GO:0005642 annulate lamellae: Components, Assembly and Research Methods
Research-grade guide for scientists and biopharma professionals
Key Takeaways
• Annulate lamellae (GO:0005642) are stacked endoplasmic reticulum (ER) membranes containing a high density of nuclear pores, thought to form from excess nuclear membrane components.
• They are continuous with and embedded within the ER, and are observed in many cell types, especially rapidly dividing cells and some pathogen-infected cells.
• Annulate lamellae are enriched in nucleoporins and nuclear pore complex components, and their assembly is dependent on RanBP2 and other nuclear pore proteins.
• They are implicated in nuclear pore assembly, nuclear expansion, and intracellular pathogen replication, but their precise function remains underexplored.
• Research methods include electron microscopy, immunofluorescence, proteomics, and CRISPR-based perturbation of nucleoporin genes.
• Key genes and proteins include NUP214, NUP153, RANBP2, NUP98, and other nucleoporins that localize to annulate lamellae.
Description
Annulate lamellae (GO:0005642) are specialized stacks of endoplasmic reticulum (ER) membranes that contain a high density of nuclear pore complexes, resembling the nuclear envelope but located in the cytoplasm. They were first described in the 1960s and have since been observed in a wide range of cell types, including embryonic, germ, and cancer cells, as well as in cells infected by certain intracellular pathogens. Despite their discovery decades ago, the function of annulate lamellae remains incompletely understood, and they have been described as an organelle in search of a function. Recent studies have begun to uncover their role in nuclear pore assembly and nuclear expansion, highlighting their importance in cell biology. Understanding annulate lamellae is crucial for researchers studying nuclear envelope dynamics, intracellular trafficking, and host-pathogen interactions.
annulate lamellae At A Glance
| GO ID | GO:0005642 |
|---|---|
| GO term | annulate lamellae |
| Ontology | cellular_component |
| Synonym | none |
| Major function | Stacks of ER membranes containing nuclear pores; implicated in nuclear pore assembly and nuclear expansion |
| Cellular location | Cytoplasm, continuous with and embedded within the endoplasmic reticulum |
| Associated components | Nuclear pore complex proteins (nucleoporins), including RanBP2, NUP214, NUP153 |
| Organisms | Observed in many eukaryotes, including vertebrates and invertebrates |
What Is GO:0005642?
According to the Gene Ontology, annulate lamellae (GO:0005642) are defined as stacks of endoplasmic reticulum (ER) membranes containing a high density of nuclear pores, thought to form from excess nuclear membrane components, that have been described in a number of different cells. Annulate lamellar membranes are continuous with and embedded within the ER.
Why Is annulate lamellae Important in Cell Biology?
Annulate lamellae are important because they represent a distinct membrane domain that links the endoplasmic reticulum to nuclear pore biology, and they are increasingly recognized as dynamic structures involved in nuclear envelope remodeling and cell division. They are also exploited by intracellular pathogens, such as viruses, to facilitate replication, making them relevant to infectious disease research. Furthermore, their presence in cancer cells and during development suggests roles in proliferation and differentiation. Understanding annulate lamellae can provide insights into fundamental cellular processes and may open new avenues for therapeutic intervention.
• Annulate lamellae are involved in nuclear pore assembly and nuclear expansion during cell growth.
• They serve as platforms for intracellular pathogen replication, including viruses and parasites.
• They are abundant in rapidly dividing cells, such as embryonic and cancer cells, suggesting a role in proliferation.
• They may act as a reservoir of nuclear pore components for nuclear envelope reassembly after mitosis.
• Dysregulation of annulate lamellae-associated proteins has been linked to cancer and developmental disorders.
• They are a model system for studying membrane organization and nuclear pore complex assembly.
• Their study can reveal mechanisms of ER remodeling and membrane contact sites.
• They are potential targets for antiviral and anticancer therapies.
Structure and Composition of annulate lamellae
Membrane organization and ER continuity
In simple terms: Annulate lamellae are like stacks of flattened bags made of ER membrane that are studded with nuclear pores.
Annulate lamellae consist of parallel stacks of ER-derived membranes that are continuous with the rough endoplasmic reticulum. These membranes contain a high density of nuclear pore complexes, which are embedded in the stacked cisternae. The continuity with the ER suggests that annulate lamellae form from excess nuclear membrane components and may serve as a specialized subdomain of the ER.
Nuclear pore complexes in annulate lamellae
In simple terms: The pores in annulate lamellae are the same type of channels that control traffic into and out of the nucleus.
The nuclear pores within annulate lamellae are structurally similar to those in the nuclear envelope and contain nucleoporins such as NUP214, NUP153, and RANBP2. These pore complexes are thought to be assembled de novo or derived from the nuclear envelope during mitosis. The presence of functional nuclear pores in annulate lamellae suggests they may participate in nucleocytoplasmic transport or serve as storage sites for pore components.
Assembly and dynamics
In simple terms: Annulate lamellae form when there are too many nuclear membrane building blocks, and they can be taken apart and reused.
Annulate lamellae are dynamic structures that assemble from excess nuclear membrane components, particularly during cell division or in response to increased nuclear pore demand. Recent work shows that RanBP2-dependent assembly of annulate lamellae drives nuclear pore assembly and nuclear expansion. They can disassemble and be reabsorbed into the ER or nuclear envelope as needed.
Protein composition and interacting partners
In simple terms: Annulate lamellae are made of many proteins that also build the nuclear pore, plus some ER proteins.
Proteomic studies have identified numerous nucleoporins and nuclear envelope proteins in annulate lamellae, including NUP98, NUP62, and NUP214. They also contain ER-resident proteins such as calnexin and calreticulin, consistent with their ER origin. The composition varies depending on cell type and physiological state, suggesting specialized functions.
Key Genes Involved in GO:0005642 annulate lamellae
The following genes and proteins are key components or regulators of annulate lamellae, based on published literature.
| Gene | Major Role | Research Relevance |
|---|---|---|
| RANBP2 | Ran-binding protein 2; nucleoporin that promotes annulate lamellae assembly and nuclear pore assembly | Knockout or knockdown to study annulate lamellae formation and nuclear expansion |
| NUP214 | Nucleoporin localized to annulate lamellae; involved in nuclear pore complex structure | Mutational analysis to dissect pore assembly |
| NUP153 | Nucleoporin present in annulate lamellae; roles in nuclear import and pore organization | Tagged knock-in for live imaging of annulate lamellae |
| NUP98 | Nucleoporin found in annulate lamellae; implicated in nuclear pore biogenesis | Overexpression or knockout to test function in annulate lamellae |
| NUP62 | Central channel nucleoporin; may localize to annulate lamellae | Antibody staining and proteomics |
| NUP107 | Scaffold nucleoporin; part of the Nup107-160 complex | CRISPR knockout to assess annulate lamellae integrity |
| NUP160 | Component of the Nup107-160 complex; potential role in annulate lamellae | Knockdown studies |
| NUP85 | Nucleoporin in the Nup107-160 complex | Mutagenesis to test pore assembly |
| NUP133 | Nucleoporin involved in early pore assembly | Knockout models |
| NUP155 | Nucleoporin with roles in nuclear envelope and annulate lamellae | Point mutations to study dynamics |
| NUP188 | Nucleoporin possibly present in annulate lamellae | Proteomic profiling |
| NUP205 | Nucleoporin linked to annulate lamellae | RNAi knockdown |
| NUP93 | Nucleoporin in the inner ring | CRISPR knock-in for localization |
| NUP35 | Nucleoporin in the inner ring | Overexpression studies |
| NUP54 | Nucleoporin in the central channel | Functional assays |
| NUP58 | Nucleoporin in the central channel | Live-cell imaging |
| NUP88 | Nucleoporin associated with annulate lamellae | Knockout in cell lines |
| NUP50 | Nucleoporin with roles in nuclear transport | Tagged knock-in |
How Is annulate lamellae Regulated?
The formation and dynamics of annulate lamellae are regulated by the cell cycle, particularly during mitosis when nuclear envelope breakdown and reassembly occur. RanBP2 has been identified as a key regulator that promotes annulate lamellae assembly and nuclear expansion. Additionally, the availability of excess nuclear membrane components and nucleoporins influences annulate lamellae formation. Viral infections can also induce annulate lamellae, likely by hijacking host membrane and pore machinery.
annulate lamellae and Human Disease
| Gene | Disease / Biology | Potential Experimental Model |
|---|---|---|
| RANBP2 | Cancer, viral infection | Knockout cell lines, xenograft models |
| NUP214 | Leukemia, developmental defects | Point mutation knock-in |
| NUP153 | Cancer, nuclear pore disease | Overexpression and knockout |
| NUP98 | Leukemia, developmental disorders | CRISPR knock-in of fusion proteins |
| NUP62 | Neurodegeneration | Conditional knockout mice |
Annulate lamellae in cancer
Annulate lamellae are frequently observed in cancer cells, where they may support rapid proliferation by providing a reservoir of nuclear pore components. Their presence correlates with high metabolic activity and nuclear envelope remodeling, suggesting a role in tumor growth. Targeting annulate lamellae-associated proteins, such as RANBP2, could be a potential therapeutic strategy.
Annulate lamellae and intracellular pathogens
Several intracellular pathogens, including viruses and parasites, induce annulate lamellae to facilitate their replication. For example, certain viruses remodel ER membranes to form annulate lamellae, which may serve as platforms for viral genome replication or assembly. Understanding these interactions could lead to new antiviral approaches.
Annulate lamellae in developmental disorders
Mutations in nucleoporins that localize to annulate lamellae have been linked to developmental disorders, such as those affecting the nervous system. Disruption of annulate lamellae function may impair nuclear pore assembly and nuclear expansion, contributing to disease pathology.
From annulate lamellae-Related Genes to Experimental Models
| Research Question | Suitable Model |
|---|---|
| What is the role of RANBP2 in annulate lamellae assembly? | RANBP2 knockout cell lines |
| How do point mutations in nucleoporins affect annulate lamellae? | Point mutation knock-in via CRISPR |
| Where and when are annulate lamellae formed? | Tagged knock-in of nucleoporins with fluorescent proteins |
| Does overexpression of NUP98 induce annulate lamellae? | Overexpression cell models |
| What proteins localize to annulate lamellae? | Proteomics of isolated annulate lamellae |
| How do pathogens hijack annulate lamellae? | Infection models with knockout cells |
How to Study the annulate lamellae Process
| Method | What It Measures | Typical Application |
|---|---|---|
| Transmission electron microscopy | Ultrastructure of annulate lamellae | Visualization in cells and tissues |
| Immunofluorescence | Localization of nucleoporins | Detection of annulate lamellae in fixed cells |
| Live-cell imaging | Dynamics of annulate lamellae | Tracking assembly and disassembly |
| Proteomics | Protein composition | Identification of novel components |
| CRISPR knockout screening | Genes required for annulate lamellae | Functional genomics |
| RNA-seq | Transcriptional changes | Pathogen infection studies |
| Proximity labeling | Interacting proteins | Mapping annulate lamellae interactome |
| Correlative light and electron microscopy | Structure-function correlation | High-resolution mapping |
Electron microscopy
Transmission electron microscopy (TEM) is the gold standard for visualizing annulate lamellae, revealing their stacked membrane structure and nuclear pores. Immunoelectron microscopy can localize specific nucleoporins to these structures.
Fluorescence microscopy
Immunofluorescence and live-cell imaging with fluorescently tagged nucleoporins allow dynamic tracking of annulate lamellae in cells. Super-resolution microscopy can resolve pore distribution.
Proteomics
Mass spectrometry-based proteomics of isolated annulate lamellae or proximity labeling can identify their protein composition. This approach has revealed enrichment of nucleoporins and ER proteins.
CRISPR screening
Genome-wide CRISPR knockout screens can identify genes required for annulate lamellae formation and function. Candidate genes can be validated by imaging and biochemical assays.
How CRISPR Can Be Used to Study GO:0005642 annulate lamellae
Knockout
CRISPR knockout of nucleoporin genes such as RANBP2 or NUP214 can abolish annulate lamellae formation, allowing researchers to study their function in nuclear pore assembly and nuclear expansion. Knockout cell lines are valuable for loss-of-function studies.
Point Mutation
Introducing point mutations in nucleoporin genes via CRISPR can mimic disease-associated variants and reveal their impact on annulate lamellae structure and dynamics. This approach helps dissect domain-specific functions.
Knock-in
Knock-in of fluorescent tags (e.g., GFP) into endogenous nucleoporin loci enables live-cell imaging of annulate lamellae without overexpression artifacts. Tagged knock-in models are essential for tracking dynamics.
Overexpression
Overexpression of nucleoporins such as NUP98 or RANBP2 can induce annulate lamellae formation, providing a gain-of-function system to study their biogenesis and downstream effects. Overexpression models are useful for identifying sufficiency.
How EDITGENE Supports annulate lamellae Research
Researchers studying annulate lamellae-related genes often need to determine whether a candidate gene is causally involved in their formation, maintenance, or function. EDITGENE provides comprehensive CRISPR-based services to accelerate this research.
Contact EDITGENE today to design your custom CRISPR model for annulate lamellae research.
Frequently Asked Questions About annulate lamellae
What is annulate lamellae?
Annulate lamellae are stacks of endoplasmic reticulum membranes containing a high density of nuclear pores, defined as GO:0005642.
What genes are involved in annulate lamellae?
Key genes include RANBP2, NUP214, NUP153, NUP98, and other nucleoporins.
Where are annulate lamellae found?
They are found in the cytoplasm, continuous with and embedded within the endoplasmic reticulum, in many cell types.
What is the function of annulate lamellae?
They are thought to serve as reservoirs of nuclear pore components and are involved in nuclear pore assembly and nuclear expansion.
How are annulate lamellae studied?
Common methods include electron microscopy, immunofluorescence, proteomics, and CRISPR screening.
Are annulate lamellae associated with diseases?
Yes, they are observed in cancer and pathogen-infected cells, and nucleoporin mutations are linked to developmental disorders.
What is the GO term for annulate lamellae?
The Gene Ontology term is GO:0005642, under the cellular_component ontology.
Do annulate lamellae contain nuclear pores?
Yes, they contain a high density of nuclear pore complexes similar to those in the nuclear envelope.
How do annulate lamellae form?
They are thought to form from excess nuclear membrane components and are regulated by proteins such as RanBP2.
Can CRISPR be used to study annulate lamellae?
Yes, CRISPR knockout, knock-in, and point mutation models are powerful tools to study annulate lamellae genes.
Conclusion
Annulate lamellae (GO:0005642) are enigmatic yet important cellular structures that link the endoplasmic reticulum to nuclear pore biology. Despite decades of study, their precise functions are still being uncovered, with recent advances highlighting roles in nuclear pore assembly and nuclear expansion. They are implicated in cancer, infectious disease, and developmental disorders, making them a compelling subject for further research. Leveraging modern CRISPR technologies and advanced imaging, researchers can now dissect the molecular mechanisms of annulate lamellae with unprecedented precision.
References
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- 2. Oliveira L et al.. 2026. Annulate lamellae - an underexplored cellular structure.. J Cell Sci 139(14) PMID: 42478519
- 3. Wischnitzer S. 1970. The annulate lamellae.. Int Rev Cytol 27:65-100 PMID: 4906737
- 4. Kessel RG. 1989. The annulate lamellae--from obscurity to spotlight.. Electron Microsc Rev 2(2):257-348 PMID: 2491346
- 5. Merisko EM. 1989. Annulate lamellae: an organelle in search of a function.. Tissue Cell 21(3):343-54 PMID: 2683210
- 6. Kessel RG. 1992. Annulate lamellae: a last frontier in cellular organelles.. Int Rev Cytol 133:43-120 PMID: 1374369
- 8. Lin J et al.. 2026. RanBP2-dependent annulate lamellae drive nuclear pore assembly and nuclear expansion.. Nat Commun 17(1) PMID: 41882018
