The Secretory Component and the J Chain

Cunningham‐Rundles, Charlotte

doi:10.1007/978-1-4684-0805-8_5

Cited by 19 publications

(26 citation statements)

References 75 publications

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“…Bacterial Strains and Culture Conditions-Polyamine-requiring mutants, E. coli MA261 (speB speC gly leu thr thi) (20), HT283 (speA speB speC speED thr pro thi) (21), and DR112 (speA speB) (22) were kindly provided by Dr. W. K. Maas (New York University School of Medicine), Dr. H. Tabor (National Institute of Health), and Dr. D. R. Morris (University of Washington), respectively. A 38 -deficient mutant, E. coli KT1100 rpoS::tet (23), was kindly supplied by Dr. K. Tanaka (University of Tokyo).…”

Section: Methodsmentioning

confidence: 99%

Polyamines Enhance Synthesis of the RNA Polymerase ς38 Subunit by Suppression of an Amber Termination Codon in the Open Reading Frame

Yoshida¹,

Kashiwagi²,

Kawai³

et al. 2002

Journal of Biological Chemistry

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The mechanisms by which polyamines stimulate synthesis of the RNA polymerase 38 subunit in Escherichia coli were studied. Polyamine stimulation was observed only in strains in which the 33rd codon of RpoS mRNA is a UAG termination codon instead of a CAG codon for glutamine in wild-type E. coli. Readthrough of the termination codon by Gln-tRNA supE was stimulated by polyamines. This stimulation was found to be caused by an increase in both the level of suppressor tRNA supE and the binding affinity of Gln-tRNA supE for ribosomes. The stimulatory effect was observed with a UAG termination codon but not with UGA and UAA codons. Readthrough of the UAG termination codon at the 270th amino acid position of RpoS mRNA was also stimulated by polyamines, indicating that polyamines stimulate readthrough of a UAG codon regardless of its location within the RpoS mRNA. When cell viability of an E. coli strain having a termination codon in the 33rd position of RpoS mRNA was compared using cells cultured with or without putrescine, it was higher in cells cultured with putrescine than in cells cultured without putrescine. The level of 38 subunit in the cells cultured with putrescine was higher than that in cells cultured without putrescine on days 2, 4, and 8, but the level of 70 subunit was almost the same in cells cultured with or without putrescine. These results confirm that elevated expression of the rpoS gene is important for cell viability at late stationary phase.Polyamines, aliphatic cations present in almost all living organisms, are necessary for normal cell growth (1, 2). Because polyamines interact with nucleic acids and mostly exist as polyamine-RNA complexes in cells (3, 4), their proliferative effects are presumed to be caused by stimulation of nucleic acid and protein synthesis. In fact, it has been reported that polyamines stimulate the synthesis of some protein species in vitro (5-7) and in vivo (8, 9), induce the in vivo assembly of 30 S ribosomal subunits (10 -12), and increase the fidelity of protein synthesis (13-15), altogether suggesting that polyamines regulate protein synthesis at several different steps.In Escherichia coli, the synthesis of OppA protein, a periplasmic substrate-binding protein of the oligopeptide uptake system, is strongly stimulated by the addition of putrescine to a polyamine-requiring mutant, MA261 (9). We found that (i) the stimulation of OppA synthesis takes place at the level of translation; (ii) the position and secondary structure of the ShineDalgarno (SD) 1 sequence (16) on OppA mRNA are important for this stimulation (17); and (iii) polyamines cause a structural change of the SD sequence and the initiation codon AUG of OppA mRNA, facilitating formation of the initiation complex (18). We also found that polyamines increase the translation of adenylate cyclase (Cya) mRNA by facilitating UUG codon-dependent initiation (19). Analysis of RNA secondary structure suggests that exposure of the SD sequence of mRNA is a prerequisite for polyamine stimulation of UUG codon-dependent init...

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Section: Methodsmentioning

confidence: 99%

Polyamines Enhance Synthesis of the RNA Polymerase ς38 Subunit by Suppression of an Amber Termination Codon in the Open Reading Frame

Yoshida¹,

Kashiwagi²,

Kawai³

et al. 2002

Journal of Biological Chemistry

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“…Bacterial Strains, Plasmids, and Culture Conditions-A polyaminerequiring mutant, E. coli MA261 (16), provided by Dr. W. K. Maas, New York University School of Medicine, and its polyamine uptake-deficient mutant KK313 potF::Km (17) were grown in medium A in the absence of polyamines as described previously (18). A proton-translocating ATPase mutant, KK313 potF::Km atp Ϫ , was derived from E. coli KK313 potF::Km by transduction of a P1 phage-infected lysate of E. coli DK8 (⌬(atpB-atpC) ilv::Tn10, Ref.…”

Section: Methodsmentioning

confidence: 99%

Excretion and Uptake of Putrescine by the PotE Protein in Escherichia coli

Kashiwagi

Shibuya

Tomitori

et al. 1997

Journal of Biological Chemistry

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The structure and function of the polyamine transport protein PotE was studied. Uptake of putrescine by PotE was dependent on the membrane potential. In contrast, the putrescine-ornithine antiporter activity of PotE studied with inside-out membrane vesicles was not dependent on the membrane potential (Kashiwagi, K., Miyamoto, S., Suzuki, F., Kobayashi, H., and Igarashi, K. (1992) Proc. Natl. Acad. Sci. U. S. A. 89, 4529 -4533). The K m values for putrescine uptake and for putrescine-ornithine antiporter activity were 1.8 and 73 M, respectively. Uptake of putrescine was inhibited by high concentrations of ornithine. This effect of ornithine appears to be due to putrescine-ornithine antiporter activity because it occurs only after accumulation of putrescine within cells and because ornithine causes excretion of putrescine. Thus, PotE can function not only as a putrescine-ornithine antiporter to excrete putrescine but also as a putrescine uptake protein.Both the NH 2 and COOH termini of PotE were located in the cytoplasm, as determined by the activation of alkaline phosphatase and ␤-galactosidase by various PotE-fusion proteins. The activities of putrescine uptake and excretion were studied using mutated PotE proteins. It was found that glutamic acid 207 was essential for both the uptake and excretion of putrescine by the PotE protein and that glutamic acids 77 and 433 were also involved in both activities. These three glutamic acids are located on the cytoplasmic side of PotE, and the function of these three residues could not be replaced by other amino acids. Putrescine transport activities did not change significantly with mutations at the other 13 glutamic acid or aspartic acid residues in PotE.

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“…Our finding that the mRNAs coding for the lower doublet migrated slower (Fig. 3, fractions [10][11][12][13][14] than those coding for the upper doublet (Fig. 3, fractions [8][9][10][11][12] argues strongly that the lower doublet is not derived proteolytically from the upper doublet.…”

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confidence: 99%

“…Only these latter secreted forms of SC have been isolated and characterized from various secretions (13 (14,15) from rabbit liver and lactating mammary gland. Two New Zealand White rabbits were used.…”

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confidence: 99%

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Receptor-mediated transcellular transport of immunoglobulin: synthesis of secretory component as multiple and larger transmembrane forms.

Mostov¹,

Kraehenbuhl²,

Blobel³

1980

Proc. Natl. Acad. Sci. U.S.A.

212

102

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We have characterized the early biosynthetic forms of secretory component (SC). SC is synthesized in various glandular epithelial cells and functions in transepithelial transport of certain polymeric immunoglobulins. In rabbit, mature SC is known to be heterogeneous, consisting of two or three immunologically related glycoproteins. Using translation of mRNA from rabbit mammary gland or liver in a wheat germ cell-free system supplemented with dog pancreas microsomal vesicles, we discovered that the translation products of SC mRNA include at least four distinct polypeptides. Moreover, we found that all four polypeptides are synthesized not as soluble secretory forms but as considerably larger transmembrane forms that are core-glycosylated and asymmetrically integrated into the dog pancreas microsomal vesicles in a translation-coupled manner. We therefore conclude that the mature secreted forms of SC are endoproteolytic fragments derived from and comprising the ectoplasmic portion of the transmembrane precursor forms. The detection of transmembrane precursor forms for mature SC provides a protein structural basis for their function as receptors mediating transepithelial transport of immuno-globulin molecules.

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The Secretory Component and the J Chain

Cited by 19 publications

References 75 publications

Polyamines Enhance Synthesis of the RNA Polymerase ς38 Subunit by Suppression of an Amber Termination Codon in the Open Reading Frame

Polyamines Enhance Synthesis of the RNA Polymerase ς38 Subunit by Suppression of an Amber Termination Codon in the Open Reading Frame

Excretion and Uptake of Putrescine by the PotE Protein in Escherichia coli

Receptor-mediated transcellular transport of immunoglobulin: synthesis of secretory component as multiple and larger transmembrane forms.

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