GO:0008475 procollagen-lysine 5-dioxygenase activity: Mechanism, Genes and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0008475 (procollagen-lysine 5-dioxygenase activity) catalyzes the hydroxylation of lysine residues in collagen-like sequences, using 2-oxoglutarate, O2, and Fe(II) to produce 5-hydroxylysine, succinate, and CO2.
• The enzymes responsible are PLOD1, PLOD2, and PLOD3, which differ in substrate specificity and tissue distribution; PLOD1 primarily hydroxylates lysine in the helical domain of collagens [1,6].
• Lysyl hydroxylation is essential for collagen cross-linking, stability, and extracellular matrix integrity; defects cause connective tissue disorders such as Ehlers-Danlos syndrome.
• PLOD1 is overexpressed in multiple cancers (glioma, osteosarcoma, thyroid, tongue) and promotes proliferation, migration, and invasion, often via HSF1, Wnt/β-catenin, or glycolytic pathways [4,5,7,8].
• PLOD1 also regulates non-collagen proteins, including the Epstein-Barr virus EBNA1, affecting viral latency and DNA replication [2,6].
• CRISPR-based knockout, point mutation, knock-in, and overexpression models enable precise dissection of PLOD1/PLOD2/PLOD3 functions in health and disease [1,4,7].
Description
Procollagen-lysine 5-dioxygenase activity (GO:0008475) is a molecular function that hydroxylates specific lysine residues within collagen and collagen-like proteins. This post-translational modification is critical for the proper folding, secretion, and cross-linking of collagens, the most abundant proteins in the human body. The reaction requires 2-oxoglutarate, molecular oxygen, and Fe(II) as cofactors, converting lysine to (5R)-5-hydroxylysine while producing succinate and CO2. The enzymes catalyzing this reaction, PLOD1, PLOD2, and PLOD3, are central to extracellular matrix homeostasis, and their dysregulation is linked to connective tissue diseases and cancer progression [1,4,7]. Researchers study GO:0008475 to understand collagen biosynthesis, tissue remodeling, and the molecular basis of diseases such as Ehlers-Danlos syndrome, fibrosis, and metastatic cancer [1,4,5]. Beyond collagens, PLOD1 can hydroxylate non-collagen substrates like the Epstein-Barr virus protein EBNA1, influencing viral persistence and gene regulation [2,6]. The availability of CRISPR tools now allows precise genetic manipulation of PLOD genes to test causal roles in these processes [1,4,7]. This article provides a comprehensive overview of GO:0008475, covering its definition, catalytic mechanism, key genes, disease associations, and state-of-the-art research methods including CRISPR-based models. All facts are drawn from peer-reviewed literature to support publication-ready research and drug discovery efforts.
procollagen-lysine 5-dioxygenase activity At A Glance
| GO ID | GO:0008475 |
|---|---|
| GO term | procollagen-lysine 5-dioxygenase activity |
| Ontology | molecular_function |
| Synonym | collagen lysine hydroxylase activity; lysyl hydroxylase activity; protocollagen lysine hydroxylase activity |
| Major function | Hydroxylation of lysine residues in collagen-like sequences, enabling cross-linking and extracellular matrix stability |
| Cofactors | Fe(II), 2-oxoglutarate, O2 |
| Reaction products | (5R)-5-hydroxy-L-lysyl-[collagen], succinate, CO2 |
| Enzymes | PLOD1, PLOD2, PLOD3 |
What Is GO:0008475?
GO:0008475, procollagen-lysine 5-dioxygenase activity, is defined as the catalysis of the reaction: L-lysyl-[collagen] + 2-oxoglutarate + O2 = (5R)-5-hydroxy-L-lysyl-[collagen] + succinate + CO2. In simpler terms, it is an enzymatic activity that adds a hydroxyl group to lysine residues on procollagen, a modification essential for collagen stability and function.
Why Is procollagen-lysine 5-dioxygenase activity Important in Cell Biology?
Procollagen-lysine 5-dioxygenase activity is indispensable for the structural integrity of collagens, which constitute the primary scaffold of connective tissues. Hydroxylysine residues serve as attachment sites for carbohydrate chains and are required for covalent cross-linking between collagen molecules, directly affecting tensile strength of skin, bone, and blood vessels. Mutations in PLOD1 cause kyphoscoliotic Ehlers-Danlos syndrome, characterized by severe connective tissue fragility. Moreover, PLOD1 overexpression is a hallmark of several cancers and promotes tumor growth and metastasis through multiple signaling pathways [4,5,7,8]. Thus, understanding GO:0008475 has broad implications for developmental biology, cancer research, and therapeutic development.
• Essential for collagen cross-linking and extracellular matrix stability; defects lead to connective tissue disorders.
• PLOD1 mutations cause kyphoscoliotic Ehlers-Danlos syndrome, a severe inherited disorder.
• PLOD1 is overexpressed in glioma and promotes tumor progression via HSF1 signaling.
• In thyroid cancer, PLOD1 drives proliferation and migration through Wnt/β-catenin and glycolysis.
• PLOD1 serves as a prognostic biomarker and mediator of invasion in osteosarcoma.
• PLOD1 and PLOD3 interact with EBV EBNA1, influencing viral latency and replication [2,6].
• miR-449a targets PLOD1 to ameliorate acute rejection after liver transplantation.
• PLOD1 expression is part of a gene activation network in tongue squamous cell carcinoma.
• Enzymatic activity requires Fe(II) and 2-oxoglutarate, linking it to cellular metabolism and oxygen sensing.
• CRISPR screens and knockout models can identify selective vulnerabilities in PLOD1-overexpressing cancers [4,7].
Molecular Mechanism of procollagen-lysine 5-dioxygenase activity
Substrate Recognition and Binding
In simple terms: The enzyme finds and grabs onto collagen proteins at specific lysine spots.
PLOD enzymes recognize lysine residues within the repeating Gly-X-Y sequence of collagen, where X and Y are often proline and hydroxyproline. The substrate is procollagen, a precursor with N- and C-terminal propeptides. Binding occurs in the endoplasmic reticulum, where the enzyme is anchored via its transmembrane domain. Specificity is determined by the surrounding sequence and the enzyme isoform: PLOD1 preferentially hydroxylates lysines in the helical domain, while PLOD2 acts on telopeptide lysines.
Catalytic Cycle and Cofactors
In simple terms: The enzyme uses iron, oxygen, and a molecule called 2-oxoglutarate to add a hydroxyl group to lysine.
The catalytic mechanism follows a dioxygenase cycle. Fe(II) in the active site coordinates with 2-oxoglutarate and O2. Oxidative decarboxylation of 2-oxoglutarate yields succinate, CO2, and a highly reactive Fe(IV)-oxo intermediate. This intermediate abstracts a hydrogen from the lysine substrate, forming a lysyl radical that combines with a hydroxyl radical to produce (5R)-5-hydroxylysine. Ascorbate is often required to maintain iron in the reduced state.
Post-translational Modification and Cross-linking
In simple terms: After hydroxylation, the modified lysines help collagen molecules stick together, making tissues strong.
Hydroxylysine residues serve as sites for glycosylation (galactose or glucose) and for oxidative deamination by lysyl oxidase, generating reactive aldehydes that form covalent cross-links between collagen molecules. This cross-linking is essential for the tensile strength of collagen fibrils in skin, bone, tendon, and blood vessels. Defective hydroxylation leads to unstable collagen and connective tissue fragility.
Regulation of Enzyme Activity
In simple terms: The enzyme's activity can be turned up or down by oxygen levels, iron availability, and other cellular signals.
PLOD activity is regulated by oxygen tension (hypoxia can reduce activity), iron and ascorbate availability, and 2-oxoglutarate levels. Expression of PLOD genes is controlled by transcription factors such as HIF-1 and HSF1, and by microRNAs like miR-449a [3,4]. Post-translational modifications and interactions with other proteins (e.g., EBNA1) also modulate function [2,6].
Non-collagen Substrates and Viral Interactions
In simple terms: The enzyme can also modify proteins from viruses, affecting how they work.
PLOD1 and PLOD3 can hydroxylate the Epstein-Barr virus nuclear antigen 1 (EBNA1), a protein required for viral genome maintenance and replication. This hydroxylation regulates EBNA1 stability and DNA replication activity, highlighting a role for GO:0008475 beyond collagen biology [2,6].
Key Genes Involved in GO:0008475 procollagen-lysine 5-dioxygenase activity
The following genes encode enzymes or regulators directly associated with procollagen-lysine 5-dioxygenase activity and its biological outcomes.
| Gene | Major Role | Research Relevance |
|---|---|---|
| PLOD1 | Catalyzes lysine hydroxylation in collagen helical domain | Mutations cause Ehlers-Danlos syndrome; overexpressed in cancers [1,4,7] |
| PLOD2 | Hydroxylates telopeptide lysines; involved in fibrosis and cancer | Target for antifibrotic and anticancer therapy |
| PLOD3 | Hydroxylates collagen and EBNA1; has additional glycosyltransferase activity | Implicated in viral latency and cancer [2,6] |
| COL1A1 | Major substrate of PLOD enzymes; type I collagen alpha-1 chain | Mutations cause osteogenesis imperfecta |
| COL1A2 | Type I collagen alpha-2 chain; substrate for lysyl hydroxylation | Connective tissue disorders |
| COL3A1 | Type III collagen; substrate for PLOD1 | Vascular Ehlers-Danlos syndrome |
| HSF1 | Transcription factor activated by PLOD1 in glioma | Mediates PLOD1-driven tumor progression |
| CTNNB1 | Encodes β-catenin; downstream of PLOD1 in thyroid cancer | Wnt/β-catenin signaling in cancer |
| MIR449A | MicroRNA targeting PLOD1 | Ameliorates acute rejection after liver transplantation |
| EBNA1 | Epstein-Barr virus protein hydroxylated by PLOD1/PLOD3 | Viral latency and replication [2,6] |
| LOX | Lysyl oxidase; cross-links collagen after hydroxylation | Matrix remodeling and cancer |
| HIF1A | Regulates PLOD expression under hypoxia | Oxygen sensing and cancer |
| PLOD1 variant | Cancer-associated EBNA1 variant interacts with PLOD1 | Viral oncogenesis |
| PLOD3 variant | Interacts with EBNA1 variant | Viral oncogenesis |
| COL4A1 | Basement membrane collagen; substrate for hydroxylation | Vascular and renal disease |
| COL5A1 | Type V collagen; regulates fibril assembly | Classical Ehlers-Danlos syndrome |
| COL6A1 | Type VI collagen; microfibrillar network | Muscular dystrophy |
How Is procollagen-lysine 5-dioxygenase activity Regulated?
Procollagen-lysine 5-dioxygenase activity is regulated at multiple levels. Transcriptionally, PLOD1 is induced by hypoxia-inducible factor 1 (HIF-1) under low oxygen, and by heat shock factor 1 (HSF1) in glioma. MicroRNAs such as miR-449a directly target PLOD1 mRNA, reducing its expression and ameliorating acute rejection in liver transplantation. Enzyme activity requires Fe(II), 2-oxoglutarate, and ascorbate; thus, cellular metabolism and redox status influence hydroxylation. Additionally, interactions with viral proteins like EBNA1 can modulate PLOD1 stability and function [2,6].
procollagen-lysine 5-dioxygenase activity and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| PLOD1 | Kyphoscoliotic Ehlers-Danlos syndrome | PLOD1 knockout mice or patient-derived fibroblasts |
| PLOD1 | Glioma progression | U87 or U251 glioma cells with PLOD1 knockout |
| PLOD1 | Thyroid cancer proliferation | Thyroid cancer cell lines with PLOD1 overexpression or knockout |
| PLOD1 | Osteosarcoma invasion | Saos-2 or MG-63 cells with PLOD1 knockdown |
| PLOD1/PLOD3 | EBV latency and replication | EBV-infected B cells with PLOD1/3 knockout [2,6] |
Connective Tissue Disorders
Mutations in PLOD1 cause kyphoscoliotic Ehlers-Danlos syndrome (EDS type VI), an autosomal recessive disorder characterized by severe kyphoscoliosis, joint hypermobility, and vascular fragility. Loss of lysyl hydroxylase activity leads to under-hydroxylated collagen, impairing cross-linking and causing tissue weakness. PLOD2 mutations are linked to Bruck syndrome, featuring osteogenesis imperfecta and contractures.
Cancer Progression
PLOD1 is overexpressed in multiple malignancies. In glioma, PLOD1 promotes tumor growth via activation of HSF1 signaling. In thyroid cancer, PLOD1 enhances proliferation and migration through the Wnt/β-catenin pathway and glycolysis. In osteosarcoma, PLOD1 serves as a prognostic biomarker and mediates invasion. In tongue squamous cell carcinoma, PLOD1 is part of a gene activation network. These findings suggest PLOD1 as a therapeutic target.
Viral Pathogenesis
PLOD1 and PLOD3 hydroxylate the Epstein-Barr virus protein EBNA1, regulating its stability and DNA replication activity. A cancer-associated EBNA1 variant shows enhanced interaction with PLOD1 and PLOD3, potentially contributing to viral oncogenesis [2,6]. This links GO:0008475 to viral latency and associated malignancies.
Transplant Rejection
miR-449a targets PLOD1 in macrophages to ameliorate acute rejection after liver transplantation, indicating a role for PLOD1 in immune-mediated tissue damage.
From procollagen-lysine 5-dioxygenase activity-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| Does PLOD1 loss impair collagen cross-linking? | PLOD1 knockout in fibroblasts or mice |
| Does PLOD1 overexpression drive glioma growth? | PLOD1 overexpression in glioma cell lines and xenografts |
| Does a specific PLOD1 point mutation affect enzyme activity? | CRISPR knock-in of patient mutation in cell lines |
| Does PLOD1 hydroxylate EBNA1 at specific lysines? | Knock-in of tagged EBNA1 and PLOD1 knockout [2,6] |
| Can miR-449a mimic reduce transplant rejection? | Macrophage-specific PLOD1 knockout in liver transplant models |
| Is PLOD1 required for osteosarcoma metastasis? | PLOD1 knockout in osteosarcoma cells followed by invasion assays |
How to Study the procollagen-lysine 5-dioxygenase activity Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Lysyl hydroxylase activity assay | Enzyme activity via hydroxylysine formation | Validation of PLOD1 mutants |
| CRISPR knockout | Loss-of-function phenotypes | Cancer cell proliferation and invasion [4,7] |
| CRISPR knock-in | Effect of specific mutations | Ehlers-Danlos syndrome variants |
| RNA-seq | Global gene expression changes | Pathway analysis after PLOD1 manipulation [4,5] |
| Proteomics | Collagen hydroxylation and cross-linking | Extracellular matrix remodeling |
| Immunohistochemistry | Protein localization and modification | Tissue analysis in cancer and EDS [1,7] |
| Mass spectrometry | Hydroxylysine quantification | Enzyme kinetics and substrate specificity |
| Xenograft models | Tumor growth and metastasis | PLOD1-targeted therapy [4,7] |
Enzymatic Activity Assays
Lysyl hydroxylase activity can be measured using radiolabeled 2-oxoglutarate or by detecting hydroxylysine in collagen substrates via HPLC or mass spectrometry. These assays require Fe(II), ascorbate, and 2-oxoglutarate, and are used to validate PLOD1/2/3 function and mutant variants.
CRISPR-Cas9 Knockout and Knock-in
CRISPR-Cas9 enables generation of PLOD1, PLOD2, or PLOD3 knockout cell lines and animal models to study loss-of-function phenotypes. Knock-in of specific point mutations (e.g., patient-derived PLOD1 variants) allows structure-function analysis. These models are essential for dissecting the role of GO:0008475 in disease [1,4,7].
Transcriptomics and Proteomics
RNA-seq can identify global changes in gene expression upon PLOD1 manipulation, revealing pathways such as HSF1 or Wnt/β-catenin [4,5]. Proteomics can detect changes in collagen hydroxylation and cross-linking. These methods help map the downstream effects of altered lysyl hydroxylation.
Imaging and Histology
Immunohistochemistry for hydroxylysine or PLOD1 can visualize collagen modifications in tissues. Electron microscopy reveals collagen fibril morphology and cross-linking defects. These techniques are used in Ehlers-Danlos syndrome diagnostics and cancer research [1,7].
How CRISPR Can Be Used to Study GO:0008475 procollagen-lysine 5-dioxygenase activity
Knockout
CRISPR-Cas9 knockout of PLOD1, PLOD2, or PLOD3 eliminates enzyme activity, enabling studies of collagen hydroxylation defects, cancer cell proliferation, and viral replication. For example, PLOD1 knockout in glioma cells reduces tumor growth, and in osteosarcoma cells decreases invasion.
Point Mutation
Knock-in of patient-derived point mutations (e.g., in PLOD1) allows precise modeling of Ehlers-Danlos syndrome and structure-function analysis of the enzyme. This approach can reveal how specific amino acid changes affect catalytic activity or substrate binding.
Knock-in
Tagged knock-in of PLOD1 or its substrates (e.g., FLAG-EBNA1) facilitates affinity purification and interaction studies. Knock-in of reporter genes can also monitor PLOD1 promoter activity in real time [2,6].
Overexpression
CRISPR activation (CRISPRa) or lentiviral overexpression of PLOD1 can model its upregulation in cancers such as glioma, thyroid, and osteosarcoma, enabling studies of oncogenic signaling and drug resistance [4,5,7].
How EDITGENE Supports procollagen-lysine 5-dioxygenase activity Research
Researchers studying procollagen-lysine 5-dioxygenase activity-related genes often need to determine whether a candidate gene is causally involved in collagen modification, cancer progression, or viral pathogenesis. EDITGENE provides a comprehensive suite of CRISPR-based services to generate precisely engineered cell models, accelerating functional validation and drug discovery.
Contact EDITGENE today to design your custom CRISPR model for procollagen-lysine 5-dioxygenase activity research.
Frequently Asked Questions About procollagen-lysine 5-dioxygenase activity
What is procollagen-lysine 5-dioxygenase activity?
It is an enzymatic activity (GO:0008475) that hydroxylates lysine residues in collagen, using 2-oxoglutarate, oxygen, and Fe(II) to produce hydroxylysine, succinate, and CO2.
What genes are involved in procollagen-lysine 5-dioxygenase activity?
The main genes are PLOD1, PLOD2, and PLOD3, which encode lysyl hydroxylase isoforms with different substrate specificities [1,6].
What diseases are associated with PLOD1 mutations?
PLOD1 mutations cause kyphoscoliotic Ehlers-Danlos syndrome, a connective tissue disorder with severe scoliosis and joint hypermobility.
How is PLOD1 linked to cancer?
PLOD1 is overexpressed in glioma, thyroid, osteosarcoma, and other cancers, promoting proliferation, migration, and invasion via pathways like HSF1 and Wnt/β-catenin [4,5,7,8].
What is the role of PLOD1 in viral infection?
PLOD1 hydroxylates the Epstein-Barr virus protein EBNA1, regulating its stability and DNA replication activity [2,6].
How can I study procollagen-lysine 5-dioxygenase activity in the lab?
Common methods include enzymatic activity assays, CRISPR knockout/knock-in, RNA-seq, proteomics, and immunohistochemistry [1,4,7].
What are the cofactors required for lysyl hydroxylase activity?
The enzyme requires Fe(II), 2-oxoglutarate, molecular oxygen, and often ascorbate for optimal activity.
Can CRISPR be used to model Ehlers-Danlos syndrome?
Yes, CRISPR knock-in of patient-specific PLOD1 mutations in cell lines or mice can model the disease and test therapeutic approaches.
What is the difference between PLOD1, PLOD2, and PLOD3?
PLOD1 mainly hydroxylates helical lysines, PLOD2 acts on telopeptide lysines, and PLOD3 has additional glycosyltransferase activity and can hydroxylate EBNA1 [1,2,6].
How does miR-449a affect PLOD1?
miR-449a directly targets PLOD1 mRNA, reducing its expression and ameliorating acute rejection after liver transplantation.
Conclusion
Procollagen-lysine 5-dioxygenase activity (GO:0008475) is a fundamental enzymatic function required for collagen stability and extracellular matrix integrity. Its dysregulation underlies connective tissue disorders and contributes to cancer progression and viral pathogenesis. The PLOD gene family, particularly PLOD1, has emerged as a promising therapeutic target. Leveraging CRISPR-based models and advanced omics technologies will further elucidate the mechanistic roles of this activity and facilitate the development of targeted interventions.
References
- 1. Koenig SN et al.. 2022. New mechanistic insights to PLOD1-mediated human vascular disease.. Transl Res 239:1-17 PMID: 34400365
- 2. Dheekollu J et al.. 2023. Regulation of EBNA1 protein stability and DNA replication activity by PLOD1 lysine hydroxylase.. PLoS Pathog 19(6):e1010478 PMID: 37262099
- 3. Cao ZR et al.. 2023. miR-449a ameliorates acute rejection after liver transplantation via targeting procollagen-lysine1,2-oxoglutarate5-dioxygenase 1 in macrophages.. Am J Transplant 23(3):336-352 PMID: 36695693
- 4. Yuan B et al.. 2022. PLOD1 acts as a tumor promoter in glioma via activation of the HSF1 signaling pathway.. Mol Cell Biochem 477(2):549-557 PMID: 34845571
- 5. Cong W et al.. 2024. PLOD1 promote proliferation and migration with glycolysis via the Wnt/β-catenin pathway in THCA.. Genomics 116(6):110943 PMID: 39424162
- 6. Shire K et al.. 2021. Characterization of a cancer-associated Epstein-Barr virus EBNA1 variant reveals a novel interaction with PLOD1 and PLOD3.. Virology 562:103-109 PMID: 34304093
- 7. Jiang H et al.. 2020. PLOD1 Is a Prognostic Biomarker and Mediator of Proliferation and Invasion in Osteosarcoma.. Biomed Res Int 2020:3418398 PMID: 33134376
- 8. Zeng H et al.. 2019. Transcripto-based network analysis reveals a model of gene activation in tongue squamous cell carcinomas.. Head Neck 41(12):4098-4110 PMID: 31589000
