1
|
Kim MJ, Park SL, Kim SH, Park HJ, Sung BH, Sohn JH, Bae JH. Modulation of Kex2p Cleavage Site for In Vitro Processing of Recombinant Proteins Produced by Saccharomyces cerevisiae. J Microbiol Biotechnol 2023; 33:1513-1520. [PMID: 37482809 DOI: 10.4014/jmb.2306.06024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2023] [Revised: 06/26/2023] [Accepted: 06/26/2023] [Indexed: 07/25/2023]
Abstract
Kex2 protease (Kex2p) is a membrane-bound serine protease responsible for the proteolytic maturation of various secretory proteins by cleaving after dibasic residues in the late Golgi network. In this study, we present an application of Kex2p as an alternative endoprotease for the in vitro processing of recombinant fusion proteins produced by the yeast Saccharomyces cerevisiae. The proteins were expressed with a fusion partner connected by a Kex2p cleavage sequence for enhanced expression and easy purification. To avoid in vivo processing of fusion proteins by Kex2p during secretion and to guarantee efficient removal of the fusion partners by in vitro Kex2p processing, P1', P2', P4, and P3 sites of Kex2p cleavage sites were elaborately manipulated. The general use of Kex2p in recombinant protein production was confirmed using several recombinant proteins.
Collapse
Affiliation(s)
- Mi-Jin Kim
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
| | - Se-Lin Park
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
- Department of Food Science and Technology, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Seung Hwa Kim
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
- Department of Biosystem and Bioengineering, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Hyun-Joo Park
- Cellapy Bio Inc., Bio-Venture Center 211, Daejeon 34141, Republic of Korea
| | - Bong Hyun Sung
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
- Department of Biosystem and Bioengineering, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon 34113, Republic of Korea
| | - Jung-Hoon Sohn
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
- Department of Biosystem and Bioengineering, KRIBB School of Bioscience, Korea University of Science and Technology (UST), Daejeon 34113, Republic of Korea
- Cellapy Bio Inc., Bio-Venture Center 211, Daejeon 34141, Republic of Korea
| | - Jung-Hoon Bae
- Synthetic Biology Research Center, Korea Research Institute of Bioscience and Biotechnology, Daejeon 34141, Republic of Korea
| |
Collapse
|
2
|
Abstract
The proprotein convertases (PCs) are secretory mammalian serine proteinases related to bacterial subtilisin-like enzymes. The family of PCs comprises nine members, PC1/3, PC2, furin, PC4, PC5/6, PACE4, PC7, SKI-1/S1P, and PCSK9 (Fig. 3.1). While the first seven PCs cleave after single or paired basic residues, the last two cleave at non-basic residues and the last one PCSK9 only cleaves one substrate, itself, for its activation. The targets and substrates of these convertases are very varied covering many aspects of cellular biology and communication. While it took more than 22 years to begin to identify the first member in 1989-1990, in less than 14 years they were all characterized. So where are we 20 years later in 2011? We have now reached a level of maturity needed to begin to unravel the mechanisms behind the complex physiological functions of these PCs both in health and disease states. We are still far away from comprehensively understanding the various ramifications of their roles and to identify their physiological substrates unequivocally. How do these enzymes function in vivo? Are there other partners to be identified that would modulate their activity and/or cellular localization? Would non-toxic inhibitors/silencers of some PCs provide alternative therapies to control some pathologies and improve human health? Are there human SNPs or mutations in these PCs that correlate with disease, and can these help define the finesses of their functions and/or cellular sorting? The more we know about a given field, the more questions will arise, until we are convinced that we have cornered the important angles. And yet the future may well reserve for us many surprises that may allow new leaps in our understanding of the fascinating biology of these phylogenetically ancient eukaryotic proteases (Fig. 3.2) implicated in health and disease, which traffic through the cells via multiple sorting pathways (Fig. 3.3).
Collapse
Affiliation(s)
- Nabil G Seidah
- Biochemical Neuroendocrinology Laboratory, Clinical Research Institute of Montreal, Montreal, QC, Canada H2W 1R7.
| |
Collapse
|
3
|
Shaw E. Cysteinyl proteinases and their selective inactivation. ADVANCES IN ENZYMOLOGY AND RELATED AREAS OF MOLECULAR BIOLOGY 2006; 63:271-347. [PMID: 2407065 DOI: 10.1002/9780470123096.ch5] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The affinity-labeling of cysteinyl proteinases may now be carried out with a number of peptide-derived reagents with selectivity, particularly for reactions carried out in vitro. These reagents have been described with emphasis on their selectivity for cysteine proteinases and lack of action on serine proteinases, the most likely source of side reactions among proteinases. Perhaps a crucial feature of this selectivity is an enzyme-promoted activation due to initial formation of a hemiketal, which may destabilize the reagent. Prominent among the reagent types that have this class selectivity are the peptidyl diazomethyl ketones, the acyloxymethyl ketones, the peptidylmethyl sulfonium salts, and peptidyl oxides analogous to E-64. The need for specific inhibitors capable of inactivating the target enzyme in intact cells and animals is inevitably pushing the biochemical application of these inhibitors into more complex molecular environments where the possibilities of competing reactions are greatly increased. In dealing with the current state and potential developments for the in vivo use of affinity-labeling reagents of cysteine proteinases, the presently known variety of cysteinyl proteinases had to be considered. Therefore this chapter has, at the same time, attempted to survey these proteinases with respect to specificity and gene family. The continual discovery of new proteinases will increase the complexity of this picture. At present the lysosomal cysteine proteinases cathepsins B and L and the cytoplasmic calcium-dependent proteinases are reasonable goals for a fairly complete metabolic clarification. The ability of investigators to inactivate individual members of this family in vivo, possibly without complications due to concurrent inactivation of serine proteinases by improvements in reagent specificity, is increasing. Among the cysteine proteinases, at least those of the papain super family, hydrophobic interactions in the S2 and S3 subsites are important and some specificity has been achieved by taking advantage of topographical differences among members of this group. Some of this has probably involved surface differences removed from the regions involved in proteolytic action. The emerging cysteine proteinases include some which, in contrast to the papain family, have a pronounced specificity in S1 for the binding of basic side chains, familiar in the trypsin family of serine proteinases. At least a potential conflict with serine proteinases can be avoided by choice of a covalent bonding mechanism. The departing group region, has not been exploited. As a sole contributor to binding, this region may be rather limited as a source of specificity.(ABSTRACT TRUNCATED AT 400 WORDS)
Collapse
Affiliation(s)
- E Shaw
- Friedrich Miescher-Institut, Basel, Switzerland
| |
Collapse
|
4
|
Discovery of the Proprotein Convertases and their Inhibitors. REGULATION OF CARCINOGENESIS, ANGIOGENESIS AND METASTASIS BY THE PROPROTEIN CONVERTASES (PCS) 2006. [PMCID: PMC7122317 DOI: 10.1007/1-4020-5132-8_1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The members of the convertase family play a central role in the processing of various protein precursors ranging from hormones and growth factors to viral envelope proteins and bacterial toxins. The proteolysis of these precursors that occurs at basic residues is mediated by the proprotein convertases (PCs), namely: PC1, PC2, Furin, PACE4, PC4, PC5 and PC7. The proteolysis at non-basic residues is performed by subtilisin/kexin-like isozyme-1 (S1P/SKI-1) and the newly identified neural apoptosis-regulated convertase-1 (NARC-1/PCSK9). These proteases have key roles in many physiological processes and various pathologies including cancer, obesity, diabetes, neurodegenerative diseases and autosomal dominant hypercholesterolermia. Here we summarize the discovery of the proprotein convertases and their inhibitors, discuss their properties, roles, resemblance and differences
Collapse
|
5
|
Rockwell NC, Thorner JW. The kindest cuts of all: crystal structures of Kex2 and furin reveal secrets of precursor processing. Trends Biochem Sci 2004; 29:80-7. [PMID: 15102434 DOI: 10.1016/j.tibs.2003.12.006] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Pro-hormone or pro-protein convertases are a conserved family of eukaryotic serine proteases found in the secretory pathway. These endoproteases mature precursors for peptides and proteins that perform a wide range of physiologically important and clinically relevant functions. The first member of this family to be identified was Kex2 in the yeast Saccharomyces cerevisiae. One mammalian member of this family - furin - is responsible for processing substrates that include insulin pro-receptor, human immunodeficiency virus gp160 glycoprotein, Ebola virus glycoprotein, and anthrax protective antigen. Recent determination of the crystal structures for the catalytic core domains of both Kex2 and furin - the first for any members of this family - provide remarkable insights and a new level of understanding of substrate specificity and catalysis by the pro-protein convertases.
Collapse
Affiliation(s)
- Nathan C Rockwell
- Department of Molecular and Cell Biology, Division of Biochemistry and Molecular Biology, University of California at Berkeley, Room 16, Barker Hall, Berkeley, CA 94720-3202, USA
| | | |
Collapse
|
6
|
Abstract
The archetypal status of alpha(1)-antitrypsin in biology and medicine grew from the finding, thirty years ago, by Carl-Bertil Laurell, of the association of its deficiency with emphysema. In biology, alpha(1)-antitrypsin now provides the model for both the structure and the remarkable mechanism of the serpin protease inhibitors that control the key proteolytic pathways of the body. In medicine, the plasma deficiency of alpha(1)-antitrypsin has drawn attention to protease-antiprotease imbalance as a contributory cause of chronic obstructive pulmonary disease. But even more significantly, the finding that the common genetic deficiency of alpha(1)-antitrypsin was also associated with the development of liver cirrhosis introduced the new entity of the conformational diseases. The proposal that the same general mechanism was responsible for the best known of the conformational diseases, the common late-onset dementias, was controversial. It was vindicated however by the recent finding that a mutation, which results in the liver aggregation of alpha(1)-antitrypsin, also results in a typical late-onset dementia when it occurs in a brain-specific homologue of alpha(1)-antitrypsin. The extensive development of such diverse fields of studies, each based on alpha(1)-antitrypsin, is a measure of the encouragement Laurell gave to younger colleagues in the field. It also reflects the great advantage of linked contributions from clinical as well as basic sciences. Time after time, scientific controversies and deadlocks have been solved by landmark clinical cases, which have revealed unexpected findings and insights, within and beyond the fields of study.
Collapse
Affiliation(s)
- Robin W Carrell
- Cambridge Institute for Medical Research, University of Cambridge, CB2 2XY, Cambridge, UK.
| |
Collapse
|
7
|
Taylor NA, Van De Ven WJM, Creemers JWM. Curbing activation: proprotein convertases in homeostasis and pathology. FASEB J 2003; 17:1215-27. [PMID: 12832286 DOI: 10.1096/fj.02-0831rev] [Citation(s) in RCA: 173] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The proprotein convertases (PCs) are a seven-member family of endoproteases that activate proproteins by cleavage at basic motifs. Expression patterns for individual PCs vary widely, and all cells express several members. The list of substrates activated by PCs has grown to include neuropeptides, peptide hormones, growth and differentiation factors, receptors, enzymes, adhesion molecules, blood coagulation factors, plasma proteins, viral coat proteins, and bacterial toxins. It has become clear that the PC family plays a crucial role in a variety of physiological processes and is involved in the pathology of diseases such as cancer, viral infection, and Alzheimer's disease. Recent studies using PC inhibitors have demonstrated their potential as therapeutic targets. Despite the avalanche of in vitro data, the physiological role of individual PCs has remained largely elusive. Recently, however, knockout mouse models have been developed for furin, PC1, PC2, PC4, PC6B, LPC, and PACE4, and human patients with PC1 deficiency have been identified. The phenotypes range from undetectable to early embryonic lethality. The major lesson learned from these studies is that specific PC-substrate pairs do exist, but that there is substantial redundancy for the majority of substrates. To some extent, redundancy may be cell type and even species dependent.
Collapse
Affiliation(s)
- Neil A Taylor
- Laboratory of Molecular Oncology, Department for Human Genetics, University of Leuven and Flanders Interuniversity Institute for Biotechnology, Gasthuisberg O/N 6, Herestraat 49, B-3000 Leuven, Belgium
| | | | | |
Collapse
|
8
|
Ohkubo K, Naito Y, Fujiwara T, Miyazaki JI, Ikehara Y, Ono J. Inhibitory effect of the alpha1-antitrypsin Pittsburgh type-mutant (alpha1-PIM/R) on proinsulin processing in the regulated secretory pathway of the pancreatic beta-cell line MIN6. Endocr J 2003; 50:9-20. [PMID: 12733705 DOI: 10.1507/endocrj.50.9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
To elucidate its effect on proinsulin processing, we introduced the expression of a Pittsburgh type-mutant, alpha1-protease inhibitor M/R (alpha1-PIM/R) and its chimera protein with growth hormone (GH) (GHalpha1-PIM/R) into MIN6 cells. In metabolic labeling and chasing experiments with [3H]-Leu and [35S]-Met, proinsulin appeared in the medium during stimulatory secretion only from MIN6 clones expressing GHalpha1-PIM/R and, surprisingly, alpha1-PIM/R, but not from the clones of either the control or alpha1-PI. The major part of alpha1-PIM/R was secreted through the constitutive pathway and about 10% of total secreted alpha1-PIM/R in the chase periods entered the regulated pathway. On the other hand, GHalpha1-PIM/R was mainly transported to the secretory granules and about 80% of the total secreted GHalpha1-PIM/R in the chase periods was secreted during stimulatory secretion. In the first 3 h chase periods without stimulation, only alpha1-PIM/R and no GHalpha1-PIM/R appeared in the medium, thus suggesting that alpha1-PIM/R might be transported through a constitutive-like pathway for those periods. The alpha1-PI, which had no inhibitory effect on proinsulin processing, showed similar secretion pathways to those of alpha1-PIM/R. This implies that some part of alpha1-PIM/R and alpha1-PI entered the regulated pathway, not due to any specific interaction between the processing endoproteases and serine protease inhibitors, but due to some type of passive transport in a nonselective manner. The inhibitory effect of alpha1-PIM/R in the regulated secretory pathway was slightly but clearly evident when it was expressed in MIN6 beta-cells.
Collapse
Affiliation(s)
- Kumiko Ohkubo
- Department of Laboratory Medicine, Fukuoka University School of Medicine, Fukuoka 814-0180, Japan
| | | | | | | | | | | |
Collapse
|
9
|
|
10
|
Leung KW, Liaw YC, Chan SC, Lo HY, Musayev FN, Chen JZ, Fang HJ, Chen HM. Significance of local electrostatic interactions in staphylococcal nuclease studied by site-directed mutagenesis. J Biol Chem 2001; 276:46039-45. [PMID: 11598114 DOI: 10.1074/jbc.m106620200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In this paper, we show that amino acids Glu(73) and Asp(77) of staphylococcal nuclease cooperate unequally with Glu(75) to stabilize its structure located between the C-terminal helix and beta-barrel of the protein. Amino acid substitutions E73G and D77G cause losses of the catalytic efficiency of 24 and 16% and cause thermal stability losses of 22 and 26%, respectively, in comparison with the wild type (WT) protein. However, these changes do not significantly change global and local secondary structures, based on measurements of fluorescence and CD(222 nm). Furthermore, x-ray diffraction analysis of the E75G protein shows that the overall structure of mutant and WT proteins is similar. However, this mutation does cause a loss of essential hydrogen bonding and charge interactions between Glu(75) and Lys(9), Tyr(93), and His(121). In experiments using double point mutations, E73G/D77G, E73G/E75G, and E75G/D77G, significant changes are seen in all mutants in comparison with WT protein as measured by fluorescence and CD spectroscopy. The losses of thermal stability are 47, 59, and 58%, for E73G/D77G, E73G/E75G, and E75G/D77G, respectively. The triple mutant, E73G/E75G/D77G, results in fluorescence intensity and CD(222 nm) close to those of the denatured state and in a thermal stability loss of 65% relative to the WT protein. Based on these results, we propose a model in which significant electrostatic interactions result in the formation of a locally stable structure in staphylococcal nuclease.
Collapse
Affiliation(s)
- K W Leung
- Department of Biochemistry, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong
| | | | | | | | | | | | | | | |
Collapse
|
11
|
Meydan D, Nilsson T, Törnblom M, Hagmar L, Hellgren D, Fuscoe JC, Lambert B. The frequency of illegitimate TCRbeta/gamma gene recombination in human lymphocytes: influence of age, environmental exposure and cytostatic treatment, and correlation with frequencies of t(14;18) and hprt mutation. Mutat Res 1999; 444:393-403. [PMID: 10521679 DOI: 10.1016/s1383-5718(99)00110-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Chromosome translocations in lymphoid malignancies often involve V(D)J recombinase mediated events giving rise to aberrant T-cell receptor (TCR) and immunoglobulin genes, which have been suggested to be useful as markers of genomic instability, genotoxic exposure and cancer risk. Illegitimate rearrangements involving the TCRbeta/gamma loci on chromosome 7 create TCRbeta/gamma hybrid genes which occur at low frequency in peripheral blood lymphocytes (PBLs) of normal healthy individuals. To evaluate the utility of this marker, we studied the possible effects of age and genotoxic exposures on the TCRbeta/gamma gene variant frequency (VF), and compared the frequencies of hypoxanthine guanine phosphoribosyl transferase (hprt) mutation, hprt exon 2/3 deletion, t(14;18) and TCRbeta/gamma gene rearrangements in cells from the same donors. The TCRbeta/gamma VF ranged five-fold among 16 middle aged blood donors with a mean of 0.74+/-0.29/10(5) PBLs, which is consistent with our previous estimate in healthy subjects. The TCRbeta/gamma VF was found to increase from birth until early adult life, and then to decrease with increasing age. Four testis cancer patients, who 6 years earlier had been treated with etoposide and other cytostatic drugs, showed TCRbeta/gamma VF similar to that in healthy controls. No increase of the TCRbeta/gamma VF was found among non-smoking PAH-exposed aluminum smelter workers compared to non-smoking controls. Smoking smelter workers showed decreased TCRbeta/gamma VF compared to non-smoking workers and controls, but in a follow-up study 2 years later the difference was no longer statistically significant, although the smoking smelter workers still showed a lower TCRbeta/gamma VF than the controls. No correlation was obtained between the TCRbeta/gamma VF and the t(14;18) or hprt mutant frequency (MF) in a group of healthy individuals. However, there was a statistically significant correlation between the TCRbeta/gamma VF and the hprt exon 2/3 deletion frequency in PBL DNA from the same donors. These results show that the TCRbeta/gamma VF in healthy individuals changes with age and correlates with the frequency of hprt exon 2/3 deletion, another marker of aberrant V(D)J recombination in T-cells. However, no effect of smoking or present or previous exposure to genotoxic agents on TCRbeta/gamma VF was observed in this study. Thus, further studies are needed to prove the utility of TCRbeta/gamma gene rearrangement as a marker of genotoxic exposure.
Collapse
Affiliation(s)
- D Meydan
- Department of Biosciences, Environmental Medicine Unit, CNT, Novum, The Karolinska Institute, SE-141 57, Huddinge, Sweden
| | | | | | | | | | | | | |
Collapse
|
12
|
Tsujikawa M, Okabayashi K, Morita M, Tanabe T. Secretion of a variant of human single-chain urokinase-type plasminogen activator without an N-glycosylation site in the methylotrophic yeast, Pichia pastoris and characterization of the secreted product. Yeast 1998. [DOI: 10.1002/(sici)1097-0061(199605)12:6<541::aid-yea935>3.0.co;2-a] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
|
13
|
Carrell R, Lomas D, Stein P, Whisstock J. Dysfunctional variants and the structural biology of the serpins. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1998; 425:207-22. [PMID: 9433503 DOI: 10.1007/978-1-4615-5391-5_20] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- R Carrell
- Department of Haematology, University of Cambridge, England
| | | | | | | |
Collapse
|
14
|
Nakayama K. Furin: a mammalian subtilisin/Kex2p-like endoprotease involved in processing of a wide variety of precursor proteins. Biochem J 1997; 327 ( Pt 3):625-35. [PMID: 9599222 PMCID: PMC1218878 DOI: 10.1042/bj3270625] [Citation(s) in RCA: 624] [Impact Index Per Article: 23.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Limited endoproteolysis of inactive precursor proteins at sites marked by paired or multiple basic amino acids is a widespread process by which biologically active peptides and proteins are produced within the secretory pathway in eukaryotic cells. The identification of a novel family of endoproteases homologous with bacterial subtilisins and yeast Kex2p has accelerated progress in understanding the complex mechanisms underlying the production of the bioactive materials. Seven distinct proprotein convertases of this family (furin, PC2, PC1/PC3, PC4, PACE4, PC5/PC6, LPC/PC7/PC8/SPC7) have been identified in mammalian species, some having isoforms generated via alternative splicing. The family has been shown to be responsible for conversion of precursors of peptide hormones, neuropeptides, and many other proteins into their biologically active forms. Furin, the first proprotein convertase to be identified, has been most extensively studied. It has been shown to be expressed in all tissues and cell lines examined and to be mainly localized in the trans-Golgi network, although some proportion of the furin molecules cycle between this compartment and the cell surface. This endoprotease is capable of cleaving precursors of a wide variety of proteins, including growth factors, serum proteins, including proteases of the blood-clotting and complement systems, matrix metalloproteinases, receptors, viral-envelope glycoproteins and bacterial exotoxins, typically at sites marked by the consensus Arg-Xaa-(Lys/Arg)-Arg sequence. The present review covers the structure and function of mammalian subtilisin/Kex2p-like proprotein convertases, focusing on furin (EC 3.4.21.85).
Collapse
Affiliation(s)
- K Nakayama
- Institute of Biological Sciences and Gene Experiment Center, University of Tsukuba, Tsukuba Science City, Ibaraki 305, Japan
| |
Collapse
|
15
|
Abstract
It has been well established that peptide precursors usually undergo limited proteolysis at pairs or single basic amino acids during their biosynthetic process. This posttranslational modification paradigm is common for numerous membrane-spanning and secreted proteins, neuropeptides, and peptide hormones of physiological significance, in which endoproteolytic cleavage is invariably essential for the accurate biosynthesis and full activity of the mature products. Establishment of an effective peptide profile is dependent on not only the presence of peptide precursor, but also the presence and the enzymatic specificities of cleavage enzymes. We have, therefore, characterized the spatial and temporal patterns of six subtilisin-like serine endoproteases known to be involved in proprotein processing, including furin, PC1, PC2, PC4, PC5, and PACE4, in rat prenatal development and related the results to the expression patterns of several peptide precursors. We have observed largely distinct and sometimes complementary expression patterns of individual PCs in various embryonic structures, suggesting PCs may be functionally distinct in processing different sets of proprotein substrates in development. From these studies, numerous tentative enzyme-substrate relationships in various embryonic structures have been proposed and should encourage more studies to test the in vitro cleavage potentialities of individual PCs toward these precursors. In the future, knowledge gained from these studies, when combined with insights gained from in vivo perturbation and genetic ablation studies, should lead to final comprehensive understanding of specific precursors cleaved by specific enzymes at specific cleavage sites in known spatial and temporal expression patterns during development.
Collapse
Affiliation(s)
- M Zheng
- Department of Neuroscience and Cell Biology, UMDNJ-Robert Wood Johnson Medical School, Piscataway 08854, USA
| | | |
Collapse
|
16
|
Dalton T, Paria BC, Fernando LP, Huet-Hudson YM, Dey SK, Andrews GK. Activation of the chicken metallothionein promoter by metals and oxidative stress in cultured cells and transgenic mice. Comp Biochem Physiol B Biochem Mol Biol 1997; 116:75-86. [PMID: 9080664 DOI: 10.1016/s0305-0491(96)00224-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Cis-acting elements in the chicken metallothionein promoter were tested for their ability to direct responses of reporter genes to metal ions and oxidative stress in transfected mouse cells and in transgenic mice. In addition, protein interactions with the promoter were analyzed by the electrophoretic mobility shift assay. In transient transfection assays and in transgenic mice, 107-bp of the chicken MT promoter was sufficient to direct responses to Zn. This promoter region also directed response to oxidative stress in transfected cells and transgenic mice, but in transgenic mice, maximal responsiveness to oxidative stress apparently involved other elements in the proximal promoter region (307-bp). The proximal 200-bp of the promoter contains sequences homologous to a metal response element (-47-bp), Sp1 binding sites (-70-bp and -161-bp), and an antioxidant response element (-189-bp). Electrophoretic mobility shift assay demonstrated that metal response element binding activity was low in control Hepa cell nuclear extracts, but was induced 6-fold after 45 min of H2O2 treatment. In contrast, Sp1 binding remained unchanged, and no evidence for specific binding to the core antioxidant response element consensus sequence was obtained. These studies demonstrate that cis-acting elements mediating induction of metallothionein gene expression by metals and oxidative stress are present in the chicken metallothionein promoter and suggest a role for increased binding of the transcription factor MTF-1 to the metal response element(s).
Collapse
Affiliation(s)
- T Dalton
- Department of Biochemistry and Molecular Biology, Ralph L. Smith Research Center, University of Kansas Medical Center, Kansas City 66160-7421, USA
| | | | | | | | | | | |
Collapse
|
17
|
Meydan D, Lambert B, Hellgren D. Frequency and cell specificity of T-cell receptor interlocus recombination in human cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 1997; 30:245-253. [PMID: 9366901 DOI: 10.1002/(sici)1098-2280(1997)30:3<245::aid-em1>3.0.co;2-k] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Immunoglobulin and T-cell receptor (TCR) genes are assembled by a site-specific rearrangement known as V(D)J [variable-(diversity)-joining] recombination. These rearrangements occur normally in pre-B- and pre-T-cells using signal sequences adjacent to coding exons for immunoglobulin and TCR genes, respectively. However, aberrant recombination may result in the generation of hybrid TCR genes by joining of TCR-beta with TCR-gamma specific sequences. Such hybrid TCR genes occur at a low frequency in peripheral blood lymphocytes (PBL) of healthy individuals, and can be detected by PCR amplification. We have determined the in vivo frequency of hybrid V gamma-J beta 1 TCR (hybrid TCR) genes in lymphocyte DNA from 12 healthy individuals. The average frequency was found to be 5.83 in 0.75 x 10(6) PBL, with a threefold difference between the highest and lowest individual value. The presence of similar TCR gene rearrangements in individual samples suggests that T-cells with a hybrid TCR gene are capable of clonal expansion in vivo. The individual hybrid TCR gene frequency remained relatively constant during 72 hours of in vitro cultivation. In long-term culture, the frequency gradually decreased, and after 28 days no hybrid TCR genes were detectable in lymphocyte DNA. These results show that T-cells with a hybrid TCR gene are able to respond to mitogen stimulation in vitro, and may have a proliferative disadvantage or are selected against during prolonged in vitro cultivation. No hybrid TCR genes were detected in ten proliferating T-cell clones, indicating that the rate of hybrid TCR gene formation is < 2.0 x 10(-8) per cell per cell division. No hybrid TCR genes were detected in DNA from B-lymphocytes, sperm, granulocytes, fibroblasts, keratinocytes, and three B-lymphoblastoid ataxia telangiectasia cell lines. In agreement with previous reports, the frequency of hybrid TCR genes in peripheral blood DNA from two ataxia telangiectasia patients was found to be more than 15-fold higher than in lymphocytes from normal individuals. These data show that formation of hybrid TCR genes is restricted to T-cells in vivo, and occurs at a very low frequency, if at all, in proliferating T-cells in vitro, and with an increased frequency in patients with ataxia telangiectasia.
Collapse
Affiliation(s)
- D Meydan
- Karolinska Institute, Department of Biosciences, Huddinge, Sweden
| | | | | |
Collapse
|
18
|
Tsujikawa M, Okabayashi K, Morita M, Tanabe T. Secretion of a variant of human single-chain urokinase-type plasminogen activator without an N-glycosylation site in the methylotrophic yeast, Pichia pastoris and characterization of the secreted product. Yeast 1996; 12:541-53. [PMID: 8771709 DOI: 10.1002/(sici)1097-0061(199605)12:6%3c541::aid-yea935%3e3.0.co;2-a] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Human single-chain urokinase-type plasminogen activator without an N-glycosylation site (scu-PA-Q302) was produced in the methylotrophic yeast, Pichia pastoris using the shortened prepeptide sequence of a fungal aspartic proteinase, Mucor pusillus rennin (MPR). The level of urokinase-type plasminogen activator (u-PA) immunoreactive material in YPM medium was 0.47 mg/l; however, most of the secreted product had been processed to smaller polypeptides. The N-terminal amino acid sequence of major species was identical to that of the low molecular weight two-chain u-PA. Some approaches to minimizing the proteolysis of scu-PA-Q302 were attempted. Addition of Triton X-100, L-arginine and ammonium phosphate to the YPM medium minimized the proteolysis of scu-PA-Q302 and increased the yield of immunoreactive material to approximately 5 mg/l. Use of proteinase A- or proteinase B-deficient strains of yeast did not reduce the degradation. Co-expression of scu-PA-Q302 and urinary trypsin inhibitor resulted in partial reduction of the major species of proteolysis. Scu-PA-Q302 was purified from the culture supernatant of the improved medium by two successive chromatographies on Phenyl-Sepharose and S-Sepharose. The purified protein had a molecular weight of 47 kDa. It did not contain detectable N-linked oligosaccharides, but contained O-linked oligosaccharides attached to the light chain. N-terminal amino acid sequencing of the purified preparation showed that the shortened prepeptide sequence of MPR was correctly processed by the Pichia yeast. Scu-PA-Q302 closely resembles natural scu-PA with respect to its enzymatic activity against the chromogenic substrate S-2444 and its in vitro fibrinolytic properties.
Collapse
|
19
|
Ledgerwood EC, Brennan SO, Cawley NX, Loh YP, George PM. Yeast aspartic protease 3 (Yap3) prefers substrates with basic residues in the P2, P1 and P2' positions. FEBS Lett 1996; 383:67-71. [PMID: 8612794 DOI: 10.1016/0014-5793(96)00219-0] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
The yeast aspartic protease Yap3 is localised to the secretory pathway and correctly cleaves pro-alpha-mating factor at its dibasic sites. We determined the specificity of Yap3 for mono-, di-, and multi-basic cleavage sites in the context of 15 residue synthetic proalbumin peptides. Yap3 cleaved after dibasic ArgArg and LysArg sites but not after monobasic Arg sites even when there was an additional arginine at -6 and/or -4. Yap3 did not cleave a tetra-arginine site and tri-basic sites (RRR and RRK) were poor substrates. Cleavage always occurred C-terminal to the last arginine in the di- or tri-basic sequence. The optimal cleavage site sequence was RR DR and this substrate was cleaved 8-9-fold faster than the normal RR DA sequence. In contrast to Kex2, Yap3 did not remove the propeptide from normal proalbumin or a range of natural or recombinant proalbumin variants. However at pH 4.0 Yap3 slowly cleaved proalbumin and albumin between domains 2 and 3.
Collapse
Affiliation(s)
- E C Ledgerwood
- Molecular Pathology Laboratory, Clinical Biochemistry, Christchurch Hospital, New Zealand
| | | | | | | | | |
Collapse
|
20
|
Carrell RW, Stein PE. The biostructural pathology of the serpins: critical function of sheet opening mechanism. BIOLOGICAL CHEMISTRY HOPPE-SEYLER 1996; 377:1-17. [PMID: 8929809 DOI: 10.1515/bchm3.1996.377.1.1] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The serpins illustrate the way in which the study of a protein family as a whole can clarify the functions of its individual members. Although the individual serpins have become remarkably diversified by evolution they all share a common structural pathology. We have previously shown how plotting of the dysfunctional natural mutations of the serpins on a template structure defines the domains controlling the mobility of the reactive centre loop of the molecule. Here we compare these natural mutations with reciprocal mutations in recombinants that restore the inhibitory stability of a labile member of the family, plasminogen activator inhibitor-1 (PAI-1). The combined results emphasise the critical part played by residues involved in the sliding movement that opens the A-sheet to allow reactive loop insertion. It is concluded that changes in these residues provide the prime explanation for the ready conversion of PAI-1 to the inactive latent state. The consistency of the overall results gives confidence in predicting the likely consequences of mutations in individual serpins. In particular the two common polymorphic mutations present in human angiotensinogen are likely to affect molecular stability and hence may be contributory factors to the observed association with vascular disease.
Collapse
Affiliation(s)
- R W Carrell
- Department of Haematology, University of Cambridge, UK
| | | |
Collapse
|
21
|
Ledgerwood EC, George PM, Peach RJ, Brennan SO. Endoproteolytic processing of recombinant proalbumin variants by the yeast Kex2 protease. Biochem J 1995; 308 ( Pt 1):321-5. [PMID: 7755581 PMCID: PMC1136879 DOI: 10.1042/bj3080321] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The yeast Kex2 protease is regarded as the prototype of the eukaryotic family of subtilisin-like serine proteases involved in processing after dibasic amino acid sequences. Here we investigate the specificity of Kex2 using recombinant human proalbumin variants. Proalbumins with the processing site sequences Arg-Arg and Lys-Arg were cleaved after the dibasic sequence at approximately the same rate by Kex2 in vitro, and yeast expressing either of these sequences secreted mature albumin into the culture medium. As expected, the Arg-Gly-Val-Phe-His-Arg-albumin (proalbumin Lille) was not a substrate for Kex2 and neither was the Arg-Gly-Arg-Phe-His-Arg-albumin. In contrast to the mammalian endoproteases furin and the hepatic proalbumin convertase, the Kex2 protease was adversely affected by a P4 arginine. There was an 85% decrease in the cleavage of Arg-Gly-Arg-Phe-Arg-Arg-albumin compared with normal; also chicken proalbumin with an Arg-Phe-Ala-Arg processing site sequence was not a substrate for Kex2. A P1' arginine had a marked negative effect on processing and N-terminal sequence analysis confirmed that cleavage was occurring at the P1-P1' bond. The sequence context surrounding the classical dibasic site is critical in determining susceptibility to cleavage by the Kex2 protease.
Collapse
Affiliation(s)
- E C Ledgerwood
- Molecular Pathology Laboratory, Christchurch Hospital, New Zealand
| | | | | | | |
Collapse
|
22
|
Post-translational requirements for functional factor V and factor VIII secretion in mammalian cells. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)32558-9] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
|
23
|
Brennan SO, Nakayama K. Furin has the proalbumin substrate specificity and serpin inhibitory properties of an in situ hepatic convertase. FEBS Lett 1994; 338:147-51. [PMID: 8307172 DOI: 10.1016/0014-5793(94)80353-6] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Furin, a KEX2 protease homolog with high RNA expression in the liver is an excellent candidate as a hepatic proprotein convertase. Here we show that purified recombinant furin has the same proalbumin specificity and serpin inhibitory properties as the in situ hepatic convertase. There was rapid cleavage at the -RRD- site of normal human proalbumin but there no significant cleavage of natural unprocessed variants with cleavage site sequences of -RRV-, -HRD-, -RQD-, or -CRD-. Cleavage of the latter was not increased by S-aminoethylation. Furin was specifically inhibited by alpha 1-antitrypsin Pittsburgh (358 Met-->Arg), (K1/2 = 3 microM) but not by 50 microM normal antitrypsin M or by antithrombin, however, antithrombin/heparin was a good inhibitor (K1/2 = 9 microM). The pH optimum for proalbumin cleavage was between pH 5.5 and 6.0, indicating that furin is potentially fully active within secretory vesicles, the site of proalbumin cleavage.
Collapse
Affiliation(s)
- S O Brennan
- Molecular Pathology Laboratory, Clinical Biochemistry Christchurch Hospital, New Zealand
| | | |
Collapse
|
24
|
Rehemtulla A, Barr PJ, Rhodes CJ, Kaufman RJ. PACE4 is a member of the mammalian propeptidase family that has overlapping but not identical substrate specificity to PACE. Biochemistry 1993; 32:11586-90. [PMID: 8218226 DOI: 10.1021/bi00094a015] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Proteins that transit the constitutive pathway of secretion frequently require proteolytic processing after a pair of basic amino acids to attain their full functional activity. A ubiquitously expressed calcium-dependent subtilisin-like serine protease, named PACE or furin, can cleave precursor polypeptides specifically at pairs of basic amino acids where an arginine residue is present in the P4 position. Another member of this protease family, PACE4, was cloned recently by a PCR-based strategy and was also shown to be ubiquitously expressed. We have expressed PACE4 by transient DNA transfection of COS-1 cells and have shown that the cDNA encodes a 120-kDa polypeptide that is present in cell extracts but not in conditioned medium of transfected cells. The substrate specificities of PACE and PACE4 for cleavage of pro-von Willebrand factor were studied in parallel using a transient DNA cotransfection system. Like PACE, PACE4 was able to process pro-vWF to its mature form, and efficient cleavage required both the P4 arginine and the P2 lysine. These data, taken together with previously published data showing that PACE4 cannot process pro-factor IX, demonstrate that PACE and PACE4 have overlapping but not identical substrate specificities. Further differences between PACE and PACE4 specificities were elucidated by monitoring inhibition of processing activity mediated by the serine protease inhibitor alpha 1-antitrypsin Pittsburgh mutant. Pro-vWF processing by PACE was inhibited by expression of the alpha 1-antitrypsin Pittsburgh mutant, whereas processing of pro-vWF by PACE4 was not affected.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- A Rehemtulla
- Department of Molecular and Cellular Genetics, Genetics Institute, Cambridge, Massachusetts 02148
| | | | | | | |
Collapse
|
25
|
Anderson ED, Thomas L, Hayflick JS, Thomas G. Inhibition of HIV-1 gp160-dependent membrane fusion by a furin-directed alpha 1-antitrypsin variant. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(19)74548-7] [Citation(s) in RCA: 152] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
|
26
|
Rufaut N, Brennan S, Hakes D, Dixon J, Birch N. Purification and characterization of the candidate prohormone-processing enzyme SPC3 produced in a mouse L cell line. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(20)80727-3] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
27
|
Zan WC, Xu WF, Chi CW. Protein and gene structure analysis of an albumin genetic variant: proalbumin Wu Yang (-2 Arg-->His). INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1993; 41:441-6. [PMID: 8320037 DOI: 10.1111/j.1399-3011.1993.tb00463.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
An electrophoretically slow genetic variant of human serum albumin was isolated from a patient with bis-albuminemia in Xin Jiang who originated in the province of He Nan, county Wu Yang. Based on the FPLC-CNBr peptide profiles of the variant and normal albumins, the mutated CNBr peptide of the variant was found. Both the mutated and corresponding normal CNBr peptides were further subjected to trypsin digestion. An additional peptide peak from the mutated CNBr peptide was found in the HPLC mapping. The amino acid sequence of this peptide was determined to be Gly-Val-Phe-His-Arg corresponding to the fragment of albumin propeptide from position -5 to -1 with an -2 Arg-->His mutation. The N-terminal sequence of the mutated CNBr peptide was also determined to be Arg-Gly-Val-Phe-His*-Arg-Asp-Ala-His-Lys-, namely the N-terminal part of the mutated proalbumin. According to the known genomic structure of proalbumin, the gene fragments neighbouring the propeptide DNA sequences of the normal and variant albumins were amplified in vitro by polymerase chain reaction. The PCR products with 390 bp were then cloned into M13 vector, respectively. The nucleotide sequence analyses demonstrated that the codon CGT for -2 Arg was mutated to CAT for His. Thus, the point substitution was confirmed both at protein and gene levels. The above genetic variant of albumin was named proalbumin Wu Yang (-2 Arg-->His) being the first instance of the Lille type found in China.
Collapse
Affiliation(s)
- W C Zan
- Shanghai Institute of Biochemistry, Academia Sinica, China
| | | | | |
Collapse
|
28
|
Rhodes C, Thorne B, Lincoln B, Nielsen E, Hutton J, Thomas G. Processing of proopiomelanocortin by insulin secretory granule proinsulin processing endopeptidases. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53605-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
29
|
Oda K, Misumi Y, Ikehara Y, Brennan SO, Hatsuzawa K, Nakayama K. Proteolytic cleavages of proalbumin and complement Pro-C3 in vitro by a truncated soluble form of furin, a mammalian homologue of the yeast Kex2 protease. Biochem Biophys Res Commun 1992; 189:1353-61. [PMID: 1482351 DOI: 10.1016/0006-291x(92)90223-8] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
We have recently purified and characterized a truncated soluble form of furin from which the predicted transmembrane domain and cytoplasmic tail were deleted (Hatsuzawa, K., Nagahama, M., Takahashi, S., Takada, K., Murakami, K., and Nakayama, K. (1992) J. Biol. Chem. 267, 16094-16099). Our results showed that furin resembles the yeast Kex2 protease with respect to both its enzymic properties and substrate specificity. Here we demonstrate that the soluble form of furin is capable of converting the precursors of albumin and the third component of complement (proalbumin and pro-C3, respectively) in vitro to mature proteins. Thus furin mimics the Ca(2+)-dependent proalbumin and pro-C3 convertases found in the Golgi membranes (Brennan, S. O., and Peach, R. J. (1988) FEBS Lett. 229, 167-170; Oda, K. (1992) J. Biol. Chem. 267, 17465-17471). Furthermore we show that the variant alpha 1-antitrypsin Pittsburgh, which is a specific inhibitor of the Golgi proalbumin convertase, inhibits not only the Golgi pro-C3 convertase, but also the soluble furin. These results suggest a role for furin in the cleavage of proproteins transported via the constitutive pathway.
Collapse
Affiliation(s)
- K Oda
- Department of Biochemistry, Fukuoka University School of Medicine, Japan
| | | | | | | | | | | |
Collapse
|
30
|
|
31
|
Cloning and functional expression of Dfurin2, a subtilisin-like proprotein processing enzyme of Drosophila melanogaster with multiple repeats of a cysteine motif. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)41914-x] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
|
32
|
Ledgerwood EC, George PM, Bathurst IC, Brennan SO. The predicted proteinase furin is not the hepatic proalbumin convertase. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1159:9-12. [PMID: 1390914 DOI: 10.1016/0167-4838(92)90068-o] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Rat and chicken liver microsomal membranes were used to investigate the relationship between proalbumin processing activity and the predicted proteinase furin. Two polyclonal antisera directed against the predicted catalytic domain of furin showed the highest level of immunoreactivity in a microsomal fraction that had minimal proalbumin converting activity. Extracts of the fraction containing most converting activity lacked detectable furin. In addition, the proalbumin convertase was not inhibited by the anti-furin antisera. These results strongly suggest that furin is not responsible for the in vivo cleavage of proalbumin.
Collapse
Affiliation(s)
- E C Ledgerwood
- Molecular Pathology Laboratory, Christchurch Hospital, New Zealand
| | | | | | | |
Collapse
|
33
|
Molloy S, Bresnahan P, Leppla S, Klimpel K, Thomas G. Human furin is a calcium-dependent serine endoprotease that recognizes the sequence Arg-X-X-Arg and efficiently cleaves anthrax toxin protective antigen. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42016-9] [Citation(s) in RCA: 544] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
34
|
|
35
|
Affiliation(s)
- M A Romanos
- Department of Cell Biology, Wellcome Research Laboratories, Beckenham, Kent, U.K
| | | | | |
Collapse
|
36
|
Stanton C, Wallin R. Processing and trafficking of clotting factor X in the secretory pathway. Effects of warfarin. Biochem J 1992; 284 ( Pt 1):25-31. [PMID: 1599403 PMCID: PMC1132692 DOI: 10.1042/bj2840025] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Clotting factor X undergoes several post-translational processing steps in the liver before the protein appears in blood as the mature two-chain zymogen. In this study we have followed the factor X precursor through the secretory pathway in rat liver in order to identify the site for proteolytic processing of the precursor into a two-chain form and the site for warfarin inhibition of precursor trafficking within the pathway. Isolated rat liver Golgi apparatus was shown to harbour two single-chains of factor X precursors of 70 and 74 kDa and the heavy (50 kDa) and light chains of factor X. It was demonstrated that the two-chain factor X form was produced from a late processing form of the factor X precursor, which indicated that the site for proteolytic conversion to a two-chain form was in the trans-Golgi compartment. The 70 and 74 kDa single-chain precursors and also the light chain of the two-chain form were shown to contain the factor X propeptide which is normally removed before the coagulation factor appears in blood. The data demonstrate that intra-chain cleavage of a single chain factor X precursor in the trans-Golgi compartment can precede release of the propeptide. Warfarin was shown to affect trafficking of the factor X precursor between the endoplasmic reticulum (ER) and the Golgi apparatus. The data suggest a link between vitamin K-dependent gamma-carboxylation of the precursor and its exit from the ER. Warfarin administration resulted in accumulation of factor X precursors associated with the ER membrane. These precursors appear to be stabilized from intracellular degradation while in the ER. In contrast to the large increase in the factor X precursor concentration in the ER membrane, there was no change in the prothrombin precursor concentration as a result of warfarin action on the liver. However, intracellular turnover of the microsomal prothrombin precursor pool in warfarin-treated rats resulted in a pool of less negatively charged proteins, indicating ongoing protein synthesis but inhibition of gamma-carboxylation. The data are consistent with previous findings [Wallin & Martin (1988) J. Biol. Chem. 263, 9994-10001] suggesting that prothrombin and factor X are processed differently by the vitamin K-dependent carboxylase in the ER membrane.
Collapse
Affiliation(s)
- C Stanton
- Department of Medicine/Rheumatology, Bowman Gray School of Medicine, Wake Forest University, Winston-Salem, NC 27157
| | | |
Collapse
|
37
|
Seidah NG, Chrétien M. Proprotein and prohormone convertases of the subtilisin family Recent developments and future perspectives. Trends Endocrinol Metab 1992; 3:133-40. [PMID: 18407092 DOI: 10.1016/1043-2760(92)90102-7] [Citation(s) in RCA: 122] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Limited proteolysis of precursors at specific pairs of basic residues and/or at single basic amino acids is a widespread mechanism by which the cell expresses a repertoire of biologically active proteins and peptides. The cloning and cellular expression of the yeast KEX2 gene product demonstrated that this enzyme belongs to the subtilisin family of serine proteinases, and that it exhibits exquisite selectivity for cleavage post pairs of basic residues in a number of yeast and mammalian precursors. The search for the homologous mammalian convertases led to the identification and molecular cloning of three new members of the family, furin, PCI, and PC2. Whereas furin is almost ubiquitous, PCI and PC2 localize mostly in endocrine and neuroendocrine tissues and cells. Coexpression of each gene product with proproteins demonstrated that each proteinase selectively cleaved these precursors at distinct pairs of LysArg and ArgArg residues. In human and mouse, the genes coding for furin, PCI, and PC2 reside on three different chromosomes. Overexpression of PO and PC2 in Sf9 cells in the baculovirus system demonstrated that these enzymes are not secreted and that they both retained their N-terminal prodomain.
Collapse
Affiliation(s)
- N G Seidah
- Laboratories of Biochemical and Molecular Neuroendocrinology, respectively, Clinical Research Institute of Montréal, Montréal, Québec, Canada H2W 1R7
| | | |
Collapse
|
38
|
Seeboth PG, Heim J. In-vitro processing of yeast alpha-factor leader fusion proteins using a soluble yscF (Kex2) variant. Appl Microbiol Biotechnol 1992; 35:771-6. [PMID: 1367896 DOI: 10.1007/bf00169893] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The Saccharomyces cerevisiae KEX2 gene encodes the membrane-bound endoprotease yscF, which is responsible for the site-specific endoproteolytic cleavages at pairs of basic amino acid residues in the alpha-factor precursor. In order to obtain soluble yscF activity, a mutant KEX2 gene lacking 600 bp coding for the C-terminal 200 amino acids was constructed. Expression of the truncated KEX2 gene in yeast led to the secretion of an active soluble yscF protein (yscFs). The soluble yscF protein is able to efficiently cleave heterologous protein precursors in-vitro, as demonstrated for alpha-factor leader-hIGF1 and alpha-factor leader-hirudin fusion proteins.
Collapse
Affiliation(s)
- P G Seeboth
- Ciba-Geigy Ltd., Biotechnology Department, Basel, Switzerland
| | | |
Collapse
|
39
|
Johansen TE, Schifter S, Vogel CK, Tolstoy S, Schwartz TW. Processing of pro-CGRP in a rat medullary thyroid carcinoma cell line transfected with protease inhibitors. Mol Cell Endocrinol 1991; 82:51-60. [PMID: 1761166 DOI: 10.1016/0303-7207(91)90008-g] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
A rat medullary thyroid carcinoma cell line, CA77, was used to study the effect of a series of biosynthesized protease inhibitors on the proteolytic cleavage of the endogenously synthesized pro-CGRP. This cell line efficiently converted the pro-CGRP to mature CGRP as assessed by chromatography of cell extracts followed by radioimmunoassay for CGRP. CA77 cells were transfected with expression vectors encoding protease inhibitors: the Arg-serpins, alpha 1-antitrypsin Pittsburgh (358 Met----Arg) and plasminogen activator inhibitor 1, the Kazal type serine protease inhibitor, pancreatic secretory trypsin inhibitor, and the general thiol protease inhibitor, cystatin C. Only the chromatography of cell extracts from CA77 cells transfected with a plasmid encoding cystatin C showed an apparent higher content of unprocessed pro-CGRP as compared to non-transfected cells. No effect on pro-CGRP processing could be measured in the CA77 cells transfected with plasmids encoding the three serine protease inhibitors. CA77 cells were also transfected with two constructs encoding chimeric proteins consisting of cystatin C and the precursor for neuropeptide Y. Release experiments using 8-bromo cAMP as the secretagogue showed that the chimer was co-released with CGRP. However, no effect of this chimer upon pro-CGRP processing could be detected. It is concluded that the processing of pro-CGRP in the CA77 cell line was very efficient and that four different protease inhibitors and two cystatin C/NPY chimers synthesized by this neuroendocrine cell line had only minimal effect upon the processing of CGRP.
Collapse
Affiliation(s)
- T E Johansen
- University Department of Clinical Chemistry, Rigshospitalet, Copenhagen, Denmark
| | | | | | | | | |
Collapse
|
40
|
The processing of human proinsulin and chicken proalbumin by rat hepatic vesicles suggests a convertase specific for X-Y-Arg-Arg or Arg-X-Y-Arg sequences. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)54667-6] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
41
|
Fleer R, Yeh P, Amellal N, Maury I, Fournier A, Bacchetta F, Baduel P, Jung G, L'Hôte H, Becquart J. Stable Multicopy Vectors for High–Level Secretion of Recombinant Human Serum Albumin by Kluyveromyces Yeasts. ACTA ACUST UNITED AC 1991; 9:968-75. [PMID: 1367806 DOI: 10.1038/nbt1091-968] [Citation(s) in RCA: 117] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
We have designed stable pKD1 derivatives for efficient secretion of recombinant human serum albumin (rHSA) by industrial strains of Kluyveromyces yeasts. A comparison of this multi-copy expression system with isogenic cassettes integrated at chromosomal loci demonstrated that high level secretion of rHSA is a function of gene dosage in K. lactis. Various signal sequences could be used, and the secretion levels were independent of the presence of the native pro peptide. The mitotic stability of the pKD1-based expression vectors was found to be species and strain dependent and was influenced by promoter strength and culture conditions. Vector stability was drastically enhanced when the HSA gene was expressed from an inducible promoter: 90% of the transformed cells still harbored the vector after 100 generations of non-selective growth in uninduced culture conditions. Secretion levels in the range of several grams per liter of correctly folded and processed rHSA were obtained at the pilot scale, thus making the industrial production of pharmaceutical-grade, Kluyveromyces-derived rHSA economically feasible.
Collapse
Affiliation(s)
- R Fleer
- Rhône-Poulenc Rorer, Biotechnology Department, Vitry sur Seine, France
| | | | | | | | | | | | | | | | | | | |
Collapse
|
42
|
Misumi Y, Oda K, Fujiwara T, Takami N, Tashiro K, Ikehara Y. Functional expression of furin demonstrating its intracellular localization and endoprotease activity for processing of proalbumin and complement pro-C3. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)55396-5] [Citation(s) in RCA: 114] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
|
43
|
Barr PJ, Mason OB, Landsberg KE, Wong PA, Kiefer MC, Brake AJ. cDNA and gene structure for a human subtilisin-like protease with cleavage specificity for paired basic amino acid residues. DNA Cell Biol 1991; 10:319-28. [PMID: 1713771 DOI: 10.1089/dna.1991.10.319] [Citation(s) in RCA: 93] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A cDNA encoding the human fur gene product was isolated from a human hepatoma cell line. The cDNA encodes a protein with significant amino acid sequence identity to the prokaryotic subtilisin family of serine proteases. More extensive sequence identity was found when the protein was compared with eukaryotic proteases such as PRB1 of Saccharomyces cerevisiae, and with PC2 and PC3, the only other known mammalian subtilisin-like proteases. In contrast to these proteins, however, the fur gene product shares a more extensive topographic and functional homology with the KEX2 endoprotease of S. cerevisiae. Each protease contains a signal peptide, a glycosylated extra cytoplasmic domain, a hydrophobic membrane-spanning region, and a short, hydrophilic "tail" sequence. As with KEX2, the expressed human protease was shown to cleave mammalian proproteins at their paired basic amino acid processing sites. We have, therefore, proposed the function-based acronym PACE (paired basic amino acid cleaving enzyme) for this prototypic mammalian proprotein processing enzyme.
Collapse
Affiliation(s)
- P J Barr
- Chiron Corporation, Emeryville, CA 94608
| | | | | | | | | | | |
Collapse
|
44
|
Abstract
Human prorenin is the enzymatically inactive biosynthetic precursor of renin. Recent interest has focused on the posttranslational sorting and processing of prorenin to renin since markedly increased levels of circulating prorenin have been associated with both physiological and pathological changes. These observations raise the question of whether prorenin processing may be a regulatory event in renin production in the kidney. In the juxtaglomerular cells of the kidney, prorenin can be sorted to either of two pathways: 1) the regulated pathway, which is mediated by secretory granules, where a thiol protease resembling cathepsin B processes prorenin to renin by cleavage of the amino terminal 43-amino acid prosegment, which allows exposure of the active site of renin, or 2) the constitutive pathway, which is not regulated and does not involve conversion of prorenin to renin. Studies in which segments of prorenin are modified by site-directed mutagenesis suggest that the prosegment and glycosylation are not required for sorting, although they may influence or participate in sorting, or both. Certain areas in the prosegment are important determinants of enzyme activity and ability to cleave the prosegment. Further structural analysis of prorenin will be useful to assess details of its sorting and processing. In addition, a number of extrarenal tissues such as uterine lining, ovarian theca, corpus luteum, pituitary, and adrenal, express the renin gene. These tissues have different capabilities to sort and process prorenin compared with kidney, and some tissues secrete only prorenin. Whether prorenin-to-renin conversion is necessary to activate these local renin-angiotensin systems is a key issue.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- W A Hsueh
- Department of Medicine, University of Southern California School of Medicine, Los Angeles 90033
| | | |
Collapse
|
45
|
Bresnahan PA, Leduc R, Thomas L, Thorner J, Gibson HL, Brake AJ, Barr PJ, Thomas G. Human fur gene encodes a yeast KEX2-like endoprotease that cleaves pro-beta-NGF in vivo. J Cell Biol 1990; 111:2851-9. [PMID: 2269657 PMCID: PMC2116363 DOI: 10.1083/jcb.111.6.2851] [Citation(s) in RCA: 322] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Extracts from BSC-40 cells infected with vaccinia recombinants expressing either the yeast KEX2 prohormone endoprotease or a human structural homologue (fur gene product) contained an elevated level of a membrane-associated endoproteolytic activity that could cleave at pairs of basic amino acids (-LysArg- and -ArgArg-). The fur-directed activity (furin) shared many properties with Kex2p including activity at pH 7.3 and a requirement for calcium. By using antifurin antibodies, immunoblot analysis detected two furin translation products (90 and 96 kD), while immunofluorescence indicated localization to the Golgi apparatus. Coexpression of either Kex2p or furin with the mouse beta-nerve growth factor precursor (pro-beta-NGF) resulted in greatly enhanced conversion of the precursor to mature nerve growth factor. Thus, the sequence homology shared by furin and the yeast KEX2 prohormone processing enzyme is reflected by significant functional homology both in vitro and in vivo.
Collapse
Affiliation(s)
- P A Bresnahan
- Vollum Institute, Oregon Health Sciences University, Portland 97201-3098
| | | | | | | | | | | | | | | |
Collapse
|
46
|
Specificity of yeast KEX2 protease for variant human proalbumins is identical to the in vivo specificity of the hepatic proalbumin convertase. J Biol Chem 1990. [DOI: 10.1016/s0021-9258(18)45765-1] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
|
47
|
Wise RJ, Barr PJ, Wong PA, Kiefer MC, Brake AJ, Kaufman RJ. Expression of a human proprotein processing enzyme: correct cleavage of the von Willebrand factor precursor at a paired basic amino acid site. Proc Natl Acad Sci U S A 1990; 87:9378-82. [PMID: 2251280 PMCID: PMC55168 DOI: 10.1073/pnas.87.23.9378] [Citation(s) in RCA: 227] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Intracellular proteolytic processing of precursor polypeptides is an essential step in the maturation of many proteins, including plasma proteins, hormones, neuropeptides, and growth factors. Most frequently, propeptide cleavage occurs after paired basic amino acid residues. To date, no mammalian propeptide processing enzyme with such specificity has been purified or cloned and functionally characterized. We report the isolation and functional expression of a cDNA encoding a propeptide-cleaving enzyme from a human liver cell line. The encoded protein, called PACE (paired basic amino acid cleaving enzyme), has structural homology to the well-characterized subtilisin-like protease Kex2 from yeast. The functional specificity of PACE for mediating propeptide cleavage at paired basic amino acid residues was demonstrated by the enhancement of propeptide processing of human von Willebrand factor when coexpressed with PACE in COS-1 cells.
Collapse
Affiliation(s)
- R J Wise
- Genetics Institute, Cambridge, MA 02140
| | | | | | | | | | | |
Collapse
|
48
|
van de Ven WJ, Voorberg J, Fontijn R, Pannekoek H, van den Ouweland AM, van Duijnhoven HL, Roebroek AJ, Siezen RJ. Furin is a subtilisin-like proprotein processing enzyme in higher eukaryotes. Mol Biol Rep 1990; 14:265-75. [PMID: 2094803 DOI: 10.1007/bf00429896] [Citation(s) in RCA: 194] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The human fur gene encodes a protein, designated furin, the C-terminal half of which contains a transmembrane and a cysteine-rich receptor-like domain. The N-terminal half of furin exhibits striking primary amino acid sequence similarity to the catalytic domains of members of the subtilisin family of serine proteases. We here report characteristics of the furin protein and propose a three-dimensional model for its presumptive catalytic domain with characteristics, that predict furin to exhibit an endoproteolytic cleavage selectivity at paired basic residues. This prediction is substantiated by transfection and cotransfection experiments, using COS-1 cells. Full length fur cDNA evokes the specific synthesis of two polypeptides of about 100 kDa and 90 kDa as appeared from Western blot analysis of transfected COS-1 cells using a polyclonal anti-furin antiserum. Functional analysis of furin was performed by cotransfection of fur cDNA with cDNA encoding the 'wild type' precursor of von Willebrand factor (pro-vWF) and revealed an increased proteolytic processing of provWF. In contrast, cotransfection of fur cDNA with a recombinant derivative (provWFgly763), having the arginine residue adjacent to the proteolytic cleavage site (arg-ser-lys-arg) replaced by glycine, revealed that provWFgly763 is not processed by the fur gene product. We conclude that in higher eukaryotes, furin is the prototype of a subtilisin-like class of proprotein processing enzymes with substrate specificity for paired basic residues.
Collapse
Affiliation(s)
- W J van de Ven
- Molecular Oncology Section, University of Leuven, Belgium
| | | | | | | | | | | | | | | |
Collapse
|
49
|
Misumi Y, Ohkubo K, Sohda M, Takami N, Oda K, Ikehara Y. Intracellular processing of complement pro-C3 and proalbumin is inhibited by rat alpha 1-protease inhibitor variant (Met352----Arg) in transfected cells. Biochem Biophys Res Commun 1990; 171:236-42. [PMID: 2393391 DOI: 10.1016/0006-291x(90)91382-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Complement C3, when its cDNA was transfected into COS-1 cells, was synthesized as a precursor, pro-C3, which was intracellularly processed into the alpha and beta subunits, although not completely. A cDNA for rat alpha 1-protease inhibitor (alpha 1-PI) was mutated in vitro to encode its variant with the modified active site (Met352----Arg). In cells co-transfected with the mutant alpha 1-PI cDNA and the C3 cDNA, pro-C3 expressed was secreted without being processed into the subunits. Co-transfection of the mutant alpha 1-PI cDNA and the albumin cDNA also resulted in the inhibition of intracellular conversion of proalbumin into serum-type albumin. No inhibition of the processing of each preform was observed in cells co-transfected with the normal alpha 1-PI cDNA. Taken together, the results indicate that the alpha 1-PI variant (Met352----Arg) expressed inhibits specifically an intracellular enzyme which is involved in the proteolytic processing of both pro-C3 and proalbumin.
Collapse
Affiliation(s)
- Y Misumi
- Department of Biochemistry and Radioisotope Laboratory, Fukuoka University School of Medicine, Japan
| | | | | | | | | | | |
Collapse
|
50
|
Spaete RR, Saxena A, Scott PI, Song GJ, Probert WS, Britt WJ, Gibson W, Rasmussen L, Pachl C. Sequence requirements for proteolytic processing of glycoprotein B of human cytomegalovirus strain Towne. J Virol 1990; 64:2922-31. [PMID: 2159553 PMCID: PMC249476 DOI: 10.1128/jvi.64.6.2922-2931.1990] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Truncated versions of the human cytomegalovirus (CMV) strain Towne glycoprotein B (gB) gene were stably expressed in CHO cell lines. The calcium-specific ionophore A23187 inhibited proteolytic cleavage of C-terminal-truncated gB expressed by cell line 67.77. These inhibition studies also showed that the 93-kilodalton cleavage product most likely represents the N-terminal cleavage fragment of gB. The ionophore carboxyl cyanide m-chlorophenyl-hydrazone was used to show that proteolytic cleavage of gB did not occur in the endoplasmic reticulum. Two-dimensional polyacrylamide gel electrophoresis demonstrated that the N- and C-terminal cleavage products of gB remained associated by disulfide linkages after cleavage. Expression studies using constructs in which 80% or all of the N terminus was deleted demonstrated that the N terminus was required for secretion of the gB molecule. The amino acid sequence at the site of cleavage was shown to be critical for cleavage by a cellular protease. Our results indicate that an arginine-to-threonine change at either amino acid 457 or 460, a lysine-to-glutamine change at amino acid 459, or all three substitutions together block gB cleavage. The effect on proteolysis of the arginine-to-threonine amino acid change at residue 457 (position -4 relative to the cleavage site) demonstrated that a basic pair of amino acids at the endoproteolytic processing site is not the only requirement in cis for gB cleavage.
Collapse
Affiliation(s)
- R R Spaete
- Chiron Corporation, Emeryville, California 94608-2916
| | | | | | | | | | | | | | | | | |
Collapse
|