing factors secreted by D. discoideum in its medium. In addition, folate increases motility in parental D. discoideum cells, but not in lrrkA KO cells, suggesting that LrrkA plays a pivotal role in the cellular response to folate. On the contrary, lrrkA KO cells regulate gene transcription in response to folate in a manner indistinguishable from parental cells. Overall, based on analysis of mutant phenotypes, we identify gene products that participate in the control of intracellular killing, cell motility, and gene transcription in response to folate. These observations reveal a mechanism by which D. discoideum encountering bacterially-secreted folate can migrate, engulf, and kill bacteria more efficiently.
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Affiliation(s)
- Romain Bodinier
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Ayman Sabra
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Jade Leiba
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Anna Marchetti
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Otmane Lamrabet
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Imen Ayadi
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Vedrana Filić
- Division of Molecular Biology, Ruder Boskovic Institute, Zagreb, Croatia
| | - Takefumi Kawata
- Department of Biology, Faculty of Science, Toho University, Tokyo, Japan
| | - Igor Weber
- Division of Molecular Biology, Ruder Boskovic Institute, Zagreb, Croatia
| | - Pierre Cosson
- Department of Cell Physiology and Metabolism, Faculty of Medicine, University of Geneva, Geneva, Switzerland
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Podgorski II, Pinterić M, Marčinko D, Popović Hadžija M, Filić V, Ciganek I, Pleše D, Balog T, Sobočanec S. Combination of sirtuin 3 and hyperoxia diminishes tumorigenic properties of MDA-MB-231 cells. Life Sci 2020; 254:117812. [PMID: 32428596 DOI: 10.1016/j.lfs.2020.117812] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/06/2020] [Accepted: 05/14/2020] [Indexed: 01/09/2023]
Abstract
AIMS Since the role of the major mitochondrial NAD+-dependent deacetylase, sirtuin 3 (Sirt3), is differential in cancer, opposite to the well-known tumor-suppressing effect of hyperoxia, this study aimed to investigate the role of Sirt3 in triple-negative breast cancer (TNBC) cell line MDA-MB-231 upon hyperoxic (95% O2) conditions. MAIN METHODS MDA-MB-231 cells were stably transfected with Flag-tagged Sirt-3 or empty plasmid. Western blot and real-time PCR were used to monitor the expression of proteins or genes involved in mitochondrial biogenesis, metabolic regulation and antioxidant defense. Immunocytochemistry and confocal microscopy were used to confirm the cellular localization and abundance of proteins. Flow cytometry was used to analyze mitochondrial mass, potential and ROS production, and MTT test as a measure of metabolic activity. Mitotic index analysis, colony-forming unit assay, DNA damage and Annexin V-FITC analyses were used to assess the differences in the growth and apoptosis rate. KEY FINDINGS Although Sirt3 seemed to improve mitochondrial properties by increasing mitochondrial mass and potential, metabolic activity (Warburg effect) and antioxidative defense (SOD2, Cat), it also increased mitochondrial ROS, induced DNA damage, timp-1 expression, formation of multinucleated cells and apoptosis, and finally markedly reduced the proliferation of MDA-MB-231 cells. All these effects were even more evident upon the hyperoxic treatment, thus pointing towards combined negative effect of Sirt3 and hyperoxia on MDA-MB-231 cells. SIGNIFICANCE Both Sirt3 and hyperoxia, alone or in combination, have the potential to negatively affect the malignant properties of the MDA-MB-231 cells and should be further explored as a possible therapy for TNBC.
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Affiliation(s)
- Iva I Podgorski
- Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia.
| | - Marija Pinterić
- Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia
| | - Dora Marčinko
- Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia
| | | | - Vedrana Filić
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Ivan Ciganek
- Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia
| | - Denis Pleše
- Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia
| | - Tihomir Balog
- Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia
| | - Sandra Sobočanec
- Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia
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Buljubašić M, Hlevnjak A, Repar J, Đermić D, Filić V, Weber I, Zahradka K, Zahradka D. RecBCD- RecFOR-independent pathway of homologous recombination in Escherichia coli. DNA Repair (Amst) 2019; 83:102670. [PMID: 31378505 DOI: 10.1016/j.dnarep.2019.102670] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 07/05/2019] [Accepted: 07/05/2019] [Indexed: 10/26/2022]
Abstract
The RecA protein is a key bacterial recombination enzyme that catalyzes pairing and strand exchange between homologous DNA duplexes. In Escherichia coli, RecA protein assembly on DNA is mediated either by the RecBCD or RecFOR protein complexes. Correspondingly, two recombination pathways, RecBCD and RecF (or RecFOR), are distinguished in E. coli. Inactivation of both pathways in recB(CD) recF(OR) mutants results in severe recombination deficiency. Here we describe a novel, RecBCD- RecFOR-independent (RecBFI) recombination pathway that is active in ΔrecBCD sbcB15 sbcC(D) ΔrecF(OR) mutants of E. coli. In transductional crosses, these mutants show only four-fold decrease of recombination frequency relative to the wild-type strain. At the same time they recombine 40- to 90-fold better than their sbcB+ sbcC+ and ΔsbcB sbcC counterparts. The RecBFI pathway strongly depends on recA, recJ and recQ gene functions, and moderately depends on recG and lexA functions. Inactivation of dinI, helD, recX, recN, radA, ruvABC and uvrD genes has a slight effect on RecBFI recombination. After exposure to UV and gamma irradiation, the ΔrecBCD sbcB15 sbcC ΔrecF mutants show moderately increased DNA repair proficiency relative to their sbcB+ sbcC+ and ΔsbcB sbcC counterparts. However, introduction of recA730 allele (encoding RecA protein with enhanced DNA binding properties) completely restores repair proficiency to ΔrecBCD sbcB15 sbcC ΔrecF mutants, but not to their sbcB+ sbcC+ and ΔsbcB sbcC derivatives. Fluorescence microscopy with UV-irradiated recA-gfp fusion mutants suggests that the kinetics of RecA filament formation might be slowed down in the RecBFI pathway. Inactivation of 3'-5' exonucleases ExoVII, ExoIX and ExoX cannot activate the RecBFI pathway in ΔrecBCD ΔsbcB sbcC ΔrecF mutants. Taken together, our results show that the product of the sbcB15 allele is crucial for RecBFI pathway. Besides protecting 3' overhangs, SbcB15 protein might play an additional, more active role in formation of the RecA filament.
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Affiliation(s)
- Maja Buljubašić
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Ana Hlevnjak
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Jelena Repar
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Damir Đermić
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Vedrana Filić
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Igor Weber
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Ksenija Zahradka
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Davor Zahradka
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia.
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Filić V, Marinović M, Šoštar M, Weber I. Modulation of small GTPase activity by NME proteins. J Transl Med 2018; 98:589-601. [PMID: 29434248 DOI: 10.1038/s41374-018-0023-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2017] [Revised: 12/06/2017] [Accepted: 12/29/2017] [Indexed: 12/26/2022] Open
Abstract
NME proteins are reported to influence signal transduction activity of small GTPases from the Ras superfamily by diverse mechanisms in addition to their generic NDP kinase activity, which replenishes the cytoplasmic pool of GTP. Comprehensive evidence shows that NME proteins modulate the activity of Ras GTPases, in particular members of the Rho family, via binding to their major activators GEFs. Direct interaction between several NMEs and Ras GTPases were also indicated in vitro and in vivo. These modes of regulation are mainly independent of the NME's kinase activity. NMEs also modulate the Ras-mediated signal transduction by interfering with the formation of a Ras signaling complex at the plasma membrane. In several examples, NMEs were proposed to perform the role of GAP proteins by promoting hydrolysis of the bound GTP, but this activity still requires additional verification. Early suggestions that NMEs can activate small GTPases by direct phosphorylation of the bound GDP, or by high-rate loading of GTP onto a closely apposed GTPase, were largely dismissed. In this review article, we survey and put into perspective published examples of identified and hypothetical mechanisms of Ras signaling modulation by NME proteins. We also point out involvement of NMEs in the transcriptional regulation of components of Ras GTPases-mediated signal transduction pathways, and reciprocal regulation of NME function by small GTPases, particularly related to NME's binding to membranes.
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Affiliation(s)
- Vedrana Filić
- Ruđer Bošković Institute, Division of Molecular Biology, Bijenička 54, HR-10000, Zagreb, Croatia
| | - Maja Marinović
- Ruđer Bošković Institute, Division of Molecular Biology, Bijenička 54, HR-10000, Zagreb, Croatia
| | - Marko Šoštar
- Ruđer Bošković Institute, Division of Molecular Biology, Bijenička 54, HR-10000, Zagreb, Croatia
| | - Igor Weber
- Ruđer Bošković Institute, Division of Molecular Biology, Bijenička 54, HR-10000, Zagreb, Croatia.
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Marinović M, Šoštar M, Filić V, Antolović V, Weber I. Quantitative imaging of Rac1 activity in Dictyostelium cells with a fluorescently labelled GTPase-binding domain from DPAKa kinase. Histochem Cell Biol 2016; 146:267-79. [DOI: 10.1007/s00418-016-1440-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2016] [Indexed: 02/06/2023]
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Sobočanec S, Filić V, Matovina M, Majhen D, Šafranko ŽM, Hadžija MP, Krsnik Ž, Kurilj AG, Šarić A, Abramić M, Balog T. Prominent role of exopeptidase DPP III in estrogen-mediated protection against hyperoxia in vivo. Redox Biol 2016; 8:149-59. [PMID: 26774752 PMCID: PMC4732022 DOI: 10.1016/j.redox.2016.01.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2015] [Revised: 01/05/2016] [Accepted: 01/08/2016] [Indexed: 02/07/2023] Open
Abstract
A number of age-related diseases have a low incidence in females, which is attributed to a protective effect of sex hormones. For instance, the female sex hormone estrogen (E2) has a well established cytoprotective effect against oxidative stress, which strongly contributes to ageing. However, the mechanism by which E2 exerts its protective activity remains elusive. In this study we address the question whether the E2-induced protective effect against hyperoxia is mediated by the Nrf-2/Keap-1 signaling pathway. In particular, we investigate the E2-induced expression and cellular distribution of DPP III monozinc exopeptidase, a member of the Nrf-2/Keap-1 pathway, upon hyperoxia treatment. We find that DPP III accumulates in the nucleus in response to hyperoxia. Further, we show that combined induction of hyperoxia and E2 administration have an additive effect on the nuclear accumulation of DPP III. The level of nuclear accumulation of DPP III is comparable to nuclear accumulation of Nrf-2 in healthy female mice exposed to hyperoxia. In ovariectomized females exposed to hyperoxia, supplementation of E2 induced upregulation of DPP III, Ho-1, Sirt-1 and downregulation of Ppar-γ. While other cytoprotective mechanisms cannot be excluded, these findings demonstrate a prominent role of DPP III, along with Sirt-1, in the E2-mediated protection against hyperoxia. DPP III accumulates in the nucleus in response to hyperoxia. Additive effect of hyperoxia and E2 on nuclear accumulation of DPP III is observed. Protective effect of E2 is associated with increased DPP III, Ho-1 and Sirt-1.
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Affiliation(s)
- Sandra Sobočanec
- Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia.
| | - Vedrana Filić
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | - Mihaela Matovina
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Zagreb, Croatia
| | - Dragomira Majhen
- Division of Molecular Biology, Ruđer Bošković Institute, Zagreb, Croatia
| | | | | | - Željka Krsnik
- Croatian Institute for Brain Research, University of Zagreb School of Medicine, Zagreb, Croatia
| | - Andrea Gudan Kurilj
- Department of Veterinary Pathology, Faculty of Veterinary Medicine, University of Zagreb, Zagreb, Croatia
| | - Ana Šarić
- Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia
| | - Marija Abramić
- Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Zagreb, Croatia
| | - Tihomir Balog
- Division of Molecular Medicine, Ruđer Bošković Institute, Zagreb, Croatia
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Antolović V, Marinović M, Filić V, Weber I. A simple optical configuration for cell tracking by dark-field microscopy. J Microbiol Methods 2014; 104:9-11. [PMID: 24950007 DOI: 10.1016/j.mimet.2014.06.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2014] [Revised: 06/04/2014] [Accepted: 06/04/2014] [Indexed: 10/25/2022]
Abstract
We describe a simple optical configuration for dark-field microscopy at low magnification, realized with the use of standard microscope components. An inherent high contrast makes this method attractive for computer-assisted tracking and counting of microorganisms. We applied this setup for dark-field microscopy to measure the speed of migrating Dictyostelium amoebae.
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Affiliation(s)
- Vlatka Antolović
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia.
| | - Maja Marinović
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia.
| | - Vedrana Filić
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia.
| | - Igor Weber
- Division of Molecular Biology, Ruđer Bošković Institute, Bijenička 54, HR-10000 Zagreb, Croatia.
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13
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Filić V, Marinović M, Faix J, Weber I. The IQGAP-related protein DGAP1 mediates signaling to the actin cytoskeleton as an effector and a sequestrator of Rac1 GTPases. Cell Mol Life Sci 2014; 71:2775-85. [DOI: 10.1007/s00018-014-1606-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2013] [Revised: 02/26/2014] [Accepted: 03/10/2014] [Indexed: 11/24/2022]
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14
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Abstract
Rac proteins are the only canonical Rho family GTPases in Dictyostelium, where they act as key regulators of the actin cytoskeleton. To monitor the dynamics of activated Rac1 in Dictyostelium cells, a fluorescent probe was developed that specifically binds to the GTP-bound form of Rac1. The probe is based on the GTPase-binding domain (GBD) from PAK1 kinase, and was selected on the basis of yeast two-hybrid, GST pull-down and fluorescence resonance energy transfer assays. The PAK1 GBD localizes to leading edges of migrating cells and to endocytotic cups. Similarly to its role in vertebrates, activated Rac1 therefore appears to control de novo actin polymerization at protruding regions of the Dictyostelium cell. Additionally, we found that the IQGAP-related protein DGAP1, which sequesters active Rac1 into a quaternary complex with actin-binding proteins cortexillin I and cortexillin II, localizes to the trailing regions of migrating cells. Notably, PAK1 GBD and DGAP1, which both bind to Rac1-GTP, display mutually exclusive localizations in cell migration, phagocytosis and cytokinesis, and opposite dynamics of recruitment to the cell cortex upon stimulation with chemoattractants. Moreover, cortical localization of the PAK1 GBD depends on the integrity of the actin cytoskeleton, whereas cortical localization of DGAP1 does not. Taken together, these results imply that Rac1 GTPases play a dual role in regulation of cell motility and polarity in Dictyostelium.
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Affiliation(s)
- Vedrana Filić
- Ruder Bošković Institute, Division of Molecular Biology, Bijenička 54, HR-10000 Zagreb, Croatia
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15
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Jelicić B, Traven A, Filić V, Sopta M. Mitochondrial dysfunction enhances Gal4-dependent transcription. FEMS Microbiol Lett 2005; 253:207-13. [PMID: 16239078 DOI: 10.1016/j.femsle.2005.09.033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2005] [Revised: 09/20/2005] [Accepted: 09/23/2005] [Indexed: 11/23/2022] Open
Abstract
Mitochondrial dysfunction has been shown to elicit broad effects on nuclear gene expression. We show here that transcription dependent on the prototypical acidic activator Gal4 is responsive to mitochondrial dysfunction. In cells with no mitochondrial DNA, Gal4-dependent gene expression is elevated. A minimal Gal4 activator containing the DNA binding and activation domain is sufficient for this response. Transcription dependent on a fusion of Gal4 to a heterologous DNA binding domain is similarly elevated in a mitochondrial mutant. Analysis of different Gal4-dependent promoters and gel mobility shift assays suggest that the effect of mitochondrial dysfunction on Gal4 activity is related to increased DNA binding to the cognate Gal4 element. Given that fermentation is the only means to obtain energy in respiratory deficient cells, it is possible that higher Gal4 activity in cells with dysfunctional mitochondria works to promote more efficient fermentation of galactose.
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Affiliation(s)
- Branka Jelicić
- Department of Molecular Biology, Ruder Bosković Institute, Bijenicka 54, 10000 Zagreb, Croatia
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