IgA Interaction with Carboxy-Terminal 43-kD Fragment of Fibronectin in IgA Nephropathy

Abstract. IgA deposition in the glomerular mesangial matrix is a prerequisite for the diagnosis of IgA nephropathy, and circulating IgA-containing complex has been implicated in this process. Since fibronectin is known to be involved in the assembly of extracellular matrix, this study was conducted to investigate whether fibronectin and its fragments are present in sera of patients and are capable of binding IgA1. Sera from patients with IgA nephropathy were purified by heparin-affinity chromatography, and column eluate were analyzed for the presence of fibronectin using Western blot and a set of anti-fibronectin monoclonal antibodies. Native fibronectin was digested with cathepsin D to obtain fragments similar to those of serum fibronectin. The capacity of fibronectin to bind IgA was examined with a mixture of purified IgA1 and cathepsin D-digested fibronectin fragments. A 43-kD carboxy-terminal fragment of fibronectin was detected in samples derived from sera of patients with IgA nephropathy but not in healthy control subjects. A similar-sized fragment was generated by cathepsin D digestion of the native molecule and was shown to bind to IgA1 in vitro. Since the carboxy-terminal domain is known to be critical in assembling exogenous fibronectin into the extracellular matrix, the affinity to IgA1 to a fragment found in patients may have pathogenic potential to mediate extracellular IgA deposition in IgA nephropathy.

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Differential Processing of Propeptide Inhibitors of Rap Phosphatases in Bacillus subtilis

Journal of Bacteriology ◽

10.1128/jb.182.2.303-310.2000 ◽

2000 ◽

Vol 182 (2) ◽

pp. 303-310 ◽

Cited By ~ 109

Author(s):

Min Jiang ◽

Roberto Grau ◽

Marta Perego

Keyword(s):

Bacillus Subtilis ◽

Phosphatase Activity ◽

Response Regulators ◽

Histidine Kinases ◽

Physiological Processes ◽

Carboxy Terminal Domain ◽

Activation Level ◽

Sporulation Initiation ◽

Carboxy Terminal

ABSTRACT In the phosphorelay signal transduction system for sporulation initiation in Bacillus subtilis, the opposing activities of histidine kinases and aspartyl phosphate phosphatases determine the cell's decision whether to continue with vegetative growth or to initiate the differentiation process. Regulated dephosphorylation of the Spo0A and Spo0F response regulators allows a variety of negative signals from physiological processes that are antithetical to sporulation to impact on the activation level of the phosphorelay. Spo0F∼P is the known target of two related phosphatases, RapA and RapB. In addition to RapA and RapB, a third member of the Rap family of phosphatases, RapE, specifically dephosphorylated the Spo0F∼P intermediate in response to competence development. RapE phosphatase activity was found to be controlled by a pentapeptide (SRNVT) generated from within the carboxy-terminal domain of the phrE gene product. A synthetic PhrE pentapeptide could (i) complement the sporulation deficiency caused by deregulated RapE activity of aphrE mutant and (ii) inhibit RapE-dependent dephosphorylation of Spo0F∼P in in vitro experiments. The PhrE pentapeptide did not inhibit the phosphatase activity of RapA and RapB. These results confirm previous conclusions that the specificity for recognition of the target phosphatase is contained within the amino acid sequence of the pentapeptide inhibitor.

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The Nsp1p Carboxy-Terminal Domain Is Organized into Functionally Distinct Coiled-Coil Regions Required for Assembly of Nucleoporin Subcomplexes and Nucleocytoplasmic Transport

Molecular and Cellular Biology ◽

10.1128/mcb.21.23.7944-7955.2001 ◽

2001 ◽

Vol 21 (23) ◽

pp. 7944-7955 ◽

Cited By ~ 50

Author(s):

Susanne M. Bailer ◽

Carolin Balduf ◽

Ed Hurt

Keyword(s):

Protein Import ◽

Coiled Coil ◽

Nucleocytoplasmic Transport ◽

Nuclear Pore ◽

Temperature Sensitive ◽

Nuclear Pores ◽

Terminal Domain ◽

Carboxy Terminal Domain ◽

Carboxy Terminal

ABSTRACT Nucleoporin Nsp1p, which has four predicted coiled-coil regions (coils 1 to 4) in the essential carboxy-terminal domain, is unique in that it is part of two distinct nuclear pore complex (NPC) subcomplexes, Nsp1p-Nup57p-Nup49p-Nic96p and Nsp1p-Nup82p-Nup159p. As shown by in vitro reconstitution, coiled-coil region 2 (residues 673 to 738) is sufficient to form heterotrimeric core complexes and can bind either Nup57p or Nup82p. Accordingly, interaction of Nup82p with Nsp1p coil 2 is competed by excess Nup57p. Strikingly, coil 3 and 4 mutants are still assembled into the core Nsp1p-Nup57p-Nup49p complex but no longer associate with Nic96p. Consistently, the Nsp1p-Nup57p-Nup49p core complex dissociates from the nuclear pores in nsp1coil 3 and 4 mutant cells, and as a consequence, defects in nuclear protein import are observed. Finally, the nsp1-L640Stemperature-sensitive mutation, which maps in coil 1, leads to a strong nuclear mRNA export defect. Thus, distinct coiled-coil regions within Nsp1p-C have separate functions that are related to the assembly of different NPC subcomplexes, nucleocytoplasmic transport, and incorporation into the nuclear pores.

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FCP1, a Phosphatase Specific for the Heptapeptide Repeat of the Largest Subunit of RNA Polymerase II, Stimulates Transcription Elongation

Molecular and Cellular Biology ◽

10.1128/mcb.22.21.7543-7552.2002 ◽

2002 ◽

Vol 22 (21) ◽

pp. 7543-7552 ◽

Cited By ~ 39

Author(s):

Subhrangsu S. Mandal ◽

Helen Cho ◽

Sungjoon Kim ◽

Kettly Cabane ◽

Danny Reinberg

Keyword(s):

Rna Polymerase ◽

Rna Polymerase Ii ◽

Transcription Elongation ◽

Carboxy Terminal Domain ◽

Transcription Factor Iif ◽

Transcript Elongation ◽

Rnap Ii ◽

Carboxy Terminal

ABSTRACT FCP1, a phosphatase specific for the carboxy-terminal domain of RNA polymerase II (RNAP II), was found to stimulate transcript elongation by RNAP II in vitro and in vivo. This activity is independent of and distinct from the elongation-stimulatory activity associated with transcription factor IIF (TFIIF), and the elongation effects of TFIIF and FCP1 were found to be additive. Genetic experiments resulted in the isolation of several distinct fcp1 alleles. One of these alleles was found to suppress the slow-growth phenotype associated with either the reduction of intracellular nucleotide concentrations or the inhibition of other transcription elongation factors. Importantly, this allele of fcp1 was found to be lethal when combined individually with two mutations in the second-largest subunit of RNAP II, which had been shown previously to affect transcription elongation.

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Tubulin phosphorylation by casein kinase II is similar to that found in vivo.

The Journal of Cell Biology ◽

10.1083/jcb.105.4.1731 ◽

1987 ◽

Vol 105 (4) ◽

pp. 1731-1739 ◽

Cited By ~ 80

Author(s):

L Serrano ◽

J Díaz-Nido ◽

F Wandosell ◽

J Avila

Keyword(s):

Neuroblastoma Cells ◽

Casein Kinase Ii ◽

Casein Kinase ◽

Carboxy Terminal Domain ◽

Phosphatase Treatment ◽

Microtubule Protein ◽

Carboxy Terminal ◽

Brain Tubulin

Purified brain tubulin subjected to an exhaustive phosphatase treatment can be rephosphorylated by casein kinase II. This phosphorylation takes place mainly on a serine residue, which has been located at the carboxy-terminal domain of the beta-subunit. Interestingly, tubulin phosphorylated by casein kinase II retains its ability to polymerize in accordance with descriptions by other authors of in vivo phosphorylated tubulin. Moreover, the V8 phosphopeptide patterns of both tubulin phosphorylated in vitro by casein kinase II and tubulin phosphorylated in vivo in N2A cells are quite similar, and different from that of tubulin phosphorylated in vitro by Ca/calmodulin-dependent kinase II. On the other hand, we have found an endogenous casein kinase II-like activity in purified brain microtubule protein that uses GTP and ATP as phosphate donors, is inhibited by heparin, and phosphorylates phosphatase-treated tubulin. Thus it appears that a casein kinase II-like activity should be considered a candidate for the observed phosphorylation of beta-tubulin in vivo in brain or neuroblastoma cells.

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Spatial and temporal control of nonmuscle myosin localization: identification of a domain that is necessary for myosin filament disassembly in vivo.

The Journal of Cell Biology ◽

10.1083/jcb.112.4.677 ◽

1991 ◽

Vol 112 (4) ◽

pp. 677-688 ◽

Cited By ~ 59

Author(s):

T T Egelhoff ◽

S S Brown ◽

J A Spudich

Keyword(s):

Critical Role ◽

Surface Proteins ◽

Myosin Filament ◽

Chain Gene ◽

Multicellular Development ◽

Filament Assembly ◽

Carboxy Terminal Domain ◽

Carboxy Terminal

Myosin null mutants of Dictyostelium are defective for cytokinesis, multicellular development, and capping of surface proteins. We have used these cells as transformation recipients for an altered myosin heavy chain gene that encodes a protein bearing a carboxy-terminal 34-kD truncation. This truncation eliminates threonine phosphorylation sites previously shown to control filament assembly in vitro. Despite restoration of growth in suspension, development, and ability to cap cell surface proteins, these delta C34-truncated myosin transformants display severe cytoskeletal abnormalities, including excessive localization of the truncated myosin to the cortical cytoskeleton, impaired cell shaped dynamics, and a temporal defect in myosin dissociation from beneath capped surface proteins. These data demonstrate that the carboxy-terminal domain of myosin plays a critical role in regulating the disassembly of the protein from contractile structures in vivo.

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A novel mitogen-inducible gene product related to p50/p105-NF-kappa B participates in transactivation through a kappa B site.

Molecular and Cellular Biology ◽

10.1128/mcb.12.2.685 ◽

1992 ◽

Vol 12 (2) ◽

pp. 685-695 ◽

Cited By ~ 137

Author(s):

V Bours ◽

P R Burd ◽

K Brown ◽

J Villalobos ◽

S Park ◽

...

Keyword(s):

Amino Acids ◽

Human Peripheral Blood ◽

Carcinoma Cells ◽

Nf Kappa B ◽

Reading Frame ◽

Amino Terminal ◽

Carboxy Terminal Domain ◽

Carboxy Terminal ◽

Inducible Gene

A Rel-related, mitogen-inducible, kappa B-binding protein has been cloned as an immediate-early activation gene of human peripheral blood T cells. The cDNA has an open reading frame of 900 amino acids capable of encoding a 97-kDa protein. This protein is most similar to the 105-kDa precursor polypeptide of p50-NF-kappa B. Like the 105-kDa precursor, it contains an amino-terminal Rel-related domain of about 300 amino acids and a carboxy-terminal domain containing six full cell cycle or ankyrin repeats. In vitro-translated proteins, truncated downstream of the Rel domain and excluding the repeats, bind kappa B sites. We refer to the kappa B-binding, truncated protein as p50B by analogy with p50-NF-kappa B and to the full-length protein as p97. p50B is able to form heteromeric kappa B-binding complexes with RelB, as well as with p65 and p50, the two subunits of NF-kappa B. Transient-transfection experiments in embryonal carcinoma cells demonstrate a functional cooperation between p50B and RelB or p65 in transactivation of a reporter plasmid dependent on a kappa B site. The data imply the existence of a complex family of NF-kappa B-like transcription factors.

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RNA polymerase II carboxy-terminal domain contributes to the response to multiple acidic activators in vitro.

Genes & Development ◽

10.1101/gad.5.12b.2431 ◽

1991 ◽

Vol 5 (12b) ◽

pp. 2431-2440 ◽

Cited By ~ 52

Author(s):

S M Liao ◽

I C Taylor ◽

R E Kingston ◽

R A Young

Keyword(s):

Rna Polymerase ◽

Rna Polymerase Ii ◽

Terminal Domain ◽

Carboxy Terminal Domain ◽

Carboxy Terminal

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Definition of an Ets1 protein domain required for nuclear localization in cells and DNA-binding activity in vitro.

Molecular and Cellular Biology ◽

10.1128/mcb.9.12.5718 ◽

1989 ◽

Vol 9 (12) ◽

pp. 5718-5721 ◽

Cited By ~ 54

Author(s):

K E Boulukos ◽

P Pognonec ◽

B Rabault ◽

A Begue ◽

J Ghysdael

Keyword(s):

Dna Binding ◽

Binding Activity ◽

Protein Domain ◽

Nuclear Targeting ◽

Dna Binding Activity ◽

Carboxy Terminal Domain ◽

Definition Of ◽

Carboxy Terminal ◽

Nuclear Phosphoproteins

Ets1 and Ets2 are nuclear phosphoproteins which bind to DNA in vitro and share two domains of strong identity. Deletion analyses of each of these conserved regions in Ets1 demonstrated that integrity of the carboxy-terminal domain, also conserved in the more distantly related elk and erg gene products, is essential for both nuclear targeting and DNA-binding activity in vitro.

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Kin28, the TFIIH-Associated Carboxy-Terminal Domain Kinase, Facilitates the Recruitment of mRNA Processing Machinery to RNA Polymerase II

Molecular and Cellular Biology ◽

10.1128/mcb.20.1.104-112.2000 ◽

2000 ◽

Vol 20 (1) ◽

pp. 104-112 ◽

Cited By ~ 121

Author(s):

Christine R. Rodriguez ◽

Eun-Jung Cho ◽

Michael-C. Keogh ◽

Claire L. Moore ◽

Arno L. Greenleaf ◽

...

Keyword(s):

Rna Polymerase ◽

Rna Polymerase Ii ◽

Terminal Domain ◽

Carboxy Terminal Domain ◽

Capping Enzyme ◽

Carboxy Terminal ◽

Polyadenylation Factor ◽

Enzyme Targeting

ABSTRACT The cotranscriptional placement of the 7-methylguanosine cap on pre-mRNA is mediated by recruitment of capping enzyme to the phosphorylated carboxy-terminal domain (CTD) of RNA polymerase II. Immunoblotting suggests that the capping enzyme guanylyltransferase (Ceg1) is stabilized in vivo by its interaction with the CTD and that serine 5, the major site of phosphorylation within the CTD heptamer consensus YSPTSPS, is particularly important. We sought to identify the CTD kinase responsible for capping enzyme targeting. The candidate kinases Kin28-Ccl1, CTDK1, and Srb10-Srb11 can each phosphorylate a glutathione S-transferase–CTD fusion protein such that capping enzyme can bind in vitro. However, kin28 mutant alleles cause reduced Ceg1 levels in vivo and exhibit genetic interactions with a mutant ceg1 allele, whilesrb10 or ctk1 deletions do not. Therefore, only the TFIIH-associated CTD kinase Kin28 appears necessary for proper capping enzyme targeting in vivo. Interestingly, levels of the polyadenylation factor Pta1 are also reduced in kin28 mutants, while several other polyadenylation factors remain stable. Pta1 in yeast extracts binds specifically to the phosphorylated CTD, suggesting that this interaction may mediate coupling of polyadenylation and transcription.

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