Abstract
We describe a cDNA encoding a serine proteinase inhibitor present in placental tissue and the cytosolic fraction of K562 cells. On the basis of its interaction with thrombin, through which it was discovered, the inhibitor has been operationally named the placental thrombin inhibitor (PTI). Amino acid sequence comparisons suggest that its reactive center is located at Arg-341 and Cys-342, that it lacks a classical N-terminal signal sequence, and that it has the highest degree of similarity to intracellular serine proteinase inhibitors (serpins), such as the human monocyte/neutrophil elastase inhibitor and the equine leukocyte elastase inhibitor. PTI also resembles these inhibitors in that it contains oxidation-sensitive residues adjacent to the reactive site. The PTI cDNA was expressed in rabbit reticulocyte lysate and in COS-7 cells and a 42-kDa protein was produced. Recombinant PTI formed a 67-kDa complex when incubated with thrombin. The ability of native PTI to bind thrombin was destroyed by incubation with iodoacetamide. Analysis of human tissue mRNA indicated that PTI is expressed widely with the highest levels in cardiac and skeletal muscle and placenta. We conclude that PTI is a member of an emerging class of intracellular serpins.
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- Bird P., Gething M. J., Sambrook J. Translocation in yeast and mammalian cells: not all signal sequences are functionally equivalent. J Cell Biol. 1987 Dec;105(6 Pt 2):2905–2914. doi: 10.1083/jcb.105.6.2905. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bollen A., Herzog A., Cravador A., Hérion P., Chuchana P., Vander Straten A., Loriau R., Jacobs P., van Elsen A. Cloning and expression in Escherichia coli of full-length complementary DNA coding for human alpha 1-antitrypsin. DNA. 1983;2(4):255–264. doi: 10.1089/dna.1983.2.255. [DOI] [PubMed] [Google Scholar]
- Chomczynski P., Sacchi N. Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction. Anal Biochem. 1987 Apr;162(1):156–159. doi: 10.1006/abio.1987.9999. [DOI] [PubMed] [Google Scholar]
- Coughlin P. B., Tetaz T., Salem H. H. Identification and purification of a novel serine proteinase inhibitor. J Biol Chem. 1993 May 5;268(13):9541–9547. [PubMed] [Google Scholar]
- Dubin A., Travis J., Enghild J. J., Potempa J. Equine leukocyte elastase inhibitor. Primary structure and identification as a thymosin-binding protein. J Biol Chem. 1992 Apr 5;267(10):6576–6583. [PubMed] [Google Scholar]
- Gu M. X., York J. D., Warshawsky I., Majerus P. W. Identification, cloning, and expression of a cytosolic megakaryocyte protein-tyrosine-phosphatase with sequence homology to cytoskeletal protein 4.1. Proc Natl Acad Sci U S A. 1991 Jul 1;88(13):5867–5871. doi: 10.1073/pnas.88.13.5867. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Huber R., Carrell R. W. Implications of the three-dimensional structure of alpha 1-antitrypsin for structure and function of serpins. Biochemistry. 1989 Nov 14;28(23):8951–8966. doi: 10.1021/bi00449a001. [DOI] [PubMed] [Google Scholar]
- Kozak M. Point mutations define a sequence flanking the AUG initiator codon that modulates translation by eukaryotic ribosomes. Cell. 1986 Jan 31;44(2):283–292. doi: 10.1016/0092-8674(86)90762-2. [DOI] [PubMed] [Google Scholar]
- Kraft R., Tardiff J., Krauter K. S., Leinwand L. A. Using mini-prep plasmid DNA for sequencing double stranded templates with Sequenase. Biotechniques. 1988 Jun;6(6):544-6, 549. [PubMed] [Google Scholar]
- Madison E. L., Bird P. A vector, pSHT, for the expression and secretion of protein domains in mammalian cells. Gene. 1992 Nov 2;121(1):179–180. doi: 10.1016/0378-1119(92)90179-s. [DOI] [PubMed] [Google Scholar]
- Owen W. G. Evidence for the formation of an ester between thrombin and heparin cofactor. Biochim Biophys Acta. 1975 Oct 20;405(2):380–387. doi: 10.1016/0005-2795(75)90103-8. [DOI] [PubMed] [Google Scholar]
- Panaccio M., Lew A. PCR based diagnosis in the presence of 8% (v/v) blood. Nucleic Acids Res. 1991 Mar 11;19(5):1151–1151. doi: 10.1093/nar/19.5.1151. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ray C. A., Black R. A., Kronheim S. R., Greenstreet T. A., Sleath P. R., Salvesen G. S., Pickup D. J. Viral inhibition of inflammation: cowpox virus encodes an inhibitor of the interleukin-1 beta converting enzyme. Cell. 1992 May 15;69(4):597–604. doi: 10.1016/0092-8674(92)90223-y. [DOI] [PubMed] [Google Scholar]
- Remold-O'Donnell E., Chin J., Alberts M. Sequence and molecular characterization of human monocyte/neutrophil elastase inhibitor. Proc Natl Acad Sci U S A. 1992 Jun 15;89(12):5635–5639. doi: 10.1073/pnas.89.12.5635. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Remold-O'Donnell E., Nixon J. C., Rose R. M. Elastase inhibitor. Characterization of the human elastase inhibitor molecule associated with monocytes, macrophages, and neutrophils. J Exp Med. 1989 Mar 1;169(3):1071–1086. doi: 10.1084/jem.169.3.1071. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sanders M. C., Goldstein A. L., Wang Y. L. Thymosin beta 4 (Fx peptide) is a potent regulator of actin polymerization in living cells. Proc Natl Acad Sci U S A. 1992 May 15;89(10):4678–4682. doi: 10.1073/pnas.89.10.4678. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Thompson E. A., Salem H. H. Modification of human thrombin: effect on thrombomodulin binding. Thromb Haemost. 1988 Jun 16;59(3):415–420. [PubMed] [Google Scholar]
- Travis J., Salvesen G. S. Human plasma proteinase inhibitors. Annu Rev Biochem. 1983;52:655–709. doi: 10.1146/annurev.bi.52.070183.003255. [DOI] [PubMed] [Google Scholar]
- Vieira J., Messing J. Production of single-stranded plasmid DNA. Methods Enzymol. 1987;153:3–11. doi: 10.1016/0076-6879(87)53044-0. [DOI] [PubMed] [Google Scholar]
- Ye R. D., Ahern S. M., Le Beau M. M., Lebo R. V., Sadler J. E. Structure of the gene for human plasminogen activator inhibitor-2. The nearest mammalian homologue of chicken ovalbumin. J Biol Chem. 1989 Apr 5;264(10):5495–5502. [PubMed] [Google Scholar]
- von Heijne G., Liljeström P., Mikus P., Andersson H., Ny T. The efficiency of the uncleaved secretion signal in the plasminogen activator inhibitor type 2 protein can be enhanced by point mutations that increase its hydrophobicity. J Biol Chem. 1991 Aug 15;266(23):15240–15243. [PubMed] [Google Scholar]