GO:0005787 signal peptidase complex: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• GO:0005787 (signal peptidase complex) is a conserved endoplasmic reticulum membrane complex that removes N-terminal signal peptides from secretory and membrane proteins.
• The human complex contains five subunits (SEC11A, SEC11C, SPCS1, SPCS2, SPCS3) and shares structural homology with the yeast complex.
• Beyond signal peptide cleavage, the complex acts as a quality control enzyme for membrane proteins and participates in ER-to-nucleus signaling.
• The complex is a host factor for multiple pathogens, including Zika virus and rotavirus, and is essential in Schistosoma japonicum.
• SEC11A upregulation is a biomarker of poor prognosis in head and neck squamous cell carcinoma.
• CRISPR knockout, point mutation, knock-in, and overexpression models are key tools for dissecting signal peptidase complex function.
Description
The signal peptidase complex (GO:0005787) is a multi-subunit membrane-bound protease complex located in the endoplasmic reticulum (ER) that catalyzes the cleavage of N-terminal signal peptides from newly synthesized secretory and membrane proteins. This proteolytic event is essential for protein maturation, trafficking, and function, and the complex is conserved from yeast to humans. The human complex comprises five subunits: SEC11A, SEC11C, SPCS1, SPCS2, and SPCS3, with SEC11A and SEC11C serving as the catalytic subunits. Structural studies have revealed the determinants for signal peptide cleavage and provided a framework for understanding substrate recognition. Beyond its canonical role, the complex has been implicated in membrane protein quality control and in an ER-to-nucleus signaling pathway through cleavage of the pseudoprotease iRhom2. These findings highlight the signal peptidase complex as a multifunctional hub in ER biology. Researchers study GO:0005787 to understand protein biogenesis, ER stress responses, and host-pathogen interactions, as well as to identify therapeutic targets in cancer and infectious diseases.
signal peptidase complex At A Glance
| GO ID | GO:0005787 |
|---|---|
| GO term | signal peptidase complex |
| Ontology | biological_process |
| Synonym | None listed |
| Major function | Cleavage of N-terminal signal peptides from secretory and membrane proteins |
| Subunit composition | SEC11A, SEC11C, SPCS1, SPCS2, SPCS3 |
| Cellular location | Endoplasmic reticulum membrane |
| Conservation | Conserved from yeast to humans |
| Additional roles | Membrane protein quality control, ER-to-nucleus signaling |
What Is GO:0005787?
The signal peptidase complex is a protein complex that removes signal peptides from the N-terminus of proteins as they are translocated into the endoplasmic reticulum. This cleavage is a critical step in the maturation of secretory and membrane proteins. The complex is embedded in the ER membrane and consists of multiple subunits, including catalytic and auxiliary components.
Why Is signal peptidase complex Important in Cell Biology?
The signal peptidase complex is essential for the biogenesis of a large fraction of the proteome, as it catalyzes the removal of signal peptides from secretory and membrane proteins. Its dysfunction or dysregulation is linked to cancer progression, viral infections, and parasite survival, making it a potential therapeutic target.
• Essential for protein maturation and trafficking in the secretory pathway.
• Acts as a quality control enzyme for membrane proteins, influencing ER homeostasis.
• Participates in ER-to-nucleus signaling via cleavage of iRhom2.
• Required for Zika virus infection in placental trophoblasts.
• Mediates rotavirus VP7 processing and virion assembly.
• Inhibition affects development and survival of Schistosoma japonicum.
• SEC11A upregulation is a poor prognosis biomarker in head and neck squamous cell carcinoma.
• Provides a model for studying signal peptide cleavage mechanisms.
• Potential target for antiviral and antiparasitic therapies.
• Enables CRISPR-based functional genomics of ER biology.
What Happens During signal peptidase complex?
Signal peptide recognition and binding
In simple terms: The complex grabs the signal peptide as the protein enters the ER.
The signal peptidase complex recognizes the N-terminal signal peptide of nascent polypeptides as they are translocated into the ER. Structural studies of the human complex have revealed the determinants for signal peptide cleavage, including a conserved catalytic site and a hydrophobic groove that accommodates the signal peptide.
Catalytic cleavage of the signal peptide
In simple terms: The complex cuts off the signal peptide, freeing the mature protein.
The catalytic subunits SEC11A and SEC11C perform the proteolytic cleavage of the signal peptide. This cleavage occurs on the luminal side of the ER membrane and is essential for the release of the mature protein into the secretory pathway.
Quality control of membrane proteins
In simple terms: The complex also checks and helps dispose of problematic membrane proteins.
Beyond its canonical role, the human signal peptidase complex acts as a quality control enzyme for membrane proteins. It can recognize and cleave aberrant membrane proteins, targeting them for degradation, thereby maintaining ER protein homeostasis.
ER-to-nucleus signaling via iRhom2
In simple terms: The complex can send signals from the ER to the nucleus by cutting a specific protein.
The signal peptidase complex cleaves the pseudoprotease iRhom2, releasing a fragment that translocates to the nucleus and regulates gene expression. This reveals an ER-to-nucleus signaling pathway that links the complex to transcriptional control.
Key Genes Involved in GO:0005787 signal peptidase complex
The following genes encode subunits of the signal peptidase complex or are directly associated with its function.
| Gene | Major Role | Research Relevance |
|---|---|---|
| SEC11A | Catalytic subunit of the signal peptidase complex | Essential for signal peptide cleavage; biomarker in head and neck cancer |
| SEC11C | Catalytic subunit paralog | Contributes to signal peptidase activity; potential redundancy with SEC11A |
| SPCS1 | Non-catalytic subunit | Required for complex stability and function; host factor for Zika virus |
| SPCS2 | Non-catalytic subunit | Structural component; involved in substrate recognition |
| SPCS3 | Non-catalytic subunit | Essential for complex assembly and activity |
| iRhom2 | Pseudoprotease substrate | Cleaved by signal peptidase complex to mediate ER-to-nucleus signaling |
| VP7 | Rotavirus glycoprotein | Processed by signal peptidase complex for virion assembly |
| Zika virus polyprotein | Viral substrate | Requires signal peptidase complex for maturation |
| SEC11A (Schistosoma japonicum) | Catalytic subunit homolog | Inhibition affects parasite development and survival |
| SPCS1 (Schistosoma japonicum) | Non-catalytic subunit homolog | Potential drug target in schistosomiasis |
| SEC11A (HNSCC) | Overexpressed in tumors | Poor prognosis biomarker |
| SPCS2 (HNSCC) | Subunit | Potential therapeutic target |
| SPCS3 (HNSCC) | Subunit | Potential therapeutic target |
| SEC11C (HNSCC) | Subunit | Potential therapeutic target |
| SPCS1 (HNSCC) | Subunit | Potential therapeutic target |
How Is signal peptidase complex Regulated?
The signal peptidase complex is regulated at multiple levels. Its expression can be induced by ER stress, and its activity is influenced by the availability of substrates and interacting proteins. In cancer, SEC11A upregulation is associated with poor prognosis, suggesting transcriptional or post-transcriptional regulation. The complex also participates in ER-to-nucleus signaling, which may feed back on its own expression.
signal peptidase complex and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| SEC11A | Head and neck squamous cell carcinoma | Knockout or overexpression in HNSCC cell lines |
| SPCS1 | Zika virus infection | Knockout in placental trophoblast cells |
| SPCS1/SPCS2/SPCS3 | Rotavirus infection | Knockout in intestinal epithelial cells |
| SEC11A (Schistosoma) | Schistosomiasis | RNAi or CRISPR in parasite |
| iRhom2 | ER-to-nucleus signaling | Knockout or point mutation in mammalian cells |
Cancer
SEC11A upregulation is a biomarker of poor prognosis in head and neck squamous cell carcinoma, and other subunits may also contribute to tumor progression. The signal peptidase complex supports the secretion of pro-tumorigenic factors and may be a therapeutic target.
Viral infections
The signal peptidase complex is a host factor for Zika virus in placental trophoblasts and mediates rotavirus VP7 processing and virion assembly. Inhibition of the complex could reduce viral replication.
Parasitic infections
Inhibition of signal peptidase complex expression affects the development and survival of Schistosoma japonicum, suggesting it as a target for antiparasitic drugs.
ER protein quality control diseases
The complex acts as a quality control enzyme for membrane proteins, and its dysfunction may contribute to diseases linked to ER stress and protein misfolding.
From signal peptidase complex-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the role of SEC11A in cancer cell proliferation? | CRISPR knockout of SEC11A in HNSCC cell lines |
| How does SPCS1 support Zika virus replication? | Knockout of SPCS1 in placental trophoblasts |
| Does signal peptidase complex cleavage of iRhom2 regulate gene expression? | Point mutation of cleavage site in iRhom2 |
| What is the impact of SEC11A overexpression on tumor growth? | Overexpression of SEC11A in xenograft models |
| How does signal peptidase complex inhibition affect Schistosoma survival? | CRISPR knockout in Schistosoma japonicum |
| What is the structural basis of signal peptide cleavage? | Knock-in of tagged SEC11A for structural studies |
How to Study the signal peptidase complex Process
| Method | What It Measures | Typical Application |
|---|---|---|
| CRISPR knockout | Loss-of-function phenotype | Identify essential subunits in cancer or infection |
| RNA-seq | Transcriptional changes | Assess ER stress response upon complex inhibition |
| Proteomics | Protein interactions and abundance | Purify complex and identify subunits |
| Cryo-EM | High-resolution structure | Determine cleavage mechanism |
| Site-directed mutagenesis | Catalytic activity | Map active site residues |
| Overexpression | Gain-of-function phenotype | Study SEC11A in cancer |
| RNAi | Gene silencing | Study parasite development |
| Viral plaque assay | Viral replication | Test host factor requirement |
CRISPR knockout screens
Genome-wide CRISPR knockout screens can identify signal peptidase complex subunits as essential genes in cancer cell lines or host factors for viral infection.
Proteomics and interactomics
Affinity purification coupled with mass spectrometry can reveal the subunit composition and interacting partners of the signal peptidase complex.
Structural biology
Cryo-EM and X-ray crystallography have provided high-resolution structures of the human signal peptidase complex, revealing determinants for signal peptide cleavage.
Functional assays
In vitro cleavage assays using purified complex and radiolabeled substrates can measure catalytic activity and substrate specificity.
How CRISPR Can Be Used to Study GO:0005787 signal peptidase complex
Knockout
CRISPR knockout of signal peptidase complex subunits (e.g., SEC11A, SPCS1) can abolish complex activity, leading to accumulation of uncleaved signal peptides and ER stress. This approach is used to study essentiality in cancer cells and host factor requirements for viruses.
Point Mutation
Point mutations in catalytic residues of SEC11A or in the cleavage site of substrates like iRhom2 can dissect the specificity and downstream signaling of the complex.
Knock-in
Knock-in of epitope-tagged subunits (e.g., HA-SEC11A) enables affinity purification and localization studies, facilitating structural and interactome analyses.
Overexpression
Overexpression of SEC11A in cancer cell lines or xenografts can model its role in tumor progression and validate it as a therapeutic target.
How EDITGENE Supports signal peptidase complex Research
Researchers studying signal peptidase complex-related genes often need to determine whether a candidate gene is causally involved in ER biology, cancer, or infection. EDITGENE provides comprehensive CRISPR services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for signal peptidase complex research.
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| SEC11A Knockout HEK293 Cell Line | EDJ-KQ8026 | Human | 23478 | Details Get a Quote |
| SEC11C Knockout HEK293 Cell Line | EDJ-KQ10633 | Human | 90701 | Details Get a Quote |
| SEC11C Knockout A-549 Cell Line | EDJ-KQ38132 | Human | 90701 | Details Get a Quote |
| SEC11C Knockout HCT 116 Cell Line | EDJ-KQ38133 | Human | 90701 | Details Get a Quote |
| SEC11C Knockout HeLa Cell Line | EDJ-KQ38134 | Human | 90701 | Details Get a Quote |
| SEC11A Knockout A-549 Cell Line | EDJ-KQ33806 | Human | 23478 | Details Get a Quote |
| SEC11A Knockout HCT 116 Cell Line | EDJ-KQ33807 | Human | 23478 | Details Get a Quote |
| SEC11A Knockout HeLa Cell Line | EDJ-KQ33808 | Human | 23478 | Details Get a Quote |
| SPCS2 Knockout HEK293 Cell Line | EDJ-KQ50907 | Human | 9789 | Details Get a Quote |
| SPCS1 Knockout HEK293 Cell Line | EDJ-KQ51223 | Human | 28972 | Details Get a Quote |
| SPCS2 Knockout HeLa Cell Line | EDJ-KQ55256 | Human | 9789 | Details Get a Quote |
| SPCS1 Knockout HeLa Cell Line | EDJ-KQ56080 | Human | 28972 | Details Get a Quote |
| SPCS2 Knockout A-549 Cell Line | EDJ-KQ63733 | Human | 9789 | Details Get a Quote |
| SPCS1 Knockout A-549 Cell Line | EDJ-KQ64564 | Human | 28972 | Details Get a Quote |
| SPCS2 Knockout HCT 116 Cell Line | EDJ-KQ72192 | Human | 9789 | Details Get a Quote |
Displaying Records 1 To 15 Of 16 Records
Frequently Asked Questions About signal peptidase complex
What is the signal peptidase complex?
The signal peptidase complex (GO:0005787) is an ER membrane complex that cleaves N-terminal signal peptides from secretory and membrane proteins.
What genes are involved in the signal peptidase complex?
The human complex includes SEC11A, SEC11C, SPCS1, SPCS2, and SPCS3.
Where is the signal peptidase complex located?
It is located in the endoplasmic reticulum membrane.
What is the function of GO:0005787?
It catalyzes the removal of signal peptides and also functions in membrane protein quality control and ER-to-nucleus signaling.
How is the signal peptidase complex regulated?
Its expression can be induced by ER stress, and it is regulated by substrate availability and interacting proteins.
What diseases are associated with the signal peptidase complex?
It is linked to cancer, viral infections (Zika, rotavirus), and parasitic infections (schistosomiasis).
What is the role of SEC11A in cancer?
SEC11A upregulation is a biomarker of poor prognosis in head and neck squamous cell carcinoma.
How can CRISPR be used to study the signal peptidase complex?
CRISPR knockout, point mutation, knock-in, and overexpression can dissect subunit functions and disease relevance.
What model systems are used to study the signal peptidase complex?
Human cell lines, yeast, and parasites are common models.
What methods are used to study the signal peptidase complex?
CRISPR screens, proteomics, structural biology, and functional assays are key methods.
Conclusion
The signal peptidase complex (GO:0005787) is a central player in ER protein biogenesis, with expanding roles in quality control, signaling, and disease. Its subunit genes are promising targets for cancer, antiviral, and antiparasitic therapies. Continued research using CRISPR and other advanced tools will further illuminate its mechanisms and therapeutic potential.
References
- 1. Liaci AM et al.. 2021. Structure of the human signal peptidase complex reveals the determinants for signal peptide cleavage.. Mol Cell 81(19):3934-3948.e11 PMID: 34388369
- 2. Zanotti A et al.. 2022. The human signal peptidase complex acts as a quality control enzyme for membrane proteins.. Science 378(6623):996-1000 PMID: 36454823
- 3. Dulloo I et al.. 2024. Cleavage of the pseudoprotease iRhom2 by the signal peptidase complex reveals an ER-to-nucleus signaling pathway.. Mol Cell 84(2):277-292.e9 PMID: 38183983
- 4. Rother M et al.. 2021. Signal peptidase complex subunit 1 is an essential Zika virus host factor in placental trophoblasts.. Virus Res 296:198338 PMID: 33577859
- 5. Zhu X et al.. 2026. Signal peptidase complex mediates rotavirus VP7 processing and virion assembly.. PLoS Pathog 22(3):e1013688 PMID: 41860932
- 7. Yang WB et al.. 2023. Inhibition of signal peptidase complex expression affects the development and survival of Schistosoma japonicum.. Front Cell Infect Microbiol 13:1136056 PMID: 36936776
- 8. Hu C et al.. 2022. Signal peptidase complex catalytic subunit SEC11A upregulation is a biomarker of poor prognosis in patients with head and neck squamous cell carcinoma.. PLoS One 17(6):e0269166 PMID: 35653344
