Two splice variants of Golgi-microtubule-associated protein of 210 kDa (GMAP-210) differ in their binding to the cis-Golgi network

2001 ◽  
Vol 357 (3) ◽  
pp. 699-708 ◽  
Author(s):  
Francisco RAMOS-MORALES ◽  
Carmen VIME ◽  
Michel BORNENS ◽  
Concepción FEDRIANI ◽  
Rosa M. RIOS
Keyword(s):  
Golgi Apparatus ◽  
Structural Integrity ◽  
Fluorescent Protein ◽  
Genomic Sequence ◽  
Splice Variants ◽  
Microtubule Network ◽  
Terminal Domain ◽  
Golgi Network

GMAP-210 (Golgi-microtubule-associated protein of 210kDa) is a peripheral Golgi protein that interacts with the minus end of microtubules through its C-terminus and with cis-Golgi network membranes through its N-terminus; it participates in the maintenance of the structural integrity of the Golgi apparatus [Infante, Ramos-Morales, Fedriani, Bornens and Rios (1999) J. Cell Biol. 145, 83–98]. We report here the cloning of a new isoform of GMAP-210 that lacks amino acid residues 105–196. On the basis of the analysis of the gmap-210 genomic sequence, we propose that the small isoform, GMAP-200, arises from alternative splicing of exon 4 of the primary transcript. Overexpression of GMAP-200 induces perturbations in both the Golgi apparatus and the microtubule network that are similar to those previously reported for GMAP-210 overexpression. We show that both isoforms are able to oligomerize under overexpression conditions. Analysis in vitro and in vivo, with the green fluorescent protein as a marker, reveals that the binding of the N-terminal domain of GMAP-200 to the cis-Golgi network membranes is lower than that of the N-terminal domain of GMAP-210. Implications for the regulation of interaction between the cis-Golgi network and microtubules are discussed.

scholarly journals GMAP-210, A Cis-Golgi Network-associated Protein, Is a Minus End Microtubule-binding Protein

1999 ◽  
Vol 145 (1) ◽  
pp. 83-98 ◽  
Author(s):  
Carlos Infante ◽  
Francisco Ramos-Morales ◽  
Concepción Fedriani ◽  
Michel Bornens ◽  
Rosa M. Rios
Keyword(s):  
Golgi Apparatus ◽  
Fluorescent Protein ◽  
Binding Protein ◽  
Coiled Coil ◽  
Microtubule Network ◽  
Microtubule Binding ◽  
Terminal Domain ◽  
Green Fluorescent ◽  
Golgi Network

We report that a peripheral Golgi protein with a molecular mass of 210 kD localized at the cis-Golgi network (Rios, R.M., A.M. Tassin, C. Celati, C. Antony, M.C. Boissier, J.C. Homberg, and M. Bornens. 1994. J. Cell Biol. 125:997–1013) is a microtubule-binding protein that associates in situ with a subpopulation of stable microtubules. Interaction of this protein, now called GMAP-210, for Golgi microtubule-associated protein 210, with microtubules in vitro is direct, tight and nucleotide-independent. Biochemical analysis further suggests that GMAP-210 specifically binds to microtubule ends. The full-length cDNA encoding GMAP-210 predicts a protein of 1,979 amino acids with a very long central coiled-coil domain. Deletion analyses in vitro show that the COOH terminus of GMAP-210 binds to microtubules whereas the NH2 terminus binds to Golgi membranes. Overexpression of GMAP-210–encoding cDNA induced a dramatic enlargement of the Golgi apparatus and perturbations in the microtubule network. These effects did not occur when a mutant lacking the COOH-terminal domain was expressed. When transfected in fusion with the green fluorescent protein, the NH2-terminal domain associated with the cis-Golgi network whereas the COOH-terminal microtubule-binding domain localized at the centrosome. Altogether these data support the view that GMAP-210 serves to link the cis-Golgi network to the minus ends of centrosome-nucleated microtubules. In addition, this interaction appears essential for ensuring the proper morphology and size of the Golgi apparatus.

scholarly journals Divergent functions and distinct localization of the Notch ligands DLL1 and DLL3 in vivo

2007 ◽  
Vol 178 (3) ◽  
pp. 465-476 ◽  
Author(s):  
Insa Geffers ◽  
Katrin Serth ◽  
Gavin Chapman ◽  
Robert Jaekel ◽  
Karin Schuster-Gossler ◽  
...  
Keyword(s):  
Golgi Apparatus ◽  
Mouse Embryos ◽  
Functional Equivalence ◽  
Presomitic Mesoderm ◽  
Drosophila Wing ◽  
Wing Discs ◽  
Golgi Network ◽  
Notch Ligands

The Notch ligands Dll1 and Dll3 are coexpressed in the presomitic mesoderm of mouse embryos. Despite their coexpression, mutations in Dll1 and Dll3 cause strikingly different defects. To determine if there is any functional equivalence, we replaced Dll1 with Dll3 in mice. Dll3 does not compensate for Dll1; DLL1 activates Notch in Drosophila wing discs, but DLL3 does not. We do not observe evidence for antagonism between DLL1 and DLL3, or repression of Notch activity in mice or Drosophila. In vitro analyses show that differences in various domains of DLL1 and DLL3 individually contribute to their biochemical nonequivalence. In contrast to endogenous DLL1 located on the surface of presomitic mesoderm cells, we find endogenous DLL3 predominantly in the Golgi apparatus. Our data demonstrate distinct in vivo functions for DLL1 and DLL3. They suggest that DLL3 does not antagonize DLL1 in the presomitic mesoderm and warrant further analyses of potential physiological functions of DLL3 in the Golgi network.

scholarly journals Requirement for the E1 Helicase C-Terminal Domain in Papillomavirus DNA ReplicationIn Vivo

2016 ◽  
Vol 90 (6) ◽  
pp. 3198-3211 ◽  
Author(s):  
Monika Bergvall ◽  
David Gagnon ◽  
Steve Titolo ◽  
Michaël Lehoux ◽  
Claudia M. D'Abramo ◽  
...  
Keyword(s):  
Dna Replication ◽  
Structural Integrity ◽  
Alpha Helix ◽  
Helicase Domain ◽  
Atp Binding Site ◽  
Terminal Domain ◽  
Replication Activity

ABSTRACTThe papillomavirus (PV) E1 helicase contains a conserved C-terminal domain (CTD), located next to its ATP-binding site, whose functionin vivois still poorly understood. The CTD is comprised of an alpha helix followed by an acidic region (AR) and a C-terminal extension termed the C-tail. Recent biochemical studies on bovine papillomavirus 1 (BPV1) E1 showed that the AR and C-tail regulate the oligomerization of the protein into a double hexamer at the origin. In this study, we assessed the importance of the CTD of human papillomavirus 11 (HPV11) E1in vivo, using a cell-based DNA replication assay. Our results indicate that combined deletion of the AR and C-tail drastically reduces DNA replication, by 85%, and that further truncation into the alpha-helical region compromises the structural integrity of the E1 helicase domain and its interaction with E2. Surprisingly, removal of the C-tail alone or mutation of highly conserved residues within the domain still allows significant levels of DNA replication (55%). This is in contrast to the absolute requirement for the C-tail reported for BPV1 E1in vitroand confirmed herein vivo. Characterization of chimeric proteins in which the AR and C-tail from HPV11 E1 were replaced by those of BPV1 indicated that while the function of the AR is transferable, that of the C-tail is not. Collectively, these findings define the contribution of the three CTD subdomains to the DNA replication activity of E1in vivoand suggest that the function of the C-tail has evolved in a PV type-specific manner.IMPORTANCEWhile much is known about hexameric DNA helicases from superfamily 3, the papillomavirus E1 helicase contains a unique C-terminal domain (CTD) adjacent to its ATP-binding site. We show here that this CTD is important for the DNA replication activity of HPV11 E1in vivoand that it can be divided into three functional subdomains that roughly correspond to the three conserved regions of the CTD: an alpha helix, needed for the structural integrity of the helicase domain, followed by an acidic region (AR) and a C-terminal tail (C-tail) that have been shown to regulate the oligomerization of BPV1 E1in vitro. Characterization of E1 chimeras revealed that, while the function of the AR could be transferred from BPV1 E1 to HPV11 E1, that of the C-tail could not. These results suggest that the E1 CTD performs multiple functions in DNA replication, some of them in a virus type-specific manner.

The stathmin phosphoprotein family: intracellular localization and effects on the microtubule network

1998 ◽  
Vol 111 (22) ◽  
pp. 3333-3346 ◽  
Author(s):  
O. Gavet ◽  
S. Ozon ◽  
V. Manceau ◽  
S. Lawler ◽  
P. Curmi ◽  
...  
Keyword(s):  
Mitotic Spindle ◽  
Intracellular Signaling ◽  
Splice Variants ◽  
Intracellular Localization ◽  
Phosphorylation Site ◽  
Dependent Manner ◽  
Microtubule Depolymerization ◽  
Microtubule Network

Stathmin is a small regulatory phosphoprotein integrating diverse intracellular signaling pathways. It is also the generic element of a protein family including the neural proteins SCG10, SCLIP, RB3 and its two splice variants RB3′ and RB3″. Stathmin itself was shown to interact in vitro with tubulin in a phosphorylation-dependent manner, sequestering free tubulin and hence promoting microtubule depolymerization. We investigated the intracellular distribution and tubulin depolymerizing activity in vivo of all known members of the stathmin family. Whereas stathmin is not associated with interphase microtubules in HeLa cells, a fraction of it is concentrated at the mitotic spindle. We generated antisera specific for stathmin phosphoforms, which allowed us to visualize the regulation of phosphorylation-dephosphorylation during the successive stages of mitosis, and the partial localization of stathmin phosphorylated on serine 16 at the mitotic spindle. Results from overexpression experiments of wild-type and novel phosphorylation site mutants of stathmin further suggest that it induces depolymerization of interphase and mitotic microtubules in its unphosphorylated state but is inactivated by phosphorylation in mitosis. Phosphorylation of mutants 16A25A and 38A63A on sites 38 and 63 or 16 and 25, respectively, was sufficient for the formation of a functional spindle, whereas mutant 16A25A38A63E retained a microtubule depolymerizing activity. Transient expression of each of the neural phosphoproteins of the stathmin family showed that they are at least partially associated to the Golgi apparatus and not to other major membrane compartments, probably through their different NH2-terminal domains, as described for SCG10. Most importantly, like stathmin and SCG10, overexpressed SCLIP, RB3 and RB3″ were able to depolymerize interphase microtubules. Altogether, our results demonstrate in vivo the functional conservation of the stathmin domain within each protein of the stathmin family, with a microtubule destabilizing activity most likely essential for their specific biological function(s).

scholarly journals A New Focal Adhesion Protein That Interacts with Integrin-Linked Kinase and Regulates Cell Adhesion and Spreading

2001 ◽  
Vol 153 (3) ◽  
pp. 585-598 ◽  
Author(s):  
Yizeng Tu ◽  
Yao Huang ◽  
Yongjun Zhang ◽  
Yun Hua ◽  
Chuanyue Wu
Keyword(s):  
Cell Adhesion ◽  
Focal Adhesion ◽  
Fluorescent Protein ◽  
Cytoskeleton Organization ◽  
Terminal Domain ◽  
Integrin Linked Kinase ◽  
Ch2 Domain ◽  
Green Fluorescent

Integrin-linked kinase (ILK) is a multidomain focal adhesion (FA) protein that functions as an important regulator of integrin-mediated processes. We report here the identification and characterization of a new calponin homology (CH) domain-containing ILK-binding protein (CH-ILKBP). CH-ILKBP is widely expressed and highly conserved among different organisms from nematodes to human. CH-ILKBP interacts with ILK in vitro and in vivo, and the ILK COOH-terminal domain and the CH-ILKBP CH2 domain mediate the interaction. CH-ILKBP, ILK, and PINCH, a FA protein that binds the NH2-terminal domain of ILK, form a complex in cells. Using multiple approaches (epitope-tagged CH-ILKBP, monoclonal anti–CH-ILKBP antibodies, and green fluorescent protein–CH-ILKBP), we demonstrate that CH-ILKBP localizes to FAs and associates with the cytoskeleton. Deletion of the ILK-binding CH2 domain abolished the ability of CH-ILKBP to localize to FAs. Furthermore, the CH2 domain alone is sufficient for FA targeting, and a point mutation that inhibits the ILK-binding impaired the FA localization of CH-ILKBP. Thus, the CH2 domain, through its interaction with ILK, mediates the FA localization of CH-ILKBP. Finally, we show that overexpression of the ILK-binding CH2 fragment or the ILK-binding defective point mutant inhibited cell adhesion and spreading. These findings reveal a novel CH-ILKBP–ILK–PINCH complex and provide important evidence for a crucial role of this complex in the regulation of cell adhesion and cytoskeleton organization.

scholarly journals A microtubule-binding protein associated with membranes of the Golgi apparatus.

1986 ◽  
Vol 103 (6) ◽  
pp. 2229-2239 ◽  
Author(s):  
V J Allan ◽  
T E Kreis
Keyword(s):  
Golgi Apparatus ◽  
Culture Cell ◽  
Proteinase K ◽  
Microtubule Network ◽  
Microtubule Binding ◽  
Golgi Stack ◽  
Cell Extracts ◽  
Triton X

A monoclonal antibody (M3A5), raised against microtubule-associated protein 2 (MAP-2), recognized an antigen associated with the Golgi complex in a variety of non-neuronal tissue culture cells. In double immunofluorescence studies M3A5 staining was very similar to that of specific Golgi markers, even after disruption of the Golgi apparatus organization with monensin or nocodazole. M3A5 recognized one band of Mr approximately 110,000 in immunoblots of culture cell extracts; this protein, designated 110K, was enriched in Golgi stack fractions prepared from rat liver. The 110K protein has been shown to partition into the aqueous phase by Triton X-114 extraction of a Golgi-enriched fraction and was eluted after pH 11.0 carbonate washing. It is therefore likely to be a peripheral membrane protein. Proteinase K treatment of an isolated Golgi stack fraction resulted in complete digestion of the 110K protein, both in the presence and absence of Triton X-100. A the 110K protein is accessible to protease in intact vesicles in vitro, it is presumably located on the cytoplasmic face of the Golgi membrane in vivo. The 110K protein was able to interact specifically with taxol-polymerized microtubules in vitro. These results suggest that the 110K protein may serve to link the Golgi apparatus to the microtubule network and so may belong to a novel class of proteins: the microtubule-binding proteins.

scholarly journals Characterization and Application of a Glucose-Repressible Promoter in Francisella tularensis

2008 ◽  
Vol 74 (7) ◽  
pp. 2161-2170 ◽  
Author(s):  
Joseph Horzempa ◽  
Deanna M. Tarwacki ◽  
Paul E. Carlson ◽  
Cory M. Robinson ◽  
Gerard J. Nau
Keyword(s):  
Gene Expression ◽  
Francisella Tularensis ◽  
Gene Function ◽  
Fluorescent Protein ◽  
Genomic Sequence ◽  
Protein A ◽  
Hypothetical Protein ◽  
Protein Levels

ABSTRACT Francisella tularensis, the causative agent of tularemia, is a category A biodefense agent. The examination of gene function in this organism is limited due to the lack of available controllable promoters. Here, we identify a promoter element of F. tularensis LVS that is repressed by glucose (termed the Francisella glucose-repressible promoter, or FGRp), allowing the management of downstream gene expression. In bacteria cultured in medium lacking glucose, this promoter induced the expression of a red fluorescent protein allele, tdtomato. FGRp activity was used to produce antisense RNA of iglC, an important virulence factor, which severely reduced IglC protein levels. Cultivation in glucose-containing medium restored IglC levels, indicating the usefulness of this promoter for controlling both exogenous and chromosomal gene expression. Moreover, FGRp was shown to be active during the infection of human macrophages by using the fluorescence reporter. In this environment, the FGRp-mediated expression of antisense iglC by F. tularensis LVS resulted in reduced bacterial fitness, demonstrating the applicability of this promoter. An analysis of the genomic sequence indicated that this promoter region controls a gene, FTL_0580, encoding a hypothetical protein. A deletion analysis determined the critical sites essential for FGRp activity to be located within a 44-bp region. This is the first report of a conditional promoter and the use of antisense constructs in F. tularensis, valuable genetic tools for studying gene function both in vitro and in vivo.

scholarly journals Development of a Fluorescent Tool for Studying Legionella bozemanae Intracellular Infection

2021 ◽  
Vol 9 (2) ◽  
pp. 379
Author(s):  
Breanne M. Head ◽  
Christopher I. Graham ◽  
Teassa MacMartin ◽  
Yoav Keynan ◽  
Ann Karen C. Brassinga
Keyword(s):  
Growth Kinetics ◽  
Legionella Pneumophila ◽  
Fluorescent Protein ◽  
Disease Incidence ◽  
Acanthamoeba Castellanii ◽  
Infection Model ◽  
Intracellular Infection ◽  
Green Fluorescent

Legionnaires’ disease incidence is on the rise, with the majority of cases attributed to the intracellular pathogen, Legionella pneumophila. Nominally a parasite of protozoa, L. pneumophila can also infect alveolar macrophages when bacteria-laden aerosols enter the lungs of immunocompromised individuals. L. pneumophila pathogenesis has been well characterized; however, little is known about the >25 different Legionella spp. that can cause disease in humans. Here, we report for the first time a study demonstrating the intracellular infection of an L. bozemanae clinical isolate using approaches previously established for L. pneumophila investigations. Specifically, we report on the modification and use of a green fluorescent protein (GFP)-expressing plasmid as a tool to monitor the L. bozemanae presence in the Acanthamoeba castellanii protozoan infection model. As comparative controls, L. pneumophila strains were also transformed with the GFP-expressing plasmid. In vitro and in vivo growth kinetics of the Legionella parental and GFP-expressing strains were conducted followed by confocal microscopy. Results suggest that the metabolic burden imposed by GFP expression did not impact cell viability, as growth kinetics were similar between the GFP-expressing Legionella spp. and their parental strains. This study demonstrates that the use of a GFP-expressing plasmid can serve as a viable approach for investigating Legionella non-pneumophila spp. in real time.

scholarly journals CRISPR/Cas9-based generation of a recombinant double-reporter pseudorabies virus and its characterization in vitro and in vivo

2021 ◽  
Vol 52 (1) ◽  
Author(s):  
Peng-Fei Fu ◽  
Xuan Cheng ◽  
Bing-Qian Su ◽  
Li-Fang Duan ◽  
Cong-Rong Wang ◽  
...  
Keyword(s):  
Pseudorabies Virus ◽  
Fluorescent Protein ◽  
Antiviral Agents ◽  
Firefly Luciferase ◽  
Inhibitory Effect ◽  
Economic Losses ◽  
Green Fluorescent ◽  
Swine Herds

AbstractPseudorabies, caused by pseudorabies virus (PRV) variants, has broken out among commercial PRV vaccine-immunized swine herds and resulted in major economic losses to the pig industry in China since late 2011. However, the mechanism of virulence enhancement of variant PRV is currently unclear. Here, a recombinant PRV (rPRV HN1201-EGFP-Luc) with stable expression of enhanced green fluorescent protein (EGFP) and firefly luciferase as a double reporter virus was constructed on the basis of the PRV variant HN1201 through CRISPR/Cas9 gene-editing technology coupled with two sgRNAs. The biological characteristics of the recombinant virus and its lethality to mice were similar to those of the parental strain and displayed a stable viral titre and luciferase activity through 20 passages. Moreover, bioluminescence signals were detected in mice at 12 h after rPRV HN1201-EGFP-Luc infection. Using the double reporter PRV, we also found that 25-hydroxycholesterol had a significant inhibitory effect on PRV both in vivo and in vitro. These results suggested that the double reporter PRV based on PRV variant HN1201 should be an excellent tool for basic virology studies and evaluating antiviral agents.

scholarly journals BanLec-eGFP Chimera as a Tool for Evaluation of Lectin Binding to High-Mannose Glycans on Microorganisms

Biomolecules ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 180
Author(s):  
Zorana Lopandić ◽  
Luka Dragačević ◽  
Dragan Popović ◽  
Uros Andjelković ◽  
Rajna Minić ◽  
...  
Keyword(s):  
Fluorescent Protein ◽  
Lectin Binding ◽  
Three Dimensional ◽  
Data Bank ◽  
Salmonella Typhi ◽  
Excitation Wavelength ◽  
Protein Data Bank Entry ◽  
High Mannose

Fluorescently labeled lectins are useful tools for in vivo and in vitro studies of the structure and function of tissues and various pathogens such as viruses, bacteria, and fungi. For the evaluation of high-mannose glycans present on various glycoproteins, a three-dimensional (3D) model of the chimera was designed from the crystal structures of recombinant banana lectin (BanLec, Protein Data Bank entry (PDB): 5EXG) and an enhanced green fluorescent protein (eGFP, PDB 4EUL) by applying molecular modeling and molecular mechanics and expressed in Escherichia coli. BanLec-eGFP, produced as a soluble cytosolic protein of about 42 kDa, revealed β-sheets (41%) as the predominant secondary structures, with the emission peak maximum detected at 509 nm (excitation wavelength 488 nm). More than 65% of the primary structure was confirmed by mass spectrometry. Competitive BanLec-eGFP binding to high mannose glycans of the influenza vaccine (Vaxigrip®) was shown in a fluorescence-linked lectin sorbent assay (FLLSA) with monosaccharides (mannose and glucose) and wild type BanLec and H84T BanLec mutant. BanLec-eGFP exhibited binding to mannose residues on different strains of Salmonella in flow cytometry, with especially pronounced binding to a Salmonella Typhi clinical isolate. BanLec-eGFP can be a useful tool for screening high-mannose glycosylation sites on different microorganisms.

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