1
|
Mótyán JA, Tőzsér J. The human retroviral-like aspartic protease 1 (ASPRV1): from in vitro studies to clinical correlations. J Biol Chem 2024:107634. [PMID: 39098535 DOI: 10.1016/j.jbc.2024.107634] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 07/25/2024] [Accepted: 07/27/2024] [Indexed: 08/06/2024] Open
Abstract
The human retroviral-like aspartic protease 1 (ASPRV1) is a retroviral-like protein that was first identified in the skin due to its expression in the stratum granulosum layer of the epidermis. Accordingly, it is also referred to as skin-specific aspartic protease (SASPase). Similar to the retroviral polyproteins, the full-length ASPRV1 also undergoes self-proteolysis, the processing of the precursor is necessary for the auto-activation of the protease domain. ASPRV1's functions are well established at the level of the skin: it is part of the epidermal proteolytic network and has a significant contribution to skin moisturization via the limited proteolysis of filaggrin; its only natural protein substrate identified so far. Filaggrin and ASPRV1 are also specific for mammalians, these proteins provide unique features for the skins of these species, and the importance of filaggrin processing in hydration is proved by the fact that some ASPRV1 mutations are associated with skin diseases such as ichthyosis. ASPRV1 was also found to be expressed in macrophage-like neutrophil cells, indicating that its functions are not limited to the skin. In addition, differential expression of ASPRV1 was detected in many diseases, with yet unknown significance. The currently known enzymatic characteristics - that had been revealed mainly by in vitro studies - and correlations with pathogenic phenotypes imply potentially important functions in multiple cell types, which makes the protein a promising target of functional studies. In this review we describe the currently available knowledge and future perspective in regard to ASPRV1.
Collapse
Affiliation(s)
- János András Mótyán
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary.
| | - József Tőzsér
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| |
Collapse
|
2
|
Liu K, Hu S, Qiu L, Wang M, Zhang Z, Sun G, Zhang Y. Nrf1 is not a direct target gene of SREBP1, albeit both are integrated into the rapamycin-responsive regulatory network in human hepatoma cells. PLoS One 2023; 18:e0294508. [PMID: 38011090 PMCID: PMC10681226 DOI: 10.1371/journal.pone.0294508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Accepted: 11/02/2023] [Indexed: 11/29/2023] Open
Abstract
The essential role of protein degradation by ubiquitin-proteasome system is exerted primarily for maintaining cellular protein homeostasis. The transcriptional activation of proteasomal genes by mTORC1 signaling depends on Nrf1, but whether this process is directly via SREBP1 remains elusive. In this study, our experiment evidence revealed that Nrf1 is not a direct target of SREBP1, although both are involved in the rapamycin-responsive regulatory networks. Closely scrutinizing two distinct transcriptomic datasets unraveled no significant changes in transcriptional expression of Nrf1 and almost all proteasomal subunits in either siSREBP2-silencing cells or SREBP1-∕-MEFs, when compared to equivalent controls. However, distinct upstream signaling to Nrf1 dislocation by p97 and its processing by DDI1/2, along with downstream proteasomal expression, may be monitored by mTOR signaling, to various certain extents, depending on distinct experimental settings in different types of cells. Our further evidence has been obtained from DDI1-∕-(DDI2insC) cells, demonstrating that putative effects of mTOR on the rapamycin-responsive signaling to Nrf1 and proteasomes may also be executed partially through a DDI1/2-independent mechanism, albeit the detailed regulatory events remain to be determined.
Collapse
Affiliation(s)
- Keli Liu
- Bioengineering College, Chongqing University, Shapingba District, Chongqing, China
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, Jiangjin District, Chongqing, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Chongqing University, Shapingba District, Chongqing, China
| | - Shaofan Hu
- Bioengineering College, Chongqing University, Shapingba District, Chongqing, China
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, Jiangjin District, Chongqing, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Chongqing University, Shapingba District, Chongqing, China
| | - Lu Qiu
- Bioengineering College, Chongqing University, Shapingba District, Chongqing, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Chongqing University, Shapingba District, Chongqing, China
- School of Life Sciences, Zhengzhou University, Zhengzhou, Henan, China
| | - Meng Wang
- Bioengineering College, Chongqing University, Shapingba District, Chongqing, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Chongqing University, Shapingba District, Chongqing, China
| | - Zhengwen Zhang
- Laboratory of Neuroscience, Institute of Cognitive Neuroscience and School of Pharmacy, University College London, London, England, United Kingdom
| | - Guiyin Sun
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, Jiangjin District, Chongqing, China
| | - Yiguo Zhang
- Chongqing University Jiangjin Hospital, School of Medicine, Chongqing University, Jiangjin District, Chongqing, China
- The Laboratory of Cell Biochemistry and Topogenetic Regulation, College of Bioengineering, Chongqing University, Shapingba District, Chongqing, China
| |
Collapse
|
3
|
Arrigoni R, Santacroce L, Ballini A, Palese LL. AI-Aided Search for New HIV-1 Protease Ligands. Biomolecules 2023; 13:biom13050858. [PMID: 37238727 DOI: 10.3390/biom13050858] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2023] [Revised: 05/15/2023] [Accepted: 05/16/2023] [Indexed: 05/28/2023] Open
Abstract
The availability of drugs capable of blocking the replication of microorganisms has been one of the greatest triumphs in the history of medicine, but the emergence of an ever-increasing number of resistant strains poses a serious problem for the treatment of infectious diseases. The search for new potential ligands for proteins involved in the life cycle of pathogens is, therefore, an extremely important research field today. In this work, we have considered the HIV-1 protease, one of the main targets for AIDS therapy. Several drugs are used today in clinical practice whose mechanism of action is based on the inhibition of this enzyme, but after years of use, even these molecules are beginning to be interested by resistance phenomena. We used a simple artificial intelligence system for the initial screening of a data set of potential ligands. These results were validated by docking and molecular dynamics, leading to the identification of a potential new ligand of the enzyme which does not belong to any known class of HIV-1 protease inhibitors. The computational protocol used in this work is simple and does not require large computational power. Furthermore, the availability of a large number of structural information on viral proteins and the presence of numerous experimental data on their ligands, with which it is possible to compare the results obtained with computational methods, make this research field the ideal terrain for the application of these new computational techniques.
Collapse
Affiliation(s)
- Roberto Arrigoni
- Bioenergetics and Molecular Biotechnologies (IBIOM), CNR Institute of Biomembranes, 70125 Bari, Italy
| | - Luigi Santacroce
- Interdisciplinary Department of Medicine (DIM), University of Bari Aldo Moro, 70124 Bari, Italy
| | - Andrea Ballini
- Department of Clinical and Experimental Medicine, University of Foggia, 71122 Foggia, Italy
| | - Luigi Leonardo Palese
- Department of Translational Biomedicine and Neurosciences-(DiBraiN), University of Bari Aldo Moro, 70124 Bari, Italy
| |
Collapse
|
4
|
Mótyán JA, Kassay N, Matúz K, Tőzsér J. Different Mutation Tolerance of Lentiviral (HIV-1) and Deltaretroviral (BLV and HTLV) Protease Precursors. Viruses 2022; 14:v14091888. [PMID: 36146695 PMCID: PMC9505669 DOI: 10.3390/v14091888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 08/17/2022] [Accepted: 08/24/2022] [Indexed: 11/16/2022] Open
Abstract
The bovine leukemia virus (BLV) and the human T-lymphothropic viruses (HTLVs) are members of the deltaretrovirus genus of Retroviridae family. An essential event of the retroviral life cycle is the processing of the polyproteins by the viral protease (PR); consequently, these enzymes became important therapeutic targets of the anti-retroviral drugs. As compared to human immunodeficiency viruses (HIVs), the deltaretroviruses have a different replication strategy, as they replicate predominantly in the DNA form, by forcing the infected cell to divide, unlike HIV-1, which replicates mainly by producing a vast number of progeny virions and by reinfection. Due to bypassing the error-prone reverse transcription step of replication, the PRs of deltaretroviruses did not undergo such extensive evolution as HIV PRs and remained more highly conserved. In this work, we studied the abilities of wild-type and modified BLV, HTLV (type 1, 2 and 3), and HIV-1 PRs (fused to an N-terminal MBP tag) for self-processing. We designed a cleavage site mutant MBP-fused BLV PR precursor as well, this recombinant enzyme was unable for self-proteolysis, the MBP fusion tag decreased its catalytic efficiency but showed an unusually low Ki for the IB-268 protease inhibitor. Our results show that the HTLV and BLV deltaretrovirus PRs exhibit lower mutation tolerance as compared to HIV-1 PR, and are less likely to retain their activity upon point mutations at various positions, indicating a higher flexibility of HIV-1 PR in tolerating mutations under selective pressure.
Collapse
Affiliation(s)
- János András Mótyán
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Correspondence: (J.A.M.); (J.T.); Tel.: +36-52-512-900 (J.A.M. & J.T.)
| | - Norbert Kassay
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - Krisztina Matúz
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
| | - József Tőzsér
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary
- Correspondence: (J.A.M.); (J.T.); Tel.: +36-52-512-900 (J.A.M. & J.T.)
| |
Collapse
|
5
|
Zhang H, Xue Y, Yang X, Liu J, Liu Q. Toxoplasma gondii UBL-UBA shuttle proteins regulate several important cellular processes. FASEB J 2021; 35:e21898. [PMID: 34727385 DOI: 10.1096/fj.202100662rr] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 08/06/2021] [Accepted: 08/18/2021] [Indexed: 11/11/2022]
Abstract
Toxoplasma gondii is an obligate intracellular apicomplexan parasite causing lethal diseases in immunocompromised patients. UBL-UBA shuttle proteins (DDI1, RAD23, and DSK2) are important components of the ubiquitin-proteasome system. By degrading ubiquitinated proteins, UBL-UBA shuttle proteins regulate many cellular processes. However, the specific processes regulated by UBL-UBA shuttle proteins remain elusive. Here, we revealed that the deletion of shuttle proteins results in a selective accumulation of ubiquitinated proteins in the nucleus and aberrant DNA replication. ROP18 was mistargeted and accumulated in the shuttle protein mutant strain, resulting in the recruitment of immunity-related GTPases to the parasitophorous vacuole membrane (PVM). Furthermore, the mistargeting of ROP18 and the recruitment of Irgb6 to the PVM were also observed in the DDI1 mutant strain. DDI1 is a nonclassical UBL-UBA shuttle protein homologous to the HIV-1 protease. Molecular docking showed that DDI1 was a potential target of HIV-1 protease inhibitors. However, these inhibitors blocked the growth of T gondii in vitro but not in vivo. In conclusion, the Toxoplasma UBL-UBA shuttle protein regulates several important cellular processes and the mistargeting of ROP18 may be a representative of the abnormal homeostasis caused by shuttle protein mutation.
Collapse
Affiliation(s)
- Heng Zhang
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China.,Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Yangfei Xue
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China.,Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Xu Yang
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China.,Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Jing Liu
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China.,Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| | - Qun Liu
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, China.,Key Laboratory of Animal Epidemiology of the Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China
| |
Collapse
|
6
|
Development of a Bio-Layer Interferometry-Based Protease Assay Using HIV-1 Protease as a Model. Viruses 2021; 13:v13061183. [PMID: 34205716 PMCID: PMC8235736 DOI: 10.3390/v13061183] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Revised: 06/09/2021] [Accepted: 06/19/2021] [Indexed: 11/16/2022] Open
Abstract
Proteolytic enzymes have great significance in medicine and the pharmaceutical industry and are applied in multiple fields of life sciences. Therefore, cost-efficient, reliable and sensitive real-time monitoring methods are highly desirable to measure protease activity. In this paper, we describe the development of a new experimental approach for investigation of proteolytic enzymes. The method was designed by the combination of recombinant fusion protein substrates and bio-layer interferometry (BLI). The protease (PR) of human immunodeficiency virus type 1 (HIV-1) was applied as model enzyme to set up and test the method. The principle of the assay is that the recombinant protein substrates immobilized to the surface of biosensor are specifically cleaved by the PR, and the substrate processing can be followed by measuring change in the layer thickness by optical measurement. We successfully used this method to detect the HIV-1 PR activity in real time, and the initial rate of the signal decrease was found to be proportional to the enzyme activity. Substrates representing wild-type and modified cleavage sites were designed to study HIV-1 PR's specificity, and the BLI-based measurements showed differential cleavage efficiency of the substrates, which was proven by enzyme kinetic measurements. We applied this BLI-based assay to experimentally confirm the existence of extended binding sites at the surface of HIV-1 PR. We found the measurements may be performed using lysates of cells expressing the fusion protein, without primary purification of the substrate. The designed BLI-based protease assay is high-throughput-compatible and enables real-time and small-volume measurements, thus providing a new and versatile approach to study proteolytic enzymes.
Collapse
|
7
|
Kassay N, Mótyán JA, Matúz K, Golda M, Tőzsér J. Biochemical Characterization, Specificity and Inhibition Studies of HTLV-1, HTLV-2, and HTLV-3 Proteases. Life (Basel) 2021; 11:life11020127. [PMID: 33562087 PMCID: PMC7915765 DOI: 10.3390/life11020127] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Revised: 02/02/2021] [Accepted: 02/03/2021] [Indexed: 01/03/2023] Open
Abstract
The human T-lymphotropic viruses (HTLVs) are causative agents of severe diseases including adult T-cell leukemia. Similar to human immunodeficiency viruses (HIVs), the viral protease (PR) plays a crucial role in the viral life-cycle via the processing of the viral polyproteins. Thus, it is a potential target of anti-retroviral therapies. In this study, we performed in vitro comparative analysis of human T-cell leukemia virus type 1, 2, and 3 (HTLV-1, -2, and -3) proteases. Amino acid preferences of S4 to S1′ subsites were studied by using a series of synthetic oligopeptide substrates representing the natural and modified cleavage site sequences of the proteases. Biochemical characteristics of the different PRs were also determined, including catalytic efficiencies and dependence of activity on pH, temperature, and ionic strength. We investigated the effects of different HIV-1 PR inhibitors (atazanavir, darunavir, DMP-323, indinavir, ritonavir, and saquinavir) on enzyme activities, and inhibitory potentials of IB-268 and IB-269 inhibitors that were previously designed against HTLV-1 PR. Comparative biochemical analysis of HTLV-1, -2, and -3 PRs may help understand the characteristic similarities and differences between these enzymes in order to estimate the potential of the appearance of drug-resistance against specific HTLV-1 PR inhibitors.
Collapse
Affiliation(s)
- Norbert Kassay
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (N.K.); (K.M.); (M.G.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - János András Mótyán
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (N.K.); (K.M.); (M.G.)
- Correspondence: (J.A.M.); (J.T.); Tel.: +36-52-512-900 (J.A.M. & J.T.)
| | - Krisztina Matúz
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (N.K.); (K.M.); (M.G.)
| | - Mária Golda
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (N.K.); (K.M.); (M.G.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - József Tőzsér
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (N.K.); (K.M.); (M.G.)
- Correspondence: (J.A.M.); (J.T.); Tel.: +36-52-512-900 (J.A.M. & J.T.)
| |
Collapse
|
8
|
Biochemical Characterization of Human Retroviral-Like Aspartic Protease 1 (ASPRV1). Biomolecules 2020; 10:biom10071004. [PMID: 32640672 PMCID: PMC7408472 DOI: 10.3390/biom10071004] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Revised: 06/26/2020] [Accepted: 06/30/2020] [Indexed: 12/25/2022] Open
Abstract
The human retroviral-like aspartic protease 1 (ASPRV1) is a mammalian retroviral-like enzyme that catalyzes a critical proteolytic step during epidermal differentiation; therefore, it is also referred to as skin-specific aspartic protease (SASPase). Neutrophil granulocytes were also found recently to express ASPRV1 that is involved in the progression of acute chronic inflammation of the central nervous system, especially in autoimmune encephalomyelitis. Thus, investigation of ASPRV1 is important due to its therapeutic or diagnostic potential. We investigated the structural characteristics of ASPRV1 by homology modeling; analysis of the proposed structure was used for interpretation of in vitro specificity studies. For in-vitro characterization, activities of SASP28 and SASP14 enzyme forms were measured using synthetic oligopeptide substrates. We demonstrated that self-processing of SASP28 precursor causes autoactivation of the protease. The highest activity was measured for GST-SASP14 at neutral pH and at high ionic strength, and we proved that pepstatin A and acetyl-pepstatin can also inhibit the protease. In agreement with the structural characteristics, the relatively lower urea dissociation constant implied lower dimer stability of SASP14 compared to that of HIV-1 protease. The obtained structural and biochemical characteristics support better understanding of ASPRV1 function in the skin and central nervous system.
Collapse
|
9
|
Hamazaki J, Murata S. ER-Resident Transcription Factor Nrf1 Regulates Proteasome Expression and Beyond. Int J Mol Sci 2020; 21:ijms21103683. [PMID: 32456207 PMCID: PMC7279161 DOI: 10.3390/ijms21103683] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 05/18/2020] [Accepted: 05/20/2020] [Indexed: 02/06/2023] Open
Abstract
Protein folding is a substantively error prone process, especially when it occurs in the endoplasmic reticulum (ER). The highly exquisite machinery in the ER controls secretory protein folding, recognizes aberrant folding states, and retrotranslocates permanently misfolded proteins from the ER back to the cytosol; these misfolded proteins are then degraded by the ubiquitin–proteasome system termed as the ER-associated degradation (ERAD). The 26S proteasome is a multisubunit protease complex that recognizes and degrades ubiquitinated proteins in an ATP-dependent manner. The complex structure of the 26S proteasome requires exquisite regulation at the transcription, translation, and molecular assembly levels. Nuclear factor erythroid-derived 2-related factor 1 (Nrf1; NFE2L1), an ER-resident transcription factor, has recently been shown to be responsible for the coordinated expression of all the proteasome subunit genes upon proteasome impairment in mammalian cells. In this review, we summarize the current knowledge regarding the transcriptional regulation of the proteasome, as well as recent findings concerning the regulation of Nrf1 transcription activity in ER homeostasis and metabolic processes.
Collapse
|
10
|
Golda M, Mótyán JA, Mahdi M, Tőzsér J. Functional Study of the Retrotransposon-Derived Human PEG10 Protease. Int J Mol Sci 2020; 21:ijms21072424. [PMID: 32244497 PMCID: PMC7212762 DOI: 10.3390/ijms21072424] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 12/11/2022] Open
Abstract
Paternally expressed gene 10 (PEG10) is a human retrotransposon-derived imprinted gene. The mRNA of PEG10 encodes two protein isoforms: the Gag-like protein (RF1PEG10) is coded by reading frame 1, while the Gag-Pol-like polyprotein (RF1/RF2PEG10) is coded by reading frames 1 and 2. The proteins are translated by a typical retroviral frameshift mechanism. The protease (PR) domain of RF2PEG10 contains an -Asp-Ser-Gly- sequence, which corresponds to the consensus -Asp-Ser/Thr-Gly- active-site motif of retroviral aspartic proteases. The function of the aspartic protease domain of RF2PEG10 remains unclear. To elucidate the function of PEG10 protease (PRPEG10), we designed a frameshift mutant (fsRF1/RF2PEG10) for comparison with the RF1/RF2PEG10 form. To study the effects of PRPEG10 on cellular proliferation and viability, mammalian HEK293T and HaCaT cells were transfected with plasmids coding for either RF1/RF2PEG10, the frameshift mutant (fsRF1/RF2PEG10), or a PR active-site (D370A) mutant fsRF1/RF2PEG10. Our results indicate that fsRF1/RF2PEG10 overexpression results in increased cellular proliferation. Remarkably, transfection with fsRF1/RF2PEG10 had a detrimental effect on cell viability. We hypothesize that PRPEG10 plays an important role in the function of this retroviral remnant, mediating the proliferation of cells and possibly implicating it in the inhibition of apoptosis.
Collapse
Affiliation(s)
- Mária Golda
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (M.G.); (M.M.)
- Doctoral School of Molecular Cell and Immune Biology, University of Debrecen, 4032 Debrecen, Hungary
| | - János András Mótyán
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (M.G.); (M.M.)
- Correspondence: (J.A.M.); (J.T.)
| | - Mohamed Mahdi
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (M.G.); (M.M.)
| | - József Tőzsér
- Department of Biochemistry and Molecular Biology, Faculty of Medicine, University of Debrecen, 4032 Debrecen, Hungary; (M.G.); (M.M.)
- Correspondence: (J.A.M.); (J.T.)
| |
Collapse
|