scholarly journals Characterization of dominant and recessive assembly-defective mutations in mouse neurofilament NF-M.

1990 ◽  
Vol 111 (5) ◽  
pp. 1987-2003 ◽  
Author(s):  
P C Wong ◽  
D W Cleveland
Keyword(s):  
Wild Type ◽  
Carboxy Terminus ◽  
M Gene ◽  
Amino Terminal ◽  
Filament Assembly ◽  
Carboxy Terminal ◽  
Filament Network ◽  
Dominant Mutants ◽  
Amino Acid Epitope

We have generated a set of amino- and carboxy-terminal deletions of the neurofilament NF-M gene and determined the molecular consequences of forced expression of these mutant constructs in mouse fibroblasts. To follow the expression of mutant NF-M subunits in transfected cells, a 12 amino acid epitope (from the human c-myc protein) was expressed at the carboxy terminus of each mutant. We show that NF-M molecules missing up to 90 or 70% of the nonhelical carboxy-terminal tail or amino-terminal head domains, respectively, incorporate readily into an intermediate filament network comprised either of vimentin or NF-L, whereas deletions into either the amino- or carboxy-terminal alpha-helical rod region generate assembly-incompetent polypeptides. Carboxy-terminal deletions into the rod domain invariably yield dominant mutants which rapidly disrupt the array of filaments comprised of NF-L or vimentin. Accumulation of these mutant NF-M subunits disrupts vimentin filament arrays even when present at approximately 1% the level of the wild-type subunits. In contrast, the amino-terminal deletions into the rod produce pseudo-recessive mutants that perturb the wild-type NF-L or vimentin arrays only modestly. The inability of such amino-terminal mutants to disrupt wild-type subunits defines a region near the amino-terminal alpha-helical rod domain (residues 75-126) that is required for the earliest steps in filament assembly.

scholarly journals Assembly properties of dominant and recessive mutations in the small mouse neurofilament (NF-L) subunit.

1990 ◽  
Vol 111 (5) ◽  
pp. 2005-2019 ◽  
Author(s):  
S R Gill ◽  
P C Wong ◽  
M J Monteiro ◽  
D W Cleveland
Keyword(s):  
Amino Acids ◽  
Insertional Mutagenesis ◽  
Wild Type ◽  
Recessive Mutations ◽  
Filament Assembly ◽  
Head Domain ◽  
Filament Networks ◽  
Carboxy Terminal ◽  
Network Disruption ◽  
Dominant Mutants

We have generated a set of amino- and carboxy-terminal deletions of the NF-L neurofilament gene and determined the assembly properties of the encoded subunits after coexpression with vimentin or wild-type NF-L. NF-L molecules missing greater than 30% (31 amino acids of the head) or 90% (128 amino acids of the tail) failed to incorporate into intermediate filament networks. Carboxy-terminal deletions into the rod domain yield dominant mutants that disrupt arrays assembled from wild-type subunits, even when present at levels of approximately 2% of the wild-type subunits. Even mutants retaining 55% of the tail (61 amino acids) disrupt normal arrays when accumulated above approximately 10% of wild-type subunits. Since deletion of greater than 90% of the head domain produces "recessive" assembly incompetent subunits that do not affect wild-type filament arrays, whereas smaller deletions yield efficient network disruption, we conclude that some sequence(s) in the head domain (within residues 31-87) are required for the earliest steps in filament assembly. Insertional mutagenesis in the nonhelical spacer region within the rod domain reveals that as many as eight additional amino acids can be tolerated without disrupting assembly competence.

scholarly journals Characterization of Immunodominant Linear B-Cell Epitopes on the Carboxy Terminus of the Rinderpest Virus Nucleocapsid Protein

2004 ◽  
Vol 11 (4) ◽  
pp. 658-664 ◽  
Author(s):  
Kang-Seuk Choi ◽  
Jin-Ju Nah ◽  
Young-Joon Ko ◽  
Shien-Young Kang ◽  
Kyoung-Jin Yoon ◽  
...  
Keyword(s):  
Antigenic Site ◽  
Enzyme Linked Immunosorbent Assay ◽  
Carboxy Terminus ◽  
Rinderpest Virus ◽  
N Protein ◽  
Amino Terminal ◽  
Immunogenic Epitope ◽  
Carboxy Terminal ◽  
Gst Fusion Proteins

ABSTRACT The nucleocapsid (N) protein of rinderpest virus (RPV) is one of the most abundant and immunogenic viral proteins expressed during natural or experimental infection. To identify immunogenic epitopes on the N protein, different forms of RPV N protein, including the full-length protein (N1-525), an amino-terminal construct (N1-179), and a carboxy-terminal construct (N414-496), were expressed in Escherichia coli as glutathione S-transferase (GST) fusion proteins. The antigenicity of each recombinant protein was evaluated by Western immunoblotting. All recombinants were recognized by hyperimmune RPV bovine antisera, indicating that immunoreactive epitopes may be present at both ends of the N protein. However, GST-N414-496 was much more antigenic than GST-N1-179 when tested with sera from vaccinated cattle, suggesting that an immunodominant or highly immunogenic epitope(s) may be located at the carboxy terminus of the N protein. Epitope mapping with overlapping peptides representing different regions of the carboxy terminus (amino acids 415 to 524) revealed three nonoverlapping antigenic sites in regions containing the residues 440VPQVRKETRASSR452 (site 1), 479PEADTDPL486 (site 2), and 520DKDLL524 (site 3). Among these, antigenic site 2 showed the strongest reactivity with hyperimmune anti-RPV bovine sera in a peptide enzyme-linked immunosorbent assay but did not react with hyperimmune caprine sera raised against peste-des-petits-ruminants virus, which is antigenically closely related to RPV. Identification of an immunodominant linear antigenic site at the carboxy terminus of the N protein may provide an antigen basis for designing diagnostics specific for RPV.

Structural differences between repressed and derepressed forms of p60c-src

1989 ◽  
Vol 9 (6) ◽  
pp. 2648-2656
Author(s):  
A MacAuley ◽  
J A Cooper
Keyword(s):  
Kinase Activity ◽  
Kinase Domain ◽  
Terminal Region ◽  
Phosphorylation Sites ◽  
Carboxy Terminus ◽  
Kinase Activation ◽  
Amino Terminal ◽  
Structural Differences ◽  
Carboxy Terminal ◽  
Pronase E

The kinase activity of p60c-src is derepressed by removal of phosphate from Tyr-527, mutation of this residue to Phe, or binding of a carboxy-terminal antibody. We have compared the structures of repressed and active p60c-src, using proteases. All forms of p60c-src are susceptible to proteolysis at the boundary between the amino-terminal region and the kinase domain, but there are several sites elsewhere that are more sensitive to trypsin digestion in repressed than in derepressed forms of p60c-src. The carboxy-terminal tail (containing Tyr-527) is more sensitive to digestion by pronase E and thermolysin when Tyr-527 is not phosphorylated. The kinase domain fragment released with trypsin has kinase activity. Relative to intact p60c-src, the kinase domain fragment shows altered substrate specificity, diminished regulation by the phosphorylated carboxy terminus, and novel phosphorylation sites. The results identify parts of p60c-src that change conformation upon kinase activation and suggest functions for the amino-terminal region.

Expression and characterization of von Willebrand factor dimerization defects in different types of von Willebrand disease

Blood ◽  
2001 ◽  
Vol 97 (7) ◽  
pp. 2059-2066 ◽  
Author(s):  
Reinhard Schneppenheim ◽  
Ulrich Budde ◽  
Tobias Obser ◽  
Jacqueline Brassard ◽  
Kerstin Mainusch ◽  
...  
Keyword(s):  
Von Willebrand Factor ◽  
Recombinant Expression ◽  
Von Willebrand Disease ◽  
Disulfide Bonding ◽  
Amino Terminal ◽  
Carboxy Terminal ◽  
Type 3 ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Dimerization defects of von Willebrand factor (vWF) protomers underlie von Willebrand disease (vWD) type 2A, subtype IID (vWD 2A/IID), and corresponding mutations have been identified at the 3′ end of the vWF gene in exon 52. This study identified and expressed 2 additional mutations in this region, a homozygous defect in a patient with vWD type 3 (C2754W) and a heterozygous frameshift mutation (8566delC) in a patient with vWD type 2A, subtype IIE. Both mutations involve cysteine residues that we propose are possibly essential for dimerization. To prove this hypothesis, transient recombinant expression of each of the 2 mutations introduced in the carboxy-terminal vWF fragment II and in the complete vWF complementary DNA, respectively, were carried out in COS-7 cells and compared with expression of vWD 2A/IID mutation C2773R and the wild-type (WT) sequence in COS-7 cells. Recombinant WT vWF fragment II assembled correctly into a dimer, whereas recombinant mutant fragments were monomeric. Homozygous expression of recombinant mutant full-length vWF resulted in additional dimers, probably through disulfide bonding at the amino-terminal multimerization site, whereas recombinant WT vWF correctly assembled into multimers. Coexpression of recombinant mutant and recombinant WT vWF reproduced the multimer patterns observed in heterozygous individuals. Our results suggest that a common defect of vWF biosynthesis—lack of vWF dimerization—may cause diverse types and subtypes of vWD. We also confirmed previous studies that found that disulfide bonding at the vWF amino-terminal is independent of dimerization at the vWF carboxy-terminal.

scholarly journals Immunochemical Characterization of a Human Sperm Fibrous Sheath Protein, Its Developmental Expression Pattern, and Morphogenetic Relationships with Actin

1997 ◽  
Vol 45 (7) ◽  
pp. 909-922 ◽  
Author(s):  
Denise Escalier ◽  
Jean-Marc Gallo ◽  
Joseph Schrével
Keyword(s):  
Human Sperm ◽  
Developmental Expression ◽  
Immunogold Electron Microscopy ◽  
Fibrous Sheath ◽  
Protein Deposition ◽  
Amino Terminal ◽  
Sequential Extraction Procedures ◽  
Carboxy Terminal ◽  
Developmental Expression Pattern

Among the monoclonal antibodies (MAbs) prepared against human sperm extracts, MAb 4F7 was found to be specific to the human and Macaca fascicularis sperm cytoskeletal fibrous sheath (FS). In Western blotting, MAb 4F7 stains a doublet of polypeptides of about Mr 95 × 103 in extracts of human sperm cells. These polypeptides are not recognized by the KL1 anti-cytokeratin MAb, nor by the MAbs known to bind to the carboxy terminal (IFA) and to the amino terminal (ME101) rod domain of intermediate filaments. Sequential extraction procedures shows that the FS polypeptides recognized by MAb 4F7 are exposed after treatment with 8 M urea. 4F7 immunoreactivity is lost after treatment with high ionic solutions (NaCl, KCl, KI). Immunogold electron microscopy reveals that this protein is present throughout the FS. This FS antigenic determinant first accumulates in an FS proximal body in late spermatids, then in granules extending distally along the flagellum. Staining of spermatozoa with flagellar dysgenesis reveals that this FS protein colocalizes with actin no matter what the location of their abnormal assembly. These data suggest that the transient microtubule-like spindle-shaped body of as yet unknown function could be involved in FS protein deposition and that the assembly of the FS and actin could be under the control of some common morphogenetical factor(s). MAb 4F7 should allow further investigations of this periaxonemal structure in both normal and pathological conditions.

scholarly journals Physiological Osmotic Induction of Leptospira interrogans Adhesion: LigA and LigB Bind Extracellular Matrix Proteins and Fibrinogen

2007 ◽  
Vol 75 (5) ◽  
pp. 2441-2450 ◽  
Author(s):  
Henry A. Choy ◽  
Melissa M. Kelley ◽  
Tammy L. Chen ◽  
Annette K. Møller ◽  
James Matsunaga ◽  
...  
Keyword(s):  
Extracellular Matrix ◽  
Binding Activity ◽  
Surface Proteins ◽  
Microbial Pathogens ◽  
Host Proteins ◽  
Amino Terminal ◽  
Binding Domains ◽  
Multiple Ligands ◽  
Carboxy Terminal

ABSTRACTTransmission of leptospirosis occurs through contact of mucous membranes and abraded skin with freshwater contaminated by pathogenicLeptospiraspp. Exposure to physiological osmolarity induces leptospires to express high levels of the Lig surface proteins containing imperfect immunoglobulin-like repeats that are shared or differ between LigA and LigB. We report that osmotic induction of Lig is accompanied by 1.6- to 2.5-fold increases in leptospiral adhesion to immobilized extracellular matrix and plasma proteins, including collagens I and IV, laminin, and especially fibronectin and fibrinogen. Recombinant LigA-unique and LigB-unique repeat proteins bind to these same host ligands. We found that the avidity of LigB in binding fibronectin is comparable to that of theStaphylococcus aureusFnBPA D repeats. Both LigA- and LigB-unique repeats interact with the amino-terminal fibrin- and gelatin-binding domains of fibronectin, which are also recognized by fibronectin-binding proteins mediating the adhesion of other microbial pathogens. In contrast, repeats common to both LigA and LigB do not bind these host proteins, and nonrepeat sequences in the carboxy-terminal domain of LigB show only weak interaction with fibronectin and fibrinogen. A functional role for the binding activity of LigA and LigB is suggested by the ability of the recombinants to inhibit leptospiral adhesion to fibronectin by 28% and 21%, respectively. The binding of LigA and LigB to multiple ligands present in different tissues suggests that these adhesins may be involved in the initial colonization and dissemination stages of leptospirosis. The characterization of the Lig adhesin function should aid the design of Lig-based vaccines and serodiagnostic tests.

scholarly journals The scs' boundary element: characterization of boundary element-associated factors.

1997 ◽  
Vol 17 (2) ◽  
pp. 999-1009 ◽  
Author(s):  
C M Hart ◽  
K Zhao ◽  
U K Laemmli
Keyword(s):  
Dna Binding ◽  
Boundary Element ◽  
Target Genes ◽  
Polytene Chromosomes ◽  
Amino Terminal ◽  
High Affinity ◽  
Dna Binding Specificity ◽  
Carboxy Terminal ◽  
Terminal Domains

Boundary elements are thought to define the peripheries of chromatin domains and to restrict enhancer-promoter interactions to their target genes within their domains. We previously characterized a cDNA encoding the BEAF-32A protein (32A), which binds with high affinity to the scs' boundary element from the Drosophila melanogaster 87A7 hsp70 locus. Here, we report a second protein, BEAF-32B, that differs from 32A only in its amino terminus. Unlike 32A, it has the same DNA binding specificity as the complete BEAF activity affinity purified from Drosophila. We characterize three domains in these proteins. Heterocomplex formation is mediated by their identical carboxy-terminal domains, and DNA binding is mediated by their unique amino-terminal domains. The identical middle domains of 32A and 32B are dispensable for the functions described here, although they may be important for boundary element function. 32A and 32B apparently form trimers, and the ratio of 32A to 32B varies at different loci on polytene chromosomes as judged by immunofluorescence. The scs' element contains a high- and low-affinity binding site for BEAF. We observed that interaction with the low-affinity site is facilitated by binding to the high-affinity site some 200 bp distant.

scholarly journals Regions of RNase E Important for 5′-End-Dependent RNA Cleavage and Autoregulated Synthesis

2000 ◽  
Vol 182 (9) ◽  
pp. 2468-2475 ◽  
Author(s):  
Xunqing Jiang ◽  
Alexis Diwa ◽  
Joel G. Belasco
Keyword(s):  
Intrinsic Property ◽  
General Characteristic ◽  
Rna Cleavage ◽  
Rnase E ◽  
Wild Type ◽  
E Coli ◽  
Amino Terminal ◽  
Catalytically Active ◽  
Carboxy Terminal Region ◽  
Carboxy Terminal

ABSTRACT RNase E is an important regulatory enzyme that plays a key role in RNA processing and degradation in Escherichia coli. Internal cleavage by this endonuclease is accelerated by the presence of a monophosphate at the RNA 5′ end. Here we show that the preference of E. coli RNase E for 5′-monophosphorylated substrates is an intrinsic property of the catalytically active amino-terminal half of the enzyme and does not require the carboxy-terminal region. This property is shared by the related E. coli ribonuclease CafA (RNase G) and by a cyanobacterial RNase E homolog derived fromSynechocystis, indicating that the 5′-end dependence of RNase E is a general characteristic of members of this ribonuclease family, including those from evolutionarily distant species. Although it is dispensable for 5′-end-dependent RNA cleavage, the carboxy-terminal half of RNase E significantly enhances the ability of this ribonuclease to autoregulate its synthesis in E. coli. Despite similarities in amino acid sequence and substrate specificity, CafA is unable to replace RNase E in sustaining E. colicell growth or in regulating RNase E production, even when overproduced sixfold relative to wild-type RNase E levels.

scholarly journals Role of the Carboxy Terminus of Escherichia coli FtsA in Self-Interaction and Cell Division

2000 ◽  
Vol 182 (22) ◽  
pp. 6366-6373 ◽  
Author(s):  
Lucía Yim ◽  
Guy Vandenbussche ◽  
Jesús Mingorance ◽  
Sonsoles Rueda ◽  
Mercedes Casanova ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Division ◽  
Biological Function ◽  
Wild Type ◽  
Carboxy Terminus ◽  
Yeast Two Hybrid ◽  
Yeast Two Hybrid System ◽  
Carboxy Terminal ◽  
Two Hybrid

ABSTRACT The role of the carboxy terminus of the Escherichia coli cell division protein FtsA in bacterial division has been studied by making a series of short sequential deletions spanning from residue 394 to 420. Deletions as short as 5 residues destroy the biological function of the protein. Residue W415 is essential for the localization of the protein into septal rings. Overexpression of theftsA alleles harboring these deletions caused a coiled cell phenotype previously described for another carboxy-terminal mutation (Gayda et al., J. Bacteriol. 174:5362–5370, 1992), suggesting that an interaction of FtsA with itself might play a role in its function. The existence of such an interaction was demonstrated using the yeast two-hybrid system and a protein overlay assay. Even these short deletions are sufficient for impairing the interaction of the truncated FtsA forms with the wild-type protein in the yeast two-hybrid system. The existence of additional interactions between FtsA molecules, involving other domains, can be postulated from the interaction properties shown by the FtsA deletion mutant forms, because although unable to interact with the wild-type and with FtsAΔ1, they can interact with themselves and cross-interact with each other. The secondary structures of an extensive deletion, FtsAΔ27, and the wild-type protein are indistinguishable when analyzed by Fourier transform infrared spectroscopy, and moreover, FtsAΔ27 retains the ability to bind ATP. These results indicate that deletion of the carboxy-terminal 27 residues does not alter substantially the structure of the protein and suggest that the loss of biological function of the carboxy-terminal deletion mutants might be related to the modification of their interacting properties.

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