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Petese A, Cesaroni V, Cerri S, Blandini F. Are Lysosomes Potential Therapeutic Targets for Parkinson's Disease? CNS & NEUROLOGICAL DISORDERS DRUG TARGETS 2022; 21:642-655. [PMID: 34370650 DOI: 10.2174/1871527320666210809123630] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Revised: 05/16/2021] [Accepted: 06/10/2021] [Indexed: 06/13/2023]
Abstract
Parkinson´s Disease (PD) is the second most common neurodegenerative disorder, affecting ~2-3% of the population over 65 years old. In addition to progressive degeneration of nigrostriatal neurons, the histopathological feature of PD is the accumulation of misfolded α-synuclein protein in abnormal cytoplasmatic inclusions, known as Lewy Bodies (LBs). Recently, Genome-Wide Association Studies (GWAS) have indicated a clear association of variants within several lysosomal genes with risk for PD. Newly evolving data have been shedding light on the relationship between lysosomal dysfunction and alpha-synuclein aggregation. Defects in lysosomal enzymes could lead to the insufficient clearance of neurotoxic protein materials, possibly leading to selective degeneration of dopaminergic neurons. Specific modulation of lysosomal pathways and their components could be considered a novel opportunity for therapeutic intervention for PD. The purpose of this review is to illustrate lysosomal biology and describe the role of lysosomal dysfunction in PD pathogenesis. Finally, the most promising novel therapeutic approaches designed to modulate lysosomal activity, as a potential disease-modifying treatment for PD will be highlighted.
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Affiliation(s)
- Alessandro Petese
- Cellular and Molecular Neurobiology Unit, IRCCS Mondino Foundation, Pavia, Italy
| | - Valentina Cesaroni
- Cellular and Molecular Neurobiology Unit, IRCCS Mondino Foundation, Pavia, Italy
| | - Silvia Cerri
- Cellular and Molecular Neurobiology Unit, IRCCS Mondino Foundation, Pavia, Italy
| | - Fabio Blandini
- Cellular and Molecular Neurobiology Unit, IRCCS Mondino Foundation, Pavia, Italy
- Department of Brain and Behavioural Sciences, University of Pavia, Pavia, Italy
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Tayebi N, Lopez G, Do J, Sidransky E. Pro-cathepsin D, Prosaposin, and Progranulin: Lysosomal Networks in Parkinsonism. Trends Mol Med 2020; 26:913-923. [PMID: 32948448 DOI: 10.1016/j.molmed.2020.07.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/08/2020] [Accepted: 07/16/2020] [Indexed: 12/14/2022]
Abstract
Mutations in GBA1, the gene encoding the lysosomal hydrolase glucocerebrosidase (GCase), are a risk factor for parkinsonism. Pursuing the potential mechanisms underlying this risk in aging neurons, we propose a new network uniting three major lysosomal proteins: (i) cathepsin D (CTSD), which plays a major role in α-synuclein (SNCA) degradation and prosaposin (PSAP) cleavage; (ii) PSAP, essential for GCase activation and progranulin (PGRN) transport; and (iii) PGRN, impacting lysosomal biogenesis, PSAP trafficking, and CTSD maturation. We hypothesize that alterations to this network and associated receptors modify lysosomal function and subsequently impact both SNCA degradation and GCase activity. By exploring the interactions between this protein trio and each of their respective transporters and receptors, we may identify secondary risk factors that provide insight into the relationship between these lysosomal proteins, GCase, and SNCA, and reveal novel therapeutic targets.
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Affiliation(s)
- Nahid Tayebi
- Medical Genetics Branch, National Human Genetics Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Grisel Lopez
- Medical Genetics Branch, National Human Genetics Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Jenny Do
- Medical Genetics Branch, National Human Genetics Research Institute, National Institutes of Health, Bethesda, MD, USA
| | - Ellen Sidransky
- Medical Genetics Branch, National Human Genetics Research Institute, National Institutes of Health, Bethesda, MD, USA.
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3
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Boon L, Ugarte-Berzal E, Vandooren J, Opdenakker G. Protease propeptide structures, mechanisms of activation, and functions. Crit Rev Biochem Mol Biol 2020; 55:111-165. [PMID: 32290726 DOI: 10.1080/10409238.2020.1742090] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Proteases are a diverse group of hydrolytic enzymes, ranging from single-domain catalytic molecules to sophisticated multi-functional macromolecules. Human proteases are divided into five mechanistic classes: aspartate, cysteine, metallo, serine and threonine proteases, based on the catalytic mechanism of hydrolysis. As a protective mechanism against uncontrolled proteolysis, proteases are often produced and secreted as inactive precursors, called zymogens, containing inhibitory N-terminal propeptides. Protease propeptide structures vary considerably in length, ranging from dipeptides and propeptides of about 10 amino acids to complex multifunctional prodomains with hundreds of residues. Interestingly, sequence analysis of the different protease domains has demonstrated that propeptide sequences present higher heterogeneity compared with their catalytic domains. Therefore, we suggest that protease inhibition targeting propeptides might be more specific and have less off-target effects than classical inhibitors. The roles of propeptides, besides keeping protease latency, include correct folding of proteases, compartmentalization, liganding, and functional modulation. Changes in the propeptide sequence, thus, have a tremendous impact on the cognate enzymes. Small modifications of the propeptide sequences modulate the activity of the enzymes, which may be useful as a therapeutic strategy. This review provides an overview of known human proteases, with a focus on the role of their propeptides. We review propeptide functions, activation mechanisms, and possible therapeutic applications.
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Affiliation(s)
- Lise Boon
- Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, Laboratory of Immunobiology, KU Leuven, Leuven, Belgium
| | - Estefania Ugarte-Berzal
- Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, Laboratory of Immunobiology, KU Leuven, Leuven, Belgium
| | - Jennifer Vandooren
- Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, Laboratory of Immunobiology, KU Leuven, Leuven, Belgium
| | - Ghislain Opdenakker
- Rega Institute for Medical Research, Department of Microbiology, Immunology and Transplantation, Laboratory of Immunobiology, KU Leuven, Leuven, Belgium
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Demidyuk IV, Shubin AV, Gasanov EV, Kostrov SV. Propeptides as modulators of functional activity of proteases. Biomol Concepts 2015; 1:305-22. [PMID: 25962005 DOI: 10.1515/bmc.2010.025] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Most proteases are synthesized in the cell as precursor-containing propeptides. These structural elements can determine the folding of the cognate protein, function as an inhibitor/activator peptide, mediate enzyme sorting, and mediate the protease interaction with other molecules and supramolecular structures. The data presented in this review demonstrate modulatory activity of propeptides irrespective of the specific mechanism of action. Changes in propeptide structure, sometimes minor, can crucially alter protein function in the living organism. Modulatory activity coupled with high variation allows us to consider propeptides as specific evolutionary modules that can transform biological properties of proteases without significant changes in the highly conserved catalytic domains. As the considered properties of propeptides are not unique to proteases, propeptide-mediated evolution seems to be a universal biological mechanism.
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5
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Müller WEG, Schröder HC, Muth S, Gietzen S, Korzhev M, Grebenjuk VA, Wiens M, Schloßmacher U, Wang X. The silicatein propeptide acts as inhibitor/modulator of self-organization during spicule axial filament formation. FEBS J 2013; 280:1693-708. [DOI: 10.1111/febs.12183] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2012] [Revised: 02/02/2013] [Accepted: 02/06/2013] [Indexed: 11/29/2022]
Affiliation(s)
- Werner E. G. Müller
- ERC Advanced Grant Research Group at the Institute for Physiological Chemistry; University Medical Center of the Johannes Gutenberg University Mainz; Mainz; Germany
| | - Heinz C. Schröder
- ERC Advanced Grant Research Group at the Institute for Physiological Chemistry; University Medical Center of the Johannes Gutenberg University Mainz; Mainz; Germany
| | - Sandra Muth
- Institute for Physical Chemistry; Johannes Gutenberg University Mainz; Mainz; Germany
| | - Sabine Gietzen
- Institute for Physical Chemistry; Johannes Gutenberg University Mainz; Mainz; Germany
| | - Michael Korzhev
- ERC Advanced Grant Research Group at the Institute for Physiological Chemistry; University Medical Center of the Johannes Gutenberg University Mainz; Mainz; Germany
| | - Vlad A. Grebenjuk
- ERC Advanced Grant Research Group at the Institute for Physiological Chemistry; University Medical Center of the Johannes Gutenberg University Mainz; Mainz; Germany
| | - Matthias Wiens
- ERC Advanced Grant Research Group at the Institute for Physiological Chemistry; University Medical Center of the Johannes Gutenberg University Mainz; Mainz; Germany
| | - Ute Schloßmacher
- ERC Advanced Grant Research Group at the Institute for Physiological Chemistry; University Medical Center of the Johannes Gutenberg University Mainz; Mainz; Germany
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Abstract
The structure-function relationships of aspartic peptidases (APs) (EC 3.4.23.X) have been extensively investigated, yet much remains to be elucidated regarding the various molecular mechanisms of these enzymes. Over the past years, APs have received considerable interest for food applications (e.g. cheese, fermented foods) and as potential targets for pharmaceutical intervention in human diseases including hypertension, cancer, Alzheimer's disease, AIDS (acquired immune deficiency syndrome), and malaria. A deeper understanding of the structure and function of APs, therefore, will have a direct impact on the design of peptidase inhibitors developed to treat such diseases. Most APs are synthesized as zymogens which contain an N-terminal prosegment (PS) domain that is removed at acidic pH by proteolytic cleavage resulting in the active enzyme. While the nature of the AP PS function is not entirely understood, the PS can be important in processes such as the initiation of correct folding, protein stability, blockage of the active site, pH-dependence of activation, and intracellular sorting of the zymogen. This review summarizes the current knowledge of AP PS function (especially within the A1 family), with particular emphasis on protein folding, cellular sorting, and inhibition.
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Abstract
A literature survey was performed of human cathepsin D gene, cathepsin D biosynthesis, posttranslatory modifications, transport within the cell, substrate specificity and catalytic effect. Methods used to determine the activity and level of this proteinase as well as its role in the biochemistry and pathobiochemistry of cells, tissues and organs were considered.
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Follo C, Castino R, Nicotra G, Trincheri NF, Isidoro C. Folding, activity and targeting of mutated human cathepsin D that cannot be processed into the double-chain form. Int J Biochem Cell Biol 2007; 39:638-49. [PMID: 17188016 DOI: 10.1016/j.biocel.2006.11.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Revised: 11/02/2006] [Accepted: 11/06/2006] [Indexed: 11/21/2022]
Abstract
The precursor of human cathepsin D (CD) is converted into the single-chain and the double-chain active polypeptides by subsequent proteolysis reactions taking place in the endosomal-lysosomal compartment and involving specific aminoacid sequences. We have mutagenized the region of aminoacids (comprising the beta-hairpin loop) involved in the latter proteolytic maturation step and generated a mutant CD that cannot be converted into the mature double-chain form. This mutant CD expressed in rodent cells reaches the lysosome and is stable as single-chain polypeptide, bears high-mannose type sugars, binds to pepstatin A and is enzymatically active, indicating that it is correctly folded. The present work provides new insights on the aminoacid region involved in the terminal processing of human CD and on the function of the processing beta-hairpin loop.
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Affiliation(s)
- Carlo Follo
- Laboratory of Molecular Pathology, Dipartimento di Scienze Mediche, Università del Piemonte Orientale A. Avogadro, via Solaroli 17, 28100 Novara, Italy
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9
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Tsukuba T, Ikeda S, Okamoto K, Yasuda Y, Sakai E, Kadowaki T, Sakai H, Yamamoto K. Characterization of rat cathepsin E and mutants with changed active-site residues and lacking propeptides and N-glycosylation, expressed in human embryonic kidney 293T cells. FEBS J 2006; 273:219-29. [PMID: 16367762 DOI: 10.1111/j.1742-4658.2005.05062.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
To study the roles of the catalytic activity, propeptide, and N-glycosylation of the intracellular aspartic proteinase cathepsin E in biosynthesis, processing, and intracellular trafficking, we constructed various rat cathepsin E mutants in which active-site Asp residues were changed to Ala or which lacked propeptides and N-glycosylation. Wild-type cathepsin E expressed in human embryonic kidney 293T cells was mainly found in the LAMP-1-positive endosomal organelles, as determined by immunofluorescence microscopy. Consistently, pulse-chase analysis revealed that the initially synthesized pro-cathepsin E was processed to the mature enzyme within a 24 h chase. This process was completely inhibited by brefeldin A and bafilomycin A, indicating its transport from the endoplasmic reticulum (ER) to the endosomal acidic compartment. Mutants with Asp residues in the two active-site consensus motifs changed to Ala and lacking the propeptide (Leu23-Phe58) and the putative ER-retention sequence (Ser59-Asp98) were neither processed nor transported to the endosomal compartment. The mutant lacking the ER-retention sequence was rapidly degraded in the ER, indicating the importance of this sequence in correct folding. The single (N92Q or N324D) and double (N92Q/N324D) N-glycosylation-deficient mutants were neither processed into a mature form nor transported to the endosomal compartment, but were stably retained in the ER without degradation. These data indicate that the catalytic activity, propeptides, and N-glycosylation of this protein are all essential for its processing, maturation, and trafficking.
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Affiliation(s)
- Takayuki Tsukuba
- Department of Pharmacology, Graduate School of Dental Science, Kyushu University, Fukuoka, Japan
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10
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Yasuda Y, Tsukuba T, Okamoto K, Kadowaki T, Yamamoto K. The Role of the Cathepsin E Propeptide in Correct Folding, Maturation and Sorting to the Endosome. ACTA ACUST UNITED AC 2005; 138:621-30. [PMID: 16272574 DOI: 10.1093/jb/mvi159] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Cathepsin E (CE) is an endosomal aspartic proteinase of the A1 family that is highly homologous to the lysosomal aspartic proteinase cathepsin D (CD). Newly synthesized CE undergoes several proteolytic processing events to yield mature CE, from which the N-terminal propeptide usually comprising 39 amino acids is removed. To define the role of the propeptide of CE in its biosynthesis and processing, we constructed two fusion proteins using chimeric DNAs encoding the CE propeptide fused to the mature CD tagged with HA at the COOH terminus (termed ED-HA) and encoding the CD propeptide fused to the mature CE (termed DE). Pulse-chase analysis revealed that wild-type CE expressed in human embryonic kidney cells is autoproteolytically processed into mature CE within a 12-h chase, whereas the chimeric DE failed to be converted into mature CE even after a 24-h chase. The DE chimera was nevertheless capable of acid-dependent autoactivation in vitro to yield a catalytically active form, although its specificity constants (kcat/Km) were considerably high but less (35%) than those of the wild-type CE. By contrast, the chimeric ED-HA expressed in HeLa cells underwent neither processing into a catalytically active enzyme nor acid-dependent autoactivation in vitro. The ED-HA protein was less stable than wt-CD-HA, as determined on pulse-chase analysis and on trypsin digestion. These data indicate that the propeptide of CE is essential for the correct folding, maturation, and targeting of this protein to its final destination.
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Affiliation(s)
- Yoshiyuki Yasuda
- Department of Pharmacology, Graduate School of Dental Science, Kyushu University, Higashi-ku, Fukuoka 812-8582
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11
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Takizawa T, Anderson CL, Robinson JM. A Novel FcγR-Defined, IgG-Containing Organelle in Placental Endothelium. THE JOURNAL OF IMMUNOLOGY 2005; 175:2331-9. [PMID: 16081803 DOI: 10.4049/jimmunol.175.4.2331] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Placental transfer of IgG from maternal circulation to that of the fetus is crucial for fetal and newborn immunity. This process requires that IgG broach two cellular layers of the placenta. IgG transport across the first layer, the syncytiotrophoblast, is almost certainly mediated by the MHC-related FcR for IgG, FcRn. The second layer, the villus endothelium, was until recently thought to allow IgG movement nonspecifically by constitutive transcytosis in caveolae. However, we recently showed that villus endothelium expressed a separate FcR for IgG, the inhibitory motif-bearing Fc gammaRIIb2 seen most notably on macrophages and as a minor fraction of the Fc gammaRIIb expressed on B cells. Now, by quantitative microscopy, we find Fc gammaRIIb2 to be expressed abundantly in an unidentifiable and likely novel organelle of the villus endothelium, unassociated with caveolae. About half of these Fc gammaRIIb2 organelles contain IgG; the remainder lack IgG. The majority fraction (approximately 80%) of IgG-containing organelles is associated with Fc gammaRIIb. No IgG-containing organelles are associated with caveolin. These findings are compatible with Fc gammaRIIb-mediated transfer of IgG across the villus endothelium, independent of caveolae.
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MESH Headings
- Animals
- Antibody Specificity
- Antigens, CD/biosynthesis
- Antigens, CD/genetics
- Antigens, CD/metabolism
- Antigens, CD/physiology
- Caveolae/chemistry
- Caveolae/immunology
- Caveolae/metabolism
- Caveolae/ultrastructure
- Caveolin 1/metabolism
- Cell Line
- Chorionic Villi/blood supply
- Chorionic Villi/chemistry
- Chorionic Villi/immunology
- Chorionic Villi/ultrastructure
- Cryoelectron Microscopy
- Endothelium, Vascular/chemistry
- Endothelium, Vascular/immunology
- Endothelium, Vascular/metabolism
- Endothelium, Vascular/ultrastructure
- Fluorescent Antibody Technique
- Genes, Overlapping
- Histocompatibility Antigens Class I/metabolism
- Immunoglobulin G/genetics
- Immunoglobulin G/metabolism
- Microscopy, Immunoelectron
- Organelles/chemistry
- Organelles/immunology
- Organelles/metabolism
- Organelles/ultrastructure
- Pregnancy Proteins/biosynthesis
- Pregnancy Proteins/genetics
- Pregnancy Proteins/metabolism
- Pregnancy Proteins/physiology
- Receptors, Fc/metabolism
- Receptors, IgG/biosynthesis
- Receptors, IgG/genetics
- Receptors, IgG/metabolism
- Receptors, IgG/physiology
- Subcellular Fractions/chemistry
- Subcellular Fractions/immunology
- Subcellular Fractions/metabolism
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Affiliation(s)
- Toshihiro Takizawa
- Department of Physiology and Cell Biology, Ohio State University, Columbus 43210, USA
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12
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Higuchi M, Miyashita N, Nagamine Y, Watanabe A, Awata T. The complementary DNA sequence and polymorphisms of bovine procathepsin-D (CTSD). J Anim Breed Genet 2003. [DOI: 10.1046/j.1439-0388.2003.00402.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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13
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Costa-Pinto D, Trindade LS, McMahon-Pratt D, Traub-Cseko YM. Cellular trafficking in trypanosomatids: a new target for therapies? Int J Parasitol 2001; 31:536-43. [PMID: 11334939 DOI: 10.1016/s0020-7519(01)00145-x] [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: 11/23/2022]
Abstract
Pathogenic trypanosomatids cause a plethora of diseases marked by the lack of efficient vaccines and therapies. As a consequence, studies are being conducted that are geared towards the understanding of basic mechanisms and various biological aspects of these parasites that might be used as targets for new developments in these areas. One such aspect is the understanding of specific cellular trafficking mechanisms that might be attacked with the intention of disease control. In this paper, we give an overview of our current knowledge of cellular targeting mechanisms in trypanosomatids, with special emphasis on our data related to lysosomal targeting of cysteine proteinases in Leishmania.
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Affiliation(s)
- D Costa-Pinto
- Department of Biochemistry and Molecular Biology, Oswaldo Cruz Institute, FIOCRUZ, Av. Brasil 4365, RJ 21045-900, Rio de Janeiro, Brazil
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Marie-Claire C, Yabuta Y, Suefuji K, Matsuzawa H, Shinde U. Folding pathway mediated by an intramolecular chaperone: the structural and functional characterization of the aqualysin I propeptide. J Mol Biol 2001; 305:151-65. [PMID: 11114254 DOI: 10.1006/jmbi.2000.4233] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Aqualysin I, a thermostable homologue of subtilisin, requires its propeptide (ProA) to function as an intramolecular chaperone (IMC). To decipher the mechanisms through which propeptides can initiate protein folding, we characterized ProA in terms of its sequence, structure and function. Our results show that, in contrast to ProS (propeptide of subtilisin), ProA can fold spontaneously, reversibly and cooperatively into a stable monomeric alpha-beta conformation, even when isolated from its cognate protease-domain. ProA displays an indiscernible amount of tertiary structure with a considerable solvent-accessible hydrophobic surface, but is not a classical molten-globule folding intermediate. Moreover, despite showing only 21 % sequence identity with ProS, ProA can not only inhibit enzymatic activity with a magnitude tenfold greater than ProS, but can also chaperone subtilisin folding, albeit with a lower efficiency. The structure of ProA complexed with subtilisin is different from that of isolated ProA. Hence, additional interactions seem necessary to induce ProA into a compact structure. Our results also suggest that: (a) propeptides that are potent inhibitors are not necessarily better IMCs; (b) propeptides within the subtilase family appear polymorphic and; (c) the intrinsic instability within propeptides may be necessary for rapid activation of the cognate protein.
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Affiliation(s)
- C Marie-Claire
- Department of Biochemistry, Robert Wood Johnson Medical School-UMDNJ, 675 Hoes Lane, Piscataway, NJ 08854, USA
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15
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Shirakawa R, Yoshioka A, Horiuchi H, Nishioka H, Tabuchi A, Kita T. Small GTPase Rab4 regulates Ca2+-induced alpha-granule secretion in platelets. J Biol Chem 2000; 275:33844-9. [PMID: 10938270 DOI: 10.1074/jbc.m002834200] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Upon activation, platelets release many active substances stored in alpha- and dense-core granules. However, the molecular mechanisms governing regulated exocytosis are not yet fully understood. Here, we have established an assay system using permeabilized platelets to analyze the Ca(2+)-induced exocytosis of both types of granules, focusing on RabGTPases. Incubation with Rab GDP dissociation inhibitor, an inhibitory regulator of RabGTPases, reduced membrane-bound RabGTPases extensively, and caused strong inhibition of the Ca(2+)-induced secretion of von Willebrand factor (vWF) stored in alpha-granules, but not that of [(3)H]5-hydroxytryptamine (5-HT) in dense-core granules. Specifically, Rab4 co-fractionated with vWF and P-selectin (an alpha-granule marker) upon separation of platelet organelles by density gradient centrifugation. Incubation of the permeabilized platelets with cell extracts expressing the dominant negative mutant of His-tagged Rab4S22N, but not with those of similar mutant His-Rab3BT36N, inhibited the vWF secretion, whereas neither of the cell extracts affected the [(3)H]5-HT secretion. Importantly, the inhibition of vWF secretion was rescued by depleting the cell extracts of the His-Rab4S22N with nickel beads. Thus, in platelets, the regulatory mechanisms governing alpha- and dense-core granule secretions are distinct, and Rab4 is an essential regulator of the Ca(2+)-induced exocytosis of alpha-granules.
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Affiliation(s)
- R Shirakawa
- Department of Geriatric Medicine, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
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16
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Bazzett LB, Watkins CS, Gercel-Taylor C, Taylor DD. Modulation of proliferation and chemosensitivity by procathepsin D and its peptides in ovarian cancer. Gynecol Oncol 1999; 74:181-7. [PMID: 10419729 DOI: 10.1006/gyno.1999.5426] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Since the presence of precursors (pro-forms) of the aspartyl endoprotease, cathepsin D, appears to be linked with tumor progression, their presence was examined in sera and tumor tissues of ovarian cancer patients. The role of cathepsin D pro-forms was further assessed in the dysregulated proliferation and chemoresistance observed in advanced ovarian cancer. Cathepsin D was isolated from sera of ovarian cancer patients (n = 20) and normal volunteers (n = 11), as well as from solubilized normal ovarian epithelium (n = 8) and ovarian epithelial tumor tissue (n = 12). The specific molecular forms of cathepsin D were analyzed in these samples by Western immunoblot. Multiple circulating molecular weight forms of cathepsin D were identified in ovarian cancer patients ranging from 24 to 60 kDa, while in normal controls, a major band was observed at 34 kDa in all samples and minor bands corresponding to 27 and 48 kDa were detected in approximately half of the controls. To assess its consequences on ovarian cancer, the 52-kDa protein was immunoprecipitated from culture medium of an exponentially growing ovarian tumor cell line and was further purified by reverse-phase high-pressure liquid chromatography. Its effect on proliferation was assayed by determining cell doubling times and their chemosensitivity was measured in a standard cytotoxicity assay using cisplatin. In addition, decapeptides corresponding to the pro-portion of cathepsin D were analyzed in parallel. Procathepsin D and one decapeptide, peptide 2, as well as IGF-II (as a known positive) increased cell proliferation, with doubling times of 28.4, 28.8, and 30.3 h, respectively, versus untreated UL-1 cells (36.4 h). Procathepsin D treatment of UL-1 tumor cells significantly increased the cisplatin LD(50) (74.9 microgram/ml) over untreated (33.9 microgram/ml) as well as IGF-II-treated (38.8 microgram/ml) cells. Peptide 2 also showed a significant increase in LD(50) (69.5 microgram/ml) compared to untreated and peptide 1-treated cells (37.1 microgram/ml). There are several unique forms of cathepsin D expressed and accumulated by ovarian tumors and these forms are detectable in the sera of those with ovarian cancer. The presence of these procathepsin D can increase the proliferation of these tumor cells, while decreasing their sensitivity to chemotherapeutic agents. While procathepsin D and IGF-II both enhance proliferation, only procathepsin D (and peptide 2) appears to modulate chemosensitivity, suggesting a separate receptor or pathway for this consequence.
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Affiliation(s)
- L B Bazzett
- Departments of Obstetrics & Gynecology, University of Louisville School of Medicine, Louisville, Kentucky, 40292, USA
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17
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Huete-Pérez JA, Engel JC, Brinen LS, Mottram JC, McKerrow JH. Protease trafficking in two primitive eukaryotes is mediated by a prodomain protein motif. J Biol Chem 1999; 274:16249-56. [PMID: 10347181 DOI: 10.1074/jbc.274.23.16249] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Trypanosome protozoa, an early lineage of eukaryotic cells, have proteases homologous to mammalian lysosomal cathepsins, but the precursor proteins lack mannose 6-phosphate. Utilizing green fluorescent protein as a reporter, we demonstrate that the carbohydrate-free prodomain of a trypanosome cathepsin L is necessary and sufficient for directing green fluorescent protein to the lysosome/endosome compartment. A proper prodomain/catalytic domain processing site sequence is also required to free the mature protease for delivery to the lysosome/endosome compartment. A nine-amino acid prodomain loop motif, implicated in prodomain-receptor interactions in mammalian cells, is conserved in the protozoa. Site-directed mutagenesis now confirms the importance of this loop to protease trafficking and suggests that a protein motif targeting signal for lysosomal proteases arose early in eukaryotic cell evolution.
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Affiliation(s)
- J A Huete-Pérez
- Department of Pathology, University of California, San Francisco, California 94121, USA
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18
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Abstract
Cathepsin D (cath-D) overexpression in breast cancer cells is associated with increased risk of metastasis in patients according to several clinical studies. No alterations of pro-cath-D structure or activation have been demonstrated in cancer cells. However, overexpression and dysrouting of pro-cath-D in illegitimate compartments could have consequences on tumor progression. Transfection of a human cDNA cath-D expression vector increases the metastatic potential of 3Y1-Ad12 embryonic rat tumorigenic cells when intravenously injected into nude mice. The mechanism by which cath-D increases the incidence of clinical metastasis seems to involve increased cell growth and decreased contact inhibition rather than escape of cancer cells through the basement membrane. Different mechanisms are discussed by which cath-D could act as a protease following its activation or as a ligand of different membrane receptors at a more neutral pH.
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Affiliation(s)
- H Rochefort
- Institut National de la Santé et de la Recherche Médicale, Unit 148 (Hormones and Cancer), University of Montpellier I, France
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19
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Mehtani S, Gong Q, Panella J, Subbiah S, Peffley DM, Frankfater A. In vivo expression of an alternatively spliced human tumor message that encodes a truncated form of cathepsin B. Subcellular distribution of the truncated enzyme in COS cells. J Biol Chem 1998; 273:13236-44. [PMID: 9582368 DOI: 10.1074/jbc.273.21.13236] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Cathepsin B is a lysosomal cysteine protease whose increased expression is believed to be linked to the malignant progression of tumors. Alternative splicing and the use of alternative transcription initiation sites in humans produce cathepsin B mRNAs that differ in their 5'- and 3'-untranslated ends. Some human tumors also contain cathepsin B-related transcripts that lack exon 3 which encodes the N-terminal signal peptide and 34 of the 62-amino acid inhibitory propeptide. In this study we show that one such transcript, CB(-2,3), which is missing exons 2 and 3, is likely to be a functional message in tumors. Thus, CB(-2,3) was found to be otherwise complete, containing the remainder of the cathepsin B coding sequence and the part of the 3'-untranslated region that is common to all previously characterized cathepsin B mRNAs in humans. Its in vitro translation product can be folded to produce enzymatic activity against the cathepsin B-specific substrate, Nalpha-benzyloxycarbonyl-L-Arg-L-Arg-4-methylcoumaryl-7-amide. Endogenous CB(-2,3) from the metastatic human melanoma cell line, A375M, co-sediments with polysomes, indicating that it engages the eukaryotic translation machinery in these cells. Epitope-tagged forms of the truncated cathepsin B from CB(-2,3) are produced in amounts comparable to the normal protein after transient transfection into COS cells. Immunofluorescence microscopy and subcellular fractionation show this novel tumor form of cathepsin B to be associated with nuclei and other membranous organelles, where it is likely to be bound to the cytoplasmic face of the membranes. This subcellular distribution was different from the lysosomal pattern shown by the epitope-tagged, full-length cathepsin B in COS cells. These results indicate that the message missing exons 2 and 3 is likely to be translated into a catalytically active enzyme, and that alternative splicing (exon skipping) could contribute to the aberrant intracellular trafficking of cathepsin B that is observed in some human cancers.
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Affiliation(s)
- S Mehtani
- Department of Molecular and Cellular Biochemistry, Loyola University of Chicago, Stritch School of Medicine, Maywood, Illinois 60153, USA
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20
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Chirgwin JM, Schultz S, Sachdev D. Expression of chimeric human aspartic proteinases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1998; 436:139-46. [PMID: 9561211 DOI: 10.1007/978-1-4615-5373-1_19] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- J M Chirgwin
- Audie L. Murphy Veterans Administration Research Service, University of Texas Health Science Center at San Antonio 78284-7877, USA
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21
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Andersson E, Hellman L, Gullberg U, Olsson I. The role of the propeptide for processing and sorting of human myeloperoxidase. J Biol Chem 1998; 273:4747-53. [PMID: 9468538 DOI: 10.1074/jbc.273.8.4747] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Myeloperoxidase (MPO), stored in azurophil granules of neutrophils, is critical for an optimal oxygen-dependent microbicidal activity of these cells. Pro-MPO goes through a stepwise proteolytic trimming with elimination of an amino-terminal propeptide to yield one heavy and one light polypeptide chain. The propeptide of MPO may have a role in retention and folding of the nascent protein into its tertiary structure or in targeting of pro-MPO for processing and storage in granules. A propeptide-deleted pro-MPO mutant (MPODeltapro) was constructed to determine if deletion of the propeptide interferes with processing and targeting after transfection to the myeloid 32D cell line. Transfection of full-length cDNA for human MPO results in normal processing and targeting of MPO to cytoplasmic dense organelles. Although the efficiency of incorporation was lower for MPODeltapro, both pro-MPO and MPODeltapro showed heme incorporation indicating that the propeptide is not critical for this process. Deletion of the propeptide results in synthesis of a protein that lacks processing into mature two-chain forms but rather is degraded intracellularly or secreted. The finding of continued degradation of MPODeltapro in the presence of lysosomotrophic agents or brefeldin A rules out that the observed degradation takes place after transfer to granules. Intracellular pro-MPO has high mannose oligosaccharide side chains, whereas stored mature MPO was found to have both high mannose and complex oligosaccharide side chains as judged by only partial sensitivity to endoglycosidase H. The propeptide may normally interfere with the generation of certain complex oligosaccharide chain(s) supported by the finding of high mannose side chains in secreted pro-MPO and lack of them in MPODeltapro that contained complex oligosaccharide side chains only. In conclusion, elimination of the propeptide of pro-MPO blocks the maturation process and abolishes accumulation of the final product in granules suggesting a critical role of the propeptide for late processing of pro-MPO and targeting for storage in granules.
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Affiliation(s)
- E Andersson
- Department of Hematology, Research Department 2, E-blocket, University Hospital, S-221 85 Lund, Sweden
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22
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Beyer BM, Dunn BM. Self-activation of recombinant human lysosomal procathepsin D at a newly engineered cleavage junction, "short" pseudocathepsin D. J Biol Chem 1996; 271:15590-6. [PMID: 8663051 DOI: 10.1074/jbc.271.26.15590] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
To obtain a recombinant model of human cathepsin D with kinetic properties that are identical with native human liver enzyme, we have addressed the significant differences in structure and catalytic function between naturally occurring enzyme and bacterially derived pseudocathepsin D. Human procathepsin D was expressed in a baculovirus system to obtain correctly folded, glycosylated enzyme that upon acidification completely converts to the active intermediate, pseudocathepsin D. The oligosaccharide moieties of this recombinant enzyme contributed to about 5% of the apparent molecular mass of the enzyme, and the carbohydrate composition was quite similar to the native material. However, specificity constants (kcat/Km) of this glycosylated pseudoform for several synthetic chromogenic substrates were considerably less (33%-50%) than those for the native enzyme and were virtually identical with those observed with nonglycosylated pseudocathepsin D. A cleavable junction suitable for self-processing at the normal maturation point of human cathepsin D was engineered into procathepsin D according to known specificity requirements of this enzyme, and the construct was expressed using baculovirus. Following experiments that demonstrated that the new proenzyme failed to process to the expected point, the new cleavage junction was moved 6 residues toward the amino terminus of procathepsin D and expressed in Escherichia coli. After refolding, the protein containing the newly engineered junction self-processed, generating a shortened mutant form of pseudocathepsin D that is 6 residues longer at the amino terminus than the native material. The kinetic properties of this newly engineered pseudoform proved to be identical with those of the native enzyme, thus establishing an improved recombinant model for this important aspartic proteinase.
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Affiliation(s)
- B M Beyer
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, Florida 32610-0245, USA
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23
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Shinde U, Inouye M. Propeptide-mediated folding in subtilisin: the intramolecular chaperone concept. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1996; 379:147-54. [PMID: 8796319 DOI: 10.1007/978-1-4613-0319-0_16] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- U Shinde
- Department of Biochemistry, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway, NJ 08854, USA
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24
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Abstract
Many proteins, including proteases and growth factors, are synthesized as precursors in the form of pre-pro-proteins. Whereas the pre-sequences usually act as signal peptides for transport, the pro-sequences of an increasing number of these proteins have been found to be essential for the correct folding of their associated proteins. In contrast to the action of molecular chaperones, pro-sequences appear to catalyse the protein-folding reaction directly. The similarity between the pro-sequence-assisted folding mechanisms of different proteases supports the hypothesis that a common folding mechanism has developed through convergent evolution. Further, the frequent requirement of the pro-sequences for both folding and intracellular transport or secretion suggests that these two functionalities are intimately related.
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Affiliation(s)
- J Eder
- MRC Unit for Protein Function and Design, University Chemical Laboratory, Cambridge, UK
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25
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Fortenberry SC, Chirgwin JM. The propeptide is nonessential for the expression of human cathepsin D. J Biol Chem 1995; 270:9778-82. [PMID: 7730356 DOI: 10.1074/jbc.270.17.9778] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
When the 44-amino acid propeptide of human procathepsin D was deleted by mutagenesis in vitro, the mature protein was stably expressed and secreted from transfected mammalian cells. The secreted protein was correctly folded as judged by its binding to pepstatinylagarose. We were unable to detect lysosomal targeting of the propeptide-deleted protein, and targeting was not restored by the substitution of the propeptides from pepsin or renin. We conclude that its propeptide is not essential for the folding of nascent cathepsin D. Efficient lysosomal targeting in mammalian cells appears to require the precursor form of the molecule.
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Affiliation(s)
- S C Fortenberry
- Research Service, Audie L. Murphy Veterans Administration Medical Center, San Antonio, Texas, USA
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26
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Koelsch G, Mares M, Metcalf P, Fusek M. Multiple functions of pro-parts of aspartic proteinase zymogens. FEBS Lett 1994; 343:6-10. [PMID: 8163018 DOI: 10.1016/0014-5793(94)80596-2] [Citation(s) in RCA: 86] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The importance of aspartic proteinases in human pathophysiology continues to initiate extensive research. With burgeoning information on their biological functions and structures, the traditional view of the role of activation peptides of aspartic proteinases solely as inhibitors of the active site is changing. These peptide segments, or pro-parts, are deemed important for correct folding, targeting, and control of the activation of aspartic proteinase zymogens. Consequently, the primary structures of pro-parts reflect these functions. We discuss guidelines for formation of hypotheses derived from comparing the physiological function of aspartic proteinases and sequences of their pro-parts.
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Affiliation(s)
- G Koelsch
- Oklahoma Medical Research Foundation, Oklahoma City
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27
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28
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Knop M, Schiffer HH, Rupp S, Wolf DH. Vacuolar/lysosomal proteolysis: proteases, substrates, mechanisms. Curr Opin Cell Biol 1993; 5:990-6. [PMID: 8129953 DOI: 10.1016/0955-0674(93)90082-2] [Citation(s) in RCA: 79] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Proteolysis is an essential post-transcriptional process. The lysosome/vacuole is the central organelle for non-specific proteolysis in eukaryotes. Most proteases that work in the lysosome enter it via the secretory pathway. The bulk of proteins to be degraded enter this proteolytic compartment via endocytosis and autophagocytosis. Our understanding of the mechanisms involved in these processes has increased considerably, and the information obtained in these studies has enabled new, specific proteolytic pathways to be investigated in other cellular compartments, particularly in the cytoplasm.
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Affiliation(s)
- M Knop
- Institute of Biochemistry, University of Stuttgart, Germany
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29
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van den Hazel H, Kielland-Brandt M, Winther J. The propeptide is required for in vivo formation of stable active yeast proteinase A and can function even when not covalently linked to the mature region. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(17)46804-9] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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30
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Hasilik A. The early and late processing of lysosomal enzymes: proteolysis and compartmentation. EXPERIENTIA 1992; 48:130-51. [PMID: 1740186 DOI: 10.1007/bf01923507] [Citation(s) in RCA: 123] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Lysosomal enzymes are subjected to a number of modifications including carbohydrate restructuring and proteolytic maturation. Some of these reactions support lysosomal targeting, others are necessary for activation or keeping the enzyme inactive before being segregated, while still others may be adventitious. The non-segregated fraction of the enzyme is secreted and can be isolated from the medium. It is considered that the secreted lysosomal enzymes fulfill certain physiological and pathophysiological roles. By comparing the secreted and the intracellular enzymes it is possible to distinguish between the reactions that occur before and after the segregation. In this review the reactions that may influence the segregation are referred to as the early processing and those characteristic for the enzymes isolated from lysosomal compartments as the late processing. The early processing is characterized mainly by modifications of carbohydrate side chains. In the late processing, proteolytic fragmentation represents the most conspicuous changes. The review focuses on the compartmentation of the reactions and the proteolytic fragmentation of lysosomal enzyme precursors. While a plethora of proteolytic reactions are involved, our knowledge of the proteinases responsible for the particular maturation reactions remains very limited. The review points also to work with cells from patients affected with lysosomal storage disorders, which contributed to our understanding of the lysosomal apparatus.
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Affiliation(s)
- A Hasilik
- Institute for Physiological Chemistry and Pathobiochemistry, University of Münster, Germany
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